Aerosol-forming substrates, aerosol-generating articles, devices, and systems

Abstract

An aerosol-forming substrate is provided. The aerosol-forming substrate is a substantially planar aerosol-forming substrate including an upper layer and a lower layer. The upper layer and lower layer are arranged as substantially parallel planes separated by an intermediate or separating layer positioned between the upper and lower layers. The separating layer comprises one or more separating members extending between an upper surface of the lower layer and a lower surface of the upper layer. In some embodiments, the separating layer includes a separating member having a plurality of upwardly extending portions supporting the lower surface of the upper layer and a plurality of downwardly depending portions supporting the upper surface of the lower layer.

Description

[Technical Field]

[0001] The present disclosure relates to an aerosol-generating substrate and an aerosol-generating article comprising the aerosol-forming substrate. The present disclosure also relates to an aerosol-generating device and a system comprising the aerosol-generating article and the aerosol-generating device. [Background technology]

[0002] A typical aerosol-generating system may include an aerosol-generating device and an aerosol-generating article. The aerosol-generating device may include a heating means, such as a heating element, and the aerosol-generating article may include an aerosol-forming substrate. In use, the heating element of the aerosol-generating device heats the aerosol-forming substrate of the aerosol-generating article, causing an aerosol to be emitted from the aerosol-forming substrate. The aerosol can be inhaled by a user.

[0003] A typical aerosol-generating article may appear similar to a conventional cigarette. For example, such an aerosol-generating article may be a substantially cylindrical article comprising an aerosol-forming substrate and other components, such as a mouthpiece filter element, all wrapped in cigarette paper. The dimensions of a typical aerosol-generating article are often similar to those of a conventional cigarette.

[0004] Studies have shown that in such typical aerosol-generating articles, a large portion of the plug of the aerosol-forming substrate may not be heated sufficiently to form an aerosol during use. This is undesirable because this portion of the plug of the aerosol-forming substrate contributes to the costs of manufacturing and shipping the aerosol-generating article but does not contribute to the aerosol delivered to the end user. This may be true regardless of the method by which the aerosol-forming substrate is heated, for example, whether a resistance heater or an induction heater is used, and regardless of whether the plug of the aerosol-forming substrate is heated from the inside or the outside.

[0005] It is an object of the present invention to provide an aerosol-generating article comprising an aerosol-forming substrate and a substrate, wherein a majority of the aerosol-forming substrate of the aerosol-generating article is heated sufficiently to form an aerosol during use. Summary of the Invention

[0006] According to the present disclosure, there may be provided an aerosol-forming substrate including an aerosol-forming material for generating an aerosol. The aerosol-forming substrate may have a base defined by an x-dimension extending in an x-direction and a y-dimension extending in a y-direction, and a height defined by a z-dimension extending in a z-direction.

[0007] According to the present disclosure, there can be provided an aerosol-forming substrate comprising an aerosol-forming material for generating an aerosol, the aerosol-forming substrate being a planar aerosol-forming substrate having a base defined by a length extending in the x-direction and a width extending in the y-direction, and a height extending in the z-direction.

[0008] According to the present disclosure, there can be provided an aerosol-forming substrate comprising an aerosol-forming material for generating an aerosol, the aerosol-forming substrate having a base defined by x and y dimensions and a height defined by a z dimension, an airflow path defined through the aerosol-forming substrate from one side of the aerosol-forming substrate to the other side of the aerosol-forming substrate in the x / y plane, and a resistance to draw (RTD) of the substrate along the airflow path of less than 20 millimeters HO.

[0009] According to the present disclosure, there may be provided an aerosol-forming substrate including an aerosol-forming material for generating an aerosol, the aerosol-forming substrate having a substantially planar upper surface defined by a length extending in the x-direction and a width extending in the y-direction, and a substantially planar lower surface defined by the length extending in the x-direction and the width extending in the y-direction. The substantially planar upper surface and the substantially planar lower surface may be spaced apart vertically from each other by a height defined in the z-direction.

[0010] According to the present disclosure, there may be provided an aerosol-forming substrate comprising a first planar layer and a corrugated layer disposed on a surface of the first planar layer, wherein at least one of the first planar layer and the corrugated layer comprises or consists of an aerosol-forming material.

[0011] According to the present disclosure, there can be provided an aerosol-forming substrate comprising a first planar layer, a second planar layer, and a corrugated layer disposed between the first and second planar layers, wherein at least one of the first planar layer, the second planar layer, and the corrugated layer comprises or consists of an aerosol-forming material.

[0012] According to the present disclosure, there can be provided an aerosol-forming substrate comprising a first layer and a corrugated layer attached to a surface of the first layer by an adhesive, the adhesive comprising or consisting of an aerosol-forming material.

[0013] According to the present disclosure, there can be provided an aerosol-forming substrate comprising a first layer, a second layer, and an intermediate or separating layer disposed between the first and second layers, wherein the intermediate layer is attached to the first and / or second layers by an adhesive, and the adhesive comprises or consists of an aerosol-forming material.

[0014] According to the present disclosure, there can be provided an aerosol-forming substrate comprising a first layer and a corrugated layer attached to a surface of the first layer, wherein a plurality of longitudinally extending channels are defined between the first layer and the second layer by the corrugations, and a porous element is disposed within at least one of the longitudinally extending channels.

[0015] According to the present disclosure, there can be provided an aerosol-forming substrate comprising a first layer and a corrugated layer attached to a surface of the first layer, wherein a plurality of longitudinally extending channels are defined by the corrugations between the first layer and the corrugated layer, and the longitudinally extending channels are filled with a porous material, for example a porous aerosol-forming material.

[0016] According to the present disclosure, there can be provided an aerosol-forming substrate comprising a first layer, a second layer, and a corrugated layer disposed between the first and second layers, wherein a plurality of longitudinally extending channels are defined by the corrugations between the first layer and the corrugated layer and between the corrugated layer and the second layer, and wherein a porous element is disposed in at least one of the longitudinally extending channels.

[0017] According to the present disclosure, there can be provided an aerosol-forming substrate comprising a first layer and a corrugated layer attached to a surface of the first layer, wherein a plurality of longitudinally extending channels are defined by the corrugations between the first layer and the corrugated layer, and wherein one or more flavour-releasing components, e.g., components such as threads or capsules impregnated with or containing flavour components, are disposed within at least one of the longitudinally extending channels.

[0018] According to the present disclosure, there can be provided an aerosol-forming substrate comprising a first layer, a second layer, and a corrugated layer disposed between the first and second layers, wherein a plurality of longitudinally extending channels are defined by the corrugations between the first layer and the corrugated layer and between the corrugated layer and the second layer, and wherein one or more flavour-releasing components, e.g., components such as threads or capsules impregnated with or containing flavour components, are disposed within at least one of the longitudinally extending channels.

[0019] According to the present disclosure, there can be provided an aerosol-forming substrate comprising a first planar layer and a corrugated layer disposed on a surface of the first planar layer, wherein at least one of the first planar layer and the corrugated layer comprises perforations or holes for allowing air to flow through the first planar layer or the corrugated layer.

[0020] According to the present disclosure, there can be provided an aerosol-forming substrate comprising a first planar layer, a second planar layer, and a corrugated layer disposed between the first and second planar layers, wherein at least one of the first planar layer, the second planar layer, and the corrugated layer comprises perforations or holes for allowing air to flow through the first planar layer, the second planar layer, or the corrugated layer.

[0021] According to the present disclosure, there can be provided an aerosol-forming substrate comprising a first planar layer, a second planar layer, and a third planar layer disposed between the first and second planar layers, wherein the aerosol-forming substrate further comprises a first corrugated layer disposed between the first and third planar layers, and a second corrugated layer disposed between the third and second planar layers.

[0022] According to the present disclosure, there may be provided an aerosol-generating article for use in an aerosol-generating device to generate an inhalable aerosol. The aerosol-generating article may comprise an aerosol-forming substrate, for example an aerosol-forming substrate as described in one or more of the paragraphs above. Alternatively, or in addition, the aerosol-generating article may be as described in one of the following paragraphs.

[0023] According to the present disclosure, there can be provided an aerosol-generating article for use in an aerosol generating device to generate an inhalable aerosol, the aerosol-generating article comprising: an upstream article end and a downstream article end, wherein the upstream article end and the downstream article end comprise an article airflow path and an article length extending from the upstream article end to the downstream article end; and a corrugated element, wherein a transverse direction of at least a first portion of the corrugated element is non-parallel to one or both of the article length and at least a first portion of the article airflow path.

[0024] According to the present disclosure, there can be provided an aerosol-generating article for use in an aerosol generating device to generate an inhalable aerosol, the aerosol-generating article comprising an upstream article end and a downstream article end, the article length extending from the upstream article end to the downstream article end, and one or more corrugated elements, the one or more corrugated elements collectively extending at least 50% of the article length.

[0025] According to the present disclosure, there can be provided a planar aerosol-generating article for use in an aerosol generating device to generate an inhalable aerosol, the aerosol-generating article comprising: an upstream article end and a downstream article end, wherein an article length extends from the upstream article end to the downstream article end; and one or more sheets of aerosol-forming material, each of the one or more sheets of aerosol-forming material having a thickness of less than 1 mm, and wherein the one or more sheets of aerosol-forming material collectively extend along at least 50% of the length of the article.

[0026] According to the present disclosure, a substantially planar aerosol-forming substrate can be provided comprising an upper layer and a lower layer arranged in substantially parallel planes separated by a separation layer positioned between the upper and lower layers, the separation layer comprising or consisting of corrugated elements formed from a corrugated sheet having a triangular corrugated profile.

[0027] According to the present disclosure, a substantially planar aerosol-forming substrate can be provided comprising an upper layer and a lower layer arranged in substantially parallel planes separated by a separation layer positioned between the upper and lower layers, the separation layer including or consisting of one or more separation members extending between the upper surface of the lower layer and the lower surface of the upper layer.

[0028] A separating layer may also be described as an intermediate layer, i.e., a layer disposed between an upper layer and a lower layer. The terms "separating layer" and "intermediate layer" may be used interchangeably herein.

[0029] As used herein, the terms "upper layer" and "lower layer" describe the relative positions of layers of a substrate when the substrate is placed with its x / y plane horizontal.

[0030] The aerosol-forming substrate according to the present disclosure is preferably a substantially flat or substantially planar substrate. Such a substrate has a large base area relative to the volume of the substrate. Advantageously, a larger base area may provide a larger surface area for heating by the planar heater of the aerosol-generating device. Advantageously, a smaller height may reduce the temperature gradient or temperature difference across the height of the substrate during heating. For example, if the base of the substrate is heated in contact with the planar heater, a smaller distance or height between the base and the top surface may reduce the temperature difference between the base and the top surface opposite the base. Advantageously, this may allow a large portion of the substrate to be heated to a temperature at which an aerosol is emitted, while minimizing the risk of burning the hottest portion of the substrate closest to the heater. Alternatively, or in addition, this may reduce the time required to heat the substrate sufficiently to emit an aerosol. In other words, the aerosol-forming substrate may be heated quickly and efficiently.

[0031] Any aerosol-forming substrate disclosed herein may have an airflow path defined through the aerosol-forming substrate in the x / y plane, from one side of the aerosol-forming substrate to the other side of the aerosol-forming substrate. Preferably, the aerosol-forming substrate has a resistance to draw (RTD) of less than 20 millimeters of water (H2O), for example, less than 10 millimeters of water (H2O), in the direction of the airflow path. Preferably, the aerosol-forming substrate has an RTD of less than 20 millimeters of water (H2O), for example, less than 10 millimeters of water (H2O), in at least one direction in the x / y plane of the aerosol-forming substrate. An aerosol-forming substrate with a low-resistance airflow path allows for better airflow management, allowing the aerosol to be more efficiently extracted from the aerosol-forming substrate and delivered to the user. Efficient extraction allows for a lighter substrate while still producing the same aerosol experience. A lighter substrate weight may mean reduced manufacturing costs, as fewer aerosol-forming substrates are required, and reduced shipping costs, as the overall article containing the substrate is cheaper.

[0032] The aerosol-forming substrate may have an RTD in a direction perpendicular to the z-direction, the resistance to withdrawal being less than 20 millimeters HO, for example less than 10 millimeters HO. An airflow path may be defined through the aerosol-forming substrate along the x-direction from one side of the aerosol-forming substrate to the other side of the aerosol-forming substrate, such that the aerosol-forming substrate has an RTD in the x-direction of less than 20 millimeters HO, for example less than 10 millimeters HO. An airflow path may be defined through the aerosol-forming substrate along the y-direction from one side of the aerosol-forming substrate to the other side of the aerosol-forming substrate, such that the aerosol-forming substrate has an RTD in the y-direction of less than 20 millimeters HO, for example less than 10 millimeters HO.

[0033] Particularly preferably, the RTD is less than 8 millimeters H2O, such as less than 6 millimeters H2O, such as less than 4 millimeters H2O, such as less than 2 millimeters H2O. Preferably, the RTD on the airflow path through the substrate is approximately 0 millimeters H2O.

[0034] For example, the RTD may be 9.9 millimeters HO to 0 millimeters HO, e.g., 8 millimeters HO to 1 millimeter HO, or 6 millimeters HO to 2 millimeters HO, or 5 millimeters HO to 3 millimeters HO.

[0035] Unless otherwise specified, resistance to draw (RTD) is measured in accordance with ISO 6565-2015. RTD refers to the pressure required to force air through the entire length of a component, e.g., an aerosol-forming substrate. The terms "pressure drop" or "draw resistance" of a component or article can also refer to "resistance to draw." These terms generally refer to measurements in accordance with ISO 6565-2015 normally performed under test at a temperature of about 22 degrees Celsius, a pressure of about 101 kPa (about 760 Torr), and a relative humidity of about 60%, with a volumetric flow rate of about 17.5 milliliters per second at the output or downstream end of the component being measured.

[0036] The airflow path through the entire substrate may be defined in terms of porosity, e.g., the proportion of the substrate that is free of aerosol-forming material. The porosity in this case is open porosity, allowing an airflow path through the substrate. Thus, the aerosol-forming substrate may have an airflow path defined through the aerosol-forming substrate from one side of the aerosol-forming substrate to the other side of the aerosol-forming substrate in the x / y plane, and the aerosol-forming substrate may have a porosity of more than 60%, for example more than 80%, in the direction of the airflow path. The porosity may be more than 60%, for example more than 80%, in at least one direction in the x / y plane of the aerosol-forming substrate. The aerosol-forming substrate may have a porosity of more than 60%, for example more than 80%, in a direction perpendicular to the z direction. For example, an airflow path may be defined through the aerosol-forming substrate along the x direction from one side of the aerosol-forming substrate to the other side of the aerosol-forming substrate, such that the aerosol-forming substrate has a porosity of more than 60%, for example more than 80%, in the x direction. The aerosol-forming substrate may have an airflow path defined through the aerosol-forming substrate along the y direction from one side of the aerosol-forming substrate to the other side of the aerosol-forming substrate, such that the aerosol-forming substrate has a porosity of more than 60%, for example more than 80%, in the y direction. The porosity of the airflow path may be determined by the ratio of the cross-sectional area of ​​the material within the airflow path to the internal cross-sectional area of ​​the airflow path.

[0037] Preferably the porosity is between 81% and 99%, such as between 85% and 95%, for example between 88% and 92%, for example about 90% porosity in the direction of the airflow path.

[0038] The substrate may comprise an upper layer defining an upper surface and a lower layer defining a lower surface, with an airflow path defined through the aerosol-forming substrate between the upper and lower layers. For example, the substrate may comprise an upper layer defining an upper surface and a lower layer defining a lower surface, with an airflow path defined through the aerosol-forming substrate between the upper and lower layers from one side to the other. For example, the substrate may comprise an upper layer defining an upper surface and a lower layer defining a lower surface, with an airflow path defined through the aerosol-forming substrate between the upper and lower layers from one side to the other in the x / y plane. Preferably, a plurality of channels are defined through the aerosol-forming substrate between the upper and lower surfaces. The channels preferably provide a low RTD airflow path through the substrate.

[0039] The aerosol-forming substrate may comprise a separating layer disposed between the upper and lower layers. For example, the separating layer may comprise one or more ribs or struts separating the upper layer from the lower layer, preferably with the ribs or struts extending in the direction of the airflow path defined through the aerosol-forming substrate. Thus, the separating layer may define the distance between the upper and lower layers.

[0040] Preferably, the aerosol-forming substrate comprises a corrugated portion, e.g., one or more corrugated elements. For example, the separating layer may comprise or consist of a corrugated element, e.g., a corrugated material sheet. The aerosol-forming substrate may comprise an upper layer, a lower layer, and a separating layer disposed between the upper and lower layers, the separating layer comprising one or more corrugated elements. The one or more corrugated elements preferably define a plurality of airflow channels extending through the aerosol-forming substrate. In some embodiments, the corrugated structure may be combined with a single planar layer.

[0041] The use of a corrugated structure in an aerosol-forming substrate advantageously allows for the production of an aerosol-forming substrate that has a very low RTD while still being rigid enough for a user to handle. Furthermore, the use of a corrugated structure potentially allows for the production of low density, low RTD aerosol-forming substrates using high speed manufacturing methods similar to those used to manufacture corrugated cardboard.

[0042] The aerosol-forming substrate may comprise multiple corrugated elements. For example, two or more corrugated elements may be arranged in a perpendicular relationship to one another, for example, between an upper layer and a lower layer. The multiple corrugated elements may be described as being vertically stacked. For example, the aerosol-forming substrate may comprise an upper corrugated element arranged to contact the upper layer and a lower corrugated element arranged to contact the lower layer. There may also be three or more corrugated elements. For example, the substrate may comprise at least one additional corrugated element arranged between the upper corrugated element and the lower corrugated element.

[0043] The aerosol-forming substrate may comprise a plurality of corrugated elements, two or more of which are arranged laterally alongside one another between the upper and lower layers, and air flowing along an airflow path through the substrate may flow through either the first spaced-apart corrugated elements or the second spaced-apart corrugated elements.

[0044] The aerosol-forming substrate may comprise a plurality of corrugated elements, two or more of which may be arranged in transverse end-to-end relationship between the upper and lower layers, and air flowing along an airflow path through the substrate may flow through both a first spaced apart end-to-end corrugated element or a second spaced apart end-to-end corrugated element.

[0045] The aerosol-forming substrate may be defined as having a proximal end and a distal end. An airflow path may be defined through the substrate between the proximal end and the distal end. Advantageously, the airflow path may be defined by at least one corrugated element. For example, the ridges and troughs of the at least one corrugated element may be aligned substantially parallel to the direction of air flow, thereby forming an airflow path in that direction.

[0046] The aerosol-forming substrate may comprise a first corrugated element disposed at or toward the proximal end of the substrate and a second corrugated element disposed at or toward the distal end of the substrate. For example, the first and second corrugated elements may be disposed in a transverse end-to-end relationship between the upper and lower layers, with each corrugated element aligned substantially parallel to the airflow direction. In this example, the airflow path would extend through both the first and second corrugated elements.

[0047] The aerosol-forming substrate may comprise an aerosol-forming material. Preferably, the aerosol-forming material forms at least a portion of the corrugations or corrugation elements. The aerosol-forming material may be in the form of a sheet used as one or more components of the corrugations or corrugation elements. This may allow for great flexibility in selecting various combinations of aerosol-forming materials. This may also allow for the selection of non-aerosol-forming materials suitable for use for other purposes, for example to improve the structure of the substrate. In some embodiments, the entire aerosol-forming substrate is formed from the aerosol-forming material.

[0048] Thus, the aerosol-forming substrate may comprise an upper layer, a lower layer, and an intermediate layer disposed between the upper and lower layers, wherein the upper layer comprises or consists of an aerosol-forming material, e.g., the upper layer comprises or consists of an aerosol-forming material, and the lower and intermediate layers do not comprise an aerosol-forming material.

[0049] Alternatively, the aerosol-forming substrate may comprise an upper layer, a lower layer, and an intermediate layer disposed between the upper and lower layers, wherein the lower layer comprises or consists of an aerosol-forming material, e.g., the lower layer comprises or consists of an aerosol-forming material, and the upper and intermediate layers do not comprise an aerosol-forming material.

[0050] Alternatively, the aerosol-forming substrate may comprise an upper layer, a lower layer, and an intermediate layer disposed between the upper and lower layers, the intermediate layer comprising or consisting of an aerosol-forming material, for example, the intermediate layer comprising or consisting of an aerosol-forming material, and the upper and lower layers not comprising an aerosol-forming material.

[0051] Alternatively, the aerosol-forming substrate may comprise an upper layer, a lower layer, and an intermediate layer disposed between the upper and lower layers, the lower layer comprising or consisting of a first aerosol-forming material, the upper layer comprising or consisting of a second aerosol-forming material, and the intermediate layer comprising no aerosol-forming material.

[0052] Alternatively, the aerosol-forming substrate may comprise an upper layer, a lower layer, and an intermediate layer disposed between the upper and lower layers, the lower layer comprising or consisting of a first aerosol-forming material, the intermediate layer comprising or consisting of a second aerosol-forming material, and the lower layer not comprising an aerosol-forming material.

[0053] Alternatively, the aerosol-forming substrate may comprise an upper layer, a lower layer, and an intermediate layer disposed between the upper and lower layers, wherein the upper layer comprises or consists of a first aerosol-forming material, the intermediate layer comprises or consists of a second aerosol-forming material, and the upper layer does not comprise an aerosol-forming material.

[0054] Alternatively, the aerosol-forming substrate may comprise an upper layer, a lower layer, and an intermediate layer disposed between the upper and lower layers, wherein the upper layer comprises or consists of a first aerosol-forming material, the intermediate layer comprises or consists of a second aerosol-forming material, and the lower layer comprises or consists of a third aerosol-forming material.

[0055] The aerosol-forming substrate is preferably formed from a sheet of material. For example, each of the upper layer, lower layer, and middle layer is preferably formed from a sheet of material. The sheet may be a sheet of aerosol-forming material, such as a homogenized tobacco material. The sheet may also be a sheet of non-aerosol-forming material, such as a paper sheet. The thickness of any sheet forming part of the aerosol-forming substrate may be 0.02 mm to 2 mm. For example, the thickness of any sheet forming part of the aerosol-forming substrate may be 0.05 mm to 1.5 mm, such as 0.1 mm to 1 mm, such as 0.2 mm to 0.8 mm, such as 0.3 mm to 0.6 mm, or such as 0.4 mm to 0.5 mm.

[0056] In some embodiments, homogenized tobacco material sheets for use in the aerosol-forming substrates described herein may have a thickness of from 10 μm to about 300 μm. In some embodiments, homogenized tobacco material sheets for use in the aerosol-forming substrates described herein may have a basis weight of from 100 g / m 2 ~about 300g / m 2 may be.

[0057] Preferably, the upper layer comprises or is formed from a planar sheet of material, the lower layer comprises or is formed from a planar sheet of material, and the middle layer comprises or is formed from a corrugated sheet of material, whereby at least a portion of the airflow channels formed by the corrugations are at least partially surrounded by the aerosol-forming material, thereby allowing aerosol generated from the aerosol-forming material to be easily entrained in the airflow path.

[0058] The aerosol-forming substrate may comprise a first aerosol-forming material and a second aerosol-forming material. The aerosol-forming substrate may comprise a third aerosol-forming material.

[0059] The first aerosol-forming material may be the same as the second aerosol-forming material, the first aerosol-forming material may be the same as the third aerosol-forming material, e.g., the first, second, and third aerosol-forming materials may all be the same aerosol-forming material.

[0060] The first aerosol-forming material may be different from the second aerosol-forming material, e.g., may have a different composition from the second aerosol-forming material, e.g., a different aerosol former content, a different flavor content, or a different nicotine content. The first aerosol-forming material may be different from the third aerosol-forming material, e.g., may have a different composition from the third aerosol-forming material, e.g., a different aerosol former content, or a different flavor content, e.g., the first, second, and third aerosol-forming materials are all different materials.

[0061] The aerosol-forming material may be a homogenized tobacco material. For example, any of the first, second, or third aerosol-forming materials may be a homogenized tobacco material.

[0062] The aerosol-forming substrate may include an upper layer, a lower layer, and an intermediate layer disposed between the upper and lower layers, the intermediate layer being secured to at least one of the upper and lower layers by an adhesive, such as an adhesive including a gum, e.g., guar gum. If desired, the adhesive may be an aerosol-forming material. For example, the adhesive may be a homogenized tobacco slurry. The adhesive may be or include a flavorant and / or an aerosol former. Thus, it is possible to form an aerosol-forming substrate in which all components, including the adhesive, are formed from an aerosol-forming material.

[0063] In embodiments in which the substrate includes an intermediate layer, the intermediate layer may include or consist of corrugated elements.

[0064] Preferably, the airflow path is defined through the aerosol-forming substrate by channels formed or defined by the longitudinally extending corrugations of the corrugated elements. Optionally, a porous material may be disposed within the channels formed by the longitudinally extending corrugations. The porous material may comprise or consist of an aerosol-forming material. The porous material may comprise a flavorant or an aerosol former. For example, the porous material may be immersed in a liquid flavorant or a liquid aerosol former.

[0065] Flavoring agents may be disposed within channels formed by the longitudinally extending corrugations and release flavor upon heating. For example, flavor threads and / or one or more flavor capsules may be disposed within the channels. The flavor capsules may be capsules containing liquid or gel flavoring agents, such as capsules configured to release their contents upon heating, or breakable capsules designed to be broken by the user prior to use.

