Aerosol-generating article

Abstract

An aerosol-generating article for producing an inhalable aerosol upon heating, the aerosol-generating article comprising a substrate plug defining an internal volume, the internal volume comprising an aerosol-generating substrate, wherein a mass of the aerosol-generating substrate within the internal volume of the substrate plug is less than or equal to 0.3 milligrams per cubic millimetre and wherein the aerosol-generating article comprises less than or equal to 140 milligrams of aerosol-generating substrate or the mass of the aerosol-generating substrate within the internal volume of the substrate plug is less than or equal to 0.5 milligrams per cubic millimetre and wherein the aerosol-generating article comprises less than or equal to 100 milligrams of aerosol-generating substrate. The aerosol-generating article may include at least 10 milligrams and less than 100 milligrams of aerosol-generating substrate, and the aerosol-generating article may have an internal volume of at least 1 cubic centimetre.

Description

[0001] AEROSOL-GENERATING ARTICLE

[0002] The present invention relates to an aerosol-generating article, for example an aerosolgenerating article comprising an aerosol-generating substrate. The present invention also relates to an aerosol-generating device, for example an aerosol-generating device comprising a heating element, for use with the aerosol-generating article. The present invention also relates to an aerosol-generating system comprising the aerosol-generating device, for example the aerosolgenerating device comprising a heating element, and the aerosol-generating article, for example the aerosol-generating article comprising an aerosol-generating substrate.

[0003] A typical aerosol-generating system comprises an aerosol-generating device and an aerosol-generating article comprising an aerosol-generating substrate. In use, the aerosolgenerating device is arranged to heat a heating element that is positioned near, or in contact with, the aerosol-generating substrate which causes the aerosol-generating substrate to heat up and release volatile compounds. These volatile compounds are then entrained in air that is drawn through the aerosol-generating article. As the volatile compounds cool, they condense to form an aerosol that can be inhaled by a consumer.

[0004] Known electrically operated aerosol-generating systems typically heat an aerosolgenerating substrate by one or more of: conduction of heat from a heating element to an aerosolgenerating substrate, radiation of heat from a heating element to an aerosol-generating substrate or drawing heated air through an aerosol-generating substrate. Most commonly, heating is achieved by passing an electrical current through an electrically resistive heating element, giving rise to Joule heating of the heating element. Inductive heating systems have also been proposed, in which Joule heating occurs as a result of eddy currents induced in a susceptor heating element. A problem with these heating mechanisms is that they may give rise to non-uniform heating of the aerosol-generating substrate. The portion of the aerosol-generating substrate closest to the heating element is heated more quickly or to a higher temperature than portions of the aerosolgenerating substrate more remote from the heating element.

[0005] Systems that dielectrically heat an aerosol-generating substrate have been proposed, which advantageously provide uniform heating of the aerosol-generating substrate. However, known dielectric heating systems are less efficient than inductive heating systems and require complex electrical circuitry in order to achieve the necessary voltages and frequencies for dielectric heating of an aerosol-generating substrate. It would be desirable to provide a system that dielectrically heats an aerosol-generating substrate with greater efficiency, while still being realisable in a compact or handheld system.

[0006] Dielectric heating, also sometimes referred to as electronic heating, radio frequency (RF) heating, high-frequency (HF) heating, or microwave heating is a heating method where a dielectric material is subjected to high-frequency electric field or microwave electromagnetic radiation to thereby heat the dielectric material. This heating is caused by molecular dipole rotation of the dielectric material (for example an aerosol-generating substrate that has dielectric properties), caused by the alternating polarization of the dielectric material stimulated by the alternating electric field. This dipole rotation causes the molecules to push, pull, and collide with other molecules, distributing the energy to adjacent molecules of the dielectric material, and thereby causing heating of the material.

[0007] According to an aspect of the present invention, there is provided an aerosol-generating article for producing an inhalable aerosol upon heating. The aerosol-generating article may comprise a substrate plug defining an internal volume. The internal volume of the substrate plug may comprise an aerosol-generating substrate. A mass of the aerosol-generating substrate within the internal volume of the substrate plug may be less than or equal to 0.3 milligrams per cubic millimetre. The aerosol-generating article may comprise less than or equal to 140 milligrams of aerosol-generating substrate.

[0008] According to an aspect of the invention there is provided an aerosol-generating article for producing an inhalable aerosol upon heating, the aerosol-generating article comprising a substrate plug defining an internal volume, the internal volume of the substrate plug comprising an aerosol-generating substrate. A mass of the aerosol-generating substrate within the internal volume of the substrate plug may be less than or equal to 0.3 milligrams per cubic millimetre and / or the aerosol-generating article may comprise less than or equal to 140 milligrams of aerosol-generating substrate.

[0009] According to an aspect of the invention there is provided an aerosol-generating article for producing an inhalable aerosol upon heating, the aerosol-generating article comprising a substrate plug defining an internal volume, the internal volume of the substrate plug comprising an aerosol-generating substrate, wherein a mass of the aerosol-generating substrate within the internal volume of the substrate plug is less than or equal to 0.3 milligrams per cubic millimetre and wherein the aerosol-generating article comprises less than or equal to 140 milligrams of aerosol-generating substrate.

[0010] The aerosol-generating article may be particularly suitable for use with aerosol-generating devices including dielectric or microwave heating elements, which are very efficient and provide homogenous heating, and thus enable the aerosol former content of the aerosol-generating substrate of the aerosol-generating article to be reduced without compromising the levels of aerosol generated. It has, surprisingly, been found that levels of aerosol comparable to those obtained using convective or conductive heating have been obtained by heating aerosolgenerating articles according to the present invention using dielectric heating elements.

[0011] By reducing the density of the aerosol-generating substrate within the internal volume, there may be a greater surface area available for aerosolisation and a lower resistance-to-draw through the aerosol-generating substrate. In turn, this reduces condensation. Accordingly, because the delivery of aerosol is improved, a lower mass of aerosol-generating substrate is needed. This is particularly synergistic with dielectric heating because there is less need for conduction throughout the aerosol-generating substrate (microwave heating directly heats the whole aerosol-generating substrate). This is also synergistic with flat or planar consumables for aerosol-generating articles because the substrate can be positioned closer to the hearing element of the aerosol-generating device, and so there is less need for conduction though the aerosolgenerating substrate.

[0012] The high efficacy with which aerosol-generating articles of the present invention are heated using dielectric heating enables the mass of aerosol-generating substrate within the internal volume of the substrate plug, i.e. the bulk density of substrate in the aerosol-generating article, to be reduced.

[0013] The bulk density of substrate in the aerosol-generating article is determined by weighing the total mass of aerosol-generating substrate within the aerosol-generating article and dividing that value by the internal volume of the substrate plug within the aerosol-generating article.

[0014] The mass of the aerosol-generating substrate within the internal volume of the substrate plug may be less than or equal to 0.2 milligrams per cubic millimetre, for example less than or equal to 0.1 milligrams per cubic millimetre.

[0015] The mass of the aerosol-generating substrate within the internal volume of the substrate plug may be at least 0.005 milligrams per cubic millimetre, for example at least 0.01 milligrams per cubic millimetre, for example at least 0.02 milligrams per cubic millimetre, for example at least 0.04 milligrams per cubic millimetre, for example at least 0.05 milligrams per cubic millimetre.

[0016] The mass of the aerosol-generating substrate within the internal volume of the substrate plug maybe between 0.005 milligrams per cubic millimetre and 0.3 milligrams per cubic millimetre, for example between 0.01 milligrams per cubic millimetre and 0.3 milligrams per cubic millimetre, for example between 0.02 milligrams per cubic millimetre and 0.3 milligrams per cubic millimetre, for example between 0.04 milligrams per cubic millimetre and 0.3 milligrams per cubic millimetre, for example between 0.05 milligrams per cubic millimetre and 0.3 milligrams per cubic millimetre.

[0017] The mass of the aerosol-generating substrate within the internal volume of the substrate plug maybe between 0.005 milligrams per cubic millimetre and 0.2 milligrams per cubic millimetre, for example between 0.01 milligrams per cubic millimetre and 0.2 milligrams per cubic millimetre, for example between 0.02 milligrams per cubic millimetre and 0.2 milligrams per cubic millimetre, for example between 0.04 milligrams per cubic millimetre and 0.2 milligrams per cubic millimetre, for example between 0.05 milligrams per cubic millimetre and 0.2 milligrams per cubic millimetre.

