Dielectrically heated aerosol generating system with segmented heater

Abstract

A dielectrically heated aerosol generating system comprising an aerosol-forming substrate (51), a plurality of electrode pairs, and an aerosol generating device. Each electrode pair comprises a first electrode (41) spaced apart from a second electrode (42). The aerosol generating device comprises a controller configured to be connected to each electrode pair. Each electrode pair forms a capacitor with a portion of the aerosol-forming substrate (51). The controller is configured to supply an AC voltage to the plurality of electrode pairs to dielectrically heat the aerosol-forming substrate (51).

Description

[Technical field]

[0001] The present disclosure relates to an aerosol generating system, in particular to a dielectrically heated aerosol generating system. The present disclosure also relates to an aerosol generating device for use in the aerosol generating system, and to an aerosol generating article for use in the aerosol generating system. The present disclosure further relates to a method for dielectrically heating an aerosol-forming substrate. [Background technology]

[0002] Known electrically operated aerosol generating systems typically heat the aerosol-forming substrate by one or more of the following: conducting heat from a heating element to the aerosol-forming substrate, radiating heat from a heating element to the aerosol-forming substrate, or drawing heated air through the aerosol-forming substrate. Most commonly, heating is achieved by passing an electric current through an electrically resistive heating element, causing Joule heating of the heating element. Induction heating systems have also been proposed, where Joule heating occurs as a result of eddy currents induced in a susceptor heating element.

[0003] One problem with these heating mechanisms is that they can result in uneven heating of the aerosol-forming substrate: the portion of the aerosol-forming substrate closest to the heating element heats faster or to a higher temperature than the portion of the aerosol-forming substrate further away from the heating element.

[0004] A system for dielectrically heating an aerosol-forming substrate has been proposed which advantageously provides uniform heating of the aerosol-forming substrate. It would be desirable to provide a system for dielectrically heating an aerosol-forming substrate in a manner that allows for greater heating control whilst being feasible in a compact system. Summary of the Invention

[0005] In the present disclosure, a dielectrically heated aerosol generation system is provided. The aerosol generation system may include an aerosol-forming substrate. The aerosol generation system may include a plurality of electrode pairs, each electrode pair including a first electrode spaced apart from a second electrode. The aerosol generation system may include an aerosol generation device. The aerosol generation device may include a controller configured to be connected to each electrode pair. Each electrode pair may form a capacitor with a portion of the aerosol-forming substrate. The controller may be configured to supply an AC voltage to the plurality of electrode pairs to dielectrically heat the aerosol-forming substrate.

[0006] Such an aerosol-generating system is configured to generate dielectric heating of the aerosol-forming substrate due to an alternating electromagnetic field generated between the first and second electrodes of each electrode pair when an alternating voltage is applied to the first and second electrodes of each electrode pair. The dielectric heating can be uniform in the aerosol-forming substrate without the generation of hot spots. In particular, the dielectric heating reduces the possibility of combustion of the aerosol-forming substrate in contact with the first and second electrodes of each electrode pair, as compared to conventional heating that transfers heat to the aerosol-forming substrate via conduction.

[0007] Advantageously, an aerosol-generating system comprising multiple electrode pairs may provide improved control of the dielectric heating of the aerosol-forming substrate, since different parts of the aerosol-forming substrate may be heated differently, either at different times, or to different temperatures. An appropriate alternating voltage may be supplied to each electrode pair to generate the desired aerosol from that part of the aerosol-forming substrate.

[0008] The portion of the aerosol-forming substrate disposed between each electrode pair may have different properties. This may allow the properties of the aerosol generated by the aerosol generating system to be varied throughout the user experience. Advantageously, this may provide an optimal experience for the user. As an example, each different portion of the aerosol-forming substrate may have a different thickness to generate a desired volume of aerosol or aerosol generation rate of aerosol at different stages of a use session of the aerosol generating system. In a further example, each different portion of the aerosol-forming substrate may have a different composition that generates aerosols with different flavors to generate varying aerosol flavors at different stages of a use session of the aerosol generating system. Providing the aerosol generating system with multiple electrode pairs allows selectively controlled heating of different portions of the aerosol-forming substrate to obtain the desired aerosol properties at each stage of the user experience. This control may be achieved, for example, by varying the separation distance between the first and second electrodes of each electrode pair, by varying the geometric shape of the first and second electrodes of each electrode pair, or by varying the magnitude or frequency of the AC voltage supplied to each electrode pair.

[0009] In the systems of the present disclosure, the multiple electrode pairs may be arranged in any suitable manner. In some embodiments, the aerosol generating device comprises multiple electrode pairs. In some embodiments, the aerosol generating system comprises an aerosol generating article comprising an aerosol-forming substrate, the aerosol generating article further comprising multiple electrode pairs. In some embodiments, the aerosol generating system comprises an aerosol generating article comprising an aerosol-forming substrate, the aerosol generating device comprises at least one electrode of the multiple electrode pairs, and the aerosol generating article comprises at least one electrode of the multiple electrode pairs.

[0010] As used herein, the term "aerosol-forming substrate" relates to a substrate capable of releasing volatile compounds capable of forming an aerosol. Such volatile compounds may be released by heating the aerosol-forming substrate. The aerosol-forming substrate is typically part of an aerosol-generating article.

[0011] As used herein, the term "aerosol-generating article" refers to an article that includes an aerosol-forming substrate capable of releasing a volatile compound capable of forming an aerosol. For example, the aerosol-generating article may be an article that generates an aerosol that can be directly inhaled by a user sucking or puffing on a mouthpiece. The aerosol-generating article may be disposable. An article that includes an aerosol-forming substrate that includes tobacco may be called a tobacco stick.

[0012] As used herein, the term "aerosol-generating device" refers to a device that interacts with an aerosol-forming substrate to generate an aerosol. The aerosol-generating article is separate from and configured to be combined with the aerosol-generating device for heating the aerosol-generating article.

[0013] As used herein, the term "aerosol-generating system" refers to the combination of an aerosol-generating device with an aerosol-forming substrate. In an aerosol-generating system, the aerosol-forming substrate and the aerosol-generating device work together to generate an aerosol.

[0014] The aerosol generating system includes an aerosol generating device.

[0015] The present disclosure also provides an inductively heated aerosol generating device. The aerosol generating device includes a plurality of electrode pairs, each electrode pair including a first electrode spaced apart from a second electrode. The aerosol generating device further includes a controller connected to each electrode pair. The device is configured to receive an aerosol-forming substrate. Each electrode pair forms a capacitor with at least a portion of the aerosol-forming substrate. The controller is configured to supply an alternating voltage to the plurality of electrode pairs to inductively heat the aerosol-forming substrate.

[0016] The aerosol-generating system comprises an aerosol-forming substrate. In some preferred embodiments, the aerosol-generating system comprises an aerosol-generating article comprising the aerosol-forming substrate. The aerosol-generating device may be configured to receive the aerosol-generating article. The aerosol-generating device may comprise an article cavity configured to receive at least a portion of the aerosol-generating article.

[0017] The present disclosure also provides an aerosol-generating article for a dielectrically heated aerosol generating system. The aerosol-generating article includes an aerosol-forming substrate. The aerosol-generating article further includes a plurality of electrode pairs, each electrode pair including a first electrode spaced apart from a second electrode. Each electrode pair forms a capacitor with at least a portion of the aerosol-forming substrate. Preferably, at least a portion of the aerosol-forming substrate is disposed between the first electrode and the second electrode of each of the plurality of electrode pairs.

[0018] In an aerosol generating system in which an aerosol generating article is provided, the aerosol generating article comprising at least one electrode of the plurality of electrodes, the aerosol generating device may comprise at least one electrical contact. The electrical contact of the aerosol generating device may be arranged to be electrically connected to an electrode of the aerosol generating article. When the aerosol generating article comprises a plurality of electrodes, the aerosol generating device may comprise a plurality of electrical contacts. The electrical contact of the aerosol generating device may be arranged to be electrically connected to an electrode of the aerosol generating article when the aerosol generating article is received by the aerosol generating device.

[0019] In an aerosol generating system in which an aerosol-generating article is provided and the aerosol generating device includes an article cavity configured to receive at least a portion of the aerosol-generating article, at least a portion of the aerosol-forming substrate may be located within the article cavity when at least a portion of the article is received within the cavity. A plurality of electrodes may also be located within the article cavity when at least a portion of the article is received within the article cavity. At least a portion of the aerosol-forming substrate may be received between each pair of electrodes when at least a portion of the article is received within the article cavity. If the aerosol-generating article includes at least one electrode and the aerosol generating device includes at least one electrical contact configured to be electrically connected to the electrode of the aerosol-generating article, the at least one electrical contact may be disposed within the article cavity.

[0020] Where the aerosol-generating article includes an electrode pair, the first and second electrodes of the electrode pair may be disposed on opposite sides of the article. Where the aerosol-generating device includes an electrode pair and an article cavity, the first and second electrodes of the electrode pair may be disposed on opposite sides of the article cavity.

[0021] Each electrode pair forms a capacitor. Each capacitor may include a first electrode and a second electrode. Each capacitor may include a first electrode, a second electrode, and a portion of the aerosol-forming substrate. The aerosol-forming substrate may be disposed between the first electrode and the second electrode. In some embodiments, only the aerosol-forming substrate is disposed between the first electrode and the second electrode. In other words, the aerosol-forming substrate may be disposed directly between the first electrode and the second electrode without any intervening components. In some embodiments, the aerosol-forming substrate and one or more other components are disposed between the first electrode and the second electrode. In other words, the aerosol-forming substrate may be disposed indirectly between the first electrode and the second electrode with one or more additional intervening components disposed between at least one of the electrodes and the aerosol-forming substrate. For example, in some embodiments, the aerosol-generating system may comprise an aerosol-generating article including an aerosol-forming substrate and a wrapper surrounding the aerosol-forming substrate. In these embodiments, at least a portion of the aerosol-generating article may be disposed between the first electrode and the second electrode. In these embodiments, at least a portion of the aerosol-forming substrate and at least a portion of the wrapper may be disposed between the first electrode and the second electrode.

[0022] The aerosol-forming substrate may comprise one or more dielectric materials. The aerosol-forming substrate may be a dielectric material. The component disposed between the first electrode and the second electrode may comprise a dielectric material. The component disposed between the first electrode and the second electrode may be a dielectric material.

[0023] The aerosol generating device includes a controller configured to connect to each of the electrode pairs, the controller configured to supply an alternating voltage to the plurality of electrode pairs.

[0024] The controller may be configured to control the supply of AC voltage to the plurality of electrode pairs. In some embodiments, the controller may be configured to selectively control the supply of AC voltage to each electrode pair. In other words, the supply of AC voltage to a first electrode pair may be controlled independently of the supply of AC voltage to other electrode pairs. By selectively controlling the supply of AC voltage to each electrode pair, improved control over the heating of the aerosol-forming substrate is provided. For example, different portions of the aerosol-forming substrate may be heated at different times, for different durations, and to different temperatures during a session of use of the system.

[0025] In some embodiments, the controller may be configured to apply the AC voltage to one electrode pair at a time. A user input may be provided to the aerosol generating device to allow a user to control when the AC voltage is applied to each electrode pair. In some embodiments, the controller may be configured to selectively apply the AC voltage to each electrode pair in sequence. For example, the controller may first apply the AC voltage to only a first electrode pair and then apply the AC voltage to a second electrode pair.