[0066] Preferably, the airflow path or paths are defined through the aerosol-forming substrate from one side of the aerosol-forming substrate to the other side of the aerosol-forming substrate in the x / y plane. The airflow path can pass through a filter, mesh, or porous material such as porous paper, e.g., tea bag material, incorporated into the aerosol-forming substrate. The filter, mesh, or porous material can be arranged transversely to the airflow path, for example, across the proximal or downstream end of the aerosol-forming substrate. Such a filter, mesh, or porous material can advantageously function as a filter to prevent solid particles from being inhaled by the user without significantly increasing the RTD.

[0067] In this context, the term "porous" is used to mean sufficiently porous to allow the aerosol formed by the aerosol-forming substrate during use to escape through the porous layer. Advantageously, the porous layer can protect the aerosol-forming substrate from one or both of physical damage and chemical contamination. Advantageously, the porous layer can also help prevent the transfer of aerosol-forming material from the aerosol-forming substrate to a user handling the aerosol-forming substrate.

[0068] The aerosol-forming substrate may comprise a substantially planar layer and a corrugated layer secured to a surface of the substantially planar layer, such that longitudinal channels formed by longitudinally extending corrugations in the corrugated layer extend in the plane direction of the substantially planar layer.

[0069] Any of the planar layers described herein, e.g., any one or more of the first planar layer, second planar layer, upper planar layer, and lower planar layer, may be a single, integral, planar component, e.g., a planar sheet.

[0070] The aerosol-forming substrate may comprise an upper layer, a lower layer, and an intermediate layer, with at least one of the upper and lower layers comprising perforations or holes so that at least a portion of the air can flow through the upper and / or lower layer. Preferably, the aerosol-forming substrate comprises a proximal or oral end and a distal end. The perforations or holes may be located in a central portion of the aerosol-forming substrate, for example, approximately midway between the proximal or oral end and the distal end. The intermediate layer may comprise or consist of a corrugated element or corrugated layer disposed between the upper and lower layers, with longitudinal channels formed by the longitudinally extending corrugations of the corrugated element or corrugated layer extending in the planar direction of the upper and lower layers. The intermediate layer may comprise perforations or holes so that at least a portion of the air can flow through the intermediate layer in a direction perpendicular to the longitudinally extending channels. At least one of the upper, lower, and intermediate layers may be or include a mesh.

[0071] The aerosol-forming substrate may comprise an upper layer, a lower layer, and an intermediate layer, and the intermediate layer may comprise or consist of a corrugated element or layer disposed between the upper and lower layers, such that longitudinal channels formed by longitudinally extending corrugations in the corrugated element or layer extend in the plane of the upper and lower layers, and the intermediate layer comprises perforations or holes such that at least a portion of the air can flow through the intermediate layer in a direction perpendicular to the longitudinally extending channels.

[0072] The aerosol-forming substrate may have a proximal end and a distal end. The proximal end may also be referred to as the mouth end. The longitudinal channels formed by the longitudinally extending corrugations of the corrugated element or corrugated layer may extend in a direction perpendicular to the direction defined between the proximal or mouth end and the distal end. In this case, it may be particularly advantageous for the corrugated portions of the corrugated element to have perforations or holes, so that at least a portion of the air can flow through the corrugated element in a direction perpendicular to its longitudinally extending channels.

[0073] The aerosol-generating substrate may include one or more sheets of aerosol-forming material, with multiple holes or notches defined in the surface, for example, the upper or lower surface of the aerosol-forming material. When the aerosol-forming material is heated, the aerosol is generated by gases and vapors that may be released at the surface of the aerosol-forming material. Gases and vapors may also be released between the heated surface of the aerosol-forming material and the heater. Gases released between the aerosol-forming material and the heater may form bubbles that reduce the efficiency of heat transfer between the heater and the material. Multiple holes or notches defined in the surface of the aerosol-forming material may advantageously facilitate the release of volatile components of the aerosol-forming material into the airflow passing through the surface of the aerosol-forming material. For example, such holes or notches may provide low-resistance paths for gases and vapors formed by heating the aerosol-forming material to escape from the volume of the material to the surface of the material. Increasing the number of low-resistance paths from the volume of the material to the surface of the material may improve aerosol delivery and increase the utilization efficiency of the substrate.

[0074] The aerosol-forming substrate may comprise a lower layer of aerosol-forming material and a corrugated layer attached to the lower layer, for example, a corrugated layer of aerosol-forming material, and the plurality of holes or notches may be defined in at least one of the lower layer of aerosol-forming material and the corrugated layer. The plurality of holes or notches may be defined in an upper surface of the aerosol-forming substrate.

[0075] In some embodiments, at least some of the plurality of holes are blind holes that do not penetrate through the thickness of the aerosol-forming material in which they are defined, hi some embodiments, at least some of the plurality of holes are through holes that extend through the thickness of the aerosol-forming material in which they are defined.

[0076] The aerosol-forming substrate may include a corrugated element or layer, and the corrugations of the corrugated element or layer may be defined by a wavelength of the corrugation and a peak-to-trough amplitude of the corrugation. The corrugation wavelength may be 1 mm to 10 mm, for example, 1.5 mm to 8 mm, for example, 2 mm to 6 mm, for example, 2.5 mm to 5 mm, or for example, 3 mm to 4 mm. The peak-to-trough amplitude of the corrugation may be 1 mm to 10 mm, for example, 1.5 mm to 8 mm, for example, 2 mm to 6 mm, for example, 2.5 mm to 5 mm, or for example, 3 mm to 4 mm. The peak-to-trough amplitude of the corrugation is the same as the thickness, e.g., the z-dimension, of the corrugation element or corrugated layer. Thus, for a regular wave-like structure, the peak-to-trough amplitude is usually twice what is simply referred to as the amplitude (or wave amplitude, or peak-to-midpoint amplitude, or midpoint-to-trough amplitude).

[0077] The waveform may be formed with a number of different wave profiles, for example, the waveform may be further defined by a wave profile that is sinusoidal, or triangular, or rectangular, or trapezoidal, or toroidal, or parabolic.

[0078] In some examples, the aerosol-forming substrate may be formed as an extrudate of an aerosol-forming material, the extrudate having an upper surface, a lower surface, and a plurality of airflow channels defined through the aerosol-forming substrate between the upper and lower surfaces.

[0079] It may be advantageous to minimize the contact area between the upper and / or lower layers and the intermediate / separating layer. The intermediate layer may primarily provide structure to the substrate, while the upper and / or lower layer may primarily provide the aerosol-forming material. If there is significant contact between the upper / lower layer and the intermediate layer, undesirable heat conduction may occur between the upper / lower layer and the intermediate layer. As a result of heat conduction, portions of the aerosol-forming substrate may not reach the ideal aerosol-generating temperature or may not reach such temperature quickly enough. Cool spots in the aerosol-forming material may result in inefficient aerosol delivery. Cool spots in the aerosol-forming material may result in incomplete utilization of some of the aerosol-forming material. Contact between the upper or lower layer and the intermediate layer may be minimized by selecting an appropriate structure for the intermediate layer. For example, if the intermediate layer is corrugated, a triangular profile corrugation may reduce the contact area compared to, for example, a sinusoidal or trapezoidal profile corrugation.

[0080] As a further example, the intermediate layer may include ribs arranged to form walls extending perpendicular to the upper and lower layers. Such ribs form contact lines between the intermediate layer and the upper and lower layers, thereby minimizing thermal contact. The ribs may be formed from strips of material arranged such that the width of the strip defines the thickness of the intermediate layer. To facilitate assembly, multiple strips may be joined to form an array of ribs and arranged to form the intermediate layer. Alternatively, or additionally, the strips may be twisted laterally to provide a standing function at the ends of the strips and facilitate the assembly process. Advantageously, the strips may be twisted sufficiently to be "freestanding" on their ends, which may facilitate assembly.

[0081] As a further example, the intermediate layer may form an interface with the upper and lower layers. For example, the intermediate layer may include a plurality of pillars, each pillar providing an interface between the intermediate layer and at least one of the upper and lower layers. The pillars may be separate and independent. Advantageously, these pillars are interconnected to facilitate assembly. For example, the intermediate layer may include a sheet of material having upwardly and downwardly depending protrusions that function as pillars to separate the upper and lower layers while minimizing contact between the intermediate layer and the upper and lower layers. Such a structure also allows for the definition of a low-RTD airflow path between the upper and lower layers. Advantageously, such a layer may be provided by forming or embossing a sheet-like material, such as a sheet of paper. Such a layer may be formed by depositing pulp on a shaped surface, such as a shaped mesh surface. The pulp may then be dried and removed from the mesh to form the profiled intermediate layer. In some embodiments, the pulp may not be removed from the mesh, in which case the mesh may form part of the profiled intermediate layer. For example, the mesh may form the susceptor of a substrate that includes a profiled intermediate layer.

[0082] The pillars of the intermediate layer may be formed from multiple upwardly and downwardly depending structures, such as cones formed in the sheets forming the intermediate layer. The profile may resemble an egg carton. Such structures advantageously impart overall rigidity to the substrate and allow for the formation of very thin substrate layers. Furthermore, airflow through the airflow channels defined between the three-dimensional peaks and troughs of the intermediate layer may experience continuous acceleration and deceleration and may be subject to turbulence as it passes through a series of restrictions and expansions. As a result, the airflow may advantageously deliver a highly homogenized mixture of air and aerosol to the user.

[0083] A preferred embodiment of the intermediate layer may have a profile that can be described as egg-crate-like. The structure of such a layer is a regular arrangement of upwardly dependent peaks and downwardly dependent troughs. The egg-crate-like structure of the intermediate layer may be mathematically described as a surface or profile obtained by translating a first periodic curve perpendicularly relative to a second periodic curve. For example, such a surface or profile can be obtained by translating a first continuous periodic curve perpendicularly relative to a second continuous periodic curve, or by translating a first sinusoidal curve perpendicularly relative to a second sinusoidal curve. The shape, amplitude, and period of the first periodic curve may be similar to or identical to the shape, amplitude, and period of the second periodic curve. For example, one or both of the first and second periodic curves may be sinusoidal, e.g., both the first and second periodic curves are sinusoidal with the same period and amplitude. The periodic curves may have other profiles, for example, one or both of the periodic curves may be square wave, triangular wave, or trapezoidal wave. The shape of the resulting peaks and troughs depends on the shape of the curve. The shape of the intermediate layer can be described as a sinusoidal surface.

[0084] A general equation can be defined to define the shape of an egg-carton-like intermediate layer. Thus, for a sinusoidal function defined by s(x) = Asin(s / b), with horizontal planes x, y, vertical axis z, total vertical height (distance from the top of the peak to the bottom of the valley) 2A, and a periodicity of peaks and valleys every unit length 2πb, the general equation defining the shape can be written as follows: z=A(sin(x / b)+sin(y / b))

[0085] In the resulting interlayer structure, each peak (except for those at the edges of the structure) is surrounded by four troughs, and each trough (except for those at the edges of the structure) is centered between four peaks. The exact shape of the peaks and troughs depends on the shape of the periodic curves that form the x and y profile of the surface. For example, the peaks and troughs may have a substantially circular profile in plan view, or a substantially rectangular profile in plan view, e.g., the peaks and troughs may exhibit a square or diamond-shaped profile in plan view.

[0086] The configuration of the peaks and troughs can affect the airflow through the aerosol-forming substrate. For example, the intermediate layer can be positioned and / or oriented to increase turbulence in the airflow path through the article. Advantageously, increased turbulence can result in more uniform mixing of the air and vapor within the article, which can result in a more homogeneous aerosol.

[0087] The aerosol-forming substrate may have a length (x-dimension) that is approximately the same as its width (y-dimension). Alternatively, the length (x-dimension) may be greater than the width (y-dimension). For example, the length may be about 1.5 times the width, or about 2 times the width, or about 2.5 times the width, or about 3 times the width. The length (x-dimension) may be more than 3 times the width, for example, more than 4 times the width, or for example, more than 5 times the width.

[0088] The aerosol-forming substrate may have a base. The base is preferably substantially planar. The base may define a substantially planar lower surface of the aerosol-forming substrate.

[0089] The aerosol-forming substrate may be in the form of a three-dimensional shape that can be described as a cube or a rectangular parallelepiped.

[0090] The aerosol-forming substrate may have a length (x-dimension) and / or width (y-dimension) that is at least twice as large as the height (z-dimension), for example 3 times, or 4 times, or 5 times, or in some cases 6 times or more, for example 10 times, or 15 times, or 20 times the height.

[0091] The aerosol-forming substrate may have a base defined by a rectangular shape having a length and width that form the lower surface of the aerosol-forming substrate. The upper surface of the aerosol-forming substrate may be defined by a substantially identical rectangular shape spaced apart from the base by a height, for example both the lower and upper surfaces being defined as planes that are arranged on parallel planes spaced apart by a height.

[0092] The aerosol-forming substrate may have a ratio of the greatest dimension of its length (x-dimension) and its width (y-dimension) to its height (z-dimension) of from 3:1 to 25:1, such as from 4:1 to 20:1, for example from 4.2:1 to 10:1, for example from 4.5:1 to 8:1, e.g., a length to width ratio of from 4:1 to 20:1, for example from 4.2:1 to 10:1, for example from 4.5:1 to 8:1. Advantageously, these ratios may provide a compromise between at least the following four factors: the base surface area for heating, which may increase with the x and y dimensions; the temperature difference across the height of the substrate when heated at one or both of the base and top surface, which may increase with the z dimension; For substrates having x and y dimensions that are more than four times the z dimension, the structural rigidity of the substrate or article, which for a given z dimension, the x and y dimensions may decrease, and for a given x and y dimensions, the z dimension may increase; The ability of the substrate to generate a sufficient amount of aerosol to satisfy the user, which may increase with the x, y, and z dimensions.

[0093] The aerosol-forming substrate may have a length (x dimension) of from 10 mm to 50 mm, such as from 12 mm to 30 mm, for example from 14 mm to 26 mm, for example from 16 mm to 24 mm, for example from 18 mm to 22 mm, for example about 18 mm, or about 19 mm, or about 20 mm, or about 21 mm, or about 22 mm.

[0094] The aerosol-forming substrate may have a width (y dimension) of from 5mm to 20mm, such as from 8mm to 18mm, for example from 10mm to 16mm, for example from 11mm to 15mm, for example from 12mm to 14mm, for example about 13mm.

[0095] The aerosol-forming substrate may have a height (z dimension) of from 1 mm to 10 mm, such as from 1.2 mm to 8 mm, for example from 1.4 mm to 7 mm, for example from 1.6 mm to 6 mm, for example from 1.7 mm to 5 mm, for example about 1.7 mm, or about 4.5 mm, or about 2 mm, or about 3 mm, or about 4 mm.

[0096] The aerosol-forming substrate may consist solely of the aerosol-forming material.

[0097] The aerosol-forming substrate may further comprise a porous layer covering at least one surface of the aerosol-forming substrate, for example, at least the upper surface, or at least the lower surface, or at least the upper and lower surfaces. The porous layer may cover at least an end surface of the aerosol-forming substrate, for example, covering at least one airflow inlet or outlet of the aerosol-forming substrate. The porous layer may completely encase the aerosol-forming substrate. The porous layer may be a layer of porous paper or porous mesh, such as a tea bag material. The porous layer can protect the surface of the aerosol-forming substrate or protect a user handling the aerosol-forming substrate, while allowing gas components released from the aerosol-forming substrate to pass through.

[0098] The aerosol-forming substrate may comprise nicotine, which may be present in the form of tobacco material or in the form of a nicotine extract.

[0099] The aerosol-forming substrate preferably comprises or consists of a homogenized tobacco material, such as a reconstituted tobacco material or a cast leaf tobacco material.

[0100] The aerosol-forming substrate may comprise or consist of a solid aerosol-forming material. The aerosol-forming substrate may comprise a liquid aerosol-forming substrate material, for example a liquid aerosol-forming material held within a porous matrix. The aerosol-forming substrate may comprise a gel aerosol-forming material.

[0101] The first portion of the aerosol-forming substrate may include a first aerosol-forming material, and the second portion of the aerosol-forming substrate may include a second aerosol-forming material that is different from the first aerosol-forming material. For example, the first aerosol-forming material may be a first homogenized tobacco material, and the second aerosol-forming material may be a second homogenized tobacco material having a different composition from the first homogenized tobacco material. The first homogenized tobacco material composition may differ from the second tobacco composition by having at least one difference selected from the list consisting of a different aerosol-former content, a different tobacco content, a different flavorant content, a different moisture content, and a different nicotine content.

[0102] The first aerosol-forming material may be a first homogenized tobacco material, and the second aerosol-forming material may be a non-tobacco aerosol-forming material that includes an aerosol former, such as glycerin or propylene glycol, and may preferably include a flavor component and / or an active component, such as nicotine or cannabinol.

[0103] Advantageously, a substrate comprising two or more different aerosol-forming materials can allow for combinations of aerosol-forming materials that might not otherwise be available, which may enable, for example, flavor combinations that enhance the user experience.

[0104] Any one, two, or all of the aerosol-forming materials, e.g., the aerosol-forming materials in the aerosol-forming substrate, may comprise one or more organic materials, e.g., tobacco. Any one, two, or all of the aerosol-forming materials, e.g., the aerosol-forming materials in the aerosol-forming substrate, may comprise one or more of herb leaves, tobacco leaves, tobacco vein fragments, reconstituted tobacco, homogenized tobacco, extruded tobacco, and expanded tobacco.

[0105] Any one, two, or all of the aerosol-forming materials, e.g., the aerosol-forming materials in the aerosol-forming substrate, may comprise one or more aerosol formers. Suitable aerosol formers are well known in the art and include, but are not limited to, one or more aerosol formers selected from polyhydric alcohols (such as propylene glycol, polyethylene glycol, triethylene glycol, 1,3-butanediol, and glycerin), esters of polyhydric alcohols (such as glycerol monoacetate, diacetate, or triacetate), and aliphatic esters of monocarboxylic, dicarboxylic, or polycarboxylic acids (such as dimethyl dodecanedioate and dimethyl tetradecanedioate). It may be particularly preferred that the aerosol former is or comprises glycerin.

[0106] The aerosol-forming material, e.g., any one, two, or all of the aerosol-forming materials in the aerosol-forming substrate, may comprise at least 1, 2, 5, 10, or 15 weight percent aerosol formers. The aerosol-forming material may comprise more than 15 weight percent aerosol formers, e.g., more than 20 weight percent, or more than 25 weight percent, or more than 30 weight percent, or more than 40 weight percent, or more than 50 weight percent aerosol formers.

[0107] The aerosol-forming material may include 30% or less aerosol formers by weight, 25% or less aerosol formers by weight, or 20% or less aerosol formers by weight. That is, the aerosol-forming material may have an aerosol-former content of 30% or less, 25% or less, or 20% or less by weight.

[0108] The aerosol-forming material may include between 1 weight percent and 30 weight percent aerosol formers, between 1 weight percent and 25 weight percent aerosol formers, or between 1 weight percent and 20 weight percent aerosol formers.

[0109] The aerosol-forming material may include 5 weight percent to 30 weight percent aerosol formers, 5 weight percent to 25 weight percent aerosol formers, or 5 weight percent to 20 weight percent aerosol formers.

[0110] The aerosol-forming material may include 10 to 30 percent by weight of aerosol formers, 10 to 25 percent by weight of aerosol formers, or 10 to 20 percent by weight of aerosol formers.

[0111] The aerosol-forming material may include 15 to 30 percent by weight of aerosol formers, 15 to 25 percent by weight of aerosol formers, or 15 to 20 percent by weight of aerosol formers.

[0112] The aerosol-forming material may comprise at least 50 percent by weight of aerosol formers, at least 60 percent by weight of aerosol formers, or at least 70 percent by weight of aerosol formers.

[0113] The aerosol-forming material may comprise up to 85% by weight of an aerosol former, up to 80% by weight of an aerosol former, or up to 75% by weight of an aerosol former.

[0114] The aerosol-forming material may include 50 to 85 percent by weight of aerosol formers, 50 to 80 percent by weight of aerosol formers, or 50 to 75 percent by weight of aerosol formers.

[0115] The aerosol-forming material may include 60 to 85 percent by weight of aerosol formers, 60 to 80 percent by weight of aerosol formers, or 60 to 75 percent by weight of aerosol formers.

[0116] The aerosol-forming material may include 70 to 85 percent by weight of aerosol formers, 70 to 80 percent by weight of aerosol formers, or 70 to 75 percent by weight of aerosol formers.

[0117] Any one, two, or all of the aerosol-forming materials, e.g., the aerosol-forming materials in the aerosol-forming substrate, may comprise nicotine. The aerosol-forming materials may comprise natural nicotine, or synthetic nicotine, or a combination of natural and synthetic nicotine.

[0118] The aerosol-forming material may comprise at least 0.5 weight percent nicotine, at least 1 weight percent nicotine, at least 1.5 weight percent nicotine, or at least 2 weight percent nicotine, i.e., the aerosol-forming material may have a nicotine content of at least 0.5 weight percent, at least 1 weight percent, at least 1.5 weight percent, or at least 2 weight percent.

[0119] The aerosol-forming material, e.g., any one, two, or all of the aerosol-forming materials in the aerosol-forming substrate, may contain one or more cannabinoid compounds, such as one or more of tetrahydrocannabinol (THC), tetrahydrocannabinolic acid (THCA), cannabidiol (CBD), cannabidiolic acid (CBDA), cannabinol (CBN), cannabigerol (CBG), cannabigerol monomethyl ether (CBGM), cannabivarin (CBV), cannabidivarin (CBDV), tetrahydrocannabivarin (THCV), cannabichromene (CBC), cannabicyclol (CBL), cannabichromevarin (CBCV), cannabigerovarin (CBGV), cannabielsoin (CBE), and cannabicitran (CBT). The cannabinoid compound may preferably be CBD or THC. The cannabinoid compound may particularly preferably be CBD.

[0120] Any one, two, or all of the aerosol-forming materials, e.g., the aerosol-forming materials in the aerosol-forming substrate, may contain one or more flavoring agents. The one or more flavoring agents may include one or more essential oils, such as eugenol, peppermint oil, and spearmint oil; one or both of menthol and eugenol; one or both of anethole and linalool; and one or more herbaceous materials. Suitable herbaceous materials include herb leaves or other herbaceous materials derived from herbaceous plants, including, but not limited to, mints, such as peppermint and spearmint, lemon balm, basil, cinnamon, lemon basil, chives, coriander, lavender, sage, tea, thyme, and caraway. The one or more flavoring agents may include tobacco materials.

[0121] The aerosol-forming material may have a moisture content of about 5 to 25%, preferably about 7 to 15%, in the final product state. For example, the aerosol-forming substrate may be a homogenized tobacco material having a moisture content of about 5 to 25%, preferably about 7 to 15%, in the final product state.

[0122] The aerosol-forming material may include tobacco leaf, e.g., a tobacco leaf blend incorporating about 15-45%, preferably about 20-35%, of at least one of the following tobacco leaf types: bright tobacco leaf, dark tobacco leaf, and aromatic tobacco leaf. The tobacco material, e.g., tobacco leaf, is preferably ground and graded to a particle size of about 100-380 mesh, preferably about 170-320 mesh.

[0123] "Tobacco type" means one of various types of tobacco, for example, based on different curing processes that are performed on the tobacco before it is further processed into tobacco products.

[0124] Examples of bright tobaccos include Brazilian Fulcure, Indian Fulcure, Chinese Fulcure, American Fulcure, e.g., Virginia tobacco, and Tanzanian Fulcure.

[0125] Examples of aromatic tobaccos are Oriental Turkish, Greek Oriental, and Semi-Oriental tobaccos, but also Fire Cured, US Burley such as Perique, and Rustic.

[0126] Examples of dark tobaccos include dark-cured Brazilian Galpao, Burley Malawi or other African Burley, Sun-cured or air-cured Indonesian Kastri.

[0127] The aerosol-forming material may contain cellulose fibers. For example, the aerosol-forming material may contain about 1 to 15% cellulose fibers, preferably about 3 to 7% cellulose fibers. Preferably, the cellulose fibers have a length of about 10 to 250 μm, preferably about 10 to 120 μm.

[0128] The aerosol-forming material may include organic fibers, such as non-tobacco fibers or tobacco fibers. For example, the aerosol-forming material may include about 5-20%, preferably about 7-15%, tobacco fibers. The tobacco fibers are preferably derived from stems and / or petioles graded into fibers with lengths of about 10-350 μm, preferably about 10-180 μm. The aerosol-forming material may include about 10-30%, preferably about 15-25%, non-tobacco organic fibers. For example, organic fibers may be obtained from cellulose, cotton, wood, or tea plant varieties as by-products or secondary processing waste products of the tea industry. The organic fibers preferably have lengths of about 10-400 μm, preferably about 10-200 μm.

[0129] The aerosol-forming material may contain a binder. For example, the aerosol-forming material may contain about 1 to 10%, preferably about 1 to 5%, of a binder, such as any of the common gums or pectins used in the food and beverage (F&B) industry. Preferred binders include natural pectins, such as fruit pectins, e.g., citrus pectins, or tobacco pectins; guar gum, land locust bean gum, e.g., hydroxyethyl and / or hydroxypropyl versions of these gums; starches, such as modified or derivatized starches; alginates; methylcellulose, ethylcellulose, ethylhydroxymethylcellulose, and carboxymethylcellulose; dextran; and xanthan gum. A preferred binder is guar.

[0130] The aerosol-forming material may include organic vegetable glycerite. For example, the aerosol-forming material may include about 15-55%, preferably about 20-35%, of plants such as clove, echinacea, fennel, ginger, hawthorn berry, elderberry, monarda, mullein leaf, nettle, plantain, turmeric, yarrow, and combinations thereof.