[0018] The mass of the aerosol-generating substrate within the internal volume of the substrate plug maybe between 0.005 milligrams per cubic millimetre and 0.1 milligrams per cubic millimetre, for example between 0.01 milligrams per cubic millimetre and 0.1 milligrams per cubic millimetre, for example between 0.02 milligrams per cubic millimetre and 0.1 milligrams per cubic millimetre, for example between 0.04 milligrams per cubic millimetre and 0.1 milligrams per cubic millimetre, for example between 0.05 milligrams per cubic millimetre and 0.1 milligrams per cubic millimetre.

[0019] The aerosol-generating article may comprise less than or equal to 120 milligrams of aerosol-generating substrate, for example less than or equal to 110 milligrams of aerosolgenerating substrate, for example less than or equal to 100 milligrams of aerosol-generating substrate, for example less than or equal to 90 milligrams of aerosol-generating substrate, for example less than or equal to 80 milligrams of aerosol-generating substrate.

[0020] The aerosol-generating article may comprise at least 5 milligrams of aerosol-generating substrate, for example at least 10 milligrams of aerosol-generating substrate, for example at least 20 milligrams of aerosol-generating substrate, for example at least 30 milligrams of aerosolgenerating substrate, for example at least 50 milligrams of aerosol-generating substrate.

[0021] The aerosol-generating article may comprise between 5 milligrams and 140 milligrams, for example between 5 milligrams and 120 milligrams, for example between 5 milligrams and 110 milligrams, for example between 5 milligrams and 100 milligrams, for example between 5 milligrams and 90 milligrams, for example between 5 milligrams and 80 milligrams of aerosolgenerating substrate.

[0022] The aerosol-generating article may comprise between 10 milligrams and 140 milligrams, for example between 10 milligrams and 120 milligrams, for example between 10 milligrams and 110 milligrams, for example between 10 milligrams and 100 milligrams, for example between 10 milligrams and 90 milligrams, for example between 10 milligrams and 80 milligrams of aerosolgenerating substrate.

[0023] The aerosol-generating article may comprise between 20 milligrams and 140 milligrams, for example between 20 milligrams and 120 milligrams, for example between 20 milligrams and 110 milligrams, for example between 20 milligrams and 100 milligrams, for example between 20 milligrams and 90 milligrams, for example between 20 milligrams and 80 milligrams of aerosolgenerating substrate.

[0024] The aerosol-generating article may comprise between 30 milligrams and 140 milligrams, for example between 30 milligrams and 120 milligrams, for example between 30 milligrams and 110 milligrams, for example between 30 milligrams and 100 milligrams, for example between 30 milligrams and 90 milligrams, for example between 30 milligrams and 80 milligrams of aerosolgenerating substrate.

[0025] The aerosol-generating article may comprise between 50 milligrams and 140 milligrams, for example between 50 milligrams and 120 milligrams, for example between 50 milligrams and 110 milligrams, for example between 50 milligrams and 100 milligrams, for example between 50 milligrams and 90 milligrams, for example between 50 milligrams and 80 milligrams of aerosolgenerating substrate.

[0026] According to an aspect of the present invention there is provided an aerosol-generating article for producing an inhalable aerosol upon heating, the aerosol-generating article comprising a substrate plug defining an internal volume, the internal volume of the substrate plug comprising an aerosol-generating substrate, wherein a mass of the aerosol-generating substrate within the internal volume of the substrate plug is less than or equal to 0.5 milligrams per cubic millimetre and wherein the aerosol-generating article comprises less than or equal to 100 milligrams of aerosol-generating substrate.

[0027] The aerosol-generating article is particularly suitable for use with aerosol-generating devices including dielectric or microwave heating elements, which are very efficient and provide homogenous heating, and thus enable the aerosol former content of the aerosol-generating substrate of the aerosol-generating article to be reduced without compromising the levels of aerosol generated. It has, surprisingly, been found that levels of aerosol comparable to those obtained using convective or conductive heating have been obtained by heating aerosolgenerating articles according to the present invention using dielectric heating elements.

[0028] The high efficacy with which aerosol-generating articles of the present invention are heated using dielectric heating enables the mass of aerosol-generating substrate within the internal volume of the substrate plug, i.e. the bulk density of substrate in the aerosol-generating article, to be reduced.

[0029] The provision of an aerosol-generating article having a relatively low bulk density of aerosol-generating substrate may allow the aerosol-generating substrate to increase in temperature relatively quickly at the start of a user experience. This may help to ensure that all of the necessary volatile components within the aerosol-generating substrate are aerosolised simultaneously. This may advantageously prevent the less volatile components, such as aerosol former, from being delivered to the user after the more volatile components, such as nicotine. This may therefore lead to a more consistent user experience.

[0030] With flat consumables, for example including aerosol-generating substrate that is cuboidal, the gradient of temperature through the formed substrate unit is lower than in round consumables, for example cylindrical formed aerosol-generating substrates, since the whole aerosol-generating substrate is closer to the heating element. By reducing the density of aerosolgenerating substrate in the internal volume of the aerosol-generating article, the conduction of heat through the aerosol-generating substrate may be reduced, thereby increasing the gradient of temperature through the aerosol-generating substrate. The temperature gradient may be useful to ensure that the aerosol is delivered throughout the experience. With dielectric heating, the whole aerosol-generating substrate can be heated by microwaves and so there is a low temperature gradient whether or not the aerosol-generating substrate is close to the heater.

[0031] The mass of the aerosol-generating substrate within the internal volume of the substrate plug may be less than or equal to 0.4 milligrams per cubic millimetre, for example less than or equal to 0.2 milligrams per cubic millimetre, for example less than or equal to 0.1 milligrams per cubic millimetre.

[0032] The mass of the aerosol-generating substrate within the internal volume of the substrate plug may be at least 0.005 milligrams per cubic millimetre, for example at least 0.01 milligrams per cubic millimetre, for example at least 0.02 milligrams per cubic millimetre, for example at least 0.04 milligrams per cubic millimetre, for example at least 0.05 milligrams per cubic millimetre.

[0033] The mass of the aerosol-generating substrate within the internal volume of the substrate plug maybe between 0.005 milligrams per cubic millimetre and 0.5 milligrams per cubic millimetre, for example between 0.01 milligrams per cubic millimetre and 0.5 milligrams per cubic millimetre, for example between 0.02 milligrams per cubic millimetre and 0.5 milligrams per cubic millimetre, for example between 0.04 milligrams per cubic millimetre and 0.5 milligrams per cubic millimetre, for example between 0.05 milligrams per cubic millimetre and 0.5 milligrams per cubic millimetre.

[0034] The mass of the aerosol-generating substrate within the internal volume of the substrate plug maybe between 0.005 milligrams per cubic millimetre and 0.4 milligrams per cubic millimetre, for example between 0.01 milligrams per cubic millimetre and 0.4 milligrams per cubic millimetre, for example between 0.02 milligrams per cubic millimetre and 0.4 milligrams per cubic millimetre, for example between 0.04 milligrams per cubic millimetre and 0.4 milligrams per cubic millimetre, for example between 0.05 milligrams per cubic millimetre and 0.4 milligrams per cubic millimetre.

[0035] The mass of the aerosol-generating substrate within the internal volume of the substrate plug maybe between 0.005 milligrams per cubic millimetre and 0.3 milligrams per cubic millimetre, for example between 0.01 milligrams per cubic millimetre and 0.3 milligrams per cubic millimetre, for example between 0.02 milligrams per cubic millimetre and 0.3 milligrams per cubic millimetre, for example between 0.04 milligrams per cubic millimetre and 0.3 milligrams per cubic millimetre, for example between 0.05 milligrams per cubic millimetre and 0.3 milligrams per cubic millimetre.

[0036] The mass of the aerosol-generating substrate within the internal volume of the substrate plug maybe between 0.005 milligrams per cubic millimetre and 0.2 milligrams per cubic millimetre, for example between 0.01 milligrams per cubic millimetre and 0.2 milligrams per cubic millimetre, for example between 0.02 milligrams per cubic millimetre and 0.2 milligrams per cubic millimetre, for example between 0.04 milligrams per cubic millimetre and 0.2 milligrams per cubic millimetre, for example between 0.05 milligrams per cubic millimetre and 0.2 milligrams per cubic millimetre. The mass of the aerosol-generating substrate within the internal volume of the substrate plug maybe between 0.005 milligrams per cubic millimetre and 0.1 milligrams per cubic millimetre, for example between 0.01 milligrams per cubic millimetre and 0.1 milligrams per cubic millimetre, for example between 0.02 milligrams per cubic millimetre and 0.1 milligrams per cubic millimetre, for example between 0.04 milligrams per cubic millimetre and 0.1 milligrams per cubic millimetre, for example between 0.05 milligrams per cubic millimetre and 0.1 milligrams per cubic millimetre.