[0026] In some embodiments, the controller is configured to selectively supply an AC voltage to each electrode pair in a sequence, where the controller supplies an AC voltage to a first electrode pair, and then the controller supplies an AC voltage to a second electrode pair after a condition is met. The second electrode pair may be adjacent to the first electrode pair. The second electrode pair may be located toward an opposite end of the aerosol-forming substrate from the first electrode pair. Supplying an AC voltage to each electrode pair in a sequence may advantageously allow the characteristics of the generated aerosol to be changed over time in a controlled manner.

[0027] In some embodiments, the sequence may be a predetermined sequence. The controller may include a memory that stores the predetermined sequence. The predetermined sequence may provide a consistent aerosol generation experience for a user.

[0028] In some embodiments, the controller can be configured to determine the sequence of application of the AC voltage to each electrode pair. A controller capable of determining the sequence of application of the AC voltage to each electrode pair can advantageously enable a customizable user aerosol generation experience.

[0029] In some embodiments, the controller may be configured to determine a sequence of application of the AC voltage to each electrode pair based on the sensed parameters, hi some embodiments, the sequence may be determined based on at least one of a temperature of one or more of the plurality of electrode pairs, a temperature of the aerosol-forming substrate, a temperature adjacent to the aerosol-forming substrate, activation of the smoke puff sensor, and a duration of application of the AC voltage to one or more of the plurality of electrode pairs.

[0030] In some embodiments, the controller may be configured to monitor which of the plurality of electrode pairs have received the supply of alternating voltage. The controller may further include a memory configured to store which of the plurality of electrode pairs have received the supply of alternating voltage. In some embodiments, the memory may be further configured to store one or more of the temperature of the electrode pair at the start of receiving the supply of alternating voltage, the temperature of the electrode pair at the end of receiving the supply of alternating voltage, the temperature of a portion of the aerosol-forming substrate disposed between the electrode pair at the start of receiving the supply of alternating voltage, the temperature of a portion of the aerosol-forming substrate disposed between the electrode pair at the end of receiving the supply of alternating voltage, and the duration of the supply of alternating voltage to the electrode pair. Monitoring and storing these parameters may enable the aerosol generation system to determine an optimal heating profile for aerosol generation from the aerosol-forming substrate.

[0031] The aerosol generating system comprises a plurality of electrode pairs. The plurality of electrode pairs may include any suitable number of electrode pairs. A small number of electrode pairs may simplify manufacturing costs and complexity by reducing the overall complexity of the system. A large number of electrode pairs may increase the degree of control over heating of the aerosol-forming substrate provided by the aerosol generating system. In some embodiments, the plurality of electrode pairs may include 2-20 electrode pairs. The plurality of electrode pairs may include 2-15 electrode pairs, or 2-12 electrode pairs, or 5-10 electrode pairs. In some preferred embodiments, the plurality of electrode pairs may include 2-6 electrode pairs.

[0032] Systems with 2-6 electrode pairs have been found to provide a satisfactory compromise between system complexity and the degree of heating control provided.

[0033] In some embodiments, the plurality of electrode pairs may include 2 electrode pairs, 3 electrode pairs, 4 electrode pairs, 5 electrode pairs, 6 electrode pairs, 7 electrode pairs, 8 electrode pairs, 9 electrode pairs, or 10 electrode pairs. In particularly preferred embodiments, the plurality of electrode pairs may include 9 electrode pairs.

[0034] In some embodiments, a first electrode of the plurality of electrode pairs may form a first electrode array, with each electrode in the first electrode array being spaced apart by an electrode spacing distance. A second electrode of the plurality of electrode pairs may form a second electrode array, with each electrode in the second electrode array being spaced apart by an electrode spacing distance. In some embodiments, the electrode spacing distance may be between about 0.1 millimeters and about 2 millimeters. The electrode spacing distance may be between about 0.5 millimeters and about 1.5 millimeters. In some particularly preferred embodiments, the electrode spacing distance may be about 1 millimeter.

[0035] If the electrode spacing is too large, unacceptable heat losses may occur between adjacent electrode pairs. However, if the electrode spacing is too small, the electromagnetic fields between each electrode pair may interfere with each other. An electrode spacing of about 0.1 mm to about 2 mm has been found to provide a satisfactory compromise between these two factors.

[0036] In some embodiments, the first electrically insulating material may be disposed between adjacent electrodes of the first electrode array. In some embodiments, the second electrically insulating material may be disposed between adjacent electrodes of the second electrode array. In some embodiments, at least one of the first electrically insulating material and the second electrically insulating material comprises polyetheretherketone (PEEK), polyaryletherketone (PAEK), polyphenylsulfone (PPSU), and ceramic. In a preferred embodiment, the first electrically insulating material and the second electrically insulating material are the same. Preferably, the first electrically insulating material and the second electrically insulating material have a melting temperature that exceeds the temperature required to vaporize the volatile compound from the aerosol-forming substrate. In a particularly preferred embodiment, the first electrically insulating material and the second electrically insulating material have a melting point that exceeds about 250 degrees Celsius.

[0037] As used herein, "electrically conductive" means made from a material having a resistivity of 1x10^-4 ohm-meter or less. As used herein, "electrically insulating" means made from a material having a resistivity of 1x10^4 ohm-meter or greater.

[0038] The first electrically insulating material is preferably a thermally insulating material. The second electrically insulating material is preferably a thermally insulating material. As used herein, the term "thermal insulating" is used to describe a material having a bulk thermal conductivity of about 40 milliwatts per meter Kelvin (W / (mK)) or less at 23 degrees Celsius and a relative humidity of 50 percent as measured using the Modified Transient Plane Source (MTPS) method.

[0039] The first electrodes of the first electrode array may be arranged in any suitable arrangement. Similarly, the second electrodes of the second electrode array may be arranged in any suitable arrangement. In some embodiments, the electrodes of the first electrode array may be substantially grid-like. In some embodiments, the electrodes of the second electrode array may be substantially grid-like. By making the electrode array grid-like, the fraction of the aerosol-forming substrate that can be directly disposed between the electrode pairs and then dielectrically heated by the electrode pairs can be increased compared to a non-grid-like electrode array. The grid-like electrode array can also reduce heat loss in the space between the electrode pairs.

[0040] In some embodiments, the first electrode of each electrode pair may be disposed substantially parallel to the second electrode of the electrode pair. If the first electrode is disposed in a first electrode array, the first electrode may be disposed on a first plane. If the second electrode is disposed in a second electrode array, the second electrode may be disposed on a second plane. The second plane may be parallel to the first plane.

[0041] In some embodiments, the first electrode of each electrode pair may have a first length and the second electrode of each electrode pair may have a second length. The second length may be substantially the same as the first length. The first length may be between about 3 millimeters and 50 millimeters. In some embodiments, the first length may be between about 5 millimeters and 30 millimeters. In some embodiments, the first length may be between about 5 millimeters and 25 millimeters. In some embodiments, the first length may be between about 5 millimeters and 20 millimeters. For example, the first length may be about 5 millimeters, about 6 millimeters, about 7 millimeters, about 8 millimeters, about 9 millimeters, about 10 millimeters, about 11 millimeters, about 12 millimeters, about 13 millimeters, about 14 millimeters, or about 15 millimeters.

[0042] The length of the electrodes determines in part the cross-section of the aerosol-forming substrate that is heated. Heating too little or too much of the aerosol-forming substrate can result in an undesirable user experience, for example by producing an undesirable amount or quality of aerosol. The length of the electrodes also determines the power required to generate an electromagnetic field between the electrodes. The electrode lengths provided in the present disclosure allow for the production of a desired amount and quality of aerosol without consuming excessive power.

[0043] The term "length" as used herein refers to the maximum longitudinal dimension of an aerosol-generating device, a component of an aerosol-generating device, an aerosol-generating article or a component of an aerosol-generating article.

[0044] In some embodiments, the first length of the first electrode of each electrode pair may be substantially the same. In other embodiments, the first length of one of the first electrodes of the plurality of electrode pairs may be different from the first length of the other of the first electrodes of the plurality of electrode pairs. By providing two or more electrode pairs of different sizes, different amounts of aerosol-forming substrates can be aerosolized. For example, more electrode pairs may be used at the beginning of a use session of the aerosol generating system, and then relatively fewer electrode pairs may be used toward the end of the use session. This may allow for a gradual decrease in the amount of aerosol generated during the use session. Alternatively, the system may be configured such that the amount of aerosol generated is configured to gradually increase during the use session.

[0045] In some embodiments, the first electrode of each electrode pair may have a thickness of about 0.02 millimeters to about 2 millimeters. Preferably, the first electrode of each electrode pair may have a thickness of about 0.1 millimeters to about 1 millimeter. Most preferably, the first electrode of each electrode pair may have a thickness of about 0.3 millimeters to about 0.5 millimeters. In some embodiments, the second electrode of each electrode pair may have a thickness of about 0.02 millimeters to about 2 millimeters. Preferably, the second electrode of each electrode pair may have a thickness of about 0.1 millimeters to about 1 millimeter. Most preferably, the second electrode of each electrode pair may have a thickness of about 0.3 millimeters to about 0.5 millimeters. In a preferred embodiment, the thickness of the first electrode of each electrode pair may be substantially the same as the thickness of the second electrode of each electrode pair.

[0046] If the first and second electrodes of each electrode pair are not thick enough, it may be difficult to keep the electrodes aligned with each other.For example, if one of the electrodes is not particularly thin and rigid, it may be difficult to ensure that the first and second electrodes of each electrode pair remain parallel.If the first and second electrodes of each electrode pair are too thick, they may act as heat sinks, resulting in reduced thermal efficiency of the system, leading to increased power requirements, reduced power efficiency, and reduced aerosol generation.

[0047] The term "thickness" as used herein refers to the maximum transverse dimension of an aerosol-generating device, or of a component of an aerosol-generating device, an aerosol-generating article, or a component of an aerosol-generating article. The transverse dimension is the dimension measured perpendicular to the longitudinal axis, which is the direction in which the length is measured.

[0048] The first and second electrodes of each electrode pair are spaced apart. The first and second electrodes of each electrode pair may be spaced apart by a separation distance. As used herein, the term "separation distance" refers to the minimum distance between the opposing surfaces of the first and second electrodes of an electrode pair. In some embodiments, the first and second electrodes of each electrode pair are configured to be spaced apart by a separation distance of about 0.1 millimeters to about 9 millimeters. In some embodiments, the separation distance may be configured to be about 0.1 millimeters to about 6 millimeters. The separation distance may preferably be configured to be about 0.1 millimeters to about 3 millimeters. The separation distance may be configured to be about 3 millimeters. In some embodiments, the separation distance may be configured to be about 0.1 millimeters, about 0.2 millimeters, about 0.3 millimeters, about 0.4 millimeters, about 0.5 millimeters, about 0.6 millimeters, about 0.7 millimeters, about 0.8 millimeters, about 0.9 millimeters, about 1 millimeter, about 2 millimeters, about 3 millimeters, about 4 millimeters, about 5 millimeters, about 6 millimeters, about 7 millimeters, about 8 millimeters, or about 9 millimeters.

[0049] In some embodiments, the separation distance depends on the type of aerosol-forming substrate that the aerosol-generating system is configured to use.

[0050] In embodiments for use with an aerosol-forming substrate that is a shisha substrate, described in more detail below, the first electrode of each electrode pair and the second electrode of each electrode pair are configured to be separated by a separation distance of about 2 millimeters to about 9 millimeters. In some embodiments, the separation distance may be configured to be about 2 millimeters to about 6 millimeters. The separation distance may be configured to be about 2 millimeters to about 4 millimeters. More preferably, the separation distance may be configured to be about 3 millimeters. In some embodiments, the separation distance may be configured to be about 2 millimeters, about 3 millimeters, about 4 millimeters, about 5 millimeters, about 6 millimeters, about 7 millimeters, about 8 millimeters, or about 9 millimeters.