[0131] The aerosol-forming material may include organic plant extracts. For example, the aerosol-forming material may include about 1% to 15%, preferably 2% to 7%, of menthol (dl-menthol, CHO, 2-isopropyl-5-methylcyclohexanol) obtained from any of the aforementioned plants, as well as Chaerophyllum macrospermum, Mesosphaerum sidifolium, or other related plant varieties, and p-menthone-3-ol as an optional secondary alcohol, a diastereoisomer of 5-methyl-2-(propan-2-yl)cyclohexan-1-ol.

[0132] The aerosol-forming material may include plant essential oils, for example, about 0.5-5%, preferably about 1-3%, of plant essential oils, such as palm, coconut, and wood-based essential oils.

[0133] The aerosol-forming material preferably comprises an aerosol former, for example, about 5-35%, preferably about 10-25%, of an aerosol former. Suitable aerosol formers known in the art include glycerin; monohydric alcohols such as menthol; polyhydric alcohols such as triethylene glycol; esters of polyhydric alcohols such as glycerol monoacetate, glycerol diacetate, or glycerol triacetate; and aliphatic esters of monocarboxylic, dicarboxylic, or polycarboxylic acids, for example, their dimethyl esters.

[0134] The aerosol-forming material may include particles of functional materials, such as particles of carbon, graphite, activated carbon, or expanded graphite, which may, for example, increase the thermal conductivity of the aerosol-forming material and improve the efficiency of aerosol generation.

[0135] The aerosol-forming substrate may further comprise a thermally conductive layer, such as an aluminum layer, covering at least a portion of at least one surface of the aerosol-forming substrate. For example, at least a portion of the upper surface or at least a portion of the lower surface may comprise such a thermally conductive layer. The thermally conductive layer can facilitate heat transfer between a heat source and the aerosol-forming material of the aerosol-forming substrate.

[0136] The aerosol-forming substrate may further comprise a paper layer, such as a tipping paper layer, covering at least a portion of at least one surface of the aerosol-forming substrate, such as at least a portion of the upper surface or at least a portion of the lower surface. The paper layer can protect a user's hands when handling the substrate. Use of a paper layer may allow a user to insert a portion of the aerosol-forming substrate into their mouth.

[0137] The aerosol-forming substrate may comprise a conductive material. For example, the aerosol-forming material may comprise conductive particles. The conductive particles may be, for example, conductive carbon or graphite particles, or conductive metal particles, such as aluminum, stainless steel, or nickel particles.

[0138] The aerosol-forming substrate may include one or more susceptor materials. The one or more susceptor materials may be incorporated within the aerosol-forming material of the aerosol-forming substrate, for example, as particles of the susceptor material dispersed within the aerosol-forming material. The presence of the susceptor material may enable the aerosol-forming substrate to be heated by engagement with the varying electromagnetic field generated by the inductor.

[0139] If desired, the one or more susceptor materials may be incorporated into the aerosol-forming substrate as one or more strips, threads, or wires of susceptor material, for example, as one or more strips, threads, or wires of susceptor material that are positioned within the airflow path of the aerosol-forming substrate.

[0140] If desired, one or more susceptor materials may be incorporated within the aerosol-forming substrate as one or more sheets or layers of susceptor material, for example, as one or more sheets or layers of susceptor material covering an outer portion of the aerosol-forming substrate or forming a structural component of the aerosol-forming substrate.

[0141] The aerosol-forming substrate may comprise a first planar layer and a corrugated layer disposed on a surface of the first planar layer, wherein at least one of the first planar layer and the corrugated layer comprises or consists of a sheet of susceptor material.

[0142] The aerosol-forming substrate may comprise a first planar layer, a second planar layer, and a corrugated layer disposed between the first and second planar layers, wherein at least one of the first planar layer, the second planar layer, and the corrugated layer comprises or consists of a sheet of susceptor material.

[0143] The one or more sheets of susceptor material may be in the form of a mesh of susceptor material.

[0144] The susceptor material, in any form, may comprise one or more materials selected from the list consisting of aluminum, iron and iron alloys, nickel and nickel alloys, cobalt alloys, stainless steel alloys, copper alloys, carbon, expanded carbon, and graphite.

[0145] The aerosol-forming substrates disclosed herein may be manufactured using any suitable method. For example, sheets of material including the aerosol-forming material may be formed using known methods and assembled to form the aerosol-forming substrate. In some examples, an extrusion process may be used to form the aerosol-forming substrate.

[0146] Where the substrate includes corrugated layers or elements, it may be advantageous to manufacture the substrate using processes similar to those used to manufacture corrugated cardboard.

[0147] As disclosed herein, a method of making a planar corrugated aerosol-forming substrate includes the steps of providing a first continuous sheet, providing a second continuous sheet, at least one of the first sheet and the second sheet comprising or consisting of an aerosol-forming material, texturing the second continuous sheet using a fluted roller to form a continuous corrugated sheet, applying an adhesive to at least one of the continuous corrugated sheet or the first continuous sheet, attaching the continuous corrugated sheet to a surface of the first continuous sheet to form a continuous aerosol-forming substrate, and cutting the continuous aerosol-forming substrate to form the planar corrugated aerosol-forming substrate.

[0148] A method of making a planar corrugated aerosol-forming substrate includes the steps of providing a first continuous sheet, providing a second continuous sheet, providing a third continuous sheet, wherein at least one of the first sheet, the second continuous sheet, and the second sheet comprises or consists of an aerosol-forming material, texturing the second continuous sheet using a fluted roller to form a continuous corrugated sheet, applying an adhesive to at least one of the continuous corrugated sheet or the first continuous sheet, attaching a first side of the continuous corrugated sheet to a surface of the first continuous sheet, applying an adhesive to at least one of the continuous corrugated sheet and the third continuous sheet, and attaching a second side of the continuous corrugated sheet to a surface of the third continuous sheet, thereby forming a continuous aerosol-forming substrate, and cutting the continuous aerosol-forming substrate to form the planar corrugated aerosol-forming substrate.

[0149] At least one of the first, second, and third continuous sheets may be a sheet of homogenized tobacco.

[0150] The adhesive may include guar gum.The adhesive may include an aerosol-forming substrate, for example, a homogenized tobacco slurry.

[0151] According to the present disclosure, there may be provided an aerosol-generating article for use in an aerosol-generating article. The aerosol-generating article may be used to generate an inhalable aerosol. The article may comprise an aerosol-forming substrate as disclosed herein. The article may consist solely of an aerosol-forming substrate as disclosed herein. Advantageously, this may result in one or more of the following benefits: reduced manufacturing costs for the article; reduced weight of the article and therefore reduced shipping costs; and reduced waste from manufacturing or use of the article.

[0152] The aerosol-generating article may comprise an aerosol-forming substrate disposed within or assembled with an outer wrapper or casing. The outer wrapping or casing may be a cigarette wrapper. The outer wrapping or casing may be a polymeric sheet.

[0153] Optionally, the outer wrapping or outer casing may include a portion of the susceptor material, such as aluminum or stainless steel foil.

[0154] If desired, one or more perforations may be defined through the outer wrapping or outer casing. Such perforations may allow air to flow into or out of the article.

[0155] In some embodiments, the aerosol-generating article may comprise multiple components, and the multiple components, including the aerosol-forming substrate, may be assembled within an outer wrapping or outer casing.

[0156] If desired, the aerosol-generating article may comprise two or more aerosol-forming substrates as disclosed herein.

[0157] The aerosol-generating article may be defined by a length extending in the x-direction, a width extending in the y-direction, and a height extending in the z-direction. A longitudinal airflow path may be defined through the aerosol-generating article between a distal end of the article and a proximal end of the article.

[0158] The aerosol-generating article may be defined by a length extending in the x-direction between a distal end and a proximal end, a width extending in the y-direction between a first edge and a second edge, and a height extending in the z-direction between an upper surface and a lower surface. The distal portion of the aerosol-generating article may be defined between the distal end of the aerosol-generating article and a midpoint of the longitudinal axis of the aerosol-generating article. The proximal portion of the aerosol-generating article may be defined between the proximal end of the aerosol-generating article and a midpoint of the longitudinal axis of the aerosol-generating article.

[0159] The aerosol-generating article may comprise a single aerosol-forming substrate extending within the article between a proximal end and a distal end.

[0160] If desired, the aerosol-forming substrate may be located within the distal portion of the aerosol-generating article. In some embodiments, the aerosol-forming substrate may be located entirely within the distal portion of the aerosol-generating article. The proximal portion may be the portion of the article that is configured to be inserted into an aerosol-generating device.

[0161] The aerosol-generating article may further comprise a structural element disposed proximate to the aerosol-forming substrate, the structural element comprising longitudinal channels or porosity to allow an airflow path through the structural element.

[0162] The aerosol-forming substrate may be defined by its cross-section, and the structural element may have a similar or the same cross-section as the aerosol-forming substrate, for example a similar rectangular cross-section. The structural element may be a rectangular tube.

[0163] If desired, the structural elements may include corrugated elements, for example longitudinal channels within the aerosol-generating article defined by the corrugations of the corrugated elements.

[0164] The aerosol-generating article may comprise a first aerosol-forming substrate as disclosed herein that is at least partially disposed within the distal portion of the aerosol-generating article, and a second aerosol-forming substrate as disclosed herein that is at least partially disposed proximally to the first aerosol-forming substrate, for example within the proximal portion of the aerosol-generating article.

[0165] In some embodiments, an aerosol-generating article comprises multiple components including at least one aerosol-forming substrate as disclosed herein, a substantially hollow structural element, such as a hollow tube, and a mouthpiece element, such as a mouthpiece filter, which may be coaxially aligned and assembled within a wrapper or casing.

[0166] The aerosol-generating article has a length, a width, and a height. If desired, the length may be greater than the width. If desired, the width may be greater than the height.

[0167] The length of the article may be about 1.5 times the width, or about 2 times the width, or about 2.5 times the width, or about 3 times the width. The length may be greater than 3 times the width, such as greater than 4 times the width, or such as greater than 5 times the width.

[0168] The aerosol-generating article preferably has a substantially planar base. For example, the base may be defined by the substantially planar lower surface of the aerosol-forming substrate. In a preferred embodiment, the aerosol-generating article may be in the form of a three-dimensional shape that can be described as a cube or a rectangular parallelepiped.

[0169] The length of the article may be two or more times the height, for example three, four or five times the height, and optionally six or more times the height, for example ten, fifteen or twenty times the height.

[0170] The length of the article may be from 10mm to 50mm, such as from 12mm to 30mm, for example from 14mm to 26mm, for example from 16mm to 24mm, for example from 18mm to 22mm, for example about 18mm, or about 19mm, or about 20mm, or about 21mm, or about 22mm.

[0171] The width of the article may be from 5mm to 20mm, such as from 8mm to 18mm, for example from 10mm to 16mm, for example from 11mm to 15mm, for example from 12mm to 14mm, for example about 13mm.

[0172] The height of the article may be from 1 mm to 10 mm, such as from 1.2 mm to 8 mm, for example from 1.4 mm to 7 mm, for example from 1.6 mm to 6 mm, for example from 1.7 mm to 5 mm, for example about 1.7 mm, or about 4.5 mm, or about 2 mm, or about 3 mm, or about 4 mm.

[0173] The aerosol-generating article may comprise a first section and a second section removably connectable to the first section. The first section may comprise an aerosol-forming substrate as described herein, and the second section may be or comprise a mouthpiece. The second section may be a reusable mouthpiece designed for use with multiple first sections.

[0174] As noted above, the aerosol-generating article may be an aerosol-generating article for use in an aerosol-generating device to generate an inhalable aerosol, and may comprise an upstream article end and a downstream article end, and an article length extending from the upstream article end to the downstream article end. The aerosol-generating article may comprise or consist of an aerosol-forming substrate, such as any of the aerosol-forming substrates described herein.

[0175] The article or substrate may comprise a corrugated element. The corrugated element may comprise one or more perforations or holes for air flow through the corrugated element. An article airflow path extending from the upstream end of the article to the downstream end of the article may extend through the one or more perforations or holes. The one or more perforations or holes may be positioned in fluid communication with adjacent channels formed by the corrugations of the corrugated element. Advantageously, the perforations or holes may enable adjustment of the RTD of the article.

[0176] An article or substrate may comprise one or more corrugated elements that together extend along at least 50, 60, 70, 80, 90, 95, 98, or 99%, or substantially all, of the length of the article, which advantageously provides structural support to the article along a majority of the length of the article.

[0177] Alternatively, or in addition, the article or substrate may include one or more sheets of aerosol-forming material. At least one of the one or more sheets of aerosol-forming material, for example, each, may be less than 1 mm thick. The one or more sheets of aerosol-forming material may collectively extend along at least 50, 60, 70, 80, 90, 95, 98, or 99%, or substantially the entire length of the article. Advantageously, this allows the aerosol-generating article to contain more aerosol-forming material and thus last longer during use. Furthermore, advantageously, using a long, thin sheet of aerosol-forming material may result in a smaller temperature gradient across the aerosol-forming material compared to a shorter, thicker plug of aerosol-forming material.

[0178] In the context of the above two paragraphs and similar contexts, the term "extends together" or the like should not be interpreted as counting the overlapping length twice. Thus, for example, in an article having two elements spaced apart in the thickness or width direction, where one element originates from the upstream end and extends along 60% of the length of the article, and another element originates from the downstream end and extends along 60% of the length of the article, the elements, when combined, would extend along 100% of the length of the article, not 120% of the length of the article. Furthermore, two elements spaced apart along the length of the article are not considered to extend together along the length of the article across the gap between them. Thus, as an example, in an article having only two elements spaced apart along the length of the article, where one element originates from the upstream end and extends along 20% ​​of the length of the article, and another element originates from the downstream end and extends along 20% ​​of the length of the article, the elements, when combined, would extend along 40% of the length of the article, not 100% of the length of the article.

[0179] At least one, eg each, of the one or more sheets of aerosol-forming material may have a thickness of less than 1, 0.8, or 0.5 mm.

[0180] Optionally, each of the one or more sheets is less than 1 mm thick and the one or more sheets collectively extend along at least 50% of the length of the article. Optionally, each of the one or more sheets is less than 1 mm thick and the one or more sheets collectively extend along at least 70% of the length of the article. Optionally, each of the one or more sheets is less than 1 mm thick and the one or more sheets collectively extend along at least 90% of the length of the article. Optionally, each of the one or more sheets is less than 1 mm thick and the one or more sheets collectively extend along at least 95% of the length of the article. Optionally, each of the one or more sheets is less than 1 mm thick and the one or more sheets collectively extend along substantially all of the length of the article.

[0181] Optionally, each of the one or more sheets is less than 0.8 mm thick and the one or more sheets collectively extend along at least 50% of the length of the article. Optionally, each of the one or more sheets is less than 0.8 mm thick and the one or more sheets collectively extend along at least 70% of the length of the article. Optionally, each of the one or more sheets is less than 0.8 mm thick and the one or more sheets collectively extend along at least 90% of the length of the article. Optionally, each of the one or more sheets is less than 0.8 mm thick and the one or more sheets collectively extend along at least 95% of the length of the article. Optionally, each of the one or more sheets is less than 0.8 mm thick and the one or more sheets collectively extend along substantially all of the length of the article.

[0182] Optionally, each of the one or more sheets is less than 0.5 mm thick and the one or more sheets collectively extend along at least 50% of the length of the article. Optionally, each of the one or more sheets is less than 0.5 mm thick and the one or more sheets collectively extend along at least 70% of the length of the article. Optionally, each of the one or more sheets is less than 0.5 mm thick and the one or more sheets collectively extend along at least 90% of the length of the article. Optionally, each of the one or more sheets is less than 0.5 mm thick and the one or more sheets collectively extend along at least 95% of the length of the article. Optionally, each of the one or more sheets is less than 0.5 mm thick and the one or more sheets collectively extend along substantially all of the length of the article.

[0183] It may be particularly preferred that each of the one or more sheets is less than 0.8 mm thick and that the one or more sheets together extend along at least 70% of the length of the article, even more preferred that each of the one or more sheets is less than 0.5 mm thick and that the one or more sheets together extend along at least 80% of the length of the article, and most preferred that each of the one or more sheets is less than 0.5 mm thick and that the one or more sheets together extend along at least 90% or substantially the entire length of the article.

[0184] The aerosol-generating article may have an article airflow path extending from the upstream article end to the downstream article end of the article. The article or substrate may include a corrugated element. The corrugated element may be one of one or more of the corrugated elements described above. The transverse direction of at least a first portion of the corrugated element may be non-parallel to, and preferably substantially perpendicular to, one or both of the article length and at least a first portion of the article airflow path. Advantageously, this may allow the RTD of the article to be increased or adjusted.

[0185] The article airflow path may comprise the airflow path described in relation to the aerosol-forming substrate, and therefore the article airflow path may extend through the aerosol-forming substrate.

[0186] The article may have a substantially planar upper surface defined by a length extending in the x-direction and a width extending in the y-direction. The article may have a substantially planar lower surface defined by a length extending in the x-direction and a width extending in the y-direction. The substantially planar upper surface and the substantially planar lower surface may be vertically spaced apart from each other by a height defined in the z-direction. The transverse direction of at least a first portion of the corrugated elements may extend in the y-direction or the z-direction, or may be parallel. The transverse angle of at least a first portion of the corrugated elements may be at least 15, 30, 45, 60, or 75 degrees relative to one or both of the article length and at least a first portion of the article airflow path. The transverse direction of at least a first portion of the corrugated elements is preferably perpendicular to one or both of the article length and at least a first portion of the article airflow path. The first portion of the article airflow path may be at least partially defined by the first portion of the corrugated elements.

[0187] In technical fields where corrugation is common, such as corrugated paper or cardboard, there is a standard nomenclature for the three mutually perpendicular directions of a standard corrugation element. Those skilled in the art will understand this nomenclature, but a brief explanation is provided below nonetheless.

[0188] Standard corrugated elements are formed from a sheet, usually a rectangular sheet, that is bent or folded to have parallel corrugations of constant amplitude and wavelength. Standard corrugated elements extend in three mutually perpendicular directions: the machine direction, the cross direction, and the thickness direction.

[0189] While not wishing to be bound by any particular manufacturing method, the machine direction generally refers to the direction in which the material to be corrugated will be unwound from a roller to form a standard corrugation element, or will be fed into a roller, such as corrugated rollers 511 and 512 in FIG. 5, which are described in more detail below, to form the standard corrugation element. That is, for the resulting standard corrugation element, the machine direction refers to the direction extending from a point on the first corrugation peak to the nearest point on the adjacent corrugation peak. This direction is also sometimes referred to as the wavelength direction, since it is the same direction in which the wavelength of the corrugation will be measured.

[0190] For standard corrugation elements, the cross direction is perpendicular to the machine direction and extends along the corrugation peaks without change in amplitude, and is sometimes referred to herein as the longitudinal channel direction, since this is the same direction as the longitudinally extending channels formed between adjacent corrugations.

[0191] For standard corrugated elements, the thickness direction is perpendicular to the machine and cross directions and extends from the midpoint between two adjacent corrugation troughs to the nearest (i.e., opposite) corrugation peak. This direction is also sometimes referred to as the amplitude direction, since it is the same direction in which the amplitude of the corrugations is measured.

[0192] As one of ordinary skill in the art would understand after reading this disclosure, the above directions may also apply to non-standard corrugation elements, which at any point may have a local machine direction, a local cross direction, and a local thickness direction.

[0193] Any corrugated element or elements described herein may each be formed from a sheet that is bent or folded to form the corrugations. Any corrugated element or elements described herein may each be formed from a sheet that forms the corrugations by changing the sheet's orientation. The thickness of the sheet forming the corrugated element may vary by no more than 20, 10, or 5% across one or both of its length and width. The thickness of the sheet forming the corrugated element may be substantially constant. The thickness of the sheet forming the corrugated element may be less than 1, 0.8, or 0.5 millimeters. The thickness of the corrugated element may be at least two, three, or five times the minimum thickness of the sheet. All peaks of the corrugations of a corrugated element may have equal amplitudes. All troughs of the corrugations of a corrugated element may have equal amplitudes. All peaks and troughs of the corrugations of a corrugated element may have equal amplitudes. All corrugations of a corrugated element may have equal wavelengths.

[0194] The aerosol-generating article may be a planar aerosol-generating article. The aerosol-forming substrate may be a planar aerosol-forming substrate. As used herein, the term "planar" may refer to an element having two dimensions, e.g., length and width, each of which may be at least 2, 2.5, 3, 5, or 10 times the third dimension, e.g., thickness, and each of these three dimensions may be perpendicular to one another.

[0195] Thus, the aerosol-generating article may have both an article width and an article thickness perpendicular to the article length. The article width and the article length may each be at least 2, 2.5, 3, 5, or 10 times the article thickness. The aerosol-forming substrate may have both a substrate width and a substrate thickness perpendicular to the substrate length. The substrate width and the substrate length may each be at least 2, 2.5, 3, 5, or 10 times the substrate thickness.

[0196] The thickness of the article may be the smallest dimension of the article. The thickness of the article may be less than 7, 6, or 5 millimeters. The thickness of the substrate may be the smallest dimension of the substrate. The thickness of the substrate may be less than 7, 6, or 5 millimeters. Advantageously, a planar or thin article or substrate can reduce the maximum distance between the heater and the aerosol-forming material during use. This may advantageously result in a smaller temperature gradient across the aerosol-forming material, which may be heated high enough to form an aerosol at a given heater temperature, or may increase the proportion of the aerosol-forming material closest to the heater without significant risk of combustion.

[0197] The aerosol-forming substrate comprises a first planar layer. The corrugated element or one or more corrugated elements may be disposed on the first planar layer, for example, on a first or upper surface of the first planar layer. The corrugated element or one or more corrugated elements may have corrugation troughs adjacent to or in contact with the first planar layer, for example, the first surface of the first planar layer.

[0198] Optionally, in addition to the features of the above paragraph, the aerosol-forming substrate may further comprise a second planar layer. The corrugated element or one or more corrugated elements may be referred to as the first corrugated layer and may be disposed between the first and second planar layers. The corrugation peaks of the corrugated element or one or more corrugated elements may be adjacent to or in contact with the second planar layer, e.g., the second or lower surface of the second planar layer.

[0199] Optionally, in addition to the features of the above paragraph, the aerosol-forming substrate may further comprise a second corrugated layer including at least one of the one or more corrugated elements and / or one or more additional corrugated elements. The second corrugated layer may be disposed on the second planar layer, e.g., on the first or upper surface of the second planar layer. The corrugated element or the corrugation troughs of one or more corrugated elements of the second corrugated layer may be adjacent to or in contact with the second planar layer, e.g., on the first or upper surface of the second planar layer.

[0200] Optionally, in addition to the features of the above paragraphs, the aerosol-forming substrate may further comprise a third planar layer. The second planar layer may be disposed between the first and third planar layers. The peaks of the corrugations of the corrugated elements or of one or more corrugation elements of the second corrugated layer may be adjacent to or in contact with the second or lower surface of the third planar layer. Such an aerosol-forming substrate is shown in Figure 22 and described below.

[0201] Features described herein in relation to the planar layer may be applicable to the first, second and third planar layers in the above four paragraphs.

[0202] The one or more corrugated elements of the article or substrate may comprise at least two, three, four, or five corrugated elements. Advantageously, this may provide structural support only to portions of the article or substrate where support is needed, even when those parts are spaced apart. Advantageously, the use of two or more corrugated elements may allow different corrugated elements to be used to provide different levels of structural support or to serve different purposes, such as providing structural support and providing aerosol-forming material.

[0203] At least one of the at least two corrugated elements may be positioned partially or completely downstream of another of the at least two corrugated elements. When there are at least a corrugated element and a second and a third corrugated element, the second corrugated element may be partially or completely upstream of the first corrugated element, and the third corrugated element may be partially or completely downstream of the first corrugated element. The transverse direction of at least a portion of the second corrugated element may be non-parallel, e.g., perpendicular, to the transverse direction of at least a portion of the first corrugated element. The transverse direction of at least a portion of the third corrugated element may be non-parallel, e.g., perpendicular, to the transverse direction of at least a portion of the first corrugated element. Again, this may advantageously provide different levels of structural support in different regions within an article or substrate. This may also advantageously allow for easy tailoring of the airflow path, and in particular the local RTD, in different regions of the article or substrate.

[0204] As an example, the at least two corrugated elements may include a first corrugated element, a second corrugated element, and a third corrugated element. The transverse direction of at least a portion of the first corrugated element may be substantially parallel to one or both of the article airflow path and the article length. The first corrugated element may advantageously provide structural support at or near the upstream end of the article or substrate. The second corrugated element may be disposed partially or completely downstream of the first corrugated element. The transverse direction of at least a portion of the second corrugated element may be substantially perpendicular to one or both of the article airflow path and the article length. The second corrugated element may include holes or perforations to allow air to flow through the second corrugated element. The second corrugated element may advantageously increase or adjust the RTD of the article or substrate. The third corrugated element may be disposed partially or completely downstream of the second corrugated element. The transverse direction of at least a portion of the third corrugated element may be substantially parallel to one or both of the article airflow path and the article length. The third corrugated element may advantageously enable cooling of the aerosol at or near the downstream end of the article or substrate, and may advantageously provide structural support at or near the downstream end of the article or substrate.