[0037] The aerosol-generating article may comprise less than or equal to 90 milligrams of aerosol-generating substrate, for example less than or equal to 80 milligrams of aerosolgenerating substrate.

[0038] The aerosol-generating article may comprise at least 5 milligrams of aerosol-generating substrate, for example at least 10 milligrams of aerosol-generating substrate, for example at least 20 milligrams of aerosol-generating substrate, for example at least 30 milligrams of aerosolgenerating substrate, for example at least 50 milligrams of aerosol-generating substrate.

[0039] The aerosol-generating article may comprise between 5 milligrams and 100 milligrams, for example between 5 milligrams and 90 milligrams, for example between 5 milligrams and 80 milligrams of aerosol-generating substrate.

[0040] The aerosol-generating article may comprise between 10 milligrams and 100 milligrams, for example between 10 milligrams and 90 milligrams, for example between 10 milligrams and 80 milligrams of aerosol-generating substrate.

[0041] The aerosol-generating article may comprise between 20 milligrams and 100 milligrams, for example between 20 milligrams and 90 milligrams, for example between 20 milligrams and 80 milligrams of aerosol-generating substrate.

[0042] The aerosol-generating article may comprise between 30 milligrams and 100 milligrams, for example between 30 milligrams and 90 milligrams, for example between 30 milligrams and 80 milligrams of aerosol-generating substrate.

[0043] The aerosol-generating article may comprise between 50 milligrams and 100 milligrams, for example between 50 milligrams and 90 milligrams, for example between 50 milligrams and 80 milligrams of aerosol-generating substrate.

[0044] According to an aspect of the present invention there is provided an aerosol-generating article for producing an inhalable aerosol upon heating, the aerosol-generating article comprising a substrate plug defining an internal volume, the internal volume of the substrate plug comprising an aerosol-generating substrate, wherein a mass of the aerosol-generating substrate within the internal volume of the substrate plug is less than or equal to 0.4 milligrams per cubic millimetre and wherein the aerosol-generating article comprises less than or equal to 110 milligrams of aerosol-generating substrate. According to an aspect of the present invention there is provided an aerosol-generating article for producing an inhalable aerosol upon heating, the aerosol-generating article comprising a substrate plug defining an internal volume, the internal volume of the substrate plug comprising an aerosol-generating substrate, wherein a mass of the aerosol-generating substrate within the internal volume of the substrate plug is less than or equal to 0.3 milligrams per cubic millimetre and wherein the aerosol-generating article comprises less than or equal to 120 milligrams of aerosol-generating substrate.

[0045] According to an aspect of the present invention there is provided an aerosol-generating article for producing an inhalable aerosol upon heating, the aerosol-generating article comprising a substrate plug defining an internal volume, the internal volume of the substrate plug comprising an aerosol-generating substrate, wherein a mass of the aerosol-generating substrate within the internal volume of the substrate plug is less than or equal to 0.2 milligrams per cubic millimetre and wherein the aerosol-generating article comprises less than or equal to 140 milligrams of aerosol-generating substrate.

[0046] According to an aspect of the present invention there is provided an aerosol-generating article for producing an inhalable aerosol upon heating. The aerosol-generating article may comprise at least 10 milligrams and less than 100 milligrams of aerosol-generating substrate. The aerosol-generating article may have an internal volume of at least 1 cubic centimetre.

[0047] According to an aspect of the present invention there is provided an aerosol-generating article for producing an inhalable aerosol upon heating, the aerosol-generating article comprising at least 10 milligrams and less than 100 milligrams of aerosol-generating substrate, wherein the aerosol-generating article has an internal volume of at least 1 cubic centimetre.

[0048] The high efficacy with which aerosol-generating articles of the present invention are heated using dielectric heating enables the mass of aerosol-generating substrate within the internal volume of the substrate plug, i.e. the bulk density of substrate in the aerosol-generating article, to be reduced.

[0049] The aerosol-generating article may comprise at least 20 milligrams, for example at least 40 milligrams, for example at least 60 milligrams, for example at least 70 milligrams of aerosolgenerating substrate.

[0050] The aerosol-generating article may comprise less than 90 milligrams, for example less than 80 milligrams of aerosol-generating substrate.

[0051] The aerosol-generating article may comprise between 10 milligrams and 90 milligrams, for example between 10 milligrams and 80 milligrams of aerosol-generating substrate.

[0052] The aerosol-generating article may comprise between 20 milligrams and 90 milligrams, for example between 20 milligrams and 80 milligrams of aerosol-generating substrate. The aerosol-generating article may comprise between 40 milligrams and 90 milligrams, for example between 40 milligrams and 80 milligrams of aerosol-generating substrate.

[0053] The aerosol-generating article may comprise between 60 milligrams and 90 milligrams, for example between 60 milligrams and 80 milligrams of aerosol-generating substrate.

[0054] The aerosol-generating article may comprise between 70 milligrams and 90 milligrams, for example between 70 milligrams and 80 milligrams of aerosol-generating substrate.

[0055] The aerosol-generating article volume may be at least 1 .25 cubic centimetres, for example at least 1 .5 cubic centimetres.

[0056] The aerosol-generating article volume may be less than or equal to 3 cubic centimetres, for example less than or equal to 2.5 cubic centimetres.

[0057] The aerosol-generating article volume may be between 1 cubic centimetre and 3 cubic centimetres, for example between 1 cubic centimetre and 2.5 cubic centimetres.

[0058] The aerosol-generating article volume may be between 1 .25 cubic centimetres and 3 cubic centimetres, for example between 1.25 cubic centimetres and 2.5 cubic centimetres.

[0059] The aerosol-generating article volume may be between 1 .5 cubic centimetres and 3 cubic centimetres, for example between 1.5 cubic centimetres and 2.5 cubic centimetres.

[0060] The aerosol-generating article may comprise at least 3 milligrams of aerosol-generating substrate per cubic centimetre of the aerosol-generating article internal volume, for example at least 6 milligrams of aerosol-generating substrate per cubic centimetre of the aerosol-generating article internal volume, for example at least 10 milligrams of aerosol-generating substrate per cubic centimetre of the aerosol-generating article internal volume, for example at least 20 milligrams of aerosol-generating substrate per cubic centimetre of the aerosol-generating article internal volume.

[0061] The aerosol-generating article may comprise less than 100 milligrams of aerosolgenerating substrate per cubic centimetre of the aerosol-generating article internal volume, for example less than 80 milligrams of aerosol-generating substrate per cubic centimetre of the aerosol-generating article internal volume, for example less than 60 milligrams of aerosolgenerating substrate per cubic centimetre of the aerosol-generating article internal volume.

[0062] The aerosol-generating article may comprise between 3 milligrams and 100 milligrams of aerosol-generating substrate per cubic centimetre of the aerosol-generating article internal volume, for example between 3 milligrams and 80 milligrams of aerosol-generating substrate per cubic centimetre of the aerosol-generating article internal volume, for example between 3 milligrams and 60 milligrams of aerosol-generating substrate per cubic centimetre of the aerosolgenerating article internal volume.

[0063] The aerosol-generating article may comprise between 6 milligrams and 100 milligrams of aerosol-generating substrate per cubic centimetre of the aerosol-generating article internal volume, for example between 6 milligrams and 80 milligrams of aerosol-generating substrate per cubic centimetre of the aerosol-generating article internal volume, for example between 6 milligrams and 60 milligrams of aerosol-generating substrate per cubic centimetre of the aerosolgenerating article internal volume.

[0064] The aerosol-generating article may comprise between 10 milligrams and 100 milligrams of aerosol-generating substrate per cubic centimetre of the aerosol-generating article internal volume, for example between 10 milligrams and 80 milligrams of aerosol-generating substrate per cubic centimetre of the aerosol-generating article internal volume, for example between 10 milligrams and 60 milligrams of aerosol-generating substrate per cubic centimetre of the aerosolgenerating article internal volume.

[0065] The aerosol-generating article may comprise between 20 milligrams and 100 milligrams of aerosol-generating substrate per cubic centimetre of the aerosol-generating article internal volume, for example between 20 milligrams and 80 milligrams of aerosol-generating substrate per cubic centimetre of the aerosol-generating article internal volume, for example between 20 milligrams and 60 milligrams of aerosol-generating substrate per cubic centimetre of the aerosolgenerating article internal volume.