[0051] In embodiments for use with non-shisha substrates, the first electrode of each electrode pair and the second electrode of each electrode pair are configured to be spaced apart by a separation distance of about 0.1 millimeters to about 9 millimeters, e.g., about 0.1 millimeters to about 8 millimeters, about 0.1 millimeters to about 7 millimeters, about 0.1 millimeters to about 6 millimeters, about 0.5 millimeters to about 6 millimeters, about 1 millimeters to about 6 millimeters, about 1 millimeters to about 5 millimeters, about 1 millimeters to about 4 millimeters, about 1 millimeters to about 3 millimeters, about 2 millimeters to about 3 millimeters.

[0052] In some embodiments, the first electrode of each electrode pair may include a first surface, and the second electrode of each electrode pair may include a second surface. The first surface of the first electrode may face the second surface of the second electrode. The surface area of ​​the electrode surfaces is a factor that determines the electromagnetic field strength between them, and therefore the degree of dielectric heating. The surface area of ​​the electrodes also partially determines the amount of aerosol-forming substrate that is heated.

[0053] In some embodiments, the surface area of ​​the first surface of a first electrode of an electrode pair may be the same as the surface area of ​​the second surface of a second electrode of the pair, hi some embodiments, the surface area of ​​the first surface of a first electrode of an electrode pair may be different from the surface area of ​​the second surface of a second electrode of the pair.

[0054] The surface area of ​​each of the first surfaces may be from about 5 square millimeters to about 3000 square millimeters. In some preferred embodiments, the surface area of ​​each of the first surfaces may be from about 20 square millimeters to about 2000 square millimeters. In some embodiments, the surface area of ​​each of the second surfaces may be from about 5 square millimeters to about 1000 square millimeters. In some preferred embodiments, the surface area of ​​each of the second surfaces may be from about 20 square millimeters to about 500 square millimeters.

[0055] Each electrode is electrically conductive. Each electrode may include a conductive material, such as a metal.

[0056] In some preferred embodiments, the first electrode of each electrode pair may be substantially identical to the second electrode of each electrode pair. In some embodiments, each of the electrodes in the plurality of electrodes has one of the following shapes: rectangular, square, pentagonal, hexagonal, or triangular. These shapes advantageously allow adjacent electrode pairs to be spaced closely together.

[0057] In some preferred embodiments, the first electrode of each electrode pair is substantially planar and the second electrode of each electrode pair is substantially planar. The first electrode of each pair may extend substantially in a first plane and the second electrode of each pair may extend substantially in a second plane. The first plane may be substantially parallel to the second plane.

[0058] In some embodiments, the first electrode of each electrode pair may surround the second electrode of the electrode pair. In some embodiments, the second electrode of each electrode pair may surround the first electrode of the electrode pair. In some preferred embodiments, the first electrode of each electrode pair may be substantially coaxial with the second electrode of the electrode pair. In some particularly preferred embodiments, the first and second electrodes of each electrode pair may be substantially cylindrical.

[0059] In some embodiments, the first electrode of each electrode pair may be annular and define an interior passage. The second electrode of each electrode pair may be disposed within the interior passage of the first electrode of that pair. The multiple electrode pairs may be coaxially disposed along the longitudinal axis.

[0060] In some embodiments, the aerosol generating device may include multiple electrode pairs. In other embodiments, the aerosol generating article may include multiple electrode pairs. In some embodiments, the aerosol generating device may include a first electrode of each electrode pair and the aerosol generating article may include a second electrode of each electrode pair. In other embodiments, the aerosol generating device may include a second electrode of each electrode pair and the aerosol generating article may include a first electrode of each electrode pair.

[0061] In some embodiments, at least one of the first electrode of each electrode pair and the second electrode of each electrode pair is gas permeable, allowing air to flow through the electrodes. In some embodiments, at least a portion of at least one of the first electrode and the second electrode of each electrode pair may be formed from a gas permeable material. In some embodiments, one or more slots are created in at least one of the first electrode and the second electrode of each electrode pair. The one or more slots may be of any shape, size, number, and arrangement to allow sufficient air to flow through the electrodes.

[0062] The frequency of the AC voltage supplied to the first and second electrodes of each electrode pair to heat the aerosol-forming substrate may depend on factors such as the separation distance and the aerosol-forming substrate properties. In some embodiments, the frequency of the AC voltage supplied to the first and second electrodes of each electrode pair may be 10 megahertz to 100 megahertz, preferably about 10 megahertz to about 80 megahertz, more preferably about 10 megahertz to about 40 megahertz, more preferably about 10 megahertz to about 30 megahertz. In a preferred embodiment, the frequency of the AC voltage supplied to the first and second electrodes may be about 20 megahertz. The AC voltage supplied to the first and second electrodes may be a radio frequency (RF) AC voltage. As used herein, the term "radio frequency (RF) AC voltage" refers to an AC voltage that is alternating at a frequency within the radio frequency (RF) range. As used herein, radio frequency (RF) refers to a frequency of about 20 kilohertz (kHz) to about 300 megahertz (MHz). Thus, as used herein, RF frequencies include microwave frequencies.

[0063] The aerosol generating device includes a controller. The controller may include a microprocessor, a programmable microprocessor, a microcontroller, or an application specific integrated circuit chip (ASIC) or other electronic circuitry capable of providing control. The controller may include additional electronic components. For example, in some embodiments, the controller may include a sensor element, a switch element, or a display element. The controller may include an RF power sensor. The controller may include a power amplifier.

[0064] In some embodiments, the controller may be configured to control one or more relay switch circuits, the relay switch circuits operable to control the supply of the AC voltage to the one or more electrode pairs. In some embodiments, the one or more relay switch circuits include a relay switch circuit for each electrode pair, each relay switch circuit operable to control the supply of the AC voltage to one electrode pair. In other embodiments, the one or more relay switch circuits include a first relay switch circuit operable to control the supply of the AC voltage to a first group of electrode pairs and a second relay switch circuit operable to control the supply of the AC voltage to a second group of electrode pairs.

[0065] In embodiments in which the controller has memory, the memory may be volatile memory. In some embodiments, the memory may be non-volatile memory. Non-volatile memory may advantageously allow the aerosol generation system to store parameters between use sessions of the aerosol generation system where power is not provided to the controller. For example, the aerosol generation system may be able to determine which portions of the aerosol-forming substrate were or were not aerosolized in a previous use session.

[0066] The aerosol generating device may include a power source. The power source may provide an alternating voltage to the electrode pair to heat the aerosol-forming substrate. The power source may be a rechargeable power source. The power source may be a DC power source. The power source may include at least one battery. The at least one battery may include a rechargeable lithium ion battery. Alternatively, the power source may be another form of charge storage device, such as a capacitor.

[0067] The aerosol generating device may be configured to connect to an external power source to recharge the rechargeable power source. In some embodiments, the aerosol generating device is configured to connect to an external power source. For example, the aerosol generating device may be configured to connect to a mains power source.

[0068] The power source can provide between about 10 watts and about 60 watts of power to the first electrode and the second electrode of each electrode pair.

[0069] If the power source is a DC power source, the aerosol generating device may further comprise a DC / AC converter arranged to convert a DC voltage from the DC power source into an AC voltage, which may be supplied directly or indirectly to the electrode pair.

[0070] The aerosol generating device may include a puff detector configured to detect when a user puffs on the aerosol generating system. As used herein, the term "puff" is used to refer to a user puffing on the aerosol generating system to receive an aerosol. The puff detector may include a temperature sensor. The puff detector may include a pressure sensor. The puff detector may include both a temperature sensor and a pressure sensor. When the aerosol generating device includes a puff detector, the controller may be configured to provide an alternating voltage to one or more electrode pairs to heat the aerosol-forming substrate when a puff is detected by the puff detector.

[0071] The aerosol generating device may comprise an oscillator circuit. The oscillator circuit may be arranged to supply an alternating voltage to the electrode pair to heat the aerosol-forming substrate. The oscillator circuit may be connected to a controller. The controller may be configured to control the oscillator circuit.

[0072] The oscillator circuit may include a radio frequency (RF) signal generator. The oscillator circuit may include a radio frequency (RF) signal generator for each electrode pair. The RF signal generator may be any suitable type of RF signal generator. In some embodiments, the RF signal generator is a solid-state RF transistor. Advantageously, the solid-state RF transistor may be configured to generate and amplify the RF electromagnetic field. Using a single transistor to provide both the generation and amplification of the RF electromagnetic field allows the aerosol generating device to be compact. The solid-state RF transistor may be, for example, an LDMOS transistor, a GaAs FET, a SiC MESFET, or a GaN HFET.

[0073] In some embodiments, the oscillator circuit may further include a frequency synthesizer disposed between the RF signal generator and the first electrode and the second electrode of each electrode pair. The oscillator circuit may include a frequency synthesizer for each electrode pair.

[0074] In some embodiments, the oscillator circuit may further include a phase shift network disposed between the RF signal generator and the first and second electrodes of each electrode pair. When the oscillator circuit includes a phase shift network, the phase shift network splits the RF energy received from the RF signal generator into two separate equal components that are out of phase with each other. Typically, the phase shift network provides one of the components to the first electrode of each electrode pair and the other component to the second electrode of each electrode pair. The two substantially equal components of the RF energy received from the RF signal generator are preferably substantially 90 degrees or 180 degrees out of phase with each other. The two substantially equal components may be out of phase with each other by any multiple of 90 degrees or 180 degrees. It will be understood that the exact phase relationship between the two components is not important, but rather that the two components are not in phase.

[0075] In some embodiments, the phase shift network is configured to split the RF energy from the RF signal generator into two substantially equal components, one out of phase with the other, with each component being applied to a different one of the first and second electrodes of each electrode pair.

[0076] In some embodiments, the oscillator circuit may include a phase shift network for each electrode pair.

[0077] The aerosol generating device is preferably portable. The aerosol generating device may have a size comparable to a conventional cigar or cigarette. The aerosol generating device may have an overall length of about 30 millimeters to about 150 millimeters. The aerosol generating device may have an outer diameter of about 5 millimeters to about 30 millimeters. The substrate cavity may have a diameter of 2 millimeters to 20 millimeters. The substrate cavity may have a length of 2 millimeters to 20 millimeters. The aerosol generating device may be a personal vaporizer, an electronic cigarette, or a heat-not-burn device.

[0078] In embodiments comprising an aerosol-generating article, the aerosol-generating article may take any suitable form.

[0079] The aerosol-generating article comprises an aerosol-forming substrate. In some preferred embodiments, the aerosol-generating article comprises one or more electrodes of a plurality of electrode pairs. The aerosol-generating article may have one or more additional components. For example, the aerosol-generating article may have a mouthpiece, such as a mouthpiece filter. The aerosol-generating article may have at least one of a cooling element and a spacing element.

[0080] In some embodiments, the aerosol-generating article comprises a rod, which may resemble a traditional cigarette or other smoking article.

[0081] In some embodiments, the aerosol-forming substrate is surrounded by a wrapper. The wrapper may be a housing or a container. Providing a wrapper that surrounds the aerosol-forming substrate may result in no or reduced need to clean the aerosol-generating device that received the aerosol-generating article. For example, in conventional aerosol-generating devices, during heating of the aerosol-forming substrate, residue may accumulate in the article cavity or on the heating element of the device. In some embodiments, the wrapper is configured to be pierced when inserted into the aerosol-generating device to allow airflow through the aerosol-forming substrate.