[0205] Alternatively, or in addition, at least one of the at least two corrugated elements may not be located upstream or downstream of another of the at least two corrugated elements, e.g., the two corrugated elements may be in different airflow paths through the article or substrate, or at least one of the two corrugated elements may not be located in an airflow path through the article or substrate.

[0206] The corrugated element, or at least one, for example all, of the one or more corrugated elements, may comprise one or more perforations or holes, which may allow air to flow through the corrugated element or elements.

[0207] Any corrugated element described herein may comprise corrugations along at least 50, 60, 70, 80, or 90% of the transverse dimension of the corrugated element, or along substantially the entire dimension. Any corrugated element described herein may comprise corrugations along at least 50, 60, 70, 80, or 90% of the machine direction dimension of the corrugated element, or along substantially the entire dimension. Any corrugated element described herein may comprise at least 3, 5, or 10 corrugation peaks. Any corrugated element described herein may comprise at least 3, 5, or 10 corrugation troughs.

[0208] As one skilled in the art will understand after reading this disclosure, features previously described in relation to an aerosol-forming substrate may also be applicable to an aerosol-generating article. Also, features described in relation to a particular component of a substrate may also be applicable to the same particular component of the article. Thus, merely by way of example, features described in relation to the corrugated elements or aerosol-forming material of a substrate may also be applicable to the corrugated elements or aerosol-forming material of an article, respectively.

[0209] According to the present disclosure, an aerosol-generating device for housing an aerosol-forming article as disclosed herein or an aerosol-forming substrate as disclosed herein may comprise a cavity sized to house at least a portion of the aerosol-generating article or aerosol-forming substrate, a heater or heating means, a power source for supplying power to the heater or heating means, and a controller for controlling the supply of power to the heater or heating means. The aerosol-generating device is configured to heat the aerosol-forming substrate, for example an aerosol-forming substrate that is a component of the aerosol-generating article, to form an aerosol, for example an inhalable aerosol.

[0210] The cavity may have an opening through which the distal end of the aerosol-generating article can be inserted. The cavity may have any suitable cross-sectional shape. For example, the cavity may have a rectangular cross-section, e.g., a rectangular cross-section having opposing top and bottom sides that are longer in length than the left and right sides.

[0211] Preferably, at least one interior surface of the cavity is a heated surface configured to heat the aerosol-generating article. The heated surface may comprise a heater, such as a resistive heater or an infrared heater, or a susceptor configured to be heated by engagement with an inductor. The heated surface may comprise an inductor, e.g., a coil arranged to generate a fluctuating electromagnetic field within the cavity's space. The heated surface may be a surface transparent to the fluctuating electromagnetic field, such that an inductor arranged outside the cavity can project a fluctuating electromagnetic field through the heated surface to engage a susceptor arranged within the cavity.

[0212] Preferably, at least the lower surface of the cavity is a heated surface configured to heat the aerosol-generating article. Optionally, both the lower and upper surfaces of the cavity are heated surfaces configured to heat the aerosol-generating article.

[0213] Preferably, at least the lower inner surface of the cavity is substantially planar, and preferably both the lower and upper inner surfaces of the cavity are substantially planar. Preferably, the upper and lower inner surfaces of the cavity are arranged in parallel relationship to each other.

[0214] Optionally, the upper and lower inner surfaces converge along the length of the cavity such that they are slightly closer together at the distal end of the cavity than at the proximal end of the cavity. This may allow the cavity to grip an aerosol-generating article inserted therein. The inner surfaces of the side surfaces may similarly converge, resulting in gripping of the aerosol-generating article. The lower and lower inner surfaces of the cavity, and / or opposing side surfaces of the cavity, may converge by 1 to 10 degrees, for example, 2 to 8 degrees, for example, 3 to 6 degrees, for example, 4 to 5 degrees, between the proximal end of the cavity and the distal end of the cavity.

[0215] In some embodiments, the lower and upper inner surfaces may be movable relative to one another. For example, the lower and upper inner surfaces may be configured to pivot relative to one another or to move up and down relative to one another. This may allow for easy insertion of an aerosol-forming substrate or aerosol-generating article into the cavity while simultaneously moving the walls of the cavity to hold the substrate or article in place for heating. For example, relative movement of the upper and lower inner surfaces may allow the aerosol-generating article to be gripped between the two surfaces, facilitating heating of the article and facilitating proper placement of the article within the device.

[0216] The cavity may be defined by a longitudinal dimension or length, a transverse dimension or width, and a depth dimension or height, where the length and width are preferably greater than the height, for example at least twice the height.

[0217] The apparatus may include a heating surface including multiple separately operable heating zones, for example, two separately operable heating zones, or three separately operable heating zones, or four separately operable heating zones, or five separately operable heating zones, or six separately operable heating zones. The multiple separately operable heating zones may be configured to operate individually or simultaneously in any combination of two or more zones. In some examples, the multiple separately operable heating zones may be longitudinally spaced apart within the cavity. In some examples, the multiple separately operable heating zones may be transversely spaced apart within the cavity. Different heating zones may be spaced apart from one another both transversely and longitudinally. Different heating zones may be concentrically arranged with respect to one another.

[0218] The apparatus may comprise one or more resistive heaters, for example one or more resistive heaters embedded in the walls of the cavity.

[0219] The apparatus may include one or more inductors, for example, one or more inductors incorporated into or positioned to generate a varying electromagnetic field within or within the walls of the cavity, the one or more walls of the cavity comprising or consisting of a susceptor material, such that the one or more walls of the cavity are heated by engagement with the varying electromagnetic field, thereby heating an aerosol-generating article inserted within the cavity.

[0220] The device may comprise one or more insertable heating elements arranged for insertion into the aerosol-generating article so as to protrude into a cavity. The insertable heating elements may be arranged for insertion into channels defined in the aerosol-generating article, for example into channels formed by a corrugated structure of the aerosol-generating article.

[0221] The insertable heating element may be a resistance heater. The insertable heating element may be a susceptor.

[0222] The aerosol generating device may comprise a device body. The device body may comprise a heater. The aerosol generating device may comprise a mouthpiece element. The device body may comprise a device body housing. The device body housing may define a cavity for receiving at least a portion of the aerosol-generating article. The device body and the mouthpiece element may be removably connectable. The mouthpiece element may be removably connectable to the device body, for example to the device body housing.

[0223] The mouthpiece element may be removably coupleable to the device body, e.g., the device body housing, between a coupled position and a detached position. In the coupled position, the cavity may be at least partially covered, e.g., by the mouthpiece element. In the detached position, the cavity may be at least partially exposed, e.g., to allow for insertion of an article into the cavity. The mouthpiece element may be movable, e.g., pivotable about a hinge, relative to the device body, e.g., between a first position and a second position. In the first position, the cavity may be at least partially covered, e.g., by the mouthpiece element. In the second position, the cavity may be at least partially exposed, e.g., to allow for insertion of an article into the cavity. Advantageously, covering the cavity or the article within the cavity may ensure that most aerosol from the article reaches the user along a desired flow path rather than leaking into the external environment.

[0224] The device, e.g., the device body, may include a power source, e.g., a battery. In use, the power source can provide power to the heater. The device, e.g., the device body, may include a controller. The controller may be configured to control power from the power source to the heater.

[0225] The device body may have a distal end and a proximal end. The cavity may be defined in the proximal end of the device body. The mouthpiece element may have a proximal end and a distal end. The distal end of the mouthpiece element may be configured to be removably connected to the proximal end of the device body.

[0226] The mouthpiece element, or at least a portion of the mouthpiece element, may be configured to be inserted into a user's mouth. A proximal end of the mouthpiece element may be configured to be inserted into a user's mouth.

[0227] The device, e.g., one or both of the device body and the mouthpiece element, may include an air inlet. The device, e.g., the mouthpiece element, may include an air outlet. The device may include an airflow path fluidly connecting the air inlet to the air outlet. The airflow path may extend through one or both of the cavity and through the cavity. Thus, in use, the device may be configured such that when negative pressure is applied to the air outlet, e.g., by a user sucking on the air outlet, air is drawn through the air inlet and then through the aerosol-generating article contained within the cavity, thereby entraining aerosol emitted from the aerosol-forming substrate of the article and exiting through the air outlet.

[0228] According to the present disclosure, an aerosol generating system comprises an aerosol generating device as disclosed herein and an aerosol-generating article as disclosed herein. The system may comprise a plurality of such articles for use with the aerosol generating device.

[0229] As used herein, the term "aerosol-generating article" may refer to an article that is capable of generating or emitting an aerosol.

[0230] The term "aerosol-forming substrate" as used herein may refer to a substrate capable of emitting an aerosol or volatile compound capable of forming an aerosol. Such a volatile compound may be emitted by heating the aerosol-forming substrate. The aerosol-forming substrate may comprise an aerosol-forming material. The aerosol-forming substrate may be adsorbed, coated, impregnated, or loaded onto a carrier or support. The aerosol-forming substrate may conveniently be part of an aerosol-generating article or a smoking article.

[0231] As used herein, the term "aerosol-generating device" may refer to a device for use with an aerosol-generating article to enable the generation or emission of an aerosol.

[0232] As used herein, the term "aerosol generation system" refers to the combination of an aerosol generation device and one or more aerosol-forming articles for use with the device. The aerosol generation system may include additional components, such as an electrically operated aerosol generator or a charging unit for recharging an on-board power supply in an electric aerosol generator.

[0233] As used herein, the term "aerosol former" may refer to any suitable known compound or mixture of compounds that, upon use, facilitates the formation of an aerosol. The aerosol may be a dense and stable aerosol. The aerosol may be substantially resistant to thermal decomposition at the operating temperature of the aerosol-forming substrate or aerosol-generating article.

[0234] As used herein in connection with the present invention, the term "nicotine" is used to describe nicotine, nicotine base, or nicotine salts.

[0235] As used herein in connection with the present invention, the terms "proximal," "distal," "upstream," and "downstream" are used to describe the relative positions of components or portions of components of the cartridge and aerosol generation system.

[0236] As used herein, the term "longitudinal," when used with respect to the orientation of an aerosol-generating article, refers to a direction corresponding to the main longitudinal axis of the aerosol-generating article, which may extend between the upstream and downstream ends of the aerosol-generating article. During use, air may be drawn longitudinally through the aerosol-generating article.

[0237] As used herein, the term "longitudinal" may refer to the direction of the corrugation element, or, when used in reference to longitudinally extending components of the corrugation element (e.g., longitudinally extending channels), the direction across the corrugation element.

[0238] As used herein, the term "sheet" refers to a layered element having a width and length that are substantially greater than its thickness. The width of the sheet is greater than 10 mm, preferably greater than 20 mm or 30 mm. In some embodiments, sheets of material for use in forming the aerosol-forming substrates described herein can have a thickness of from 10 μm to about 1000 μm, e.g., from 10 μm to about 800, 500, or 300 μm.

[0239] As used herein, "susceptor" means an electrically conductive element that heats when subjected to a varying magnetic field, which may be the result of eddy currents and / or hysteresis losses induced in the susceptor element.

[0240] As used herein, the term "homogenized tobacco material" encompasses any tobacco material formed by agglomeration of particles of tobacco material. A sheet or web of homogenized tobacco material is formed by agglomerating particulate tobacco obtained by grinding or otherwise pulverizing one or both of tobacco lamina and tobacco stems. In addition, homogenized tobacco material may contain one or more small amounts of tobacco dust, tobacco fines, and other particulate tobacco by-products formed during tobacco processing, handling, and shipping. A sheet of homogenized tobacco material may be produced by casting, extrusion, a papermaking process, or any other suitable process known in the art.

[0241] The term "cast leaf" refers to a product made by a casting process based on casting a slurry containing plant particles (e.g., clove particles, or a mixture of tobacco and clove particles) and a binder (e.g., guar gum) onto a support surface (e.g., a belt conveyor), drying the slurry, and removing the dried sheet from the support surface. Examples of cast or cast leaf processes are described, for example, in U.S. Pat. No. 5,724,998 for making cast leaf tobacco. In the cast leaf process, particulate plant material is produced by pulverizing, grinding, or comminuting plant parts. Particles produced from one or more plant bodies are mixed with a liquid component, typically water, to form a slurry. Other components in the slurry may include fibers, binders, and aerosol formers. The particulate plant material may be agglomerated in the presence of a binder. The slurry is cast onto a support surface and dried into a sheet of homogenized plant material. Preferably, the homogenized plant material used in the article according to the present invention can be produced by casting. Such homogenized plant material may include agglomerated particulate plant material.

[0242] As used herein, withdrawal resistance is expressed in units of pressure "mmH2O or mmWG" or "millimeters of water column" and is measured in accordance with ISO 6565:2002. [Example]

[0243] The present invention is defined in the claims. However, the following provides a non-exhaustive list of non-limiting examples. Any one or more features of these examples may be combined with any one or more features of other examples, embodiments, or aspects described herein.