[0066] By adjusting the density of the formed aerosol-generating substrate (also referred to as the substrate density or the bulk density of the substrate), by adjusting the mass of aerosolgenerating substrate within the volume of the formed aerosol-generating substrate unit, it may be possible to provide a substrate with a high surface area to volume ratio, which optimises the release of aerosol from the aerosol-generating substrate upon heating.

[0067] Substrate density is defined as the ratio of the mass of substrate to the volume of the formed aerosol-generating substrate unit.

[0068] The aerosol-generating substrate may have an aerosol-generating substrate density (i.e. the bulk density of the formed aerosol-generating substrate or the bulk density of the aerosolgenerating substrate) of less than or equal to 0.55 grams per cubic centimetre, for example less than or equal to 0.50 grams per cubic centimetre, for example less than or equal to 0.45 grams per cubic centimetre, for example less than or equal to 0.40 grams per cubic centimetre.

[0069] The aerosol-generating substrate density may be at least 0.01 grams per cubic centimetre, for example at least 0.05 grams per cubic centimetre, for example at least 0.10 grams per cubic centimetre, for example at least 0.20 grams per cubic centimetre, for example at least 0.25 grams per cubic centimetre.

[0070] The aerosol-generating substrate density may be between 0.01 grams per cubic centimetre and 0.55 grams per cubic centimetre, for example between 0.01 grams per cubic centimetre and 0.50 grams per cubic centimetre, for example between 0.01 grams per cubic centimetre and 0.45 grams per cubic centimetre, for example between 0.01 grams per cubic centimetre and 0.40 grams per cubic centimetre.

[0071] The aerosol-generating substrate density may be between 0.05 grams per cubic centimetre and 0.55 grams per cubic centimetre, for example between 0.05 grams per cubic centimetre and 0.50 grams per cubic centimetre, for example between 0.05 grams per cubic centimetre and 0.45 grams per cubic centimetre, for example between 0.05 grams per cubic centimetre and 0.40 grams per cubic centimetre.

[0072] The aerosol-generating substrate density may be between 0.1 grams per cubic centimetre and 0.55 grams per cubic centimetre, for example between 0.1 grams per cubic centimetre and

[0073] 0.50 grams per cubic centimetre, for example between 0.1 grams per cubic centimetre and 0.45 grams per cubic centimetre, for example between 0.1 grams per cubic centimetre and 0.40 grams per cubic centimetre.

[0074] The aerosol-generating substrate density may be between 0.2 grams per cubic centimetre and 0.55 grams per cubic centimetre, for example between 0.2 grams per cubic centimetre and

[0075] 0.50 grams per cubic centimetre, for example between 0.2 grams per cubic centimetre and 0.45 grams per cubic centimetre, for example between 0.2 grams per cubic centimetre and 0.40 grams per cubic centimetre.

[0076] The aerosol-generating substrate density may be between 0.25 grams per cubic centimetre and 0.55 grams per cubic centimetre, for example between 0.25 grams per cubic centimetre and 0.50 grams per cubic centimetre, for example between 0.25 grams per cubic centimetre and 0.45 grams per cubic centimetre, for example between 0.25 grams per cubic centimetre and 0.40 grams per cubic centimetre.

[0077] Porosity is a measure of the volume of voids within a substrate, and is expressed as a percentage of the total volume of the substrate. A porous substrate may be preferable for the aerosol-generating article since the surface area to mass ratio is increased and therefore a larger surface for volatile evaporation is presented. A porous substrate advantageously enables air to circulate through the substrate and collect the aerosol generated by dielectric heating. The substrate may be foam or crimped. A pouch with cut filler may be used.

[0078] Computer tomography (CT) scanning, for example X-ray CT scanning, may be used to determine the porosity of the aerosol-generating substrate. Images of a sample which include solid and void parts may be obtained. Image processing software may then be used to calculate the extent of the voids in the internal structure of the aerosol-generating substrate. An example of such a method is described in Prokop and Pina: “Porosity Measurement Method by X-Ray Computer Topography”; Key Engineering Materials; March 2009. The aerosol-generating substrate of the aerosol-generating article may have a porosity of at least 60 percent, for example at least 70 percent, for example at least 75 percent, for example at least 80 percent.

[0079] The aerosol-generating substrate porosity may be less than or equal to 98 percent, for example less than or equal to 97 percent, for example less than or equal to 95 percent.

[0080] The aerosol-generating substrate porosity may be between 60 percent and 98 percent, for example between 60 percent and 97 percent, for example between 60 percent and 95 percent.

[0081] The aerosol-generating substrate porosity may be between 70 percent and 98 percent, for example between 70 percent and 97 percent, for example between 70 percent and 95 percent.

[0082] The aerosol-generating substrate porosity may be between 75 percent and 98 percent, for example between 75 percent and 97 percent, for example between 75 percent and 95 percent.

[0083] The aerosol-generating substrate porosity may be between 80 percent and 98 percent, for example between 80 percent and 97 percent, for example between 80 percent and 95 percent.

[0084] The internal volume of the substrate plug of the aerosol-generating article may have a first end, a second end, a width and a length extending between the first end and the second end. A longitudinal axis of the internal volume may be defined between the first end and the second end of the internal volume. The width of the internal volume may correspond to a maximum dimension of the internal volume in a direction that is orthogonal to the longitudinal axis of the longitudinal volume.

[0085] The internal volume of the substrate plug of the aerosol-generating article may comprise one or more cavities or chambers.

[0086] The internal volume may be quadrilateral in cross section. The internal volume may be cuboidal in cross section. The internal volume may be parallelepiped in cross section.

[0087] The internal volume may be circular in cross section.

[0088] The internal volume may be oval in cross section.

[0089] The internal volume may be elliptical in cross section.

[0090] The internal volume may spherical.

[0091] The length of the internal volume may be at least 3 millimetres, for example at least 10 millimetres, for example at least 15 millimetres.

[0092] The length of the internal volume may be less than or equal to 30 millimetres, for example less than or equal to 28 millimetres, for example less than or equal to 16 millimetres.

[0093] The length of the internal volume may be between 3 millimetres and 30 millimetres, for example between 3 millimetres and 28 millimetres, for example between 3 millimetres and 16 millimetres. The length of the internal volume may be between 10 millimetres and 30 millimetres, for example between 10 millimetres and 28 millimetres, for example between 10 millimetres and 28 millimetres.

[0094] The length of the internal volume may be between 15 millimetres and 30 millimetres, for example between 15 millimetres and 28 millimetres, for example between 15 millimetres and 16 millimetres.

[0095] The width of the internal volume may be at least 1 millimetre, for example at least 4 millimetres, for example at least 5 millimetres, for example at least 6 millimetres.

[0096] The width of the internal volume may be less than or equal to 15 millimetres, for example less than or equal to 12 millimetres, for example less than or equal to 10 millimetres, for example less than or equal to 8 millimetres.

[0097] The width of the internal volume may be between 1 millimetre and 15 millimetres, for example between 1 millimetre and 12 millimetres, for example between 1 millimetre and 10 millimetres, for example between 1 millimetre and 8 millimetres.

[0098] The width of the internal volume may be between 4 millimetres and 15 millimetres, for example between 4 millimetres and 12 millimetres, for example between 4 millimetres and 10 millimetres, for example between 4 millimetres and 8 millimetres.

[0099] The width of the internal volume may be between 5 millimetres and 15 millimetres, for example between 5 millimetres and 12 millimetres, for example between 5 millimetres and 10 millimetres, for example between 5 millimetres and 8 millimetres.

[0100] The width of the internal volume may be between 6 millimetres and 12 millimetres, for example between 6 millimetres and 10 millimetres, for example between 6 millimetres and 9 millimetres, for example between 6 millimetres and 8 millimetres.

[0101] The thickness of the internal volume may be less than or equal to 10 millimetres, for example less than or equal to 5 millimetres, for example less than or equal to 4 millimetres.

[0102] The thickness of the internal volume may be at least 0.1 millimetre, for example at least 0.5 millimetres, for example at least 1 millimetre, for example at least 1.5 millimetres, for example at least 2 millimetres.

[0103] The thickness of the internal volume may be between 0.1 millimetres and 10 millimetres, for example between 0.1 millimetres and 5 millimetres, for example between 0.1 millimetres and 4 millimetres, for example between 0.1 millimetres and 3 millimetres.