[0082] In some embodiments, the aerosol-forming substrate is surrounded by a gas-permeable wrapper. The gas-permeable wrapper may allow airflow through the aerosol-generating article. The gas-permeable wrapper may be configured to allow airflow through the aerosol-generating article in a particular direction. For example, a first portion of the wrapper may be gas-permeable, a second portion of the wrapper may be gas-permeable, and a third portion of the wrapper may be gas-impermeable. In use, airflow may enter the aerosol-forming substrate through the first portion of the wrapper that is gas-permeable, and airflow may exit the aerosol-forming substrate through the second portion of the wrapper that is gas-permeable. That is, an airflow path may exist between the first portion of the wrapper that is gas-permeable and the second portion of the wrapper that is gas-permeable.

[0083] In some embodiments, the gas permeable wrapper may be electrically insulating. An electrically insulating gas permeable wrapper may ensure that the first and second electrodes of each electrode pair are not in electrical contact.

[0084] In some embodiments where the aerosol-generating article comprises a plurality of electrode pairs, the first and second electrodes of each electrode pair may be disposed on an outer surface of the aerosol-generating article, hi some embodiments, a gas-permeable wrapper may be disposed between the first and second electrodes of each electrode pair.

[0085] In some embodiments, at least one of the first and second electrodes of each electrode pair may form at least a portion of a gas permeable wrapper. Forming at least a portion of the gas permeable wrapper may simplify manufacturing and reduce material costs.

[0086] The gas permeable wrapper may be formed from any suitable material, in some preferred embodiments, the gas permeable wrapper may include at least one of a cellulosic material, polypropylene, and polyethylene.

[0087] This may be advantageous for controlling airflow through the aerosol-generating article. Airflow through the aerosol-generating article may be passively controlled by defining an airflow path through the article. Controlling the airflow may result in improved airflow through the aerosol-forming substrate, which may then result in improved aerosol generation. In some embodiments, a first outer portion of the aerosol-generating article may be gas-permeable and a second outer portion of the aerosol-generating article may be gas-permeable. The airflow path may extend through the aerosol-generating article between the first outer portion of the aerosol-generating article and the second outer portion of the aerosol-generating article. The remaining outer portion of the aerosol-generating article may be substantially gas-impermeable. The airflow path may extend through at least a portion of the aerosol-forming substrate. When the aerosol-generating article is received within the article cavity of an aerosol-generating device, the airflow path of the aerosol-generating article may define a portion of the airflow path between the mouthpiece and the air inlet of the aerosol-generating device.

[0088] In some embodiments, the aerosol-generating article is gas permeable in a first direction and substantially gas impermeable in a second direction perpendicular to the first direction. In some embodiments, the aerosol-generating article is gas permeable in a transverse direction and substantially gas impermeable in a longitudinal axis perpendicular to the transverse direction. The first outer portion of the aerosol-generating article may be a first outer surface and the second outer portion may be a second outer surface. The first outer surface may be opposite the second outer surface. The first electrode of each electrode pair may be disposed on the first outer surface. The second electrode of each electrode pair may be disposed on the second outer surface. At least a portion of the aerosol-forming substrate may be disposed between the first outer surface and the second outer surface. At least a portion of the aerosol-forming substrate may be disposed between the first electrode and the second electrode of each electrode pair. An airflow path may extend between the first outer surface and the second outer surface.

[0089] In some embodiments, the aerosol-generating article has a thickness of from about 2 millimeters to about 10 millimeters. The thickness of the aerosol-generating article may be from about 3 millimeters to about 9 millimeters, or from about 4 millimeters to about 8 millimeters.

[0090] In some embodiments where the aerosol-generating article comprises a plurality of electrode pairs, a portion of the aerosol-forming substrate is disposed between each electrode pair, and the portions of the aerosol-forming substrate disposed between the electrode pairs are spaced apart from portions of the aerosol-forming substrate disposed between other electrode pairs. In some embodiments, each portion of the aerosol-forming substrate is thermally isolated from the other portions of the aerosol-forming substrate. In some embodiments, each portion of the aerosol-forming substrate is separated from the other portions of the aerosol-forming substrate by a material that is opaque to RF electromagnetic fields.

[0091] In some embodiments, the portion of the aerosol-forming substrate disposed between the first pair of electrodes is different from the portion of the aerosol-forming substrate disposed between the second pair of electrodes, hi some embodiments, the amount of aerosol-forming substrate disposed between each pair of electrodes is different.

[0092] The aerosol-generating article may have any suitable shape. Where the aerosol-generating device comprises an article cavity, the aerosol-generating article may have a shape that corresponds to the shape of the article cavity of the aerosol-generating device.

[0093] In some embodiments, the aerosol-generating article may be substantially disc-shaped.

[0094] In some embodiments, the aerosol-generating article may have a prismatic shape. The aerosol-generating article may have a first outer planar surface having a first shape. The aerosol-generating article may have a second outer planar surface having a second shape. The first shape may be substantially identical to the second shape. The first outer planar surface may be opposite the second outer planar surface. The aerosol-generating article may have a constant cross-sectional shape between the first outer planar surface and the second outer planar surface. The constant cross-sectional shape may be substantially identical to the first and second shapes. The first electrode may be disposed on the first outer planar surface and the second electrode may be disposed on the second outer planar surface. The first electrode may be on the first outer planar surface. The second electrode may be on the second outer planar surface.

[0095] In some embodiments, a first electrode of the electrode pair may be disposed at a first end of the aerosol-generating article and a second electrode of the electrode pair may be disposed at a second end of the aerosol-generating article opposite the first end.

[0096] In some preferred embodiments, the aerosol-generating article may have a substantially annular cylindrical shape. In some embodiments, the annular cylindrical article has a curved outer surface. The annular cylindrical article may have a passageway extending through the article defined by the inner surface. One of the first and second electrodes of the electrode pair may be disposed on the curved outer surface. The other of the first and second electrodes of the electrode pair may be disposed on the inner surface. The electrode disposed on the outer surface may substantially surround the aerosol-forming substrate. The aerosol-forming substrate may have a tubular shape. In some embodiments, the aerosol-generating article is gas permeable in a direction extending between the inner surface and the curved outer surface. In some embodiments, a portion of the inner surface of the aerosol-generating article may be gas permeable, a portion of the outer surface may be gas permeable, and the remaining portions of the inner and outer surfaces may be substantially gas impermeable. An airflow path may extend through the aerosol-generating article between the gas permeable portion of the inner surface and the gas permeable portion of the outer surface. The airflow path may extend through at least a portion of the aerosol-forming substrate. When the aerosol-generating article is received within the article cavity of the aerosol-generating device, the airflow path of the aerosol-generating article may define a portion of the airflow path through the aerosol-generating system. The airflow path may extend between a mouthpiece of the aerosol-generating system and an air inlet of the aerosol-generating device.

[0097] The aerosol-forming substrate may take any suitable form. It may be a solid or a liquid, or it may contain both solid and liquid components.

[0098] The aerosol-forming substrate may comprise nicotine. The nicotine-containing aerosol-forming substrate may comprise a nicotine salt matrix. The aerosol-forming substrate may comprise a plant-derived material. The aerosol-forming substrate preferably comprises tobacco. The tobacco-containing material preferably contains volatile tobacco flavour compounds which are released from the aerosol-forming substrate on heating. The aerosol-forming substrate may comprise a homogenised tobacco material. The homogenised tobacco material may be formed by agglomerating particulate tobacco. The aerosol-forming substrate may comprise a non-tobacco-containing material. The aerosol-forming substrate may comprise a homogenised plant-derived material.

[0099] The aerosol-forming substrate may, for example, comprise one or more of a powder, granules, pellets, pieces, spaghetti, strips, or sheets. The aerosol-forming substrate may contain one or more of herbal leaves, tobacco leaves, tobacco stem pieces, reconstituted tobacco, homogenized tobacco, extruded tobacco, and expanded tobacco. The tobacco may be flame-cured.

[0100] The aerosol-forming substrate may include at least one aerosol former. Suitable aerosol formers include compounds or mixtures of compounds that facilitate the formation of a dense, stable aerosol during use and that are substantially resistant to thermal decomposition at the operating temperatures of the shisha device. Suitable aerosol formers are well known in the art and include, but are not limited to, polyhydric alcohols such as triethylene glycol, 1,3-butanediol, and glycerin, esters of polyhydric alcohols such as glycerol monoacetate, diacetate, or triacetate, and aliphatic esters of mono-, di-, or polycarboxylic acids such as dimethyl dodecanedioate and dimethyl tetradecanedioate. Particularly preferred aerosol formers are polyhydric alcohols or mixtures thereof, such as triethylene glycol, 1,3-butanediol, and most preferably glycerin. The aerosol former may be propylene glycol. The aerosol-forming substrate may include any suitable amount of aerosol former. For example, the aerosol former content of the substrate may be 5 percent or more on a dry weight basis, and is preferably greater than 30 percent by weight on a dry weight basis. The aerosol former content may be less than about 95 percent on a dry weight basis. Preferably, the aerosol former content is up to about 55 percent on a dry weight basis.

[0101] The aerosol-forming substrate preferably comprises nicotine and at least one aerosol former. In some embodiments, the aerosol former is glycerin or a mixture of glycerin and one or more other suitable aerosol formers (such as those described above). In some embodiments, the aerosol former is propylene glycol.

[0102] In some embodiments, the aerosol-forming substrate may include at least one of water, glycerol, and propylene glycol.

[0103] The aerosol-forming substrate may include other additives and ingredients, such as flavorings. In some embodiments, the aerosol-forming substrate includes one or more sugars in any suitable amount. Preferably, the aerosol-forming substrate includes invert sugar. Invert sugar is a mixture of glucose and fructose obtained by splitting sucrose. Preferably, the aerosol-forming substrate includes about 1 weight percent to about 40 weight percent of a sugar, such as invert sugar. In some embodiments, the one or more sugars may be mixed with a suitable carrier, such as corn starch or maltodextrin.

[0104] In some embodiments, the aerosol-forming substrate comprises one or more sensory enhancers.Suitable sensory enhancers include flavorants and sensates (such as cooling agents).Suitable flavorants include natural or synthetic menthol, peppermint, spearmint, coffee, tea, spices (such as cinnamon, clove, ginger, or combinations thereof), cocoa, vanilla, fruit flavors, chocolate, eucalyptus, geranium, eugenol, agave, juniper, anethole, linalool, and any combination thereof.

[0105] Any suitable amount of aerosol-forming substrate (e.g., molasses or tobacco substrate) may be provided in the aerosol-generating article. In some preferred embodiments, from about 3 grams to about 25 grams of aerosol-forming substrate are provided in the aerosol-generating article. The cartridge may contain at least 6 grams, at least 7 grams, at least 8 grams, or at least 9 grams of aerosol-forming substrate. The cartridge may contain up to 15 grams, up to 12 grams, up to 11 grams, or up to 10 grams of aerosol-forming substrate. Preferably, from about 7 grams to about 13 grams of aerosol-forming substrate are provided in the aerosol-generating article.

[0106] The aerosol-forming substrate may be provided on or embedded within a thermally stable carrier. The term "thermally stable" is used herein to denote a material that does not substantially degrade at temperatures to which the substrate is typically heated (e.g., from about 150°C to about 300°C). The carrier may comprise a thin layer of the substrate deposited on a first major surface, or on a second outer major surface, or on both the first and second major surfaces. The carrier may be formed, for example, of paper or paper-like material, non-woven carbon fiber mat, low-mass open mesh metal screen, or perforated metal foil, or any other thermally stable polymeric matrix. Alternatively, the carrier may take the form of a powder, granules, pellets, pieces, spaghetti, strips, or sheets. The carrier may be a non-woven fiber or fiber bundle incorporating tobacco components. The non-woven fiber or fiber bundle may comprise, for example, carbon fiber, natural cellulose fiber, or cellulose derivative fiber.