[0244] Example 1 An aerosol-forming substrate comprising an aerosol-forming material for generating an aerosol, the aerosol-forming substrate having a base defined by an x-dimension extending in the x-direction and a y-dimension extending in the y-direction, and a height defined by a z-dimension extending in the z-direction. Example 1A. A substantially planar aerosol-forming substrate, such as the substrate described in Example 1, comprising an upper layer and a lower layer arranged as substantially parallel planes separated by an intermediate or separating layer positioned between the upper and lower layers, the intermediate or separating layer comprising or consisting of one or more separating members extending between the upper surface of the lower layer and the lower surface of the upper layer. Example 1B. The substrate of Example 1A, wherein the one or more separating members comprise or consist of pillars separating the upper layer from the lower layer. Example 1C. The substrate of Example 1A or Example 1B, wherein the intermediate or separating layer comprises a plurality of individual separating members. Example 1D. The substrate of either Example 1A or Example 1B, wherein the intermediate or separating layer comprises a single separating member. Example 1E. The substrate of any of Examples 1A-1D, wherein the intermediate or separating layer comprises a separating member having a plurality of upwardly extending portions supporting a lower surface of the upper layer and a plurality of downwardly depending portions supporting an upper surface of the lower layer. Example 1F. The substrate of any of Examples 1A-1E, wherein the intermediate or separating layer comprises a mesh or foam. Example 1G. The substrate of any of Examples 1A-1F, wherein one or more separating members are formed as a textured or embossed sheet having upwardly depending protrusions and downwardly depending protrusions. Example 1H. The substrate of any of Examples 1A-1G, wherein an airflow path is defined through the substrate between the upper and lower layers. Example 1I. The substrate of any of Examples 1A-1H, wherein the intermediate layer or separating layer is a sinusoidal surface, e.g., the intermediate layer or separating layer has a surface or profile obtained, e.g., by translating a first periodic curve perpendicularly relative to a second periodic curve, e.g., by translating a first continuous periodic curve perpendicularly relative to a second continuous periodic curve, e.g., by translating a first sinusoidal curve perpendicularly relative to a second sinusoidal curve. Example 1J. The substrate of Example 1I, wherein the middle or separating layer is shaped like an egg carton. Example 1K. The substrate of any of Examples 1E-1J, wherein the upwardly extending portion and / or the downwardly depending portion have a substantially circular or substantially rectangular planar profile. Example 2. An aerosol-forming substrate comprising an aerosol-forming material for generating an aerosol, the aerosol-forming substrate being a planar aerosol-forming substrate having a base defined by a length extending in the x-direction, a width extending in the y-direction, and a height extending in the z-direction. Example 2A. A substantially planar aerosol-forming substrate, such as the substrate described in Examples 1-2, comprising an upper layer and a lower layer arranged as substantially parallel planes separated by an intermediate or separating layer positioned between the upper and lower layers, the separating layer comprising or consisting of one or more separating members extending between an upper surface of the lower layer and a lower surface of the upper layer. Example 2B. The substrate of Example 2A, wherein the separating members are ribs or posts that separate the upper layer from the lower layer. Example 2C. The substrate of either Example 2A or Example 2B, wherein the separating members are longitudinally extending separating members. Example 2D. The substrate of any of Examples 2A-2C, wherein each of the separating members forms a line of contact between the separating member and one or both of the upper layer and lower layer. Example 2E. The substrate of any of Examples 2A-2D, wherein each separating member has a length dimension that is greater than its width and a width dimension that is greater than its thickness. Example 2F. The substrate of any one of Examples 2A to 2E, wherein the upper and lower layers are spaced apart by the width of the separating member. Example 2G. The substrate of any of Examples 2A-2F, wherein at least one separating member is twisted laterally, e.g., such that at least one separating member is twisted laterally so that it can stand freely on an edge, e.g., such that at least one separating member is twisted laterally so that it can stand free on an edge, e.g., such that a width dimension of the separating member extends perpendicular to the surface on which the separating member stands. Example 2H. The aerosol-forming substrate of any of Examples 2A to 2G, having a base defined by an x-dimension extending in the x-direction and a y-dimension extending in the y-direction, and a height defined by a z-dimension extending in the z-direction. Example 2I. The substrate of Example 2H, wherein the width of the extension member extends in the z-direction of the substrate. Example 2J. The substrate of Example 2H or Example 2I, wherein the length of the extension member extends in the x-direction or the y-direction. Example 3 An aerosol-forming substrate comprising an aerosol-forming material for generating an aerosol, the aerosol-forming substrate having a substantially planar upper surface defined by a length extending in the x-direction and a width extending in the y-direction, and a substantially planar lower surface defined by a length extending in the x-direction and a width extending in the y-direction, the substantially planar upper surface and the substantially planar lower surface being spaced apart vertically from each other by a height defined in the z-direction. Example 3A. 1. An aerosol-forming substrate comprising an aerosol-forming material for generating an aerosol, the aerosol-forming substrate having a base defined by x and y dimensions and a height defined by a z dimension, an airflow path defined through the aerosol-forming substrate from one side of the aerosol-forming substrate to the other side of the aerosol-forming substrate in the x / y plane, and a resistance to draw (RTD) along the airflow path of the substrate of less than 20 millimeters HO. Example 3B. An aerosol-forming substrate such as the aerosol-forming substrate described in any of Examples 1 to 3A, wherein the aerosol-forming substrate is a substantially planar aerosol-forming substrate comprising an upper layer and a lower layer, the upper layer and the lower layer being arranged in substantially parallel planes separated by an intermediate or separating layer positioned between the upper layer and the lower layer, the separating layer comprising or consisting of corrugated elements formed from a corrugated sheet having a triangular corrugated profile. Example 3C. The substrate described in Example 3B, wherein an airflow path is defined through the aerosol-forming substrate between the upper and lower layers. Example 3D. The substrate of Example 3A or Example 3B, wherein the corrugation peaks of the corrugated elements form contact lines between the separating layer and the top layer. Example 3E. The substrate of Example 3D, wherein less than 5% of the area of ​​the underside of the top layer is in physical contact with the separating layer, eg, less than 4% or less than 3% or less than 2%. Example 3F. The substrate of either Example 3B or Example 3E, wherein the corrugation troughs of the corrugated elements form a contact line between the separation layer and the top layer. Example 3G. The substrate of Example 3F, wherein less than 5% of the area of ​​the upper surface of the underlayer is in physical contact with the separating layer, such as less than 4% or less than 3% or less than 2%. Example 3H. The substrate of any of Examples 3B through 3G, wherein the separation layer comprises or consists of a corrugated sheet of paper. Example 4. An aerosol-forming substrate according to any of Examples 1 to 3H, wherein an airflow path is defined through the aerosol-forming substrate from one side of the aerosol-forming substrate to the other side of the aerosol-forming substrate in the x / y plane, and wherein the aerosol-forming substrate has a withdrawal resistance in the direction of the airflow path of less than 20 mm HO, such as less than 10 mm HO, for example less than 8 mm HO, such as less than 6 mm HO, for example less than 4 mm HO, or preferably less than 2 mm HO. Example 4A. 5. The aerosol-forming substrate according to any one of Examples 1 to 4, wherein the aerosol-forming substrate has a withdrawal resistance in at least one direction in the x / y plane of the aerosol-forming substrate of less than 20 mm H2O, for example less than 10 mm H2O. Example 5. The aerosol-forming substrate according to any one of Examples 1 to 4A, wherein the aerosol-forming substrate has a withdrawal resistance in a direction perpendicular to the z-direction of less than 20 mm H2O, such as less than 10 mm H2O. Example 6 6. The aerosol-forming substrate according to any one of Examples 1 to 5, wherein an airflow path is defined through the aerosol-forming substrate along the x-direction from one side of the aerosol-forming substrate to the other side of the aerosol-forming substrate, such that the aerosol-forming substrate has a withdrawal resistance in the x-direction of less than 20 mm HO, for example less than 10 mm HO. Example 7 7. The aerosol-forming substrate according to any one of Examples 1 to 6, wherein an airflow path is defined through the aerosol-forming substrate along the y direction from one side of the aerosol-forming substrate to the other side of the aerosol-forming substrate, such that the aerosol-forming substrate has a withdrawal resistance in the y direction of less than 20 millimeters HO, for example less than 10 millimeters HO. Example 8 8. The aerosol-forming substrate according to any one of Examples 4 to 7, wherein the withdrawal resistance is between 9.9 millimeters HO and 0 millimeters HO, for example between 8 millimeters HO and 1 millimeter HO, or between 6 millimeters HO and 2 millimeters HO, or between 5 millimeters HO and 3 millimeters HO. Example 9. An aerosol-forming substrate according to any of Examples 1 to 8, wherein an airflow path is defined through the aerosol-forming substrate from one side of the aerosol-forming substrate to the other side of the aerosol-forming substrate in the x / y plane, and wherein the aerosol-forming substrate has a porosity of more than 60%, for example more than 80%, in the direction of the airflow path. Example 9i. An aerosol-forming substrate according to any one of Examples 1 to 9, wherein the aerosol-forming substrate has a porosity of more than 60%, such as more than 80%, in at least one direction in the x / y plane of the aerosol-forming substrate. Example 10. The aerosol-forming substrate according to any one of Examples 1 to 9i, wherein the aerosol-forming substrate has a porosity perpendicular to the z-direction of more than 60%, such as more than 80%. Example 11 For example, the aerosol-forming substrate according to any one of Examples 1 to 10, excluding Example 7, wherein an airflow path is defined through the aerosol-forming substrate along the x direction from one side of the aerosol-forming substrate to the other side of the aerosol-forming substrate, such that the aerosol-forming substrate has a porosity in the x direction of more than 60%, for example more than 80%. Example 12 The aerosol-forming substrate according to any one of Examples 1 to 11, excluding Examples 6 and 11, wherein an airflow path is defined through the aerosol-forming substrate along the y direction from one side of the aerosol-forming substrate to the other side of the aerosol-forming substrate, such that the aerosol-forming substrate has a porosity in the y direction of more than 60%, for example more than 80%. Example 13 The aerosol-forming substrate according to any one of Examples 9 to 12, having a porosity of 81% to 99%, for example a porosity of 85% to 95%, for example 88% to 92%, for example about 90%. Example 14. 14. The aerosol-forming substrate of any of Examples 1 to 13, wherein the substrate comprises an upper layer defining an upper surface and a lower layer defining a lower surface, and an airflow path is defined between the upper layer and the lower layer through the aerosol-forming substrate. Example 15. 15. The aerosol-forming substrate of any of Examples 1 to 14, wherein the substrate comprises an upper layer defining an upper surface and a lower layer defining a lower surface, and an airflow path is defined between the upper layer and the lower layer through the aerosol-forming substrate from one side to the other. Example 16. 16. The aerosol-forming substrate of any of Examples 1 to 15, wherein the substrate comprises an upper layer defining an upper surface and a lower layer defining a lower surface, and wherein an airflow path is defined between the upper and lower layers in the x / y plane through the aerosol-forming substrate from one side to the other. Example 17. 17. The aerosol-forming substrate of example 16, wherein a plurality of channels are defined through the aerosol-forming substrate between the upper surface and the lower surface. Example 18. 18. The aerosol-forming substrate according to any one of Examples 16 to 17, wherein the aerosol-forming substrate comprises an intermediate or separating layer positioned between an upper layer and a lower layer. Example 19. An aerosol-forming substrate as described in example 18, wherein the intermediate or separating layer comprises one or more ribs or struts separating the upper layer from the lower layer, preferably the ribs or struts extending in the direction of an airflow path defined through the aerosol-forming substrate. Example 20. 20. The aerosol-forming substrate of any of Examples 1-19, comprising a corrugated element, for example a corrugated sheet of material. Example 21. 19. The aerosol-forming substrate of example 18, wherein the separating layer comprises or consists of a corrugated element, such as a corrugated sheet of material. Example 22. 22. The aerosol-forming substrate of any one of Examples 1 to 21, wherein the aerosol-forming substrate comprises an upper layer, a lower layer, and an intermediate or separating layer positioned between the upper and lower layers, the separating layer comprising one or more corrugated elements. Example 23. 23. The aerosol-forming substrate of example 22, wherein the one or more corrugated elements define a plurality of airflow channels extending through the aerosol-forming substrate. Example 24. 24. The aerosol-forming substrate of example 22 or 23, wherein the aerosol-forming substrate comprises a plurality of corrugated elements, two or more of the plurality of corrugated elements being disposed between the upper layer and the lower layer in a mutually perpendicular relationship. Example 25. 25. The aerosol-forming substrate of example 24, wherein the aerosol-forming substrate comprises an upper corrugated element positioned in contact with the upper layer and a lower corrugated element positioned in contact with the lower layer. Example 26. 26. The aerosol-forming substrate of example 25, further comprising at least one additional corrugated element disposed between the upper and lower corrugated elements. Example 27. 27. The aerosol-forming substrate of any one of Examples 22 to 26, wherein the aerosol-forming substrate comprises a plurality of corrugated elements, two or more of the plurality of corrugated elements being arranged side by side in the lateral direction of each other between the upper layer and the lower layer. Example 28. 27. The aerosol-forming substrate of any one of Examples 22 to 26, wherein the aerosol-forming substrate comprises a plurality of corrugated elements, two or more of the plurality of corrugated elements being arranged in a lateral end-to-end relationship between the upper and lower layers. Example 29. 29. The aerosol-forming substrate according to any one of examples 1 to 28, wherein the aerosol-forming substrate has a proximal end and a distal end, and an airflow path is defined between the proximal end and the distal end. Example 30. 30. The aerosol-forming substrate of Example 29, wherein the airflow direction extends between the proximal end and the distal end, and the airflow path is defined by at least one corrugated element aligned substantially parallel to the airflow direction, and the ridges and troughs of the at least one corrugated element. Example 31. 31. The aerosol-forming substrate of Example 30, wherein the aerosol-forming substrate comprises a first corrugated element disposed at or towards the proximal end and a second corrugated element disposed at or towards the distal end, e.g., the first and second corrugated elements are disposed in a transverse end-to-end relationship between the upper and lower layers, and each corrugated element is aligned substantially parallel to the airflow direction. Example 32. The aerosol-forming substrate of any one of Examples 1 to 31, comprising an upper layer, a lower layer, and an intermediate layer disposed between the upper and lower layers, wherein the upper layer comprises or consists of an aerosol-forming material, and the lower and intermediate layers do not comprise an aerosol-forming material. Example 33. 32. The aerosol-forming substrate of any one of Examples 1 to 31, comprising an upper layer, a lower layer, and an intermediate layer disposed between the upper and lower layers, wherein the lower layer comprises or consists of an aerosol-forming material, and the upper and intermediate layers do not comprise an aerosol-forming material. Example 34. 32. The aerosol-forming substrate of any one of Examples 1 to 31, comprising an upper layer, a lower layer, and an intermediate layer disposed between the upper and lower layers, wherein the intermediate layer comprises or consists of an aerosol-forming material, and the upper and lower layers do not comprise an aerosol-forming material. Example 35. The aerosol-forming substrate of any of Examples 1 to 31, comprising an upper layer, a lower layer, and an intermediate layer disposed between the upper and lower layers, wherein the lower layer comprises or consists of a first aerosol-forming material, the upper layer comprises or consists of a second aerosol-forming material, and the intermediate layer does not comprise an aerosol-forming material. Example 36. 32. The aerosol-forming substrate of any one of Examples 1 to 31, comprising an upper layer, a lower layer, and an intermediate layer disposed between the upper and lower layers, wherein the lower layer comprises or consists of a first aerosol-forming material, the intermediate layer comprises or consists of a second aerosol-forming material, and the lower layer does not comprise an aerosol-forming material. Example 37. 32. The aerosol-forming substrate of any one of Examples 1 to 31, comprising an upper layer, a lower layer, and an intermediate layer disposed between the upper and lower layers, wherein the upper layer comprises or consists of a first aerosol-forming material, the intermediate layer comprises or consists of a second aerosol-forming material, and the upper layer does not comprise an aerosol-forming material. Example 38. 32. The aerosol-forming substrate of any of Examples 1 to 31, comprising an upper layer, a lower layer, and an intermediate layer disposed between the upper and lower layers, wherein the upper layer comprises or consists of a first aerosol-forming material, the intermediate layer comprises or consists of a second aerosol-forming material, and the lower layer comprises or consists of a third aerosol-forming material. Example 39. 39. The aerosol-forming substrate of any of Examples 32 to 38, wherein the top layer comprises or is formed from a planar sheet of material, the bottom layer comprises or is formed from a planar sheet of material, and the middle layer comprises or is formed from a corrugated sheet of material. Example 40. The aerosol-forming substrate of any one of Examples 1 to 39, comprising a first aerosol-forming material and a second aerosol-forming material. Example 41. The aerosol-forming substrate of example 40, further comprising a third aerosol-forming material. Example 42. 41. The aerosol-forming substrate of any of examples 40, wherein the first aerosol-forming material is the same material as the second aerosol-forming material. Example 43. The aerosol-forming substrate of example 41, wherein the first aerosol-forming material is the same material as the third aerosol-forming material, e.g., the first, second, and third aerosol-forming materials are all the same aerosol-forming material. Example 44. The aerosol-forming substrate of example 40, wherein the first aerosol-forming material is different from the second aerosol-forming material, e.g., has a different composition than the second aerosol-forming material, e.g., has a different aerosol former content or a different flavor content. Example 45. The aerosol-forming substrate of example 41, wherein the first aerosol-forming material is different from the third aerosol-forming material, e.g., different in composition from the second aerosol-forming material, e.g., different aerosol former content or different flavor content, e.g., the first, second, and third aerosol-forming materials are all different materials. Example 46. The aerosol-forming substrate of any of Examples 1 to 45, wherein the aerosol-forming material is a homogenized tobacco material, for example, any of the first, second, or third aerosol-forming material is a homogenized tobacco material. Example 47. An aerosol-forming substrate according to any one of Examples 1 to 46, comprising an upper layer, a lower layer, and a separating or intermediate layer disposed between the upper and lower layers, the intermediate layer being fixed to at least one of the upper and lower layers by an adhesive. Example 48. The aerosol-forming substrate of example 47, wherein the adhesive is an aerosol-forming material, e.g., the adhesive is a homogenized tobacco slurry, or the adhesive is or comprises a flavorant and / or an aerosol former. Example 49. 49. The aerosol-forming substrate of example 47 or 48, wherein the intermediate layer comprises or consists of corrugated elements. Example 50. 50. An aerosol-forming substrate according to any of examples 1 to 49, wherein the airflow path is defined through the substrate by channels formed by longitudinally extending corrugations of the corrugated elements. Example 51. 51. An aerosol-forming substrate as described in example 50, wherein the porous material is disposed within channels formed by the longitudinally extending corrugations. Example 52. 52. The aerosol-forming substrate of example 51, wherein the porous material comprises or consists of an aerosol-forming material. Example 53. 53. An aerosol-forming substrate according to example 51 or 52, wherein the porous material comprises a flavoring agent. Example 54. 54. An aerosol-forming substrate according to any of Examples 50 to 53, wherein a flavorant is disposed within channels formed by the longitudinally extending corrugations and releases flavor, e.g., flavor threads and / or one or more flavor capsules, upon heating. Example 55. An airflow path, or an aerosol-forming substrate according to any one of Examples 1 to 54, wherein the airflow path is defined through the aerosol-forming substrate from one side of the aerosol-forming substrate to the other side of the aerosol-forming substrate in the x / y plane. Example 56. An aerosol-forming substrate according to example 55, wherein the airflow path is through a filter or mesh, or a porous material, such as porous paper, for example tea bag material, incorporated into the aerosol-forming substrate. Example 57. An aerosol-forming substrate as described in example 56, wherein a filter or mesh, or porous paper, such as a porous material, such as tea bag material, is positioned transverse to the airflow path, for example across the proximal or downstream end of the aerosol-forming substrate. Example 58. An aerosol-forming substrate according to any one of Examples 1 to 57, comprising a substantially planar layer and a corrugated layer fixed to a surface of the substantially planar layer, such that longitudinal channels formed by the longitudinally extending corrugations of the corrugated layer extend in the planar direction of the substantially planar layer. Example 59. 59. The aerosol-forming substrate of any of Examples 1-58, comprising an upper layer, a lower layer, and an intermediate layer, wherein at least one of the upper and lower layers comprises perforations or holes such that at least a portion of the air can flow through the upper and / or lower layer. Example 60. 60. The aerosol-forming substrate of example 59, wherein the aerosol-forming substrate has a proximal or mouth end and a distal end, and the perforation or hole is located in a central portion of the aerosol-forming substrate, for example, approximately halfway between the proximal or mouth end and the distal end. Example 61. An aerosol-forming substrate as described in Example 59 or 60, wherein the intermediate layer comprises or consists of a corrugated element or corrugated layer disposed between the upper and lower layers, and longitudinal channels formed by the longitudinally extending corrugations of the corrugated element or corrugated layer extend in the planar direction of the upper and lower layers. Example 62. 62. An aerosol-forming substrate as described in example 61, wherein the intermediate layer comprises perforations or holes to allow at least a portion of the air to flow through the intermediate layer in a direction perpendicular to the longitudinally extending channels. Example 63. 63. The aerosol-forming substrate of any of Examples 1 to 62, comprising an upper layer, a lower layer, and an intermediate layer, the intermediate layer comprising or consisting of a corrugated element or layer disposed between the upper and lower layers, such that longitudinal channels formed by longitudinally extending corrugations of the corrugated element or layer extend in the planar direction of the upper and lower layers, and the intermediate layer comprising perforations or holes, such that at least a portion of air can flow through the intermediate layer in a direction perpendicular to the longitudinally extending channels. Example 64. The aerosol-forming substrate of example 63, wherein the intermediate layer is a mesh. Example 65. An aerosol-forming substrate as described in Example 63 or 64, wherein the aerosol-forming substrate has a proximal or mouth end and a distal end, and the longitudinal channels formed by the longitudinally extending corrugations of the corrugated element or corrugated layer extend in a direction perpendicular to the direction defined between the proximal or mouth end and the distal end. Example 65A. 66. The aerosol-generating substrate of any of Examples 1 to 65, comprising one or more sheets of aerosol-forming material, wherein a plurality of holes or notches are defined in a surface, for example, in an upper or lower surface of the aerosol-forming material. Example 65B. The aerosol-generating substrate of any of Examples 1 to 65A, wherein the aerosol-forming substrate comprises a lower layer of aerosol-forming material and a corrugated layer attached to the lower layer, e.g., a corrugated layer of aerosol-forming material, and wherein a plurality of holes or notches are defined in at least one of the lower layer of aerosol-forming material and the corrugated layer. Example 65C. The aerosol-forming substrate of any one of Examples 1 to 65B, wherein a plurality of holes or notches are defined in the upper surface of the aerosol-forming substrate. Example 65D. The aerosol-generating article of Examples 65A-65C, wherein at least some of the plurality of holes are blind holes that do not penetrate through the thickness of the aerosol-forming material in which they are defined. Example 65E. The aerosol-generating article of any one of Examples 65A to 65D, wherein at least some of the plurality of holes are through holes extending through the thickness of the aerosol-forming material in which they are defined. Example 66. An aerosol-forming substrate comprising a first planar layer and a corrugated layer disposed on a surface of the first planar layer, wherein at least one of the first planar layer and the corrugated layer comprises or consists of an aerosol-forming material. Example 67. An aerosol-forming substrate comprising a first planar layer, a second planar layer, and a corrugated layer disposed between the first and second planar layers, wherein at least one of the first planar layer, the second planar layer, and the corrugated layer comprises or consists of an aerosol-forming material. Example 68. 1. An aerosol-forming substrate comprising a first layer and a corrugated layer attached to a surface of the first layer by an adhesive, the adhesive comprising or consisting of an aerosol-forming material. Example 69. An aerosol-forming substrate comprising a first layer, a second layer, and an intermediate layer disposed between the first layer and the second layer, the intermediate layer being attached to the first layer and / or the second layer by an adhesive, the adhesive comprising or consisting of an aerosol-forming material. Example 70. An aerosol-forming substrate comprising a first layer and a corrugated layer attached to a surface of the first layer, wherein a plurality of longitudinally extending channels are defined between the first layer and the second layer by the corrugations, and a porous element is disposed in at least one of the longitudinally extending channels. Example 71. An aerosol-forming substrate comprising a first layer and a corrugated layer attached to a surface of the first layer, wherein a plurality of longitudinally extending channels are defined by the corrugations between the first layer and the corrugated layer, and the longitudinally extending channels are filled with a porous material, e.g., a porous aerosol-forming material. Example 72. An aerosol-forming substrate comprising a first layer, a second layer, and a corrugated layer disposed between the first and second layers, wherein a plurality of longitudinally extending channels are defined by the corrugations between the first layer and the corrugated layer and between the corrugated layer and the second layer, and a porous element is disposed in at least one of the longitudinally extending channels. Example 73. An aerosol-forming substrate comprising a first layer and a corrugated layer attached to a surface of the first layer, wherein a plurality of longitudinally extending channels are defined by the corrugations between the first layer and the corrugated layer, and wherein one or more flavor-releasing components, e.g., components such as threads or capsules impregnated with or containing flavor components, are disposed within at least one of the longitudinally extending channels. Example 74. 1. An aerosol-forming substrate comprising a first layer, a second layer, and a corrugated layer disposed between the first and second layers, wherein a plurality of longitudinally extending channels are defined by the corrugations between the first and corrugated layers and between the corrugated and second layers, and wherein one or more flavor-releasing components, e.g., threads or capsules impregnated with or containing components, e.g., flavor components, are disposed within at least one of the longitudinally extending channels. Example 75. An aerosol-forming substrate comprising a first planar layer and a corrugated layer disposed on a surface of the first planar layer, at least one of the first planar layer and the corrugated layer having perforations or holes for allowing air to flow through the first planar layer or the corrugated layer. Example 76. An aerosol-forming substrate comprising a first planar layer, a second planar layer, and a corrugated layer disposed between the first and second planar layers, at least one of the first planar layer, the second planar layer, and the corrugated layer comprising perforations or holes to allow air to flow through the first planar layer, the second planar layer, or the corrugated layer. Example 77. An aerosol-forming substrate comprising a first planar layer, a second planar layer, and a third planar layer disposed between the first and second planar layers, wherein the aerosol-forming substrate further comprises a first corrugated layer disposed between the first and third planar layers, and a second corrugated layer disposed between the third and second planar layers. Example 78. 78. The aerosol-forming substrate of any one of examples 1 to 77, comprising a corrugated element or corrugated layer, wherein the corrugations of the corrugated element or corrugated layer are defined by a corrugation wavelength and a corrugation amplitude. Example 79. The aerosol-forming substrate according to example 78, wherein the waveform wavelength is 1 mm to 10 mm, for example 1.5 mm to 8 mm, for example 2 mm to 6 mm, for example 2.5 mm to 5 mm, for example 3 mm to 4 mm. Example 80. 80. The aerosol-forming substrate of example 78 or example 79, wherein the corrugation amplitude or z-axis thickness of the corrugated element or corrugated layer is from 1 mm to 10 mm, such as from 1.5 mm to 8 mm, for example from 2 mm to 6 mm, such as from 2.5 mm to 5 mm, for example from 3 mm to 4 mm. Example 80A. The aerosol-forming substrate according to any one of Examples 1 to 80, comprising at least one flat layer and at least one corrugated layer, wherein the thickness of the at least one flat layer is 0.02 mm to 2 mm, for example, 0.05 mm to 1.5 mm, for example, 0.1 mm to 1 mm, for example, 0.2 mm to 0.8 mm, for example, 0.3 mm to 0.6 mm, for example, 0.4 mm to 0.5 mm. Example 81. 81. The aerosol-forming substrate of any of Examples 78 to 80, wherein the waveform may be further defined by a waveform profile, the waveform profile being sinusoidal, or triangular, or rectangular, or trapezoidal, or toroidal, or parabolic. Example 82. 82. The aerosol-forming substrate of any of Examples 1 to 81, wherein the aerosol-forming substrate is formed as an extrusion of an aerosol-forming material and has an upper surface, a lower surface, and a plurality of airflow channels defined through the aerosol-forming substrate between the upper surface and the lower surface. Example 83. The aerosol-forming substrate according to any one of Examples 1 to 82, wherein the length (x dimension) is approximately the same as the width (y dimension). Example 84. The aerosol-forming substrate of any of Examples 1 to 82, wherein the length (x dimension) is greater than the width (y dimension), for example, the length is about 1.5 times the width, or about 2 times the width, or about 2.5 times the width, or about 3 times the width. Example 85. An aerosol-forming substrate according to example 84, wherein the length (x dimension) is greater than three times the width dimension, such as greater than four times the width dimension, for example greater than five times the width dimension. Example 86. An aerosol-forming substrate according to any of Examples 1 to 85, having a base, the base being substantially planar, eg, the base defining a substantially planar lower surface of the aerosol-forming substrate. Example 87. An aerosol-forming substrate according to any of Examples 1 to 86, wherein the aerosol-forming substrate is in the form of a three-dimensional shape that can be described as a cube or a rectangular prism. Example 88. An aerosol-forming substrate according to any one of Examples 1 to 87, wherein one or both of the length (x dimension) and width (y dimension) are at least twice the height (z dimension), for example, 3 times, 4 times, or 5 times the height, and optionally at least 6 times the height, for example, 10 times, 15 times, or 20 times the height. Example 89. An aerosol-forming substrate according to any of Examples 1 to 88, wherein the base is defined by a rectangular shape having a length and width that form the lower surface of the aerosol-forming substrate, and the upper surface of the aerosol-forming substrate is defined by a substantially identical rectangular shape that is spaced apart from the base by a height, e.g., both the lower and upper surfaces are defined as planes that are arranged on parallel planes that are spaced apart by the height. Example 90. An aerosol-forming substrate according to any of Examples 1 to 89, wherein the ratio of the greatest dimension of the length (x dimension) and width (y dimension) to the height (z dimension) is from 4:1 to 20:1, for example from 4.2:1 to 10:1, for example from 4.5:1 to 8:1, e.g., the length to width ratio is from 4:1 to 20:1, for example from 4.2:1 to 10:1, for example from 4.5:1 to 8:1. Example 91. 91. The aerosol-forming substrate according to any of Examples 1 to 90, wherein the length (x dimension) of the substrate is from 10 mm to 50 mm, for example from 12 mm to 30 mm, for example from 14 mm to 26 mm, for example from 16 mm to 24 mm, for example from 18 mm to 22 mm, for example about 18 mm, or about 19 mm, or about 20 mm, or about 21 mm, or about 22 mm. Example 92. The aerosol-forming substrate according to any of Examples 1 to 91, wherein the width (y dimension) of the substrate is 5 mm to 20 mm, for example 8 mm to 18 mm, for example 10 mm to 16 mm, for example 11 mm to 15 mm, for example 12 mm to 14 mm, for example about 13 mm. Example 93. The aerosol-forming substrate according to any of Examples 1 to 92, wherein the height (z dimension) of the substrate is 1 mm to 10 mm, for example 1.2 mm to 8 mm, for example 1.4 mm to 7 mm, for example 1.6 mm to 6 mm, for example 1.7 mm to 5 mm, for example about 1.7 mm, or about 4.5 mm, or about 2 mm, or about 3 mm, or about 4 mm. Example 94. The aerosol-forming substrate according to any one of Examples 1 to 93, wherein the aerosol-forming substrate is made entirely of an aerosol-forming material. Example 95. The aerosol-forming substrate according to any of Examples 1 to 94, further comprising a porous layer covering at least one surface of the aerosol-forming substrate, for example at least the upper surface, or at least the lower surface, or at least the upper and lower surfaces. Example 96. The aerosol-forming substrate according to any one of Examples 1 to 95, further comprising a porous layer covering at least an end face of the aerosol-forming substrate, for example covering at least one airflow inlet or outlet of the aerosol-forming substrate. Example 97. An aerosol-forming substrate as described in Example 95 or Example 96, wherein the porous layer completely encases the aerosol-forming substrate. Example 98. The aerosol-forming substrate of Example 95, Example 96, or Example 97, wherein the porous layer is porous paper or porous mesh. Example 99. The aerosol-forming substrate according to any one of Examples 1 to 98, wherein the aerosol-forming substrate contains nicotine. Example 100. 99. An aerosol-forming substrate according to any one of examples 1 to 99, wherein the aerosol-forming substrate comprises or consists of homogenized tobacco material. Example 101. 101. The aerosol-forming substrate according to any one of Examples 1 to 100, wherein the aerosol-forming substrate comprises or consists of a solid aerosol-forming material. Example 102. 102. The aerosol-forming substrate of any one of examples 1 to 101, wherein the aerosol-forming substrate comprises a liquid aerosol-forming material held within a porous matrix. Example 103. The aerosol-forming substrate according to any one of Examples 1 to 102, wherein the aerosol-forming substrate comprises a gel-like aerosol-forming material. Example 104. The aerosol-forming substrate of any of Examples 1 to 103, wherein a first portion of the aerosol-forming substrate comprises a first aerosol-forming material, and a second portion of the aerosol-forming substrate comprises a second aerosol-forming material different from the first aerosol-forming material. Example 105. The aerosol-forming substrate of example 104, wherein the first aerosol-forming material is a first homogenized tobacco material and the second aerosol-forming material is a second homogenized tobacco material having a different composition than the first homogenized tobacco material. Example 106. 106. The aerosol-forming substrate of Example 105, wherein the first homogenized tobacco material differs from the second tobacco composition by having at least one difference selected from the list consisting of a different aerosol former content, a different tobacco content, a different flavorant content, a different moisture content, and a different nicotine content. Example 107. 105. The aerosol-forming substrate of example 104, wherein the first aerosol-forming material is a first homogenized tobacco material and the second aerosol-forming material is an aerosol-forming material other than tobacco that comprises an aerosol former, e.g., glycerin or propylene glycol, preferably a flavor component and / or an active component, e.g., nicotine or cannabinol. Example 108. The aerosol-forming substrate according to any one of Examples 1 to 107, further comprising a thermally conductive layer, such as an aluminum layer, covering at least a portion of at least one surface of the aerosol-forming substrate, such as at least a portion of the upper surface or at least a portion of the lower surface. Example 109. The aerosol-forming substrate of any of Examples 1 to 108, further comprising a paper layer, such as a tipping paper layer, covering at least a portion of at least one surface of the aerosol-forming substrate, such as at least a portion of the upper surface or at least a portion of the lower surface. Example 110. 109. The aerosol-forming substrate of any of Examples 1 to 109, comprising at least one aerosol-forming material, wherein the aerosol-forming material comprises one or more organic materials, such as tobacco, for example, the aerosol-forming material comprises one or more of herb leaves, tobacco leaves, tobacco vein fragments, reconstituted tobacco, homogenized tobacco, extruded tobacco, and expanded tobacco. Example 111. 111. The aerosol-forming substrate of any of Examples 1-110, comprising at least one aerosol-forming material, the aerosol-forming material comprising one or more aerosol formers, for example, one or more aerosol formers selected from the list consisting of polyhydric alcohols, such as propylene glycol, polyethylene glycol, triethylene glycol, 1,3-butanediol, and glycerin; esters of polyhydric alcohols, such as glycerol monoacetate, glycerol diacetate, or glycerol triacetate; and aliphatic esters of monocarboxylic, dicarboxylic, or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate, preferably wherein the aerosol former is or comprises glycerin. Example 112. 112. The aerosol-forming substrate of example 111, wherein the aerosol-forming material comprises at least 1 weight percent of the aerosol former, e.g., at least 2, 5, 10, or 15 weight percent of the aerosol former. Example 112A. The aerosol-forming substrate of example 112, wherein the aerosol-forming material comprises more than 15 weight percent of the aerosol former, e.g., more than 20 weight percent, or more than 25 weight percent, or more than 30 weight percent, or more than 40 weight percent, or more than 50 weight percent of the aerosol former. Example 113. 113. The aerosol-forming substrate of any of Examples 1-112, comprising at least one aerosol-forming material, the aerosol-forming material comprising nicotine. Example 113A. The aerosol-forming substrate of example 113, wherein the aerosol-forming material comprises at least 0.5 weight percent nicotine, e.g., at least 1 weight percent nicotine, at least 1.5 weight percent nicotine, or at least 2 weight percent nicotine. Example 114. The aerosol-forming substrate of any of Examples 1 to 113A, comprising at least one aerosol-forming material, the aerosol-forming material comprising one or more cannabinoid compounds, such as one or more of tetrahydrocannabinol (THC), tetrahydrocannabinolic acid (THCA), cannabidiol (CBD), cannabidiolic acid (CBDA), cannabinol (CBN), cannabigerol (CBG), cannabigerol monomethyl ether (CBGM), cannabivarin (CBV), cannabidivarin (CBDV), tetrahydrocannabivarin (THCV), cannabichromene (CBC), cannabicyclol (CBL), cannabichromevarin (CBCV), cannabigerovarin (CBGV), cannabielsoin (CBE), and cannabicitran (CBT). It may be preferred that the cannabinoid compound is CBD or THC, and preferably the cannabinoid compound is CBD. Example 115. 115. The aerosol-forming substrate of any of Examples 1 to 114, comprising at least one aerosol-forming material, the aerosol-forming material comprising one or more flavoring agents, for example, the one or more flavoring agents comprising one or more essential oils, such as eugenol, peppermint oil, and spearmint oil; one or both of menthol and eugenol; one or both of anethole and linalool; and herbal materials, for example, herb leaves or other herbal materials derived from herbal plants, for example, mints, such as peppermint and spearmint, lemon balm, basil, cinnamon, lemon basil, chives, coriander, lavender, sage, tea, thyme, and caraway. Example 116. 116. The aerosol-forming substrate of any of Examples 1-115, comprising at least one aerosol-forming material, the aerosol-forming material comprising particles of a functional material, such as particles of carbon, graphite, activated carbon, or expanded graphite. Example 117. 117. The aerosol-forming substrate of any of examples 1-116, comprising at least one aerosol-forming material, wherein the aerosol-forming material comprises non-tobacco fibers, such as non-tobacco cellulose fibers. Example 118. 118. The aerosol-forming substrate of any of Examples 1-117, comprising at least one aerosol-forming material, the aerosol-forming material comprising a binder, for example, guar gum. Example 119. 119. The aerosol-forming substrate of any of Examples 1 to 118, comprising at least one aerosol-forming material, wherein the aerosol-forming material comprises conductive particles, such as conductive carbon or graphite particles, or conductive metal particles, such as aluminum or stainless steel or nickel particles. Example 120. 120. The aerosol-forming substrate of any of Examples 1-119, comprising one or more susceptor materials. Example 121. 121. The aerosol-forming substrate of example 120, wherein the one or more susceptor materials are incorporated within the aerosol-forming material of the aerosol-forming substrate, for example, as particles of susceptor material dispersed within the aerosol-forming material. Example 122. 122. The aerosol-forming substrate of example 120 or 121, wherein the one or more susceptor materials are incorporated into the aerosol-forming substrate as one or more strips, threads, or wires of susceptor material, for example, as one or more strips, threads, or wires of susceptor material disposed within the airflow path of the aerosol-forming substrate. Example 123. 123. The aerosol-forming substrate according to any of Examples 120 to 122, wherein the one or more susceptor materials are incorporated within the aerosol-forming substrate as one or more susceptor material sheets or layers, for example, as one or more susceptor material sheets or layers covering an outer portion of the aerosol-forming substrate or forming a structural component of the aerosol-forming substrate. Example 124. 124. The aerosol-forming substrate of any of Examples 120 to 123, wherein the aerosol-forming substrate comprises a first planar layer and a corrugated layer disposed on a surface of the first planar layer, and at least one of the first planar layer and the corrugated layer comprises or consists of a sheet of susceptor material. Example 125. 125. The aerosol-forming substrate of any of Examples 120-124, comprising a first planar layer, a second planar layer, and a corrugated layer disposed between the first and second planar layers, wherein at least one of the first planar layer, the second planar layer, and the corrugated layer comprises or consists of a sheet of susceptor material. Example 126. 126. The aerosol-forming substrate of any of Examples 123 to 125, wherein the one or more sheets of susceptor material are in the form of a mesh of susceptor material. Example 127. 127. The aerosol-forming substrate of any of Examples 120-126, wherein the susceptor material comprises one or more materials selected from the list consisting of aluminum, iron and iron alloys, nickel and nickel alloys, cobalt alloys, stainless steel alloys, copper alloys, carbon, expanded carbon, and graphite. Example 128. 127. An aerosol-generating article for use in an aerosol-generating device to generate an inhalable aerosol, the aerosol-generating article comprising an aerosol-forming substrate according to any one of Examples 1 to 127. Example 129. 128. An aerosol-generating article for use in an aerosol-generating device to generate an inhalable aerosol, the aerosol-generating article comprising an aerosol-forming substrate according to any one of Examples 1 to 127. Example 130. 130. The aerosol-generating article of example 129, wherein the aerosol-forming substrate is disposed within an outer wrapper or outer casing. Example 131. The aerosol-generating article of Example 130, wherein the outer wrapping or outer casing is a cigarette wrapper. Example 132. 131. The aerosol-generating article of Example 130, wherein the outer wrapping or outer casing is a polymeric sheet. Example 133. 133. The aerosol-generating article of any one of Examples 130-132, wherein the outer wrapping or outer casing comprises a portion of a susceptor material, such as aluminum foil or stainless steel foil. Example 134. The aerosol-generating article of any of Examples 130-133, wherein one or more perforations are defined through the outer wrapping or outer casing. Example 135. 134. The aerosol-generating article of any one of Examples 130 to 133, wherein multiple components including the aerosol-forming substrate are assembled within an outer wrapping or outer casing. Example 136. An aerosol-generating article according to any one of Examples 129 to 133, comprising two or more aerosol-forming substrates according to any one of Examples 1 to 128. Example 137. An aerosol-generating article described in any of Examples 128 to 136, wherein the aerosol-generating article has a length extending in the x-direction, a width extending in the y-direction, and a height extending in the z-direction, and a longitudinal airflow path is defined through the aerosol-generating article between the distal end of the article and the proximal end of the article. Example 138. An aerosol-generating article as described in any of Examples 128 to 137, wherein the aerosol-generating article has a length extending in the x-direction between the distal end and the proximal end, a width extending in the y-direction between the first edge and the second edge, and a height extending in the z-direction between the upper surface and the lower surface, and preferably, the distal portion of the aerosol-generating article is defined between the distal end of the aerosol-generating article and a midpoint of the longitudinal direction of the aerosol-generating article, and the proximal portion of the aerosol-generating article is defined between the proximal end of the aerosol-generating article and a midpoint of the longitudinal direction of the aerosol-generating article. Example 139. The aerosol-generating article of Example 137 or 138, comprising a single aerosol-forming substrate of any one of Examples 1 to 128 extending between a proximal end and a distal end within the article. Example 140. 140. The aerosol-generating article of Example 138 or 139, comprising an aerosol-forming substrate of any one of Examples 1 to 128 disposed within a distal portion of the aerosol-generating article. Example 141. An aerosol-generating article according to Example 138 or 139, comprising an aerosol-forming substrate according to any one of Examples 1 to 128, disposed entirely within the distal portion of the aerosol-generating article. Example 142. An aerosol-generating article as described in Example 140 or 141, further comprising a structural element positioned proximal to the aerosol-forming substrate, the structural element comprising longitudinal channels or porosity that allow an airflow path through the structural element. Example 143. 143. The aerosol-generating article of example 142, wherein the aerosol-forming substrate has a cross-section and the structural elements have similar or identical cross-sections, e.g., similar rectangular cross-sections. Example 144. 144. The aerosol-generating article of example 142 or 143, wherein the structural element is a rectangular tube. Example 145. 144. An aerosol-generating article according to example 142 or 143, wherein the structural elements comprise corrugated elements, and the longitudinal channels within the aerosol-generating article are defined by the corrugated elements. Example 146. An aerosol-generating article as described in Example 145, wherein the structural elements comprise corrugated elements, and the longitudinal channels in the aerosol-generating article are defined by the corrugations of the corrugated elements. Example 147. An aerosol-generating article as described in any one of Examples 138 or 139, comprising a first aerosol-forming substrate as described in any one of Examples 1 to 128, which is at least partially disposed within the distal portion of the aerosol-generating article, and a second aerosol-forming substrate as described in any one of Examples 1 to 128, which is disposed proximal to the first aerosol-forming substrate, for example, at least partially within the proximal portion of the aerosol-generating article. Example 148. An aerosol-generating article as described in any of Examples 130 to 147, comprising a plurality of components including at least one aerosol-forming substrate as described in any of Examples 1 to 128, a substantially hollow structural element, such as a hollow tube, and a mouthpiece element, such as a mouthpiece filter, coaxially aligned and assembled within a wrapper or casing. Example 149. An aerosol-generating article according to any one of Examples 128 to 148, wherein the aerosol-generating article has a length, a width, and a height, the length being greater than the width and the width being greater than the height. Example 150. An aerosol-generating article as described in Example 149, wherein the length is about 1.5 times the width, or about 2 times the width, or about 2.5 times the width, or about 3 times the width. Example 151. An aerosol-generating article as described in Example 149 or 150, wherein the length is more than three times the width dimension, such as more than four times the width dimension, for example more than five times the width dimension. Example 152. The aerosol-generating article of any of Examples 149-151, wherein the article comprises a substantially planar base, e.g., the base defines a substantially planar lower surface of the aerosol-forming substrate. Example 153. An aerosol-generating article according to any one of Examples 149 to 152, wherein the aerosol-generating article is in the form of a three-dimensional shape that can be described as a cube or a rectangular prism. Example 154. An aerosol-generating article according to any one of Examples 149 to 153, wherein the length is at least twice the height, for example, 3 times, or 4 times, or 5 times the height, and optionally 6 times or more the height, for example, 10 times, or 15 times, or 20 times the height. Example 155. 155. The aerosol-generating article of any of Examples 128 to 154, wherein the length of the article is 10 mm to 50 mm, for example 12 mm to 30 mm, for example 14 mm to 26 mm, for example 16 mm to 24 mm, for example 18 mm to 22 mm, for example about 18 mm, or about 19 mm, or about 20 mm, or about 21 mm, or about 22 mm. Example 156. 156. The aerosol-generating article of any of Examples 128 to 155, wherein the width of the article is from 5mm to 20mm, such as from 8mm to 18mm, for example from 10mm to 16mm, for example from 11mm to 15mm, for example from 12mm to 14mm, such as about 13mm. Example 157. 157. The aerosol-generating article of any of Examples 128 to 156, wherein the height of the article is 1 mm to 10 mm, for example 1.2 mm to 8 mm, for example 1.4 mm to 7 mm, for example 1.6 mm to 6 mm, for example 1.7 mm to 5 mm, for example about 1.7 mm, or about 4.5 mm, or about 2 mm, or about 3 mm, or about 4 mm. Example 157A. An aerosol-generating article according to any one of Examples 128 to 157, wherein the article comprises a first section and a second section removably connectable to the first section, the first section comprising an aerosol-forming substrate according to any one of Examples 1 to 127, and the second section being a mouthpiece. Example 157B. An aerosol-generating article as described in Example 157A, wherein the second section is a reusable mouthpiece designed for use with multiple first sections. Example 158. An aerosol-generating article for use in an aerosol generating device to generate an inhalable aerosol, the aerosol-generating article having an upstream article end and a downstream article end, and an article airflow path and article length extending from the upstream article end to the downstream article end. Example 159. An aerosol-generating article described in any of Examples 128 to 157B, wherein the article is for use in an aerosol generating device to generate an inhalable aerosol, the aerosol-generating article having an upstream article end and a downstream article end, and the article airflow path and article length extend from the upstream article end to the downstream article end. Example 160. 159. The aerosol-generating article of any one of Examples 158 to 159, comprising or consisting of an aerosol-forming substrate as defined in any one of Examples 1 to 127. Example 161. 161. The aerosol-generating article of any of Examples 158-160, wherein the article comprises one or more corrugated elements, preferably the one or more corrugated elements collectively extending at least 50% of the length of the article. Example 162. 162. The aerosol-generating article of Example 161, wherein the one or more corrugated elements together extend over at least 50, 60, 70, 80, 90, 95, 98, or 99%, or substantially all, of the length of the article. Example 163. An aerosol-generating article as described in Example 161 or 162, wherein at least one, e.g., each, of the one or more corrugated elements is or includes a corrugated sheet of material that is bent or folded to form a corrugation. Example 164. the aerosol-generating article comprises an aerosol-forming substrate; the aerosol-forming substrate comprises a first planar layer; An aerosol-generating article according to any one of Examples 161 to 163, wherein one or more corrugated elements are disposed on the first planar layer, e.g., on the first or upper surface of the first planar layer. Example 165. 165. The aerosol-generating article of example 164, wherein the aerosol-forming substrate comprises a second planar layer, and the one or more corrugated elements are disposed between the first and second planar layers. Example 166. 166. The aerosol-generating article of Example 165, wherein the corrugation peaks of one or more corrugated elements are adjacent to or in contact with the first planar layer. Example 167. 167. The aerosol-generating article of example 165 or 166, wherein the corrugated troughs of one or more corrugated elements are adjacent to or in contact with the second planar layer. Example 168. 168. The aerosol-generating article of any of Examples 164-167, wherein the first planar layer comprises or consists of an aerosol-forming material. Example 169. The aerosol-generating article of any of Examples 161-168, wherein at least one, e.g., each, of the one or more corrugated elements comprises or consists of an aerosol-forming material. Example 170. The aerosol-generating article of Examples 161-169, wherein one or more corrugated elements have one or more perforations or holes for allowing air to flow through the one or more corrugated elements. Example 171. The aerosol-generating article of Examples 161-170, wherein the one or more corrugated elements comprise at least two corrugated elements. Example 172. 172. The aerosol-generating article of claim 171, wherein at least one of the at least two corrugated elements is positioned partially or completely downstream of another of the at least two corrugated elements. Example 173. 173. The aerosol-generating article of example 171 or 172, wherein at least one of the at least two corrugated elements is not positioned upstream or downstream of another of the at least two corrugated elements. Example 174. An aerosol-generating article described in any of Examples 158 to 173, wherein the article comprises one or more sheets of aerosol-forming material, wherein at least one, e.g., each, of the one or more sheets of aerosol-forming material has a thickness of less than 1 mm, and wherein the one or more sheets of aerosol-forming material together extend along at least 50% of the length of the article. Example 175. The aerosol-generating article of example 174, wherein the one or more sheets of aerosol-forming material together extend over at least 60, 70, 80, 90, 95, 98, or 99%, or substantially all, of the length of the article. Example 176. The aerosol-generating article of Example 174 or 175 when dependent on any of Examples 161-172, wherein the one or more sheets of aerosol-forming material form at least one, e.g., each, of the one or more corrugated elements. Example 177. An aerosol-generating article described in any of Examples 158 to 176, wherein the article has an article airflow path extending from the upstream end of the article to the downstream end of the article, the article has a first corrugated element, and the transverse direction of at least a first portion of the first corrugated element is non-parallel, preferably perpendicular, to one or both of the article length and at least a first portion of the article airflow path. Example 178. An aerosol-generating article as described in Example 177, wherein the transverse direction of at least a first portion of the first corrugated element is perpendicular to one or both of the article length and at least a first portion of the article airflow path. Example 179. 179. The aerosol-generating article of any of Examples 177-178, wherein the first portion of the article airflow path is at least partially defined by the first portion of the first corrugated element. Example 180. An aerosol-generating article according to any one of Examples 177 to 179, wherein the aerosol-generating article has a substantially planar upper surface defined by a length, e.g., an article length extending in the x-direction, and a width extending in the y-direction. Example 181. An aerosol-generating article as described in Example 180, wherein the aerosol-generating article has a substantially planar underside defined by a length, e.g., an article length extending in the x-direction, and a width extending in the y-direction. Example 182. An aerosol-generating article as described in Example 181, wherein the substantially planar upper surface and the substantially planar lower surface are vertically spaced apart from each other by a height defined in the z direction. Example 183. An aerosol-generating article as described in Example 181, wherein the transverse direction of at least a first portion of the first corrugated element extends in the y direction or the z direction. Example 184. An aerosol-generating article according to any one of Examples 177-183, wherein the first corrugated element comprises one or more perforations or holes for allowing air to flow through the first corrugated element. Example 185. 185. The aerosol-generating article of example 184, wherein the article airflow pathway extends through one or more perforations or holes. Example 186. The aerosol-generating article of any one of Examples 177-185, wherein the aerosol-generating article comprises a second corrugated element. Example 187. 187. The aerosol-generating article of Example 186, wherein the second corrugated element is upstream of, but not downstream of, the first corrugated element. Example 188. The aerosol-generating article of Example 186, wherein the second corrugated element is neither upstream nor downstream of the first corrugated element. Example 189. 188. The aerosol-generating article of Example 187, wherein the second corrugated element is upstream of the first corrugated element, and the aerosol-generating article comprises a third corrugated element downstream of the first corrugated element. Example 190. The aerosol-generating article of any of Examples 186-189, wherein the transverse direction of at least some of the second corrugated elements is non-parallel to the transverse direction of at least some of the first corrugated elements. Example 191. The aerosol-generating article of any of Examples 177 to 190, wherein the first corrugated element is one of the one or more corrugated elements, or the first corrugated element is different from the one or more corrugated elements, and wherein the article depends directly or indirectly on Example 161. Example 192. An aerosol-generating article described in any of Examples 158 to 191, wherein the aerosol-generating article is a planar aerosol-generating article having both an article width and an article thickness perpendicular to the article length, wherein one or both of the article length and the article width are at least 2.5, 3, or 5 times the article thickness, and the article thickness is less than 7, 6, or 5 millimeters. Example 193. An aerosol generating device for containing the aerosol-forming article of any one of Examples 128 to 192 to form an inhalable aerosol, the aerosol generating device comprising: a cavity sized to contain at least a portion of the aerosol-generating article; a heater or heating means; a power source for supplying power to the heater or heating means; and a controller for controlling the supply of power to the heater or heating means. Example 194. An aerosol generating device as described in Example 193, wherein the cavity has an opening through which the distal end of the aerosol generating article can be inserted. Example 195. 195. The aerosol generating device of any of Examples 193-194, wherein the cavity has a rectangular cross-section, for example a rectangular cross-section having a top side and a bottom side that are longer than the left side and the right side. Example 196. An aerosol generating device described in any of Examples 193 to 195, wherein at least one inner surface of the cavity is a heated surface configured to heat the aerosol-generating article, such as a surface provided with a heater or a surface provided with an inductor. Example 197. An aerosol generating device as described in Example 196, wherein at least one lower surface of the cavity is a heating surface configured to heat the aerosol-generating article. Example 198. An aerosol generating device as described in Example 197, wherein both the lower and upper surfaces of the cavity are heating surfaces configured to heat the aerosol-generating article. Example 199. 199. An aerosol generating device according to any of Examples 193 to 198, wherein at least the lower inner surface of the cavity is substantially planar, preferably both the lower inner surface and the upper inner surface of the cavity are substantially planar. Example 200. An aerosol generating device as described in Example 199, wherein the upper and lower inner surfaces of the cavity are arranged in a parallel relationship to each other. Example 201. An aerosol generating device as described in Example 199, wherein the upper and lower inner surfaces converge along the length of the cavity so that they are slightly closer together at the distal end of the cavity than at the proximal end of the cavity. Example 202. 202. The aerosol generating device of example 201, wherein the upper and lower inner surfaces of the cavity converge by 1 to 10 degrees, for example 2 to 8 degrees, for example 3 to 6 degrees, for example 4 to 5 degrees, between the proximal end of the cavity and the distal end of the cavity. Example 203. An aerosol generating device described in any of Examples 199 to 202, wherein the lower inner surface and the upper inner surface are movable relative to each other, for example, the lower inner surface and the upper inner surface are configured to rotate relative to each other or move upward and downward relative to each other. Example 204. An aerosol generating device described in any of Examples 193 to 202, wherein the cavity has a longitudinal dimension or length, a transverse dimension or width, and a depth dimension or height, and the length and width are greater than the height, for example, at least twice the height. Example 205. An aerosol generating device described in any of Examples 193 to 203, wherein the device comprises a heating surface having a plurality of separately operable heating zones, for example, two separately operable heating zones, or three separately operable heating zones, or four separately operable heating zones, or five separately operable heating zones, or six separately operable heating zones. Example 206. An aerosol generating device as described in Example 1205, wherein multiple separably operable heating zones are configured to operate individually or in any combination of two or more zones at a time. Example 207. An aerosol generating device as described in Example 205 or 206, wherein multiple separably operable heating zones are longitudinally spaced apart within the cavity. Example 208. An aerosol generating device as described in example 205 or 206, wherein multiple separably operable heating zones are transversely spaced apart within the cavity. Example 209. An aerosol generating device according to any one of Examples 193 to 208, wherein the device comprises one or more resistive heaters, for example one or more resistive heaters integrated into the walls of the cavity. Example 210. An aerosol generating device described in any of Examples 193 to 209, wherein the device comprises one or more inductors, for example, one or more inductors incorporated into the walls of the cavity or arranged to generate a fluctuating electromagnetic field within the walls or within the cavity. Example 211. 211. The aerosol generating device of example 210, wherein the wall of the cavity comprises or consists of a susceptor material. Example 212. An aerosol generating device described in any of Examples 193 to 211, wherein the device comprises one or more insertable heating elements arranged to protrude into a cavity for insertion into the aerosol generating article, for example into a corrugated structure of the aerosol generating article. Example 213. 213. The aerosol generating device of Example 212, wherein the insertable heating element is a resistive heater or the heating element is a susceptor. Example 214. An aerosol generating system comprising the aerosol generating device according to any one of Examples 193 to 213 and the aerosol-generating article according to any one of Examples 128 to 192. Example 215. 1. A method of making a planar corrugated aerosol-forming substrate, comprising: providing a first continuous sheet; providing a second continuous sheet, wherein at least one of the first sheet and the second sheet comprises or consists of an aerosol-forming material; texturing a second continuous sheet using a grooved roller to form a continuous corrugated sheet; applying an adhesive to at least one of the continuous corrugated sheet or the first continuous sheet; applying a continuous corrugated sheet to a surface of a first continuous sheet to form a continuous aerosol-forming substrate; cutting the continuous aerosol-forming substrate to form a planar corrugated aerosol-forming substrate. Example 216. 1. A method of making a planar corrugated aerosol-forming substrate, comprising: providing a first continuous sheet; providing a second continuous sheet; and providing a third continuous sheet; at least one of the first sheet, the second continuous sheet, and the second sheet includes or consists of an aerosol-forming material; texturing the second continuous sheet using a grooved roller to form a continuous corrugated sheet; applying an adhesive to at least one of the continuous corrugated sheet or the first continuous sheet; applying a first side of a continuous corrugated sheet to a surface of a first continuous sheet; applying an adhesive to at least one of the continuous corrugated sheet and the third continuous sheet; and attaching a second surface of the continuous corrugated sheet to a surface of the third continuous sheet, thereby forming a continuous aerosol-forming substrate; cutting the continuous aerosol-forming substrate to form a planar corrugated aerosol-forming substrate. Example 217. The method of example 215 or 216, wherein at least one of the first, second, and third continuous sheets is a homogenized tobacco sheet. Example 218. The method of any of Examples 215-217, wherein the adhesive comprises guar gum. Example 219. The method of any of Examples 215-218, wherein the adhesive comprises an aerosol-forming substrate, such as a homogenized tobacco slurry. [Brief explanation of the drawings]