[0104] The thickness of the internal volume may be between 0.5 millimetres and 10 millimetres, for example between 0.5 millimetres and 5 millimetres, for example between 0.5 millimetres and 4 millimetres, for example between 0.5 millimetres and 3 millimetres. The thickness of the internal volume may be between 1 millimetre and 10 millimetres, for example between 1 millimetre and 5 millimetres, for example between 1 millimetre and 4 millimetres, for example between 1 millimetre and 3 millimetres.

[0105] The thickness of the internal volume may be between 1.5 millimetres and 10 millimetres, for example between 1.5 millimetres and 5 millimetres, for example between 1.5 millimetres and 4 millimetres, for example between 1.5 millimetres and 3 millimetres.

[0106] The thickness of the internal volume may be between 2 millimetres and 10 millimetres, for example between 2 millimetres and 5 millimetres, for example between 2 millimetres and 4 millimetres, for example between 2 millimetres and 3 millimetres.

[0107] The volume of the internal volume may be less than or equal to 4500 cubic millimetres, for example less than or equal to 1680 cubic millimetres, for example less than or equal to 320 cubic millimetres.

[0108] The volume of the internal volume may be at least 0.3 cubic millimetres, for example at least 20 cubic millimetres, for example at least 110 cubic millimetres.

[0109] The volume of the internal volume may be between 0.3 cubic millimetres and 4500 cubic millimetres, for example between 0.3 cubic millimetres and 1680 cubic millimetres, for example between 0.3 cubic millimetres and 320 cubic millimetres.

[0110] The volume of the internal volume may be between 20 cubic millimetres and 4500 cubic millimetres, for example between 20 cubic millimetres and 1680 cubic millimetres, for example between 20 cubic millimetres and 320 cubic millimetres.

[0111] The volume of the internal volume may be between 110 cubic millimetres and 4500 cubic millimetres, for example between 110 cubic millimetres and 1680 cubic millimetres, for example between 110 cubic millimetres and 320 cubic millimetres.

[0112] In one example of the present invention, the internal volume has a length of 16 millimetres, a width of 10 millimetres, a thickness of 3 millimetres and, therefore, a volume of 480 cubic millimetres. The formed aerosol-generating substrate is positioned between the first planar external surface and the second planar external surface, typically within the cavity. For a formed substrate having a mass of 180 milligrams, the density of aerosol-generating substrate within the aerosol-generating article is 0.375 grams per cubic centimetre.

[0113] In another example of the present invention, the internal volume has a length of 26 millimetres, a width of 6 millimetres, a thickness of 2.7 millimetres and, therefore, a volume of 421 cubic millimetres. The formed aerosol-generating substrate is positioned between the first planar external surface and the second planar external surface, typically within the cavity. For a formed substrate having a mass of 158 milligrams, the density of aerosol-generating substrate within the aerosol-generating article is 0.375 grams per cubic centimetre The aerosol-generating substrate may be assembled in an aerosol-generating article that is in the form of a rod or tubular structure, e.g. a long, thin rod or tubular structure, in order to improve filtration of the aerosol and improve the sensory performance of the aerosol-generating article.

[0114] The aerosol-generating article may comprise an upstream end and a downstream end. The internal volume may be positioned between the upstream end and the downstream end of the aerosol-generating article.

[0115] The aerosol-generating article may comprise a downstream element. The downstream element may comprise one or more of: a mouthpiece element, an aerosol-cooling element, a hollow tubular segment, a filter and a support element.

[0116] The downstream element may be positioned between the internal volume and the downstream end of the aerosol-generating article.

[0117] The aerosol-generating article may comprise an upstream element. The upstream element may comprise an upstream plug. The upstream element may be positioned between internal volume and the upstream end of the aerosol-generating article.

[0118] The aerosol-generating article may be, in examples of the invention, non-rod shaped, for example flat, spherical or a rolling tape.

[0119] The aerosol-generating article may have an oblong shape.

[0120] The aerosol-generating article may have a laminated structure, for example the aerosolgenerating article may comprise or be formed from at least two layers. In particular, the aerosolgenerating article may comprise at least two of: a first external layer, a second external layer, a frame, a first frame layer, a second frame layer, a third frame layer, a first aerosol-generating substrate layer, and a second aerosol-generating substrate layer.

[0121] The frame may be a planar frame.

[0122] The frame may define a frame aperture extending through the thickness of the frame. The frame aperture may define or form the airflow passage of the aerosol-generating article. The frame aperture may define or form the cavity of the aerosol-generating article. For example, the frame may have a hollow cuboid shape or a square hollow tube shape. As a further example, the frame may have a cross-section that is annular in shape, preferably the cross-section in an x / y plane is annular in shape. The cross-section may have an annulus shape, such as a circular annulus shape, an elliptical annulus shape, a rectangular annulus shape, or a square annulus shape.

[0123] The frame may comprise a frame outer surface. The frame outer surface may extend in a transverse direction, for example between the first planar external surface and the second planar external surface. The frame outer surface may at least partially define or form one or more external surfaces of the aerosol-generating article. For example, the frame outer surface may at least partially define or form one or more external walls of the aerosol-generating article. The frame outer surface may circumscribe or encircle the frame aperture. The frame outer surface may circumscribe or encircle the cavity.

[0124] The frame may comprise a frame inner surface. The frame inner surface may extend in a transverse direction, for example between the first planar external surface and the second planar external surface. The frame inner surface may define or form a frame aperture outer wall. The frame inner surface may define or form a cavity outer wall. The frame inner surface may circumscribe or encircle the frame aperture extending through the thickness of the frame. The frame outer surface may circumscribe or encircle the cavity.

[0125] The frame outer surface may circumscribe or encircle the frame inner surface. The frame inner surface and the frame outer surface may be concentric with one another.

[0126] Substantially flat aerosol-generating articles or substantially planar aerosol-generating articles have a large base area relative to the volume of the article. Advantageously, a larger base area may provide greater surface area for heating by a planar heater of an aerosol-generating device. Advantageously, a smaller height may allow a smaller temperature gradient or difference across the height of the aerosol-generating article during heating. For example, where the base of the aerosol-generating article is in contact with, and heated by, a planar heater, there may be a smaller temperature difference between the base and an upper surface opposing the base if the spacing, or height, between the base and the upper surface is smaller. Advantageously, this may allow heating of a greater proportion of the aerosol-generating substrate of the aerosolgenerating article to a temperature at which an aerosol is released, whilst minimising the risk of burning the hottest portion of the substrate closest to the heater. Alternatively, or in addition, this may reduce a time required to heat the aerosol-generating substrate sufficiently to release an aerosol.

[0127] The aerosol-generating article may comprise a porous container, for example a sachet, comprising aerosol-generating substrate.

[0128] Providing aerosol-generating substrate in a sachet enables the porosity of the aerosolgenerating substrate within the sachet to be controlled and optimised, which improves the consistency of aerosol-generation.

[0129] The aerosol-generating article may comprise a pouch, for example a pouch comprising an outer wall defining a substrate compartment. The substrate compartment may comprise an aerosol-generating substrate. The outer wall may be flexible.

[0130] Providing a flexible outer wall of the pouch defining the substrate compartment may, advantageously, allow the pouch to conform to the shape of a heating chamber of an aerosolgenerating device when the aerosol-generating article is received therein. Advantageously, the provision of a flexible outer wall of the pouch defining the substrate compartment may result in improved heating of the aerosol-generating substrate because a larger total surface area of the flexible outer wall may be provided in contact with a heating element of a heating chamber of an aerosol-generating device. Advantageously, the provision of a flexible outer wall of the pouch defining the substrate compartment may result in a greater proximity of the aerosol-generating substrate to a heating element of a heating chamber of an aerosol-generating device. Advantageously, the provision of a flexible outer wall of the pouch defining the substrate compartment may increase the rate of aerosolisation of the aerosol-generating substrate.

[0131] The outer wall may be air permeable. Providing an air permeable outer wall defining the substrate compartment may advantageously allow air to be drawn through the outer wall of the pouch to mix with aerosol generated within the substrate compartment, and then be inhaled by a user.

[0132] The aerosol-generating article may be in the shape of a particle.

[0133] The aerosol-generating article may comprise an inner core comprising a substrate plug defining an internal volume. The aerosol-generating article may comprise an outer shell encapsulating the inner core. The outer shell may comprise a film-forming polymer.