[0107] In some preferred embodiments, the aerosol-forming substrate may comprise tobacco, sugar, and an aerosol former. In these embodiments, the aerosol-forming substrate may comprise 10 to 40 percent by weight of tobacco. In these embodiments, the aerosol-forming substrate may comprise 20 to 50 percent by weight of sugar. In these embodiments, the aerosol-forming substrate may comprise 25 to 55 percent by weight of aerosol former. In some particularly preferred embodiments, the aerosol-forming substrate comprises 20 to 30 percent by weight of tobacco, 30 to 40 percent by weight of sugar, and 35 to 45 percent by weight of aerosol former. In some preferred embodiments, the aerosol-forming substrate may comprise about 25 percent by weight of tobacco, about 35 percent by weight of sugar, and about 40 percent by weight of aerosol former. In some preferred embodiments, the aerosol-forming substrate may comprise 15 to 30 percent by weight of tobacco, 15 to 30 percent by weight of sugar, and 45 to 55 percent by weight of aerosol former. In these preferred embodiments, the tobacco may be flue-cured tobacco. In these preferred embodiments, the sugar may be sucrose or invert sugar. In these preferred embodiments, the aerosol former may be propylene glycol.

[0108] In some embodiments, the aerosol generating system may be a shisha system. In some embodiments, the aerosol generating device may be a shisha device. The aerosol generating system may be a shisha system having a shisha device. The shisha device differs from other aerosol generating devices in that at least the volatile compounds released from the heated substrate are drawn through the liquid plate of the shisha device before being inhaled by the user. The shisha device may include two or more outlets so that more than one user can use the device at once. The shisha device may include an airflow conduit, such as a stem pipe, for directing the volatile compounds released from the aerosol-forming substrate to the liquid plate.

[0109] The term "shisha system" as used herein refers to a combination of a shisha device and an aerosol-forming substrate or an aerosol-generating article comprising an aerosol-forming substrate, in which the aerosol-forming substrate or an aerosol-generating article comprising an aerosol-forming substrate and the shisha device cooperate to generate an aerosol.

[0110] Shisha devices differ from other aerosol generating devices in that the aerosol generated by the shisha device is drawn through a liquid (typically water) before the aerosol is inhaled by the user. More specifically, when a user puffs on a shisha device, volatile compounds released from a heated aerosol-forming substrate are drawn through an airflow conduit of the shisha device into the liquid. The volatile compounds are drawn from the liquid into the headspace of the shisha device, where they form an aerosol. The aerosol in the headspace is then drawn from the headspace at a headspace outlet for inhalation by the user. The liquid (typically water) volume acts to reduce the temperature of the volatile compounds and may impart additional water content to the aerosol formed in the headspace of the shisha device. This process adds a unique characteristic to the process of using a shisha device for the user and imparts a unique characteristic to the aerosol generated by the shisha device and inhaled by the user.

[0111] The shisha device may comprise a liquid cavity configured to contain a volume of liquid. The liquid cavity may include a head space outlet. The shisha device may comprise a vessel. The liquid cavity may be an interior volume of the vessel. The vessel may be configured to contain a liquid. The vessel may define a liquid cavity. The vessel may comprise a head space outlet. The vessel may define a liquid fill level. For example, the vessel may include a liquid fill level perimeter. The liquid fill level perimeter is an indicator provided on the vessel to indicate a desired level at which the liquid cavity is intended to be filled with liquid. The head space outlet may be disposed above the liquid fill level. The head space outlet may be disposed above the liquid fill level perimeter. The vessel may include an optically transparent portion. The optically transparent portion may allow a user to observe the contents contained in the vessel. The vessel may be formed of any suitable material. For example, the vessel may be formed of glass or a rigid plastic material. In some embodiments, the vessel is removable from the remainder of the shisha assembly. In some embodiments, the vessel is removable from the aerosol-generating portion of the shisha assembly. Advantageously, a removable vessel allows a user to fill the liquid cavity with liquid, empty the liquid cavity of liquid, and clean the vessel.

[0112] The vessel may be filled by a user to a liquid fill level. The liquid preferably comprises water. The liquid may comprise water infused with one or more of a colorant and a flavorant. For example, the water may be infused with one or both of a botanical infusion and an herbal infusion.

[0113] The vessel may have any suitable shape and size. The liquid cavity may have any suitable shape and size. The headspace may have any suitable shape and size.

[0114] Typically, the shisha device according to the present disclosure is intended to be placed on a surface during use, rather than being carried by a user. Thus, the shisha device according to the present disclosure may have a particular use orientation, or a range of orientations, in which the device is intended to be oriented during use. Thus, the terms "above" and "below" as used herein refer to the relative positions of features of the shisha device or shisha system when the shisha device or shisha system is held in a use orientation.

[0115] The shisha device may comprise an article cavity for receiving an aerosol-generating article. In some embodiments, the article cavity is disposed above the liquid cavity. In these embodiments, the airflow conduit may extend from the article cavity below the liquid fill level of the liquid cavity. Advantageously, this may ensure that volatile compounds released from the aerosol-forming substrate in the article cavity are delivered from the article cavity to the liquid in the liquid cavity, rather than to the head space above the liquid cavity. In these embodiments, the airflow conduit may extend from the aerosol cavity through the head space of the liquid cavity above the liquid fill level into the liquid cavity and into the liquid below the liquid fill level. The airflow conduit may extend into the liquid cavity through the top or upper end of the liquid cavity.

[0116] In some embodiments, the article cavity is disposed below the liquid cavity. In these embodiments, a one-way valve may be disposed between the article cavity and the liquid cavity. The one-way valve may prevent liquid from the liquid cavity from entering the article cavity under the influence of gravity. In these embodiments, the one-way valve may be provided in an airflow conduit that extends from the article cavity into the liquid cavity. In these embodiments, the airflow conduit may extend below the liquid fill level in the liquid cavity. The airflow conduit may extend into the liquid cavity through a bottom end of the liquid cavity.

[0117] The shisha device may include multiple head space outlets. For example, the shisha device may include two, three, four, five, or six head space outlets. Providing multiple head space outlets may allow multiple users to draw aerosol from the liquid cavity at one time. In other words, providing multiple head space outlets may allow multiple users to use the shisha device simultaneously.

[0118] The aerosol-forming substrate may be a shisha aerosol-forming substrate. The shisha aerosol-forming substrate may also be referred to in the art as hookah, tobacco molasses, or simply molasses. The shisha aerosol-forming substrate may have a relatively high sugar content compared to traditional combustible cigarettes or tobacco-based consumables that are intended to be heated without burning to mimic the experience of smoking.

[0119] In some preferred embodiments, the aerosol-forming substrate is in the form of a suspension. For example, the aerosol-forming substrate may include molasses. As used herein, "molasses" refers to an aerosol-forming substrate composition that includes a suspension having at least about 20 weight percent sugar. For example, molasses may include at least about 25 weight percent sugar, such as at least about 35 weight percent sugar. Typically, molasses contains less than about 60 weight percent sugar, such as less than about 50 weight percent sugar.

[0120] The aerosol-forming substrate used in the shisha system is preferably a shisha substrate. As used herein, "shisha substrate" refers to an aerosol-forming substrate composition that includes at least about 20 percent by weight of sugar. The shisha substrate may include molasses. The shisha substrate may include a suspension having at least about 20 percent by weight of sugar.

[0121] The aerosol-forming substrate preferably comprises nicotine and at least one aerosol former. In some embodiments, the aerosol former is glycerin or a mixture of glycerin and one or more other suitable aerosol formers (such as those described above). In some embodiments, the aerosol former is propylene glycol.

[0122] The aerosol-forming substrate may include other additives and ingredients, such as flavorings. In some embodiments, the aerosol-forming substrate includes one or more sugars in any suitable amount. Preferably, the aerosol-forming substrate includes invert sugar. Invert sugar is a mixture of glucose and fructose obtained by splitting sucrose. Preferably, the aerosol-forming substrate includes about 1 weight percent to about 40 weight percent of a sugar, such as invert sugar. In some embodiments, the one or more sugars may be mixed with a suitable carrier, such as corn starch or maltodextrin.

[0123] Any suitable amount of aerosol-forming substrate (e.g., molasses or tobacco substrate) may be provided in the aerosol-generating article. In some preferred embodiments, from about 3 grams to about 25 grams of aerosol-forming substrate are provided in the aerosol-generating article. The cartridge may contain at least 6 grams, at least 7 grams, at least 8 grams, or at least 9 grams of aerosol-forming substrate. The cartridge may contain up to 15 grams, up to 12 grams, up to 11 grams, or up to 10 grams of aerosol-forming substrate. Preferably, from about 7 grams to about 13 grams of aerosol-forming substrate are provided in the aerosol-generating article.

[0124] In some preferred embodiments, the aerosol-forming substrate may comprise tobacco, sugar and an aerosol former. In these embodiments, the aerosol-forming substrate may comprise between 10 percent and 40 percent by weight of tobacco. In these embodiments, the aerosol-forming substrate may comprise between 20 percent and 50 percent by weight of sugar. In these embodiments, the aerosol-forming substrate may comprise between 25 percent and 55 percent by weight of an aerosol former.

[0125] The present disclosure provides a method for dielectrically heating an aerosol-forming substrate in an aerosol-generating system. The aerosol-generating system comprises an aerosol-forming substrate. The aerosol-generating system comprises a plurality of electrode pairs, each electrode pair comprising a first electrode spaced apart from a second electrode. The aerosol-generating system comprises an aerosol generating device. The aerosol generating device comprises a controller configured to be connected to each electrode pair. The method comprises disposing each electrode pair to form a capacitor with a portion of the aerosol-forming substrate and supplying an alternating voltage to one or more of the electrode pairs to dielectrically heat the aerosol-forming substrate.

[0126] In some embodiments, the method may include selectively applying an alternating voltage to individual ones of the plurality of electrode pairs.

[0127] In some embodiments, the method may include applying an alternating voltage to each selected electrode pair for a period of between 30 seconds and 180 seconds.

[0128] In some embodiments, the aerosol generating device may include a puff sensor configured to sense a user puff in the aerosol generating system, and the method may include supplying an alternating voltage to one selected electrode pair when a first user puff is detected in the aerosol generating system, and then supplying a voltage to another selected electrode pair when a second, subsequent user puff is detected in the aerosol generating system.

[0129] It will be appreciated that features described in relation to an aerosol generating device or an aerosol generating article may also be applicable to an aerosol generating system according to the present disclosure.

[0130] It should also be understood that particular combinations of the various features described above may be implemented, provided or used independently.

[0131] The following provides a non-exhaustive list of non-limiting examples, any one or more of the features of which may be combined with any one or more features of another example, embodiment, or aspect described herein.