[0245] The embodiments will now be further described with reference to the figures.

[0246] [Figure 1] FIG. 1 is a schematic end view of an aerosol-forming substrate according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic side view of the aerosol-forming substrate of FIG. [Figure 3] FIG. 3 is a schematic plan view of the aerosol-forming substrate of FIG. [Figure 4] FIG. 4 shows a schematic diagram of a corrugated element used in the aerosol-forming substrate of FIG. [Figure 5] FIG. 5 shows a schematic diagram of the apparatus used to produce the aerosol-forming substrate of FIG. [Figure 6] FIG. 6 illustrates an aerosol-generating device according to one embodiment of the present invention, the device configured to engage the aerosol-forming substrate of FIG. [Figure 7]FIG. 7 shows an end view of the aerosol generating device of FIG. [Figure 8] FIG. 8 is a schematic diagram showing the aerosol-forming substrate of FIG. 1 engaged with the aerosol-generating device of FIG. [Figure 9] FIG. 9 is a schematic end view of an aerosol-forming article according to one embodiment of the present invention, comprising the aerosol-forming substrate of FIG. [Figure 10] FIG. 10 is a perspective view of the aerosol-generating article of FIG. [Figure 11] FIG. 11 is a perspective view of an aerosol-generating article according to one embodiment of the present invention. [Figure 12] FIG. 12 is a perspective view of an aerosol-generating article according to one embodiment of the present invention. [Figure 13] FIG. 13 is a perspective view of an aerosol-generating article according to one embodiment of the present invention. [Figure 14] FIG. 14 is a schematic end view of an aerosol-forming substrate according to one embodiment of the present invention. [Figure 15] FIG. 15 is a schematic end view of an aerosol-forming substrate according to one embodiment of the present invention. [Figure 16] FIG. 16 is a schematic end view of an aerosol-forming substrate according to one embodiment of the present invention. [Figure 17] FIG. 17 is a schematic end view of an aerosol-forming substrate according to one embodiment of the present invention. [Figure 18] FIG. 18 is a schematic end view of an aerosol-forming article according to one embodiment of the present invention, comprising the aerosol-forming substrate of FIG. [Figure 19] FIG. 19 is a schematic end view of an aerosol-forming substrate according to one embodiment of the present invention. [Figure 20] FIG. 20 is a schematic side view of an aerosol-forming substrate according to one embodiment of the present invention. [Figure 21] FIG. 21 is a schematic end view of an aerosol-forming substrate according to one embodiment of the present invention. [Figure 22] FIG. 22 is a schematic end view of an aerosol-forming substrate according to one embodiment of the present invention. [Figure 23] FIG. 23 is a schematic end view of an aerosol-forming article according to one embodiment of the present invention, comprising the aerosol-forming substrate of FIG. [Figure 24] FIG. 24 is a schematic end view of an aerosol-forming article according to one embodiment of the present invention. [Figure 25] FIG. 25 is a schematic cross-sectional plan view of an aerosol-forming article according to one embodiment of the present invention. [Figure 26] FIG. 26 is a schematic end view of an aerosol-forming substrate according to one embodiment of the present invention. [Figure 27] FIG. 27 is a schematic end view of an aerosol-forming substrate according to one embodiment of the present invention. [Figure 28] FIG. 28 is a schematic cross-sectional plan view of an aerosol-forming article according to one embodiment of the present invention. [Figure 29] FIG. 29 is a schematic plan view of an aerosol-forming article according to one embodiment of the present invention. [Figure 30] FIG. 30 is a schematic side view of an aerosol-forming substrate according to one embodiment of the present invention. [Figure 31] FIG. 31 is a schematic plan view of a planar heater of an aerosol generating device according to one embodiment of the present invention. [Figure 32] FIG. 32 is a schematic plan view of a planar heater of an aerosol generating device according to one embodiment of the present invention. [Figure 33] FIG. 33 is a schematic plan view of a planar heater of an aerosol generating device according to one embodiment of the present invention. [Figure 34] FIG. 34 illustrates an aerosol generating device according to one embodiment of the present invention. [Figure 35] FIG. 35 illustrates an aerosol generating device according to one embodiment of the present invention. [Figure 36] FIG. 36 illustrates an aerosol generating device according to one embodiment of the present invention. [Figure 37] FIG. 37 illustrates an aerosol generating device according to one embodiment of the present invention. [Figure 38]FIG. 38 illustrates an aerosol-generating article according to one embodiment of the present invention. [Figure 39] FIG. 39 illustrates an exploded view of an aerosol-generating article according to one embodiment of the present invention. [Figure 40] FIG. 40 illustrates an exploded view of an aerosol-generating article according to one embodiment of the present invention. [Figure 41] FIG. 41 is a schematic end view of an aerosol-forming substrate according to one embodiment of the present invention. [Figure 42] FIG. 42 is a schematic end view of an aerosol-forming substrate according to one embodiment of the present invention. [Figure 43] FIG. 43 is a schematic plan view of the aerosol-forming substrate of FIG. [Figure 44] FIG. 44 is a schematic plan view of an aerosol-forming substrate according to one embodiment of the present invention. [Figure 45] FIG. 45 is a schematic plan view of an aerosol-forming substrate according to one embodiment of the present invention. [Figure 46] Figure 46 is a schematic end view of an aerosol-forming substrate according to one embodiment of the present invention. [Figure 47] FIG. 47 is a schematic side view of the aerosol-forming substrate of FIG. [Figure 48] FIG. 48 is a schematic plan view of the aerosol-forming substrate of FIG. [Figure 49] FIG. 49 shows a continuous sinusoidal curve extending in the x-direction. [Figure 50] FIG. 50 is a continuous sinusoidal curve extending in the y direction. [Figure 51] FIG. 51 is a schematic illustration of an intermediate or separating layer of surface morphology created by vertically translating the sinusoidal curve of FIG. 49 by the sinusoidal curve of FIG. [Figure 52] Figure 52 is a representation of a continuous trapezoidal curve. [Figure 53] FIG. 53 is a schematic plan view of a surface formed by vertically translating two trapezoidal curves to form a surface with rectangular peaks and troughs. [Figure 54]FIG. 54 is a perspective view of a surface formed by translating two trapezoidal curves vertically to form a surface with rectangular peaks and troughs. [Figure 55] FIG. 55 is a schematic plan view of FIG. 53 showing potential airflow paths through the peaks and troughs of the surface. [Figure 56] FIG. 56 is a further schematic plan view of a surface formed by translating two trapezoidal curves vertically to form a surface with rectangular peaks and troughs. [Figure 57] FIG. 57 illustrates different airflow paths created by rotating the plan view illustrated in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0247] 1, 2, and 3 illustrate end, side, and top views, respectively, of an aerosol-forming substrate 10 according to one embodiment of the present invention. The aerosol-forming substrate 10 comprises a planar upper layer 20, a planar lower layer 30, and an intermediate or separating layer 40 disposed between the upper and lower layers 20, 30.