[0134] The provision of the outer shell encapsulating the inner core makes the aerosol-generating substrate easier to handle and transport as part of the aerosol-generating article. The outer shell also protects the aerosol-generating substrate within the inner core from the outer environment, at least until the aerosol-generating article is used.

[0135] The aerosol-generating article may comprise a roll of aerosol-generating substrate. The aerosol-generating substrate may be defined by a length, a width and a thickness. The length may be greater in magnitude than the width. The width may be greater in magnitude than the thickness. At least a portion of the aerosol-generating substrate may be rolled along its length.

[0136] As the aerosol-generating substrate may be rolled along its length, the aerosol-generating article may conveniently be suitable for use in more than one usage session. For example, a portion of the aerosol-generating substrate may be unrolled from a rolled portion of the aerosolgenerating substrate such that an unrolled portion of aerosol-generating substrate is provided. The unrolled portion may be heatable for aerosol generation, without the rolled portion of the aerosol-generating substrate being heated. In this way, only a portion of the aerosol-generating substrate may be consumed in a usage session. Therefore, the aerosol-generating article is suitable for use in multiple usage session. As such, a user may conveniently only require one article for use in multiple usage sessions, for example in at least two, three, four or five usage sessions. For example, one article may be suitable for use in at least six, seven, eight, nine or ten usage sessions. Advantageously a user is not required to carry multiple aerosol-generating articles. As such, the aerosol-generating article is more convenient for the user than typical single use disposable aerosol-generating articles. The aerosol-generating substrate of the aerosol-generating article may comprise a solid aerosol-generating film. The solid aerosol-generating film may be formed by any suitable method. For example, the solid aerosol-generating film may be formed by batch casting, continuous casting or extrusion.

[0137] The solid aerosol-generating film may be self-supporting. In other words, the properties of the solid aerosol-generating film may be such that, even if the solid aerosol-generating film is formed by casting a slurry onto a support surface, the solid aerosol-generating film can be separated from the support surface.

[0138] The solid aerosol-generating film may be disposed on a support or the solid aerosolgenerating film may be sandwiched between other materials. This may enhance the mechanical stability of the solid aerosol-generating film. For example, the solid aerosol-generating film may be disposed on a laminar support.

[0139] The solid aerosol-generating film may be cut or otherwise divided into a plurality of strips or shreds that may be wrapped to form an aerosol-generating rod for inclusion in an aerosolgenerating article according to the invention. The solid aerosol-generating film may be gathered to form an aerosol-generating rod for inclusion in an aerosol-generating article according to the invention.

[0140] The solid aerosol-generating film may be textured. This may facilitate gathering of the solid aerosol-generating film to form an aerosol-generating rod for inclusion in an aerosolgenerating article according to the invention.

[0141] The solid aerosol-generating film may be crimped.

[0142] The crimped solid aerosol-generating film may have a plurality of ridges or corrugations substantially parallel to the cylindrical axis of the aerosol-generating rod. This may advantageously facilitate gathering of the crimped solid aerosol-generating film to form the aerosol-generating rod.

[0143] The solid aerosol-generating film may be textured using suitable known machinery for texturing filter tow, paper and other materials.

[0144] The solid aerosol-generating film may be crimped using a crimping unit of the type described in CH-A-691156, which comprises a pair of rotatable crimping rollers. However, it will be appreciated that the solid aerosol-generating film may be textured using other suitable machinery and processes that deform or perforate the solid aerosol-generating film.

[0145] The aerosol-generating substrate of the aerosol-generating article may be corrugated. The aerosol-generating substrate may comprise, for example, one or more sheets of substrate material, at least one of which is textured using a fluting roller to form a continuous corrugated sheet. In technical fields in which corrugation is commonplace, for example in the field of corrugated paper or cardboard, there is standard nomenclature for the three mutually perpendicular directions for a standard corrugated element. A person skilled in the field of this invention would understand this nomenclature but, nonetheless, a brief explanation is set out below.

[0146] A standard corrugated element is formed from a sheet, usually a rectangular sheet, which is bent or folded to have parallel corrugations with constant amplitude and wavelength. A standard corrugated element extends in three mutually perpendicular directions. These directions are the machine direction, the cross direction, and the thickness direction.

[0147] Without wishing to be bound to any particular manufacturing method, the machine direction generally refers to the direction in which material to be corrugated to form the standard corrugated element would be unwound from a roller, or fed into a roller, to form the standard corrugated element. This means that, in the resulting, standard corrugated element, the machine direction refers to the direction extending from a point on a first corrugation peak, to the nearest point on an adjacent corrugation peak. This direction may also be referred to as the wavelength direction, since it is in the same direction as the wavelength of the corrugations would be measured.

[0148] For a standard corrugated element, the cross direction is perpendicular to the machine direction and extends in a direction along a corrugation peak without any change in amplitude. This direction may also be referred to as the longitudinal channel direction herein, since it is the same direction as the longitudinally extending channels formed between adjacent corrugations.

[0149] For a standard corrugated element, the thickness direction is perpendicular to the machine direction and the cross direction and extends in a direction from a midpoint between two adjacent corrugation troughs, to the nearest (i.e., opposing) corrugation peak. This direction may also be referred to as the amplitude direction, since it is in the same direction in which the amplitude of the corrugations would be measured.

[0150] As the skilled person would understand after reading this disclosure, the above directions could also be applied to non-standard corrugated elements. At any point, a non-standard corrugated element may have a local machine direction, a local cross direction, and a local thickness direction.

[0151] Any corrugated element or elements described herein may each be formed from a sheet which is bent or folded to form corrugations. Any corrugated element or elements described herein may each be formed from a sheet forming corrugations through changes in direction of the sheet. All peaks of corrugations of the corrugated element may have equal amplitude. All troughs of corrugations of the corrugated element may have equal amplitude. All peaks and all troughs of corrugations of the corrugated element may have equal amplitude. All corrugations of the corrugated element may have equal wavelength.

[0152] The aerosol-generating substrate of the aerosol-generating article may comprise an aerosol former. By adjusting the amount of aerosol former in the aerosol-generating substrate it may be advantageously possible to tune the delivery of certain compounds, such as flavour compounds and / or nicotine, into the aerosol generated from the aerosol-generating substrate upon heating.

[0153] By adjusting the amount of aerosol former in the aerosol-generating substrate it may also be possible to produce a visually pleasant aerosol.

[0154] The aerosol-generating substrate of the aerosol-generating article may have an aerosol former content of at least 5 percent by weight, for example at least 15 percent by weight, for example at least 25 percent by weight, for example at least 35 percent by weight, for example at least 45 percent by weight, on a dry weight basis.

[0155] The aerosol former content of the aerosol-generating substrate may be less than or equal to 80 percent by weight, for example less than or equal to 60 percent by weight, on a dry weight basis, for example less than or equal to 50 percent by weight, on a dry weight basis.

[0156] The aerosol former content of the aerosol-generating substrate may be between 5 percent by weight and 80 percent by weight, for example between 5 percent by weight and 60 percent by weight, for example between 5 percent by weight and 50 percent by weight, on a dry weight basis.

[0157] The aerosol former content of the aerosol-generating substrate of the aerosol-generating article may be between 15 percent by weight and 80 percent by weight, for example between 15 percent by weight and 60 percent by weight, for example between 15 percent by weight and 50 percent by weight, on a dry weight basis.

[0158] The aerosol former content of the aerosol-generating substrate may be between 25 percent by weight and 80 percent by weight, for example between 25 percent by weight and 60 percent by weight, for example between 25 percent by weight and 50 percent by weight, on a dry weight basis.

[0159] The aerosol former content of the aerosol-generating substrate may be between 35 percent by weight and 80 percent by weight, for example between 35 percent by weight and 60 percent by weight, for example between 35 percent by weight and 50 percent by weight, on a dry weight basis.

[0160] The aerosol former content of the aerosol-generating substrate may be between 45 percent by weight and 80 percent by weight, for example between 45 percent by weight and 60 percent by weight, for example between 45 percent by weight and 50 percent by weight, on a dry weight basis. In an example, the mass of aerosol-generating substrate within the aerosol-generating article may be 5 milligrams.

[0161] Such an aerosol-generating article may have a aerosol former content of at least 0.25 milligrams, for example at least 0.75 milligrams, for example at least 1.25 milligrams, for example at least 1.75 milligrams.

[0162] The aerosol former content of the aerosol-generating article may be less than or equal to 4 milligrams, for example less than or equal to 3 milligrams, for example less than or equal to 2.5 milligrams, for example less than or equal to 2.25 milligrams.