[0132] Example 1 1. A dielectrically heated aerosol generating system, comprising: an aerosol-forming substrate; a plurality of electrode pairs, each electrode pair including a first electrode spaced apart from a second electrode; An aerosol generating device, comprising: an aerosol generating device including a controller configured to be connected to each electrode pair; each electrode pair forms a capacitor with a portion of the aerosol-forming substrate; A dielectrically heated aerosol generating system, wherein the controller is configured to supply an alternating voltage to a plurality of electrode pairs to dielectrically heat the aerosol-forming substrate. Example 2 2. An aerosol generation system according to Example 1, wherein the controller is configured to selectively control the supply of alternating voltage to each electrode pair. Example 3 An aerosol generation system according to Example 2, wherein the controller is configured to selectively supply an alternating voltage to each electrode pair in sequence. Example 4 4. An aerosol generating system according to example 3, wherein the sequence is a predetermined sequence. Example 5 An aerosol generation system according to Example 3, wherein the controller is configured to determine the sequence of supplying alternating voltages to each electrode pair. Example 6 An aerosol generating system according to Example 5, wherein the sequence is determined based on at least one of the temperature of one or more of the plurality of electrode pairs, the temperature of the aerosol-forming substrate, the temperature adjacent to the aerosol-forming substrate, activation of the smoke puff sensor, and the duration of supplying an alternating voltage to one or more of the plurality of electrode pairs. Example 7 An aerosol generation system according to any one of Examples 1 to 6, wherein the controller is configured to monitor which of the multiple electrode pairs has received a supply of alternating voltage, and the controller includes a memory configured to store which of the multiple electrode pairs has received a supply of alternating voltage. Example 8 An aerosol generating system according to one of Examples 1 to 7, wherein the plurality of electrode pairs comprises 2 to 15 electrode pairs, preferably 5 to 12 electrode pairs. Example 9 The aerosol generating system according to any one of Examples 1 to 8, wherein the plurality of electrode pairs includes nine electrode pairs. Example 10 An aerosol generation system according to any one of Examples 1 to 9, wherein a first electrode of a plurality of electrode pairs forms a first electrode array, each electrode in the first electrode array being spaced apart by an electrode spacing distance, and a second electrode of the plurality of electrode pairs forms a second electrode array, each electrode in the second electrode array being spaced apart by the electrode spacing distance. Example 11 The aerosol generating system according to Example 10, wherein the electrode spacing distance is about 0.1 mm to about 2 mm, preferably about 0.5 mm to about 1.5 mm. Example 12 An aerosol generation system according to one of Examples 10 or 11, wherein the electrode spacing distance is about 1 millimeter. Example 13 An aerosol generation system according to any one of Examples 10 to 12, wherein a first electrically insulating material is disposed between adjacent electrodes in the first electrode array and a second electrically insulating material is disposed between adjacent electrodes in the second electrode array. Example 14 14. The aerosol generating system according to Example 13, wherein at least one of the first electrically insulating material and the second electrically insulating material comprises at least one of PEEK, PAEK, PPSU, and ceramic. Example 15 An aerosol generation system according to any one of Examples 10 to 14, wherein the first electrode of the first electrode array is substantially grid-like and the second electrode of the second electrode array is substantially grid-like. Example 16 An aerosol generation system according to any one of Examples 1 to 15, wherein the first electrode of each electrode pair is disposed substantially parallel to the second electrode of the electrode pair. Example 17 An aerosol generating system according to any one of Examples 1 to 16, wherein the first electrode of each electrode pair has a first length and the second electrode of each electrode pair has a second length substantially the same as the first length. Example 18 An aerosol generating system according to Example 17, wherein the first lengths of the first electrodes of each electrode pair are substantially the same. Example 19 An aerosol generating system according to Example 17, wherein the first length of one of the first electrodes of the plurality of electrode pairs is different from the first length of the other of the first electrodes of the plurality of electrodes. Example 20 An aerosol generating system according to any one of Examples 1 to 19, wherein the first electrode of each electrode pair is substantially identical to the second electrode of each electrode pair. Example 21 An aerosol generating system according to Example 20, wherein each electrode of the plurality of electrodes has one of the following shapes: rectangular, square, pentagonal, hexagonal, or triangular. Example 22 An aerosol generating system according to any one of Examples 1 to 21, wherein the first electrode of each electrode pair is planar and extends substantially in a first plane, and the second electrode of each electrode pair is planar and extends substantially in a second plane. Example 23 23. The aerosol generating system according to Example 22, wherein the first plane is substantially parallel to the second plane. Example 24 An aerosol generating system according to any one of Examples 1 to 23, wherein the first electrode of each electrode pair surrounds the second electrode of the electrode pair. Example 25 25. An aerosol generating system according to Example 24, wherein the first electrode of each electrode pair is substantially coaxial with the second electrode of the electrode pair. Example 26 An aerosol generation system according to any one of Examples 24 or 25, wherein the first electrode and the second electrode of each electrode pair are substantially cylindrical. Example 27 An aerosol generating system according to any one of Examples 24 to 26, wherein the first electrode of each electrode pair is annular and defines an internal passage, and the second electrode of each electrode pair is disposed within the internal passage of the first electrode. Example 28 An aerosol-generating system according to any one of Examples 1 to 27, wherein the aerosol-generating system comprises an aerosol-generating article comprising an aerosol-forming substrate. Example 29 The aerosol generating system according to any one of Examples 1 to 28, wherein the aerosol generating device comprises a plurality of electrode pairs. Example 30 An aerosol-generating system according to any one of Examples 1 to 27, wherein the aerosol-generating system comprises an aerosol-generating article, the aerosol-generating article comprising an aerosol-forming substrate, and at least one electrode of a plurality of electrode pairs. Example 31 An aerosol generating system according to Example 30, wherein the aerosol generating article comprises at least one electrode pair of the plurality of electrode pairs. Example 32 An aerosol generating system according to embodiment 30 or 31, wherein the aerosol generating article comprises a plurality of electrode pairs. Example 33 An aerosol generating system according to Example 30, wherein the aerosol generating device comprises a first electrode of each electrode pair and the aerosol generating article comprises a second electrode of each electrode pair. Example 34 An aerosol generating system according to Example 30, wherein the aerosol generating device comprises a second electrode of each electrode pair, and the aerosol generating article comprises a first electrode of each electrode pair. Example 35 The aerosol generating system according to any one of Examples 1 to 34, wherein the aerosol generating system is a shisha system and the aerosol generating device is a shisha device. Example 36 The shisha device is a liquid cavity configured to contain a volume of liquid through which aerosol generated by the shisha device is drawn before being inhaled by a user, the liquid cavity having a head space outlet; A shisha system according to Example 35, comprising an article cavity configured to receive an aerosol-forming substrate, the article cavity being in fluid communication with the liquid cavity. Example 37 A dielectric heating type aerosol generator, comprising: a plurality of electrode pairs, each electrode pair including a first electrode spaced apart from a second electrode; a controller connected to each electrode pair; An induction heating aerosol generating device, wherein the device is configured to receive an aerosol-forming substrate, each electrode pair forms a capacitor with at least a portion of the aerosol-forming substrate, and the controller is configured to supply an alternating voltage to the multiple electrode pairs to heat the aerosol-forming substrate. Example 38 An aerosol generating device according to Example 37, wherein the controller is configured to selectively control the supply of alternating voltage to each electrode pair. Example 39 An aerosol generating device according to Example 38, wherein the controller is configured to selectively supply an alternating voltage to each electrode pair in sequence. Example 40 40. The aerosol generating apparatus according to embodiment 39, wherein the sequence is a predetermined sequence. Example 41 An aerosol generating device according to Example 39, wherein the controller is configured to determine the sequence of supplying alternating voltage to each electrode pair. Example 42 An aerosol generating device according to Example 41, wherein the sequence is determined based on at least one of the temperature of one or more of the plurality of electrode pairs, the temperature of the aerosol-forming substrate, the temperature adjacent to the aerosol-forming substrate, activation of the smoke puff sensor, and duration of supply of an alternating voltage to one or more of the plurality of electrode pairs. Example 43 An aerosol generating device according to any one of Examples 37 to 42, wherein the controller is configured to monitor which of the multiple electrode pairs has received a supply of alternating voltage, and the controller includes a memory configured to store which of the multiple electrode pairs has received a supply of alternating voltage. Example 44 1. An aerosol generating article for a dielectrically heated aerosol generating system, comprising: an aerosol-forming substrate; a plurality of electrode pairs, each electrode pair including a first electrode spaced apart from a second electrode; An aerosol-generating article, wherein each electrode pair forms a capacitor with at least a portion of the aerosol-forming substrate. Example 45 The aerosol-generating article according to Example 44, wherein the plurality of electrode pairs includes 2 to 15 electrode pairs, preferably 5 to 12 electrode pairs. Example 46 The aerosol-generating article according to example 44 or 45, wherein the plurality of electrode pairs includes nine electrode pairs. Example 47 An aerosol-generating article according to any one of Examples 44 to 46, wherein a first electrode of a plurality of electrode pairs forms a first electrode array, each electrode in the first electrode array being spaced apart by an electrode spacing distance, and a second electrode of the plurality of electrode pairs forms a second electrode array, each electrode in the second array being spaced apart by the electrode spacing distance. Example 48 The aerosol-generating article according to Example 47, wherein the electrode spacing distance is from about 0.1 mm to about 2 mm, preferably from about 0.5 mm to about 1.5 mm. Example 49 An aerosol-generating article according to any one of Examples 47 or 48, wherein the electrode spacing distance is about 1 millimeter. Example 50 An aerosol generating article according to any one of Examples 47 to 49, wherein a first electrically insulating material is disposed between adjacent electrodes in the first electrode array and a second electrically insulating material is disposed between adjacent electrodes in the second electrode array. Example 51 The aerosol-generating article of Example 50, wherein at least one of the first electrically insulating material and the second electrically insulating material comprises at least one of PEEK, PAEK, PPSU, and ceramic. Example 52 An aerosol-generating article according to any one of Examples 47 to 51, wherein the first electrode of the first electrode array is substantially grid-like and the second electrode of the second electrode array is substantially grid-like. Example 53 The aerosol-generating article of any one of Examples 44-52, wherein the first electrode of each electrode pair is disposed substantially parallel to the second electrode of each electrode pair. Example 54 An aerosol-generating article according to any one of Examples 44 to 53, wherein the first electrode of each electrode pair has a first length and the second electrode of each electrode pair has a second length substantially the same as the first length. Example 55 The aerosol-generating article according to Example 54, wherein the first lengths of the first electrodes of each electrode pair are substantially the same. Example 56 The aerosol-generating article according to Example 54, wherein the first length of one of the first electrodes of the plurality of electrode pairs is different from the first length of the other of the first electrodes of the plurality of electrodes. Example 57 The aerosol-generating article of any one of Examples 44-56, wherein the first electrode of each electrode pair is substantially identical to the second electrode of each electrode pair. Example 58 58. An aerosol-generating article according to Example 57, wherein each electrode of the plurality of electrodes has one of the following shapes: rectangular, square, pentagonal, hexagonal, or triangular. Example 59 An aerosol-generating article according to any one of Examples 44 to 58, wherein the first electrode of each electrode pair is planar and extends substantially in a first plane, and the second electrode of each electrode pair is planar and extends substantially in a second plane. Example 60 The aerosol-generating article according to Example 60, wherein the first plane is substantially parallel to the second plane. Example 61 The aerosol-generating article of any one of Examples 44-58, wherein the first electrode of each electrode pair surrounds the second electrode of the electrode pair. Example 62 The aerosol-generating article according to Example 61, wherein the first electrode of each electrode pair is substantially coaxial with the second electrode of the electrode pair. Example 63 The aerosol-generating article according to example 61 or 62, wherein the first electrode and the second electrode of each electrode pair are substantially cylindrical. Example 64 The aerosol-generating article according to any one of Examples 61 to 63, wherein the first electrode of each electrode pair is annular and defines an internal passage, and the second electrode of each electrode pair is disposed within the internal passage of the first electrode. Example 65 1. A method for dielectrically heating an aerosol-forming substrate in an aerosol-generating system, the aerosol-generating system comprising: an aerosol-forming substrate; a plurality of electrode pairs, each electrode pair including a first electrode spaced apart from a second electrode; an aerosol generating device including a controller configured to be connected to each electrode pair; The method is disposing each electrode pair so as to form a capacitor with a portion of an aerosol-forming substrate; and applying an alternating voltage to one or more of a plurality of electrode pairs to dielectrically heat the aerosol-forming substrate. Example 66 66. The method according to example 65, comprising selectively applying an alternating voltage to individual pairs of the plurality of electrode pairs. Example 67 67. The method according to example 66, comprising applying an alternating voltage to each selected electrode pair for a period of between 30 seconds and 180 seconds. Example 68 A method according to example 66 or 67, wherein the aerosol generating device includes a puff sensor configured to sense a user's puff in the aerosol generating system, and the method includes supplying an alternating voltage to one selected electrode pair when a first user's puff is detected in the aerosol generating system, and then supplying an alternating voltage to another selected electrode pair when a second, subsequent user's puff is detected in the aerosol generating system. Embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0133] [Figure 1] FIG. 1 is a schematic diagram of a dielectrically heated aerosol generation system according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a schematic diagram of a dielectrically heated aerosol generating system according to another embodiment of the present disclosure. [Diagram 3] FIG. 3 is a schematic diagram of an aerosol-generating article according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a schematic diagram of a shisha device according to an embodiment of the present disclosure. [Diagram 5]FIG. 5 is a schematic diagram of an aerosol generating article including a heating unit of a shisha device and multiple electrode pairs according to an embodiment of the present disclosure. [Figure 6] FIG. 6 is a schematic diagram of a heating unit of a shisha device including multiple electrode pairs and an aerosol-generating article according to an embodiment of the present disclosure. [Figure 7] FIG. 7 is a schematic diagram of an aerosol generating article including a heating unit of a shisha device and multiple electrode pairs according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0134] FIG. 1 is a schematic diagram of a system for dielectrically heating an aerosol-forming substrate using radio frequency (RF) electromagnetic radiation according to an embodiment of the present disclosure. The system comprises an oscillator circuit 10 including a radio frequency (RF) signal generator 11 and a phase shift network 12, and a plurality of electrode pairs. The oscillator circuit 10 is controlled by a controller (not shown). Each electrode pair includes a first electrode 41 spaced apart from a second electrode 42. The first electrode 41 of each electrode pair is connected to a first output of the phase shift network 12, and the second electrode 42 of each electrode pair is connected to a second output of the phase shift network 12. An aerosol-generating article 50 including an aerosol-forming substrate 51 is disposed between the two electrode pairs, and each electrode pair forms a capacitor with a portion of the aerosol-forming substrate 51. The aerosol-forming substrate 51 acts as a dielectric of the capacitor. The oscillator circuit 10 supplies an alternating voltage to each of the first electrode 41 and the second electrode 42, which generates an alternating electromagnetic field between the first electrode 41 and the second electrode 42. The polar molecules within the aerosol-generating article 50 align with the oscillating electromagnetic field and are agitated by the electromagnetic field as they vibrate, which causes the temperature of the aerosol-generating article 50 to increase. This type of heating has the advantage of being uniform throughout the aerosol-generating article 50 (if the polar molecules are uniformly distributed). It also has the advantage of reducing the possibility of burning of substrates in contact with the first and second electrodes, compared to conventional heating elements that transfer heat to a substrate via a conductor.