[0248] The planar upper layer 20 is formed from a sheet of paper having a thickness of 300 microns. The planar lower layer 30 is formed from a sheet of paper having a thickness of 300 microns. The middle layer 40 is a corrugated element formed from a corrugated sheet of aerosol-forming material 45. A suitable aerosol-forming material may be homogenized tobacco. Thus, the middle layer 40 may be formed from a sheet of corrugated homogenized tobacco material.

[0249] 4 illustrates a corrugated sheet of aerosol-forming material 45. The corrugations have a peak-to-trough amplitude 46 of 3 mm and a wavelength 47 of 3 mm. The sheet of aerosol-forming material 45 forming the intermediate layer 40 is 150 microns thick.

[0250] The intersections 51, 52 between the top and middle layers and between the bottom and middle layers contain adhesive that joins the respective layers together.

[0251] The aerosol-forming substrate has a length extending in the x-dimension of 80 mm, a width extending in the y-dimension of 15 mm, and a thickness extending in the z-dimension of 3.6 mm.

[0252] The corrugations of the intermediate layer 40 form a first set of longitudinal channels 61 bounded by the top layer 20 and the intermediate layer 40, and a second set of longitudinally extending channels 62 bounded by the bottom layer 30 and the intermediate layer 40. The first and second sets of longitudinally extending channels 61, 62 extend along the length of the aerosol-forming substrate between the proximal end 71 of the substrate 10 and the distal end 72 of the substrate. The longitudinally extending channels 61, 62 define an airflow path through the substrate 10. Thus, the airflow path passes through both sides of the sheet of aerosol-forming material 45. The porosity of the aerosol-forming substrate along the airflow path is approximately 90%. This results in a very low draw resistance of less than 5 mmH2O. In fact, the RTD is near zero.

[0253] The aerosol-forming material 45 may be a sheet of any suitable aerosol-forming material. By way of example, the composition of a suitable aerosol-forming material may be as follows: Percentages are given in weight percent of the final product. The aerosol-forming material may have a moisture content of about 5-25%, preferably about 7-15%, in the final product. The aerosol-forming material may further comprise: 1. Tobacco leaf; for example, a tobacco leaf blend containing about 15-45%, preferably about 20-35%, of at least one of the following tobacco leaf types: bright tobacco leaf, dark tobacco leaf, and aromatic tobacco leaf. The tobacco material is ground and graded to a particle size of about 100-380 mesh, preferably about 170-320 mesh. 2. Cellulose fibers; for example, about 1 to 15%, preferably about 3 to 7%, of cellulose fibers having a length of about 10 to 250 μm, preferably about 10 to 120 μm. 3. Tobacco fiber, for example about 5-20%, preferably about 7-15%, of any tobacco type or blend of tobacco types as a filler. The tobacco fiber is preferably derived from stems and / or petioles graded to fibers of about 10-350 μm, preferably about 10-180 μm in length. 4. Binder: for example, about 1-10%, preferably about 1-5%, of a binder such as any of the common gums or pectins used in the food and beverage (F&B) industry. Preferred binders include natural pectins, such as fruit pectins, e.g., citrus pectins, or tobacco pectins; guar gum, land locust bean gum, e.g., hydroxyethyl and / or hydroxypropyl versions of these gums; starches, e.g., modified or derivatized starches; alginates; methylcellulose, ethylcellulose, ethylhydroxymethylcellulose, and carboxymethylcellulose; dextran; and xanthan gum. A preferred binder is guar. 5. Aerosol formers, e.g., about 5-35%, preferably about 10-25%, of an aerosol former. Suitable aerosol formers known in the art include glycerin; monohydric alcohols such as menthol, polyhydric alcohols such as triethylene glycol; esters of polyhydric alcohols such as glycerol monoacetate, glycerol diacetate, or glycerol triacetate; and aliphatic esters of monocarboxylic, dicarboxylic, or polycarboxylic acids, e.g., their dimethyl esters.

[0254] "Tobacco type" means one of various types of tobacco, for example, based on different curing processes that are performed on the tobacco before it is further processed into tobacco products.

[0255] The various components may be mixed together and cast into a sheet having a desired thickness, for example, 150 microns, to form the aerosol-forming material 45. The sheet may then be dried as suitable for processing to form the aerosol-forming substrate 10.

[0256] For purposes of illustration, another aerosol-forming material that may be suitable as the sheet of aerosol-forming material 45 in the specific embodiment above may have the following composition. Percentages are given in weight percent of the final product. The aerosol-forming material may include: 1. An aerosol former, such as glycerin; for example, about 10-40%, preferably about 20-30%. 2. Organic fiber: any suitable plant variety commonly available on the market, with a purity of, for example, about 10%-30%, preferably about 15%-25%, that meets applicable FDA F&B grade requirements. For example, organic fiber may be obtained from cellulose, cotton, wood, or tea plant varieties as by-products or by-processing waste from the F&B tea industry. The organic fiber preferably has a length of about 10-400 μm, preferably about 10-200 μm. 3. Organic vegetable glycerides; for example, about 15-55%, preferably about 20-35%, of plants such as clove, echinacea, fennel, ginger, hawthorn berry, elderberry, monarda, mullein leaf, nettle, plantain, turmeric, yarrow, and combinations thereof. 4. Organic plant extracts; for example, about 1% to 15%, preferably 2% to 7%, of menthol (dl-menthol, CHO, 2-isopropyl-5-methylcyclohexanol) obtained from any of the aforementioned plants, as well as Chaerophyllum macrospermum, Mesosphaerum sidifolium, or other related plant varieties, and p-menthone-3-ol as an optional secondary alcohol as a diastereoisomer of 5-methyl-2-(propan-2-yl)cyclohexan-1-ol.

[0257] Alternatively, such aerosol-forming materials may contain about 0.5 to 5%, preferably about 1 to 3%, of plant essential oils, such as palm, coconut, and wood-derived essential oils.

[0258] 5 illustrates an apparatus 500 that may be used to manufacture the aerosol-forming substrate 10. Continuous sheets of the three main components of the aerosol-forming substrate are provided: a continuous paper sheet for forming the lower surface 30, a continuous paper sheet for forming the upper surface 20, and a continuous aerosol-forming material sheet 45 for forming the corrugated middle layer 40.

[0259] In manufacturing the aerosol-forming substrate, the following steps may be performed.

[0260] The continuous sheet of aerosol-forming material 45 is conveyed under tension over a set of corrugated or fluted rollers 511, 512. The corrugated rollers 511, 512 texture the sheet of aerosol-forming material 45 and introduce waveforms of a desired wavelength and amplitude.

[0261] Adhesive 80 is applied to the peaks of the corrugations by a first adhesive applicator 580. The corrugated sheet is then brought into contact with a continuous paper sheet which forms the bottom layer 30. The bottom layer 30 is attached to the corrugated sheet 45 and the combined layers are fed onto a conveyor belt.

[0262] Now, another adhesive is applied to the corrugated layer by a second adhesive applicator 581, and the continuous sheet forming the top layer 20 is introduced and adhered to the corrugated structure. The structure formed is now a sandwich of corrugated aerosol-forming material 45 between the top layer 20 and the bottom layer 30. The structure is sliced ​​both laterally and transversely by a slicing means 590 to form individual aerosol-forming substrates 10.

[0263] The aerosol-forming substrate may be used alone as an aerosol-generating article or may be used as a component of an aerosol-generating article, for example as further described below.

[0264] 6 and 7 illustrate an aerosol-generating device 600 configured for use with an aerosol-generating article that includes or consists of an aerosol-forming substrate 10. The device 600 is an elongated aerosol-generating device extending between a proximal end 641 and a distal end 642. The device 600 includes a battery 620, a controller 630, and a heater 660 disposed within a housing 610. The controller 630 controls the supply of power from the battery 620 to the heater 660. A cavity 650 is defined within the device 600, the cavity having an opening 653 defined within the proximal end 641 of the device. The opening 653 is rectangular in shape and sized to accommodate the cross-section of the aerosol-forming substrate 10. The cavity includes an upper planar surface 651 and a lower planar surface 652. The heater 660 is disposed within the lower planar surface 652 to heat the underside of an aerosol-forming substrate or article inserted into the cavity 650. The airflow path is configured to allow air to flow from the exterior of the device into cavity 650 .

[0265] FIG. 8 illustrates the device 600 of FIG. 6 engaging with the aerosol-forming substrate 10 of FIG. 1. There is little tolerance between the outer surface of the aerosol-forming substrate and the inner surface of the cavity 650. Thus, a tight fit is achieved between the substrate 10 and the device 600. Because the RTD of the substrate is negligible, the RTD of the system is controlled by the airflow path defined within the device. When a user inserts the substrate 10 into the cavity 650, the device can be operated. The heater 660 heats the underside of the substrate 10, thereby heating the aerosol-forming material 45. The volatile components of the aerosol-forming substrate evaporate and condense within the airflow channels 61 and 62 to form an aerosol. The user inhales the aerosol by sucking on the proximal end 71 of the aerosol-forming substrate 10. When the volatile components are depleted from the aerosol-forming material 45, the substrate is removed from the cavity and discarded.

[0266] Figure 9 illustrates an end view of an aerosol-generating article 901 including the aerosol-forming substrate 10 of Figure 1 wrapped in cigarette paper 965. A perspective view of the article 901 is illustrated in Figure 10, showing the substrate 10, the cigarette paper wrapping 965, and a further portion of tipping paper 967 wrapped around the article at a proximal end 971 of the article. The proximal end 967 may also be referred to as the mouth end, and it is intended that the user draws on the mouth end during use of the article.

[0267] Figure 11 illustrates a perspective view of another configuration of an aerosol-generating article 1101. Article 1101 is similar to article 901 described above and includes the same aerosol-forming substrate 10. Article 1101 in Figure 11 has cigarette paper 1165 covering the top and bottom planar surfaces of substrate 10, but not the sides. Additionally, a coating of tipping paper 1167 is applied to the top and bottom surfaces adjacent proximal end 1171 of article 1101.

[0268] Figure 12 illustrates a perspective view of another configuration of an aerosol-generating article 1201. Article 1201 is similar to article 901 described above and includes the same aerosol-forming substrate 10. Article 1201 in Figure 12 has cigarette paper 1265 covering the top and bottom planar surfaces of the substrate 10 and one side of the substrate. Additionally, a half-coat of tipping paper 1267 is applied adjacent to the proximal end 1271 of article 1201.

[0269] Figure 13 illustrates a perspective view of another configuration of an aerosol-generating article 1301. Article 1301 is similar to article 901 described above and includes the same aerosol-forming substrate 10. Article 1301 in Figure 13 has cigarette paper 1365 covering the top and bottom planar surfaces of substrate 10, but not the sides. Additionally, a coating of tipping paper 1367 is provided on the top and bottom surfaces adjacent proximal end 1371 of article 1301. Article 1301 is wrapped so that the corners of the article are rounded rather than squared, which may provide a more comfortable mouthfeel for the user.

[0270] Figure 14 illustrates an end view of an aerosol-forming substrate 1410 according to one embodiment of the present invention. The aerosol-forming substrate 1410 comprises a planar upper layer 1420, a planar lower layer 1430, and an intermediate or separating layer 1440 disposed between the upper layer 1420 and the lower layer 1430. The intermediate layer is formed from a corrugated sheet of material 1445. The aerosol-forming substrate 1410 of Figure 14 is similar to the aerosol-forming substrate 10 described in connection with Figure 1 above, except that the planar upper layer 1420 and the planar lower layer 1430 are formed from an aerosol-forming material, such as a sheet of homogenized tobacco, and the corrugated sheet of material 1445 does not contain any aerosol-forming material and is present for structural purposes only.

[0271] Figure 15 illustrates an end view of an aerosol-forming substrate 1510 according to one embodiment of the present invention. The aerosol-forming substrate 1510 comprises a planar upper layer 1520, a planar lower layer 1530, and an intermediate or separating layer 1540 disposed between the upper layer 1520 and the lower layer 1530. The intermediate layer is formed from a corrugated sheet of material 1545. The aerosol-forming substrate 1510 of Figure 15 is similar to the aerosol-forming substrate 10 described in connection with Figure 1 above, except that the planar lower layer 1530 and the corrugated sheet of material 1545 are formed from an aerosol-forming material, such as a sheet of homogenized tobacco, and the planar upper layer 1520 does not contain an aerosol-forming material.

[0272] Figure 16 illustrates an end view of an aerosol-forming substrate 1610 according to one embodiment of the present invention. The aerosol-forming substrate 1610 comprises a planar upper layer 1620, a planar lower layer 1630, and an intermediate or separating layer 1640 disposed between the upper layer 1620 and the lower layer 1630. The intermediate layer is formed from a corrugated sheet of material 1645. The aerosol-forming substrate 1610 of Figure 16 is similar to the aerosol-forming substrate 10 described in connection with Figure 1 above, except that the planar upper layer 1620, the planar lower layer 1630, and the corrugated sheet of material 1645 are all formed from an aerosol-forming material, such as a sheet of homogenized tobacco.

[0273] Figure 17 illustrates an end view of an aerosol-forming substrate 1710 according to one embodiment of the present invention. The aerosol-forming substrate 1710 comprises a planar bottom layer 1430 and a corrugated top layer 1745. The substrate of Figure 17 is similar to the substrate of Figure 1, except that the planar top layer is absent. Either or both of the bottom layer 1730 and the corrugated top layer 1745 may be an aerosol-forming material. Figure 18 illustrates an end view of an aerosol-generating article 1801 comprising the aerosol-forming substrate 1710 of Figure 17 wrapped in cigarette paper 1865.

[0274] FIG. 19 illustrates an end view of an aerosol-forming substrate 1910 according to one embodiment of the present invention. The aerosol-forming substrate 1910 comprises a planar upper layer 1920, a planar lower layer 1930, and an intermediate or separating layer 1940 disposed between the upper layer 1920 and the lower layer 1930. The intermediate layer is formed from a corrugated sheet 1945 of material. The aerosol-forming substrate 1910 of FIG. 19 is similar to the aerosol-forming substrate 10 described in connection with FIG. 1 above, with the addition of a top layer 1921 disposed above the upper layer 1920 and a bottom layer 1931 disposed below the lower layer 1930. Either or both of the top layer 1921 and the bottom layer 1931 may be formed from a sheet of material. For example, the sheet of material may be a thermally conductive material, such as aluminum foil, or a paper material, or a polymeric material, or a porous material, such as tea bag material.

[0275] FIG. 20 illustrates a side view of an aerosol-forming substrate 2010 according to one embodiment of the present invention. The aerosol-forming substrate 2010 comprises a planar upper layer 2020, a planar lower layer 2030, and an intermediate or separating layer 2040 disposed between the upper layer 2020 and the lower layer 2030. The aerosol-forming substrate 2010 of FIG. 20 is similar to the aerosol-forming substrate 10 described in connection with FIG. 1 above, with the addition of a top layer 2021 disposed toward the distal end 2072 of the upper layer 2020 and a bottom layer 2031 disposed toward the distal end 2072 of the lower layer 2030. The distal portion 2072 may be the portion of the substrate 2010 that is inserted into an aerosol-generating device. Either or both of the top layer 2021 and the bottom layer 2031 may be formed from a sheet or strip of material. For example, the sheet of material may be a thermally conductive material, such as aluminum foil, or a paper material, or a polymeric material, or a porous material, such as tea bag material.

[0276] Figure 21 illustrates an end view of an aerosol-forming substrate 2110 according to one embodiment of the present invention. The aerosol-forming substrate 2110 comprises a planar upper layer 2120, a planar lower layer 2130, and an intermediate or separating layer 2140 disposed between the upper layer 2120 and the lower layer 2130. The intermediate layer is formed from a corrugated sheet 2145 of material. The aerosol-forming substrate 2110 of Figure 21 is similar to the aerosol-forming substrate 10 described in connection with Figure 1 above, but further includes one or more functional elements 2191, 2192, 2193 disposed within longitudinally extending channels 2161, 2162 defined by the corrugated sheet 2145. The one or more functional elements may be longitudinal elements, such as flavor threads 2191, which are threads or strips of material impregnated with a flavorant, or longitudinal susceptor elements 2193, such as strips of stainless steel or aluminum foil. One or more of the functional elements may be individual elements, such as flavor capsules 2192, e.g., frangible capsules containing aerosol-forming material or flavorings that can be broken by the user prior to consuming the substrate.

[0277] Figure 22 illustrates an end view of an aerosol-forming substrate 2210 according to one embodiment of the present invention. The aerosol-forming substrate 2210 comprises a planar upper layer 2220, a planar lower layer 2230, and an intermediate or separating layer 2240 disposed between the upper and lower layers 2220, 2230. The intermediate layer is formed from an upper corrugated sheet of material 2246 and a lower corrugated sheet of material 2247 separated by an intermediate planar layer 2248. Any one or more of the upper layer 2220, the lower layer 2230, the upper corrugated sheet 2246, the lower corrugated sheet 2247, and the intermediate planar sheet 2248 may be formed from an aerosol-forming material. Figure 23 illustrates an end view of an aerosol-generating article 2301 including the aerosol-forming substrate 2210 of Figure 22 wrapped in cigarette paper 2365.

[0278] Figure 24 illustrates an end view of an aerosol-generating article 2401 comprising two aerosol-forming substrates 10 as described in relation to Figure 1 wrapped in cigarette paper 2365. The aerosol-forming substrates 10 are arranged laterally within the cigarette paper 2465. The substrates may have different compositions, which can facilitate the production of different flavour combinations.

[0279] FIG. 25 illustrates a planar cross-section of an aerosol-generating article 2501 comprising an aerosol-forming substrate 2510 and a structural component 2511 having approximately the same cross-sectional dimensions as the aerosol-forming substrate 2510, assembled within a wrapper 2565. The aerosol-forming substrate 2510 is disposed toward the distal end 2572 of the article, and the structural component 2511 is disposed toward the proximal end 2571 of the article. An airflow path extends through the article 2501 between the distal end 2572 and the proximal end 2571. The aerosol-forming substrate is a substrate described herein, such as the substrate described in connection with FIG. 1. The structural component 2511 may be another aerosol-generating substrate, such as a substrate described herein. The structural component may not include an aerosol-forming material. The structural component may be a tube, for example, a tube of rectangular cross-section. The structural component may be a corrugated cardboard component.

[0280] FIG. 26 illustrates an end view of an aerosol-forming substrate 2610 according to one embodiment of the present invention. The aerosol-forming substrate 2610 comprises a planar upper layer 2620, a planar lower layer 2630, and an intermediate or separating layer 2640 disposed between the upper layer 2620 and the lower layer 2630. The intermediate layer is formed from a corrugated sheet 2645 of material. The aerosol-forming substrate 2610 of FIG. 26 is similar to the aerosol-forming substrate 10 described in connection with FIG. 1 above, but further includes a porous material 2681 disposed within longitudinally extending channels 2661, 2662 defined by the corrugated sheet 2645. The porous material 2681 can control the RTD of the substrate. The porous material 2681 may comprise an aerosol-forming material, for example, may be impregnated with a liquid aerosol-forming material.

[0281] Figure 27 illustrates an end view of an aerosol-forming substrate 2710 according to one embodiment of the present invention. The aerosol-forming substrate 2710 comprises a planar upper layer 2720, a planar lower layer 2730, and an intermediate or separating layer 2740 disposed between the upper layer 2720 and the lower layer 2730. The intermediate layer is formed from a corrugated sheet 2745 of material. The aerosol-forming substrate 2710 of Figure 27 is similar to the aerosol-forming substrate 10 described in connection with Figure 1 above, but further includes a mesh 2785 across the proximal end 2771 of the substrate 2710. The mesh may help prevent particles from the substrate from being inhaled by a user.

[0282] FIG. 28 illustrates a plan cross-sectional view of an aerosol-generating article 2801 comprising an aerosol-forming substrate 2810, a structural component 2811 having approximately the same cross-sectional dimensions as the aerosol-forming substrate 2810, and a mouthpiece filter 2812, all coaxially aligned and assembled within a wrapper 2865. The aerosol-forming substrate 2810 is positioned toward a distal end 2872 of the article, the structural component 2811 is positioned proximal to the aerosol-forming substrate, and the mouthpiece filter 2812 is positioned at a proximal end 2871 of the article. An airflow path extends through the article 2801 between the distal end 2872 and the proximal end 2871. The aerosol-forming substrate is a substrate described herein, such as the substrate described in connection with FIG. 1. The structural component 2811 may be another aerosol-generating substrate, such as a substrate described herein. The structural component may not include an aerosol-forming material. The structural component may be a tube, for example, a tube of rectangular cross section. The structural components may be corrugated cardboard components. The mouthpiece filter 2812 may be formed from cellulose acetate tow.

[0283] FIG. 29 illustrates a plan view of an aerosol-generating article 2901 including an aerosol-forming substrate (not visible) contained within a cigarette paper wrapper 2965. The wrapper 2965 includes an air inlet hole 2995 that allows air to enter the article 2910 through the wrapper 2965. In a preferred embodiment, the air inlet hole may be aligned at a central position on one or both of the top and bottom of the article. The article may include two aerosol-forming substrates, one located toward the distal end 2972 ​​of the article and the other located toward the proximal end 2971 of the article. The article may be a dual-use article designed so that both aerosol-forming substrates are consumed independently. For example, the distal end may be inserted into an aerosol-generating device, the distally located aerosol-forming substrate may be consumed, and the user may draw on the proximal end of the article. The article may then be inverted and the proximal end may be inserted into an aerosol-generating device, the proximally located aerosol-forming substrate may be consumed, and the user may draw on the distal end of the article. In either case, air may be drawn into the article through the air inlet holes during consumption.

[0284] Figure 30 illustrates a side view of an aerosol-forming substrate 3010 according to one embodiment of the present invention. The aerosol-forming substrate 3010 comprises a planar upper layer 3020, a planar lower layer 3030, and an intermediate or separating layer 3040 disposed between the upper and lower layers 3020, 3030. The intermediate layer is formed from a corrugated sheet of material 3045. The corrugated sheet of material 3045 is a multiply perforated sheet of material or mesh that allows airflow through the substrate in a direction perpendicular to the direction of the corrugations (airflow is indicated by arrows in Figure 30).

[0285] FIG. 31 is a schematic plan view of a planar heater 3151 suitable for use in an aerosol-generating device according to one embodiment of the present invention, such as the aerosol-generating device 600 described with respect to FIG. 6 . The planar heater 3151 may form the underside of a cavity in the aerosol-generating device and is configured to heat an aerosol-forming substrate as described herein. In the specific example of FIG. 31 , the planar heater 3151 comprises a first heating zone 3152 located at the proximal end 3171 of the heater and a second heating zone 3153 located at the distal end 3172 of the heater. The first heating zone 3152 and the second heating zone 3153 may be formed from separate resistive heater tracks. Alternatively, the heater may be an induction heater, and the first and second heating zones may be implemented by separate induction coils acting on the susceptor material in the first or second zones. The first and second heating zones may operate independently or together, allowing for sequential heating of portions of the aerosol-forming substrate.