[0163] The aerosol former content may be between 0.25 milligrams and 4 milligrams, for example between 0.25 milligrams and 3 milligrams, for example between 0.25 milligrams and 2.5 milligrams, for example between 0.25 milligrams and 2.25 milligrams.

[0164] The aerosol former content may be between 0.75 milligrams and 4 milligrams, for example between 0.75 milligrams and 3 milligrams, for example between 0.75 milligrams and 2.5 milligrams, for example between 0.75 milligrams and 2.25 milligrams.

[0165] The aerosol former content may be between 1.25 milligrams and 4 milligrams, for example between 1.25 milligrams and 3 milligrams, for example between 1.25 milligrams and 2.5 milligrams, for example between 1.25 milligrams and 2.25 milligrams.

[0166] The aerosol former content may be between 1.75 milligrams and 4 milligrams, for example between 1.75 milligrams and 3 milligrams, for example between 1.75 milligrams and 2.5 milligrams, for example between 1.75 milligrams and 2.25 milligrams.

[0167] In an example, the mass of aerosol-generating substrate within the aerosol-generating article may be 50 milligrams.

[0168] Such an aerosol-generating article may have a aerosol former content of at least 2.5 milligrams, for example at least 7.5 milligrams, for example at least 12.5 milligrams, for example at least 17.5 milligrams.

[0169] The aerosol former content of the aerosol-generating article may be less than or equal to 40 milligrams, for example less than or equal to 30 milligrams, for example less than or equal to 25 milligrams, for example less than or equal to 22.5 milligrams.

[0170] The aerosol former content may be between 2.5 milligrams and 40 milligrams, for example between 2.5 milligrams and 30 milligrams, for example between 2.5 milligrams and 25 milligrams, for example between 2.5 milligrams and 22.5 milligrams.

[0171] The aerosol former content may be between 7.5 milligrams and 40 milligrams, for example between 7.5 milligrams and 30 milligrams, for example between 7.5 milligrams and 25 milligrams, for example between 7.5 milligrams and 22.5 milligrams. The aerosol former content may be between 12.5 milligrams and 40 milligrams, for example between 12.5 milligrams and 30 milligrams, for example between 12.5 milligrams and 25 milligrams, for example between 12.5 milligrams and 22.5 milligrams.

[0172] The aerosol former content may be between 17.5 milligrams and 40 milligrams, for example between 17.5 milligrams and 30 milligrams, for example between 17.5 milligrams and 25 milligrams, for example between 17.5 milligrams and 22.5 milligrams.

[0173] In an example, the mass of aerosol-generating substrate within the aerosol-generating article may be 100 milligrams.

[0174] Such an aerosol-generating article may have a aerosol former content of at least 5 milligrams, for example at least 15 milligrams, for example at least 25 milligrams, for example at least 35 milligrams.

[0175] The aerosol former content of the aerosol-generating article may be less than or equal to 80 milligrams, for example less than or equal to 60 milligrams, for example less than or equal to 50 milligrams, for example less than or equal to 45 milligrams.

[0176] The aerosol former content may be between 5 milligrams and 80 milligrams, for example between 5 milligrams and 60 milligrams, for example between 5 milligrams and 50 milligrams, for example between 5 milligrams and 45 milligrams.

[0177] The aerosol former content may be between 15 milligrams and 80 milligrams, for example between 15 milligrams and 60 milligrams, for example between 15 milligrams and 50 milligrams, for example between 15 milligrams and 45 milligrams.

[0178] The aerosol former content may be between 25 milligrams and 80 milligrams, for example between 25 milligrams and 60 milligrams, for example between 25 milligrams and 50 milligrams, for example between 25 milligrams and 45 milligrams.

[0179] The aerosol former content may be between 35 milligrams and 80 milligrams, for example between 35 milligrams and 60 milligrams, for example between 35 milligrams and 50 milligrams, for example between 35 milligrams and 45 milligrams.

[0180] In an example, the mass of aerosol-generating substrate within the aerosol-generating article may be 140 milligrams.

[0181] Such an aerosol-generating article may have a aerosol former content of at least 7 milligrams, for example at least 21 milligrams, for example at least 35 milligrams, for example at least 49 milligrams.

[0182] The aerosol former content of the aerosol-generating article may be less than or equal to 112 milligrams, for example less than or equal to 84 milligrams, for example less than or equal to 70 milligrams, for example less than or equal to 63 milligrams. The aerosol former content may be between 7 milligrams and 112 milligrams, for example between 7 milligrams and 84 milligrams, for example between 7 milligrams and 70 milligrams, for example between 7 milligrams and 63 milligrams.

[0183] The aerosol former content may be between 21 milligrams and 112 milligrams, for example between 21 milligrams and 84 milligrams, for example between 21 milligrams and 70 milligrams, for example between 21 milligrams and 63 milligrams.

[0184] The aerosol former content may be between 35 milligrams and 112 milligrams, for example between 35 milligrams and 84 milligrams, for example between 35 milligrams and 70 milligrams, for example between 35 milligrams and 63 milligrams.

[0185] The aerosol former content may be between 49 milligrams and 112 milligrams, for example between 49 milligrams and 84 milligrams, for example between 49 milligrams and 70 milligrams, for example between 49 milligrams and 63 milligrams.

[0186] Suitable aerosol formers for use in the manufacture of aerosol-generating substrates according to the present invention include, but are not limited to, glycerin, propylene glycol, and mixtures thereof.

[0187] In examples of the invention, the aerosol former may be glycerin and the glycerin content of the aerosol-generating substrate may be at least 5 percent by weight, for example at least 10 percent by weight, for example at least 15 percent by weight, for example at least 25 percent by weight, for example at least 35 percent by weight, for example at least 45 percent by weight, on a dry weight basis.

[0188] The glycerin content of the aerosol-generating substrate may be less than or equal to 80 percent by weight, for example less than or equal to 60 percent by weight, on a dry weight basis, for example less than or equal to 50 percent by weight, on a dry weight basis.

[0189] The glycerin content of the aerosol-generating substrate may be between 5 percent by weight and 80 percent by weight, for example between 5 percent by weight and 60 percent by weight, for example between 5 percent by weight and 50 percent by weight, on a dry weight basis.

[0190] The glycerin content of the aerosol-generating substrate may be between 10 percent by weight and 80 percent by weight, for example between 10 percent by weight and 60 percent by weight, for example between 10 percent by weight and 50 percent by weight, on a dry weight basis.

[0191] The glycerin content of the aerosol-generating substrate of the aerosol-generating article may be between 15 percent by weight and 80 percent by weight, for example between 15 percent by weight and 60 percent by weight, for example between 15 percent by weight and 50 percent by weight, on a dry weight basis.

[0192] The glycerin content of the aerosol-generating substrate may be between 25 percent by weight and 80 percent by weight, for example between 25 percent by weight and 60 percent by weight, for example between 25 percent by weight and 50 percent by weight, on a dry weight basis.

[0193] The glycerin content of the aerosol-generating substrate may be between 35 percent by weight and 80 percent by weight, for example between 35 percent by weight and 60 percent by weight, for example between 35 percent by weight and 50 percent by weight, on a dry weight basis.

[0194] The glycerin content of the aerosol-generating substrate may be between 45 percent by weight and 80 percent by weight, for example between 45 percent by weight and 60 percent by weight, for example between 45 percent by weight and 50 percent by weight, on a dry weight basis.

[0195] In an example, the mass of aerosol-generating substrate within the aerosol-generating article may be 5 milligrams.

[0196] Such an aerosol-generating article may have a glycerin content of at least 0.25 milligrams, for example at least 0.75 milligrams, for example at least 1.25 milligrams, for example at least 1.75 milligrams.

[0197] The glycerin content of the aerosol-generating article may be less than or equal to 4 milligrams, for example less than or equal to 3 milligrams, for example less than or equal to 2.5 milligrams, for example less than or equal to 2.25 milligrams.

[0198] The glycerin content may be between 0.25 milligrams and 4 milligrams, for example between 0.25 milligrams and 3 milligrams, for example between 0.25 milligrams and 2.5 milligrams, for example between 0.25 milligrams and 2.25 milligrams.

[0199] The glycerin content may be between 0.75 milligrams and 4 milligrams, for example between 0.75 milligrams and 3 milligrams, for example between 0.75 milligrams and 2.5 milligrams, for example between 0.75 milligrams and 2.25 milligrams.