[0135] In this embodiment, the plurality of electrode pairs includes two electrode pairs, although it will be appreciated that in other embodiments, the system may include three or more electrode pairs.

[0136] FIG. 2 is a schematic diagram of another system for dielectrically heating an aerosol-forming substrate according to an embodiment of the present disclosure. The system shown in FIG. 2 is similar to the system illustrated in FIG. 1, and like features are indicated with like reference numbers. The system shown in FIG. 2 differs from the system in FIG. 1 in that the system in FIG. 2 further comprises a controller 13 and a relay switch circuit 30. A relay switch circuit 30 is provided for each electrode pair 41, 42. For each relay switch circuit 30, the controller 13 is configured to energize the relay 31 to operate the switch 32 to control the supply of an alternating voltage to one of the electrode pairs. In this way, the controller can selectively supply an alternating voltage to one of the electrode pairs to heat a selected portion of the aerosol-forming substrate 51 without heating the entire aerosol-forming substrate 51.

[0137] 3a and 3b are schematic diagrams of a planar aerosol-generating article according to an embodiment of the present disclosure. FIG. 3a shows a perspective view of the aerosol-generating article 50. FIG. 3b shows a cross-sectional view of the aerosol-generating article 50. The aerosol-generating article 50 includes four electrode pairs, each of which includes a first electrode 41 and a second electrode 42. The aerosol-forming substrate 51 is disposed between the electrode pairs. The first electrode 41 of each electrode pair is substantially planar and extends substantially in a first plane. The second electrode 42 of each electrode pair is substantially planar and extends substantially in a second plane. The first plane is substantially parallel to the second plane. In this embodiment, the aerosol-generating article has a rectangular cross-sectional shape, and the aerosol-forming substrate 51 and each of the electrodes 41, 42 also have a rectangular cross-sectional shape. Of course, in other embodiments of the aerosol-generating article, the aerosol-forming substrate and the electrodes may have other cross-sectional shapes than those illustrated in FIGS. 3a and 3b.

[0138] 3c and 3d are schematic diagrams of a cylindrical aerosol-generating article 50 according to another embodiment of the present disclosure. FIG. 3c shows a perspective view of the aerosol-generating article 50. FIG. 3d shows a cross-sectional view of the aerosol-generating article 50. The aerosol-generating article 50 includes four electrode pairs, each including a first electrode 41 and a second electrode 42. The first electrode 41 of each electrode pair surrounds the second electrode 42 of the electrode pair. The first electrode 41 of each electrode pair is substantially coaxial with the second electrode 42 of the electrode pair. The first electrode 41 of each electrode pair is substantially annular and defines an internal passage. The second electrode 42 of each electrode pair is substantially cylindrical and is disposed within the internal passage of the first electrode 41 of the electrode pair. An aerosol-forming substrate 51 is disposed between the electrode pairs.

[0139] 4 is a schematic diagram of a shisha system according to an embodiment of the present disclosure. Although the principles of the present disclosure are generally applicable to dielectrically heated aerosol generating systems, a shisha system has been selected for illustrative purposes.

[0140] The shisha device 70 comprises a vessel 71 defining a liquid cavity 74. The vessel 71 is configured to hold a liquid in the liquid cavity 74 and is formed from a rigid, optically transparent material, such as glass. In this embodiment, the vessel 71 has a substantially frustoconical shape and is supported in use at its wide end on a flat, horizontal surface, such as a table or shelf. The liquid cavity 74 is divided into two sections: a liquid section 73 for receiving liquid and a head space 72 above the liquid section 73. A liquid fill level 75 is located at the boundary between the liquid section 73 and the head space 72, the liquid fill level 75 being defined on the vessel 71 by a dashed line marked on the outer surface of the vessel 71. A head space outlet 76 is provided above the liquid fill level 75 on a side wall of the vessel 71. The head space outlet 76 allows fluid to be drawn from the head space 72 out of the liquid cavity 74. A mouthpiece 78 is connected to the head space outlet 76 by a flexible hose 77. A user may suck on mouthpiece 78 to draw fluid from headspace 72 for inhalation.

[0141] The shisha device 70 further comprises a heating unit 60 including an oscillator circuit according to the present disclosure. Examples of different heating units are discussed in more detail with reference to Figures 3 and 4. The heating unit 60 is disposed above the vessel 71 by an airflow conduit 64. In this embodiment, the heating unit 60 is supported above the vessel 71 by the airflow conduit 64, but it will be understood that in other embodiments, the heating unit 60 may be supported above the vessel 71 by the housing of the shisha device or another suitable support. The airflow conduit 64 extends from the heating unit 60 into the liquid cavity 74 of the vessel 71. The airflow conduit 64 extends through the head space 72, below the liquid fill level 75, and into the liquid section 73. The airflow conduit 64 includes an outlet 67 in the liquid section 73 of the liquid cavity 74 below the liquid fill level 75. This arrangement allows air to be drawn from the heating unit 60 to a mouthpiece 78. Air may be drawn into device 70 from the external environment, enter heating unit 60, pass through heating unit 60, through airflow conduit 64, into the liquid in liquid section 73 of liquid cavity 74, exit the liquid into headspace 72, exit headspace 72 out of the vessel at headspace outlet 76, through hose 77 and drawn to mouthpiece 78.

[0142] In use, a user may suck on the mouthpiece 78 of the shisha device 70 to receive an aerosol from the shisha device 70. More specifically, an aerosol-generating article including an aerosol-forming substrate may be positioned in an article cavity in the heating unit 60 of the shisha device 60, such as the aerosol-generating article 50 of FIG. 2. The heating unit 70 may be operated to heat the aerosol-forming substrate in the aerosol-generating article and release volatile compounds from the heated aerosol-forming substrate. When a user sucks on the mouthpiece 78 of the shisha device 70, the pressure in the shisha device 70 is reduced, which draws the released volatile compounds from the aerosol-forming substrate to the heating unit 60 and into the airflow conduit 64. The volatile compounds are drawn from the airflow conduit 64 at the outlet 67 into the liquid in the liquid section 73 of the liquid cavity 74. The volatile compounds are cooled by the liquid and released into the headspace 72 above the liquid fill level 75. Volatile compounds in the headspace 72 condense to form an aerosol, which is drawn out of the headspace at headspace outlet 76 and into mouthpiece 78 for inhalation by the user.

[0143] Figure 5 shows a schematic diagram of the heating unit 60 of the shisha device 70 of Figure 4 in combination with the planar aerosol-generating article 50 of Figures 3a and 3b to form a shisha system according to an embodiment of the present disclosure. Figure 5a shows the heating unit 60 and the aerosol-generating article 50 prior to insertion of the aerosol-generating article 50 into the article cavity 20 of the heating unit 60. Figure 5b shows the aerosol-generating article 50 received in the article cavity 20 of the heating unit 60.

[0144] As shown in Figure 5a, the heating unit 60 includes an outer housing 61. The outer housing 61 forms a cylindrical tube that is open at one end for insertion of the aerosol-generating article 50 and substantially closed at the opposite end. In this embodiment, the outer housing 61 is formed from a material that is opaque to RF electromagnetic radiation, such as aluminum. However, it will be appreciated that the housing 61 need not be formed from a material that is opaque to RF electromagnetic radiation, but rather, in some embodiments, may be formed from a material that is substantially opaque to RF electromagnetic radiation, such as a ceramic or plastic material.

[0145] The closure 65 is movable over the open end of the outer housing 61 of the heating unit 60 to substantially close the open end. In this position, the outer housing 61 and the closure 65 define a heating unit cavity. The closure 65 includes an outer housing similar to the outer housing 61 of the heating unit, formed from the same material opaque to RF electromagnetic fields, and sized and shaped to align and engage with the outer housing 61 to close the open end. The closure 65 is rotatably connected to the outer housing 61 by a hinge and is rotatable between an open position shown in FIG. 5a and a closed position shown in FIG. 5b. When the closure 65 is in the open position, the open end of the outer housing 61 is open for inserting and removing the aerosol-generating article 50 into and from the heating unit cavity. When the closure 65 is in the closed position, the heating unit cavity is surrounded by a material opaque to RF electromagnetic fields such that the RF electromagnetic fields cannot propagate out of the heating unit cavity.

[0146] The sidewall of the outer housing 61 includes an air inlet (shown in FIG. 5b) to allow ambient air to enter the heating unit cavity.