[0286] FIG. 32 is a schematic plan view of a planar heater 3251 suitable for use in an aerosol-generating device according to one embodiment of the present invention, such as the aerosol-generating device 600 described with respect to FIG. 6 . The planar heater 3251 may form the underside of a cavity in the aerosol-generating device and is configured to heat an aerosol-forming substrate as described herein. In the specific example of FIG. 32 , the planar heater 3251 comprises a first heating zone 3252, a second heating zone 3253, a third heating zone 3254, and a fourth heating zone 3255 spaced successively between a proximal end 3271 of the heater and a distal end 3272 of the heater. The separate heating zones may be formed from separate resistive heater tracks. Alternatively, the heater may be an induction heater, and the heating zones may be implemented by separate induction coils acting on the susceptor material of the first or second zones. The heating zones may operate independently or together, allowing for sequential heating of portions of the aerosol-forming substrate.

[0287] FIG. 33 is a schematic plan view of a planar heater 3351 suitable for use in an aerosol-generating device according to one embodiment of the present invention, such as the aerosol-generating device 600 described with respect to FIG. 6 . The planar heater 3351 may form the underside of a cavity in the aerosol-generating device and is configured to heat an aerosol-forming substrate as described herein. In the specific embodiment of FIG. 33 , the planar heater 3351 comprises a first heating zone 3352, a second heating zone 3353, a third heating zone 3354, and a fourth heating zone 3355 spaced successively between a first lateral end 3373 of the heater and a second lateral end 3374 of the heater. The separate heating zones may be formed from separate resistive heater tracks. Alternatively, the heater may be an induction heater, and the heating zones may be implemented by separate induction coils acting on the susceptor material of the first or second zones. The heating zones may operate independently or together, allowing for sequential heating of portions of the aerosol-forming substrate.

[0288] Figure 34 shows an aerosol-generating device 3400 configured for use with an aerosol-generating article comprising or consisting of an aerosol-forming substrate as described herein. Device 3400 is similar to device 600 described above in connection with Figure 6. A cavity 3450 is defined within device 3400, with cavity 3450 having an opening 3453 defined at the proximal end 3441 of the device. Opening 3453 is dimensioned to accommodate the cross-section of the aerosol-forming substrate. The cavity comprises an upper planar surface 3451 and a lower planar surface 3452. Heaters 3460 and 3461 are disposed on both the lower planar surface 3452 and the upper planar surface and heat both the upper and lower surfaces of an aerosol-forming substrate or article inserted into cavity 3450.

[0289] FIG. 35 illustrates an aerosol-generating device 3500 configured for use with an aerosol-generating article comprising or consisting of an aerosol-forming substrate as described herein. The device 3500 is similar to the device 600 described above in connection with FIG. 6. A cavity 3550 is defined within the device 3500, with the cavity 3550 having an opening 3553 defined at the proximal end 3541 of the device. The opening 3553 is sized to accommodate the cross-section of the aerosol-forming substrate. The cavity has an upper planar surface 3551 and a lower planar surface 3552. Susceptors 3560 and 3561 are disposed on either side of the lower planar surface 3552 and protrude into the cavity. The protruding susceptor 3561 is in the shape of a pin or rod and is configured to penetrate a portion of the aerosol-generating article to heat the article from the inside. An induction coil 3463 surrounds the cavity and is configured to generate a varying magnetic field to heat the susceptors 3560 and 3561.

[0290] Figure 36 illustrates an aerosol-generating device 3600 configured for use with an aerosol-generating article comprising or consisting of an aerosol-forming substrate as described herein. The device 3600 is similar to the device 600 described above in connection with Figure 6. A cavity 3650 is defined within the device 3600, the cavity 3650 having an opening 3653 defined at a proximal end 3641 of the device. The opening 3653 is dimensioned to accommodate the cross-section of the aerosol-forming substrate. The cavity comprises an upper planar surface 3651 and a lower planar surface 3652. A susceptor 3660 is disposed within the lower planar surface 3652. A planar induction coil 3663 is disposed below the cavity and configured to generate a varying magnetic field to heat the susceptor 3660.

[0291] Figure 37 illustrates an aerosol-generating device 3700 configured for use with an aerosol-generating article 3701 that includes or consists of an aerosol-forming substrate as described herein. The device 3700 is similar to the device 600 described above in connection with Figure 6. A cavity 3750 is defined within the device 3700, the cavity 3750 having an opening 3753 defined at the proximal end 3741 of the device. The opening 3753 is dimensioned to accommodate the cross-section of the aerosol-forming substrate. The cavity comprises an upper planar surface 3751 and a lower planar surface 3752. The upper planar surface 3751 and the lower planar surface 3752 are not parallel, but rather converge slightly between the opening and the distal end 3754 of the cavity. This convergence allows the planar surfaces of the cavity to grip the aerosol-generating article 3701 when inserted into the cavity for consumption.

[0292] Figure 38 illustrates an aerosol-forming substrate 3800 comprising a corrugated layer consisting of a first planar layer 3802, a second planar layer 3804, and standard corrugation elements 3806 between the first planar layer 3802 and the second planar layer 3804. Figure 38 also illustrates the thickness direction 3811, cross direction 3812, and machine direction 3813 of the standard corrugation elements 3806.

[0293] 39 is an exploded view of an aerosol-generating article 3900. Article 3900 comprises a first planar layer 3910, a corrugated layer 3920, and a second planar layer 3930. Corrugated layer 3920 is disposed between first planar layer 3910 and second planar layer 3930. Corrugated layer 3920 includes first corrugated elements 3922, second corrugated elements 3924, and third corrugated elements 3926.

[0294] The article 3900 includes an upstream end 3940 and a downstream end 3942. The first planar layer 3910, the corrugated layer 3920, and the second planar layer 3930 all extend from the upstream end 3940 to the downstream end 3942. The article 3900 also has an article length 3944, defining an article airflow path that extends from the upstream end 3940 to the downstream end 3942. The downstream end 3942 may also be referred to as the mouth end, and it is intended that a user breathe on the mouth end during use of the article 3900.

[0295] The first planar layer 3910 is formed from a sheet of paper having a thickness of 300 microns. The second planar layer 3930 is formed from a sheet of paper having a thickness of 300 microns. The first corrugation element 3922, the second corrugation element 3924, and the third corrugation element 3926 are each formed from an aerosol-forming material, such as a sheet of homogenized tobacco. Each of the three sheets of aerosol-forming material is 150 microns thick. The three sheets are bent or folded to form the corrugations of the corrugation elements 3922, 3924, and 3926. The corrugations have a wavelength of 3 millimeters and an amplitude of 1.5 millimeters. The corrugations of the first corrugation element 3922 and the second corrugation element 3924 are sinusoidal, while the corrugation of the third corrugation element 3926 is a symmetric triangular (or zigzag) corrugation. Thus, the peak-to-trough amplitude and thickness of the corrugated layer are twice the amplitude at 3 millimeters.

[0296] The peaks of each of the corrugation elements 3922, 3924, 3926 contact the lower surface of the second planar layer 3230. The troughs of each of the corrugation elements 3922, 3924, 3926 contact the upper surface of the first planar layer 3210. Adhesive is present at these contact points, bonding the layers together.

[0297] Article 3900 has an article length extending in the x dimension of 80 mm, an article width extending in the y dimension of 15 mm, and an article thickness extending in the z dimension of 3.6 mm.

[0298] The upstream end of the first corrugation element 3922 is aligned with the upstream ends of the first and second planar layers 3910 and 3930 and the upstream end of the article 3900. The first corrugation element 3922 extends approximately 10 millimeters in the x-direction from its upstream end to its downstream end. There is a 5 millimeter space in the x-direction between the downstream end of the first corrugation element 3922 and the upstream end of the second corrugation element 3924. The second corrugation element 3924 extends approximately 50 millimeters in the x-direction from its upstream end to its downstream end. There is a 5 millimeter space in the x-direction between the downstream end of the second corrugation element 3924 and the upstream end of the third corrugation element 3926. The third corrugation element 3926 extends approximately 10 millimeters in the x-direction from its upstream end to its downstream end. The downstream end of the third corrugated element 3926 is aligned with the downstream ends of the first planar layer 3910 and the second planar layer 3930 and the downstream end of the article 3900 .

[0299] Thus, the three corrugated elements 3922, 3924, 3926 collectively extend along 70 millimeters of the 80 millimeter article length, or approximately 87.5% of the article length. Also, in this embodiment, the only sheet of aerosol-forming material forming the second corrugated element 3924 extends along 50 millimeters of the 80 millimeter article length, or approximately 62.5% of the article length. In another embodiment, there may be no spaces between the three corrugated elements 3922, 3924, 3926, such that the corrugated elements collectively extend along the entire length of the article. In another embodiment, one or both of the first planar layer 3910 and the second planar layer 3930 may be formed from a sheet of aerosol-forming material, such that the sheet of aerosol-forming material of the article collectively extends along the entire length of the article.

[0300] The transverse direction of the first corrugation element 3922 and the third corrugation element 3926 is parallel to the x-direction, the article length, and the article airflow path direction. Thus, in use, air flows transversely of the first corrugation element 3922 and the third corrugation element 3926 through channels defined by the corrugations of the first corrugation element 3922 and the third corrugation element 3926.

[0301] The transverse direction of the second corrugation elements 3924 is parallel to the y-direction and therefore perpendicular to the x-direction, the article length, and the article airflow path direction. Thus, in use, air flows through the holes in the second corrugation elements 3924 and across the channels defined by the corrugations of the second corrugation elements 3924 in the machine direction, i.e., the wavelength direction of the second corrugation elements 3924.

[0302] Article 3900 can be used with an aerosol-generating device, such as one of those described above, to generate an inhalable aerosol. For example, article 3900 could replace the substrate 10 shown in Figure 8. Article 3900 could effectively replace the aerosol-forming substrate 10 of any of Figures 10-13.

[0303] FIG. 40 is an exploded view of an aerosol-generating article 4000 that is identical to article 3900 of FIG. 39, except that corrugated layer 3920 has been replaced by another corrugated layer 4020.

[0304] The corrugated layer 4020 includes three corrugated elements 4021, 4023, 4025. The three corrugated elements 4021, 4023, 4025 extend from the upstream end to the downstream end of the article 4000 and are each formed from a sheet of aerosol-forming material, e.g., homogenized tobacco material mixed with glycerin, having a sheet thickness of 150 microns. Thus, in this embodiment, the corrugated elements and the sheet of aerosol-forming material extend along the entire length of the article.

[0305] The transverse direction of each of the three corrugation elements 4021, 4023, 4025 is parallel to the z-direction and therefore perpendicular to the x-direction, the article length, and the article airflow path direction. In use, air flows in the machine, or wavelength, direction of the corrugation elements 4021, 4023, 4025 through the passages defined between adjacent corrugation elements.

[0306] 41 illustrates an end view of an aerosol-forming substrate 4110 according to one embodiment of the present invention. The aerosol-forming substrate 4110 comprises a planar upper layer 4120, a planar lower layer 4130, and an intermediate or separating layer 4140 disposed between the upper layer 4120 and the lower layer 4130.

[0307] Both the planar top layer 4120 and the planar bottom layer 4130 are formed from a sheet of aerosol-forming material (e.g., a sheet of homogenized tobacco) having a thickness of approximately 200 microns. The aerosol-forming material may be any suitable aerosol-forming material, such as any of the aerosol-forming materials described above. The middle layer 4140 is a corrugated element formed from a corrugated sheet of non-aerosol-forming material. A suitable non-aerosol-forming material may be paper, or card, or a polymeric sheet. Thus, the middle layer 4140 may be formed from a corrugated sheet of paper. The intersections between the top and middle layers, and between the bottom and middle layers, include adhesive joining the respective layers.

[0308] The corrugations have a peak-to-trough amplitude of 3 mm and a wavelength of 3 mm. The sheet forming the intermediate layer 4140 has a thickness of approximately 300 microns. The corrugations forming the intermediate layer are triangular in shape. The triangular shape of the corrugations is achieved by using a stiff intermediate layer material (i.e., a sheet of paper) and scoring the paper as the corrugations are formed. As a result, triangular corrugations provide a stiffer substrate than corrugations with a sinusoidal profile, allowing for a smaller contact area between the intermediate layer and the upper and lower layers. When the upper and lower layers are heated, the reduced contact area means that heat loss from the upper or lower layer to the intermediate layer is minimized. This reduces the effect of cold spots in the upper and lower layers, which can cause a decrease in aerosol generation efficiency. This is particularly advantageous when the aerosol-forming substrate 4110 is heated by heaters disposed externally to the upper and lower surfaces (e.g., one or more planar heaters disposed above the upper surface and / or below the lower surface).

[0309] The aerosol-forming substrate 4110 has a length extending in the x-dimension of 80 mm, a width extending in the y-dimension of 15 mm, and a thickness extending in the z-dimension of 3.6 mm.

[0310] The triangular corrugations of the middle layer 4140 form a first set of longitudinally extending channels 4161 bounded by the top layer 4120 and the middle layer 4140, and a second set of longitudinally extending channels 4162 bounded by the bottom layer 4130 and the middle layer 4140. The first and second sets of longitudinally extending channels 4161, 4162 extend through the length dimension of the aerosol-forming substrate. The longitudinally extending channels 4161, 4162 define an airflow path through the substrate 4110. The porosity of the aerosol-forming substrate along the airflow path is approximately 90%. This provides a very low draw resistance of less than 5 mmH2O.

[0311] 42 illustrates an end view of an aerosol-forming substrate 4210 according to one embodiment of the present invention. The aerosol-forming substrate 4210 comprises a planar upper layer 4220, a planar lower layer 4230, and an intermediate or separating layer 4240 disposed between the upper and lower layers 4220, 4230.

[0312] Both planar upper layer 4220 and planar lower layer 4230 are formed from a sheet of aerosol-forming material (e.g., a sheet of homogenized tobacco) having a thickness of approximately 200 microns. The aerosol-forming material may be any suitable aerosol-forming material, such as any of the aerosol-forming materials described above. Middle layer 4240 includes a plurality of ribs 4241 of a non-aerosol-forming material. Ribs 4241 may be referred to as separating members. Suitable non-aerosol-forming materials may be paper, card, or a polymeric sheet. Thus, middle layer 4240 may be formed from a plurality of paper ribs, each rib 4241 extending between upper layer 4220 and lower layer 4230. The intersections of the ribs 4241 with the upper layer of middle layer 4240 and the intersections of the ribs with the lower layer of middle layer constitute adhesive bonding the layers together.

[0313] Each rib 4241 is formed from a strip of non-aerosol-forming material having a length, width, and thickness. By way of example, each rib 4241 may have a length of approximately 100 mm, a width of approximately 3 mm, and a thickness of approximately 300 microns. The width dimension of each strip is aligned to provide separation between the upper and lower layers. Thus, the multiple ribs provide a 3 mm separation between the upper and lower layers. When the upper and lower layers are heated, the small contact area between the upper and lower layers and the ribs minimizes heat loss from the upper or lower layer to the intermediate layer. This reduces the effect of cold spots in the upper and lower layers, which can cause a decrease in aerosol generation efficiency. This is particularly advantageous when the aerosol-forming substrate 4210 is heated by heaters disposed externally to the upper and lower surfaces (e.g., one or more planar heaters disposed above the upper surface and / or below the lower surface).

[0314] During substrate formation, the individual ribs 4241 may be joined together, for example, to form an array. By way of example, adjacent ribs may be joined by one or more laterally extending connectors. Joining the ribs in this manner may facilitate easier handling of the intermediate layer structure during substrate formation.

[0315] The aerosol-forming substrate 4210 has a length extending in the x-dimension of about 100 mm, a width extending in the y-dimension of about 12 mm, and a thickness extending in the z-dimension of about 3.4 mm.

[0316] The spaces between the ribs 4241 of the intermediate layer 4240 form longitudinally extending channels 4261 bounded by the upper layer 4220, the lower layer 4230, and the ribs 4241 of the intermediate layer 4140. The longitudinally extending channels 4261 extend through the length dimension of the aerosol-forming substrate. The longitudinally extending channels 4261 define an airflow path through the substrate 4210. The porosity of the aerosol-forming substrate along the airflow path is approximately 90%. This provides a very low draw resistance of less than 5 mmH2O.

[0317] Figure 43 is a top plan view of the aerosol-forming substrate 4210 described with reference to Figure 42. The location of the individual ribs 4241 is illustrated by the dashed lines in Figure 43. The airflow path extends from the distal end 4372 of the substrate to the proximal end 4371 of the substrate through channels defined by the ribs.

[0318] Figure 44 is a top plan view of a further aerosol-forming substrate 4410 described with reference to Figure 42. The location of individual ribs 4441 is illustrated by dashed lines in Figure 44. In contrast to the substrate of Figure 44, the ribs are laterally twisted or convoluted. Each rib is therefore free to stand on its edge, which may aid assembly. The airflow path passes through the twisted channels defined by the ribs and extends from the distal end 4472 of the substrate to the proximal end 4471 of the substrate.

[0319] The ribs do not need to be longitudinally aligned within the substrate. FIG. 45 is a top plan view of an aerosol-forming substrate having an intermediate layer including one or more ribs 4541. The individual ribs are twisted laterally and positioned between the upper and lower layers of the substrate. As shown schematically in FIG. 45, the individual ribs 4541 can function as longitudinal pillars, separating the upper and lower layers. The ribs can be longitudinally, laterally, or diagonally positioned within the substrate. Great flexibility in rib placement may be provided, allowing for the creation of various airflow channels and chambers within the substrate while minimizing heat loss caused by electrical conductivity between the upper and lower layers and the separating layer.

[0320] Figures 46, 47, and 48 illustrate end, side, and top views, respectively, of an aerosol-forming substrate 4610 according to one embodiment of the invention. The aerosol-forming substrate 4610 comprises a planar upper layer 4620, a planar lower layer 4630, and an intermediate or separating layer 4640 disposed between the upper and lower layers 4620, 4630.

[0321] Both the planar upper layer 4620 and the planar lower layer 4630 are formed from a sheet of aerosol-forming material (e.g., a sheet of homogenized tobacco) having a thickness of approximately 200 microns. The aerosol-forming material may be any suitable aerosol-forming material, such as any of the aerosol-forming materials described above. The middle layer 4640 is a three-dimensional element formed from a profiled or textured sheet of non-aerosol-forming material. Suitable non-aerosol-forming materials may be paper, or card, or a polymeric sheet. Thus, the middle layer 4640 may be formed from a profiled or textured paper sheet.

[0322] The sheet forming the middle layer is profiled to form a plurality of upwardly extending pillars 4642 and a plurality of downwardly depending pillars 4643. Termination points 4645 of the upwardly extending pillars 4642 contact the lower surface of the upper layer, and termination points 4646 of the downwardly depending pillars 4643 contact the upper surface of the lower layer. The thickness of the middle layer, the distance in the z dimension between the termination points of the downwardly depending layers and the termination points of the upwardly depending layers, is 2.5 mm.

[0323] The intersections between the top and middle layers and between the bottom and middle layers include adhesive that joins the respective layers.

[0324] Because the middle layer contacts the upper and lower layers only at distinct points 4648, heat transfer between the layers is minimized, reducing cold spots when the aerosol-forming material is heated. While individual pillars may be used to separate the upper and lower layers in some embodiments of the invention, the use of pillars extending upward and downward from the sheet of material may provide handling advantages during manufacture of the substrate. The upwardly and downwardly depending pillars 4642, 4643 may be formed by an embossing process on the sheet of material or may be formed within the sheet of material during its manufacture. The upwardly and downwardly depending pillars may have any suitable profile. The pillars may be pyramidal or conical, for example. The middle layer may resemble the shape of an egg carton.

[0325] The aerosol-forming substrate has a length extending in the x-dimension of about 90 mm, a width extending in the y-dimension of about 18 mm, and a thickness extending in the z-dimension of about 3.1 mm.

[0326] An airflow path is defined through the substrate both above and below the intermediate layer. The porosity of the aerosol-forming substrate along the airflow path is approximately 90-98%. This results in a very low draw resistance of less than 5 mmH2O. In fact, the RTD is nearly zero.

[0327] Figures 49, 50, and 51 illustrate a sinusoidal "egg crate" surface 4960 that may be used as an intermediate or separating layer in an aerosol-forming substrate disclosed herein. Figure 49 illustrates a first continuous sinusoidal curve 4912 extending in the x-direction, and Figure 50 illustrates a second continuous sinusoidal curve 4913 extending in the y-direction. Translating the first continuous sinusoidal curve with the second continuous sinusoidal curve results in a sinusoidal surface 4960. The sinusoidal surface includes a plurality of upwardly extending sinusoidal pillars 4962 and a plurality of downwardly depending sinusoidal pillars 4963.

[0328] Figure 52 illustrates a continuous trapezoidal curve 5212, which may be translated perpendicularly to itself to form a surface 5260 including a plurality of upwardly extending truncated pyramidal pillars 5262 and a plurality of downwardly depending truncated pyramidal pillars 5263. Figure 54 shows a perspective view of surface 5260. Surface 5260 may be used as an intermediate or separating layer in an aerosol-forming substrate as disclosed herein, and Figure 55 illustrates potential airflow paths that may be formed within a substrate including an intermediate layer having the form of surface 5260.

[0329] Figure 56 is a further schematic plan view of a surface 5660 formed by translating two trapezoidal curves vertically to form a surface with rectangular peaks 5662 and troughs 5663. Figure 56 also illustrates potential airflow paths that may be formed within a substrate including an intermediate layer having the form of surface 5660.

[0330] Figure 57 illustrates a further schematic plan view of surface 5760 formed by translating two trapezoidal curves vertically to form a surface with rectangular peaks 5762 and troughs 5763. Figure 56 also illustrates potential airflow paths that may be formed within a substrate including an intermediate layer having the form of surface 5760. Note that surface 5760 in Figure 57 has the same structure as surface 5660 in Figure 56, but the orientation of the surface has been changed by a 90 degree rotation, forming a more tortuous airflow path within the substrate, potentially improving aerosol mixing and generation.

[0331] For purposes of this specification and the appended claims, unless otherwise indicated, all numerical values ​​expressing amounts, quantities, percentages, and the like are to be understood as being modified in all instances by the term "about." Also, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically recited herein. Thus, in this context, a numerical value A is understood as A ± 10% for A. In this context, a numerical value A can be considered to include numerical values ​​that fall within the typical standard error of measurement for the property that A modifies. In some instances, as used in the appended claims, the number A may deviate by the percentages recited above, provided that the amount by which A deviates does not materially affect the basic and novel characteristics of the claimed invention. Also, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically recited herein.

Claims

1. A substantially planar aerosol-forming substrate comprising an upper layer and a lower layer, the upper layer and the lower layer being arranged as substantially parallel planes separated by a separation layer positioned between the upper layer and the lower layer, the separation layer comprising or consisting of one or more separation members extending between an upper surface of the lower layer and a lower surface of the upper layer.

2. 10. The substrate of claim 1, wherein the separating members are ribs or posts separating the upper layer from the lower layer, e.g., the separating members are longitudinally extending separating members.

3. 10. The substrate of claim 1, wherein the one or more separating members comprise or consist of pillars separating the upper layer from the lower layer.

4. 4. The substrate of claim 1, wherein the separation layer comprises a separation member having a plurality of upwardly extending portions supporting the lower surface of the upper layer and a plurality of downwardly depending portions supporting the upper surface of the lower layer.

5. The substrate of any of claims 1 to 4, wherein one or more separating members are formed as a textured or embossed sheet having upwardly depending protrusions and downwardly depending protrusions.

6. The substrate of any of claims 1 to 5, wherein an airflow path is defined through the substrate between the upper layer and the lower layer.

7. 7. The substrate of claim 1 or any one of claims 3 to 6, wherein the separation layer is a sinusoidal surface, for example, the separation layer has a surface or profile obtained, for example, by translating a first periodic curve perpendicularly to a second periodic curve, for example, by translating a first continuous periodic curve perpendicularly to a second continuous periodic curve, for example, by translating a first sinusoidal curve perpendicularly to a second sinusoidal curve.

8. 8. The substrate of claim 7, wherein the intermediate or separating layer is shaped like an egg carton.

9. The substrate of any one of claims 4 to 8, wherein the upwardly extending portion and / or the downwardly depending portion have a substantially circular or substantially rectangular planar profile.

10. 10. The substrate of any one of claims 1 to 9, comprising an upper layer, a lower layer, and a separation layer disposed between the upper layer and the lower layer, wherein the upper layer comprises or consists of a first aerosol-forming material, the upper layer comprises or consists of a second aerosol-forming material, and the separation layer does not comprise an aerosol-forming material.

11. 11. The substrate of claim 10, wherein the first aerosol-forming material and the second aerosol-forming material are the same type of aerosol-forming material, e.g., have the same composition, or the first aerosol-forming material and the second aerosol-forming material are different types of aerosol-forming material, e.g., have different compositions.

12. 12. An aerosol-generating article for use in an aerosol-generating device to generate an inhalable aerosol, said aerosol-generating article comprising an aerosol-forming substrate according to any one of claims 1 to 11.

13. 13. The aerosol-generating article of claim 12, wherein the aerosol-forming substrate is disposed within an outer wrapper or outer casing.

14. 14. The aerosol-generating article of claim 12 or 13, wherein the article comprises a first section and a second section removably connectable to the first section, the first section comprising an aerosol-forming substrate according to any one of claims 1 to 11, and the second section being a mouthpiece.

15. 15. The aerosol-generating article of claim 14, wherein the second section is a reusable mouthpiece designed for use with multiple first sections.

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