[0147] The heating unit 60 is disposed above the vessel 71 of the shisha device 70, above the airflow conduit 64. The airflow conduit 64 extends into the heating unit cavity and is fixedly attached to a substantially closed end of the outer housing 61 of the heating unit 60. It will be appreciated that in other embodiments, the heating unit 60 may be removably attached to the airflow conduit 64 such that the heating unit 60 may be removed for cleaning or replacement, as needed.

[0148] In this embodiment, the heating unit 70 includes a plurality of first electrical contacts 81 and a plurality of second electrical contacts 82. The first electrical contacts 81 are secured to a base 62 that is supported within the outer housing 61. The second electrical contacts 82 are secured to an inner surface of the closure 65. In this embodiment, the article cavity is defined solely by the base 62. The first electrical contacts 81 and the second electrical contacts 82 are substantially identical and include circular sheets of metal having a diameter significantly smaller than the diameter of the aerosol-generating article 50.

[0149] The heating unit 60 further includes a circuit 66 including an oscillator circuit 10. In some embodiments, the circuit 66 may also include a controller 13 and a relay switch circuit 30. The control circuit 66 is connected to a power source (not shown) of the shisha device. In this embodiment, the power source is a rechargeable lithium ion battery, and the shisha device 70 includes a power connector that allows the shisha device 70 to be connected to a mains power source to recharge the power source. Providing the shisha device 70 with a power source, such as a battery, allows the shisha device 70 to be portable and used outdoors or in places where a mains power source is not available. The first electrical contact 81 and the second electrical contact 81 are electrically connected to the control circuit 66.

[0150] 5b, when the aerosol-generating article 50 is received within the article cavity 80 of the heating unit 60 and the closure 65 is disposed in the closed position, the first electrode 41 of the aerosol-generating article 50 contacts the plurality of first electrical contacts 81 and the second electrode 42 contacts the plurality of second electrical contacts 82 of the heating unit 60. In this arrangement, a plurality of capacitors are formed by the plurality of electrode pairs.

[0151] When a user inhales on the mouthpiece 78 of the shisha device 70, air is drawn into the shisha device 70 through the air inlet in the outer housing 61. The airflow path through the aerosol-generating article 50 and the heating unit 60 is shown by the arrows in Figure 4b. Air is drawn through the air inlet in the outer housing 61 into the heating unit cavity and from the heating unit cavity into the aerosol-generating article 50. Air is drawn through the aerosol-forming substrate 51 and into the airflow conduit 64 through an opening 63 in the outer housing 61 of the heating unit 60.

[0152] In use, when a user activates the shisha device 70, power is provided from the power source to the circuit 66. In this embodiment, the shisha device is activated by the user pressing an activation button (not shown) provided on the exterior surface of the heating unit 60. It will be appreciated that in other embodiments, the shisha device may be activated in other manners, such as when a puff sensor provided on the mouthpiece 78 detects that the user is taking a puff on the mouthpiece 78. When power is provided to the oscillator circuit 10, the oscillator circuit generates two substantially equal, out-of-phase RF electromagnetic signals having a frequency between 20 kHz and 300 MHz. One of the signals is provided to the first electrode 41 of each electrode pair, and the other signal is provided to the second electrode 42 of each electrode pair. The RF electromagnetic signals provided to the first electrode 41 and the second electrode 42 of each electrode pair establish an alternating RF electromagnetic field within the article cavity 20, which dielectrically heats the aerosol-forming substrate 51, which releases the volatile compound.

[0153] FIG. 6 shows a heating unit 60 and an aerosol-generating article 50 for a shisha device forming a shisha system according to another embodiment of the present disclosure. The heating unit 60 and the aerosol-generating article 50 shown in FIG. 60 are substantially similar to the heating unit 60 and the aerosol-generating article 50 shown in FIG. 5, and like reference numbers are used to indicate like features. FIG. 6a shows the heating unit 60 and the aerosol-generating article 50 prior to inserting the aerosol-generating article 50 into the article cavity 20 of the heating unit 60. FIG. 6b shows the aerosol-generating article 50 received in the article cavity 20 of the heating unit 60.

[0154] The heating unit 60 shown in Figure 6 differs from the heating unit 60 shown in Figure 5 in that the heating unit 60 of Figure 6 includes a first electrode 41 and a second electrode 42 of each electrode pair, instead of the aerosol-generating article 50 including a first electrode 41 and a second electrode 42 of each electrode pair as in the embodiment of Figure 5. In this embodiment, the article cavity is defined by a base 62, a first wall 21 and a second wall 22. The first wall 21 and the second wall 22 are connected and disposed around a periphery of the base 62.

[0155] Figure 7 shows a schematic diagram of the heating unit 60 of the shisha device 70 of Figure 4 in combination with the aerosol-generating article 50 of Figures 3c and 3d to form a shisha system according to another embodiment of the present disclosure. The heating unit 60 shown in Figure 5 is substantially similar to the heating unit 60, and like reference numbers are used to indicate like features. Figure 7a shows the heating unit 60 and the aerosol-generating article 50 prior to inserting the aerosol-generating article 50 into the article cavity 20 of the heating unit 60. Figure 7b shows the aerosol-generating article 50 received in the article cavity 20 of the heating unit 60.

[0156] As shown in FIG. 7a, the article cavity 20 has a substantially annular cylindrical shape defined by a curved surface 91. A post 92 extends from the base 62 into the article cavity 20 coaxially with the cavity 20 and is surrounded by the curved surface 91. In this embodiment, the heating unit 60 includes a plurality of first electrical contact pads 81 on the curved surface 91 defining the cavity 20 and a plurality of second electrical contact pads 82 on an outer surface of the post 92 within the article cavity 20. Similar to FIG. 5, the first electrical contact pads 81 and the second electrical contact pads 82 are electrically connected to the circuit 66.

[0157] In this embodiment, the article 50 has an annular cylindrical shape and defines an interior passageway. The article 50 includes an annular body of an aerosol-forming substrate 51 wrapped in cigarette paper (not shown). The curved outer surface of the article 50 is complementary to the curved surface 91 that defines the article cavity 20. The interior passageway of the article 50 is also complementary to the post 92 of the article cavity 20. In this manner, the aerosol-generating article 50 fits closely within the article cavity 20, with the post 92 received within the interior passageway of the article 50. The plurality of first electrodes 41 are disposed on the curved outer surface of the article 50. The plurality of first electrodes 41 are disposed complementary to the plurality of first electrical contacts 81 in the article cavity 20 such that the first electrodes 41 are in physical contact with the first electrical contacts 81 when the aerosol-generating article 50 is received within the article cavity 20. The plurality of second electrodes 42 are disposed on the inner surface of the interior passageway of the article 50. The plurality of second electrodes 42 are arranged complementarily to the plurality of second electrical contacts 82 within the article cavity 20 such that the second electrodes 42 are in physical contact with the second electrical contacts 82 when the aerosol-generating article 50 is received within the article cavity 20.

[0158] As shown in Figure 7b, when the aerosol-generating article 50 is received within the article cavity 20 of the heating unit 60, the first electrode 41 of the aerosol-generating article 50 contacts the plurality of first electrical contacts 81 and the second electrode 42 contacts the plurality of second electrical contacts 82 of the heating unit 60. In use, air is drawn through the aerosol-generating substrate 51 of the aerosol-generating article 50 along the length of the aerosol-generating article, as shown in Figure 7b.

[0159] It will be understood that the above-described embodiments are exemplary embodiments only and that various other embodiments are contemplated in accordance with the present disclosure.

[0160] For purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing amounts, quantities, percentages, and the like are to be understood in all instances as being modified by the term "about." Also, all ranges include the maximum and minimum points disclosed, and include any intermediate ranges therein, which may or may not be specifically recited herein. Thus, in this context, the number A is to be understood as A±5%.

Claims

1. 1. A dielectrically heated aerosol generating system, comprising: an aerosol-forming substrate; a plurality of electrode pairs, each electrode pair including a first electrode spaced apart from a second electrode; An aerosol generating device, comprising: an aerosol generating device including a controller configured to be connected to each electrode pair; An dielectrically heated aerosol generating system, wherein each electrode pair forms a capacitor with a portion of the aerosol-forming substrate, and the controller is configured to supply an alternating voltage to the multiple electrode pairs to dielectrically heat the aerosol-forming substrate.

2. 2. The aerosol generating system of claim 1, wherein the controller is configured to selectively control the supply of the AC voltage to each electrode pair to dielectrically heat the aerosol-forming substrate.

3. The aerosol generation system of claim 2 , wherein the controller is configured to selectively supply the alternating voltage to each electrode pair in sequence.

4. The aerosol generation system of claim 3 , wherein the controller is configured to determine a sequence of application of the alternating voltage to each electrode pair.

5. 5. The aerosol generating system of claim 4, wherein the sequence is determined based on at least one of the temperature of one or more of the plurality of electrode pairs, the temperature of a portion of the aerosol-forming substrate, the temperature adjacent to the aerosol-forming substrate, activation of a smoke puff sensor, and duration of supply of the alternating voltage to one or more of the plurality of electrode pairs.

6. An aerosol generating system as described in any one of claims 1 to 5, wherein the controller is configured to monitor which of the plurality of electrode pairs has received the supply of the alternating voltage to dielectrically heat the aerosol-forming substrate, and the controller further includes a memory configured to store which of the plurality of electrode pairs has received the supply of the alternating voltage.

7. 7. The aerosol generation system according to claim 1, wherein the plurality of electrode pairs comprises between 2 and 15 electrode pairs, preferably between 5 and 12 electrode pairs.

8. 8. The aerosol generation system of claim 1, wherein the first electrodes of the plurality of electrode pairs form a first electrode array, each electrode in the first electrode array being spaced apart by an electrode spacing distance, and the second electrodes of the plurality of electrode pairs form a second electrode array, each electrode in the second electrode array being spaced apart by the electrode spacing distance.

9. 9. The aerosol generation system of claim 8, wherein the first electrode of the first electrode array is substantially grid-like and the second electrode of the second electrode array is substantially grid-like.

10. 10. An aerosol generation system according to any one of claims 1 to 9, wherein the first electrode of each electrode pair is planar and extends substantially in a first plane and the second electrode of each electrode pair is planar and extends substantially in a second plane, preferably the first plane being substantially parallel to the second plane.

11. An aerosol generation system according to any one of claims 1 to 10, wherein the first electrode of each electrode pair surrounds the second electrode of the electrode pair, preferably the first electrode of each electrode pair is annular and defines an internal passage, and the second electrode of each electrode pair is disposed within the internal passage of the first electrode.

12. The aerosol generation system according to any one of claims 1 to 11, wherein the aerosol generation device comprises the plurality of electrode pairs.

13. The aerosol generating system according to any one of claims 1 to 12, comprising an aerosol generating article, the aerosol generating article comprising the aerosol-forming substrate and at least one electrode of the plurality of electrode pairs.

14. The aerosol generating system is a shisha system, and the aerosol generating device is a shisha device, the shisha device comprising: a liquid cavity configured to contain a volume of liquid through which aerosol generated by the shisha device is drawn before being inhaled by a user, the liquid cavity having a head space outlet; 14. The aerosol generating system according to any one of claims 1 to 13, comprising an article cavity configured to receive the aerosol-forming substrate, the article cavity being in fluid communication with the liquid cavity.

15. 1. An aerosol generating article for a dielectrically heated aerosol generating system, the aerosol generating article comprising: an aerosol-forming substrate; a plurality of electrode pairs, each electrode pair including a first electrode spaced apart from a second electrode; An aerosol-generating article, wherein each electrode pair forms a capacitor with at least a portion of the aerosol-forming substrate.

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