[0200] The glycerin content may be between 1.25 milligrams and 4 milligrams, for example between 1.25 milligrams and 3 milligrams, for example between 1.25 milligrams and 2.5 milligrams, for example between 1.25 milligrams and 2.25 milligrams.

[0201] The glycerin content may be between 1.75 milligrams and 4 milligrams, for example between 1.75 milligrams and 3 milligrams, for example between 1.75 milligrams and 2.5 milligrams, for example between 1.75 milligrams and 2.25 milligrams.

[0202] In an example, the mass of aerosol-generating substrate within the aerosol-generating article may be 50 milligrams.

[0203] Such an aerosol-generating article may have a glycerin content of at least 2.5 milligrams, for example at least 7.5 milligrams, for example at least 12.5 milligrams, for example at least 17.5 milligrams. The glycerin content of the aerosol-generating article may be less than or equal to 40 milligrams, for example less than or equal to 30 milligrams, for example less than or equal to 25 milligrams, for example less than or equal to 22.5 milligrams.

[0204] The glycerin content may be between 2.5 milligrams and 40 milligrams, for example between 2.5 milligrams and 30 milligrams, for example between 2.5 milligrams and 25 milligrams, for example between 2.5 milligrams and 22.5 milligrams.

[0205] The glycerin content may be between 7.5 milligrams and 40 milligrams, for example between 7.5 milligrams and 30 milligrams, for example between 7.5 milligrams and 25 milligrams, for example between 7.5 milligrams and 22.5 milligrams.

[0206] The glycerin content may be between 12.5 milligrams and 40 milligrams, for example between 12.5 milligrams and 30 milligrams, for example between 12.5 milligrams and 25 milligrams, for example between 12.5 milligrams and 22.5 milligrams.

[0207] The glycerin content may be between 17.5 milligrams and 40 milligrams, for example between 17.5 milligrams and 30 milligrams, for example between 17.5 milligrams and 25 milligrams, for example between 17.5 milligrams and 22.5 milligrams.

[0208] In an example, the mass of aerosol-generating substrate within the aerosol-generating article may be 100 milligrams.

[0209] Such an aerosol-generating article may have a glycerin content of at least 5 milligrams, for example at least 15 milligrams, for example at least 25 milligrams, for example at least 35 milligrams.

[0210] The glycerin content of the aerosol-generating article may be less than or equal to 80 milligrams, for example less than or equal to 60 milligrams, for example less than or equal to 50 milligrams, for example less than or equal to 45 milligrams.

[0211] The glycerin content may be between 5 milligrams and 80 milligrams, for example between 5 milligrams and 60 milligrams, for example between 5 milligrams and 50 milligrams, for example between 5 milligrams and 45 milligrams.

[0212] The glycerin content may be between 15 milligrams and 80 milligrams, for example between 15 milligrams and 60 milligrams, for example between 15 milligrams and 50 milligrams, for example between 15 milligrams and 45 milligrams.

[0213] The glycerin content may be between 25 milligrams and 80 milligrams, for example between 25 milligrams and 60 milligrams, for example between 25 milligrams and 50 milligrams, for example between 25 milligrams and 45 milligrams.

[0214] The glycerin content may be between 35 milligrams and 80 milligrams, for example between 35 milligrams and 60 milligrams, for example between 35 milligrams and 50 milligrams, for example between 35 milligrams and 45 milligrams. In an example, the mass of aerosol-generating substrate within the aerosol-generating article may be 140 milligrams.

[0215] Such an aerosol-generating article may have a glycerin content of at least 7 milligrams, for example at least 21 milligrams, for example at least 35 milligrams, for example at least 49 milligrams.

[0216] The glycerin content of the aerosol-generating article may be less than or equal to 112 milligrams, for example less than or equal to 84 milligrams, for example less than or equal to 70 milligrams, for example less than or equal to 63 milligrams.

[0217] The glycerin content may be between 7 milligrams and 112 milligrams, for example between 7 milligrams and 84 milligrams, for example between 7 milligrams and 70 milligrams, for example between 7 milligrams and 63 milligrams.

[0218] The glycerin content may be between 21 milligrams and 112 milligrams, for example between 21 milligrams and 84 milligrams, for example between 21 milligrams and 70 milligrams, for example between 21 milligrams and 63 milligrams.

[0219] The glycerin content may be between 35 milligrams and 112 milligrams, for example between 35 milligrams and 84 milligrams, for example between 35 milligrams and 70 milligrams, for example between 35 milligrams and 63 milligrams.

[0220] The glycerin content may be between 49 milligrams and 112 milligrams, for example between 49 milligrams and 84 milligrams, for example between 49 milligrams and 70 milligrams, for example between 49 milligrams and 63 milligrams.

[0221] The aerosol-generating substrate of the aerosol-generating article may comprise a plant material.

[0222] The aerosol-generating substrate may comprise, for example, homogenised plant material. The homogenised plant material can be provided in any suitable form. For example, the homogenised plant material may be in the form of one or more sheets.

[0223] Alternatively or additionally, the homogenised plant material may be in the form of a plurality of pellets or granules.

[0224] Alternatively or additionally, the homogenised plant material may be in the form of a plurality of strands, strips or shreds. The strands of homogenised plant material may be formed from a sheet of homogenised plant material, for example by cutting or shredding, or by other methods, for example by an extrusion method.

[0225] In some embodiments, the strands may be formed in situ within the aerosol-generating substrate as a result of the splitting or cracking of a sheet of homogenised plant material during formation of the aerosol-generating substrate, for example as a result of crimping.

[0226] The plant material may comprise tobacco. With reference to the present invention, the term “tobacco” describes any plant member of the genus Nicotiana. The tobacco may comprise tobacco material from one or more of: Bright tobacco, dark tobacco, aromatic tobacco and filler tobacco.

[0227] The plant material may comprise homogenised plant material, for example homogenised tobacco material. The homogenised tobacco material may be formed by agglomerating particles of tobacco material obtained by pulverising, grinding or comminuting plant material and one or more of tobacco leaf lamina and tobacco leaf stems. The homogenised tobacco material may be produced by casting, extrusion, paper making processes or any other suitable processes known in the art.

[0228] The plant material may comprise shredded tobacco material. Shredded tobacco material may be in the form of cut filler. Alternatively, the shredded tobacco material may be in the form of a shredded sheet of homogenised tobacco material.

[0229] The cut filler may comprise other after-cut, filler or casing.

[0230] The plant material may comprise a non-tobacco plant material. The non-tobacco plant material may comprise one or more of: tea (such as black tea), rosehip seeds, apple fibres, lemon balm stems, coffee, star anise, rooibos, lavender, clove, peppermint, chamomile, rosemary, eucalyptus, ginger, dill seed, thyme, oregano and cumin.

[0231] Additionally, or alternatively, the non-tobacco plant material may comprise one or more cannabinoid compounds. The one or more cannabinoid compounds may include naturally derived cannabinoid compounds and / or synthetically derived cannabinoid compounds. The one or more cannabinoid compounds may comprise selected from the group consisting of: tetrahydrocannabinol (THC), tetrahydrocannabinolic acid (THCA), cannabidiol (CBD), cannabidiolic acid (CBDA), cannabinol (CBN), cannabigerol (CBG), cannabigerol monomethyl ether (CBGM), cannabivarin (CBV), cannabidivarin (CBDV), tetrahydrocannabivarin (THCV), cannabichromene (CBC), cannabicyclol (CBL), cannabichromevarin (CBCV), cannabigerovarin (CBGV), cannabielsoin (CBE), cannabicitran (CBT) and combinations thereof.

[0232] The aerosol-generating substrate of the aerosol-generating article may have a plant material content of at least 5 percent by weight, for example at least 10 percent by weight, for example at least 20 percent by weight, for example at least 25 percent by weight, for example at least 30 percent by weight, for example at least 40 percent by weight, for example at least 45 percent by weight, on a dry weight basis.

[0233] The plant material content of the aerosol-generating substrate may be less than or equal to 65 percent weight, for example less than or equal to 60 percent weight, for example less than or equal to 55 percent by weight, on a dry weight basis.

[0234] The plant material content of the aerosol-generating substrate may be between 5 percent by weight and 65 percent by weight, for example between 5 percent by weight and 60 percent by weight, for example between 5 percent by weight and 55 percent by weight, on a dry weight basis. The plant material content of the aerosol-generating substrate may be between 10 percent by weight and 65 percent by weight, for example between 10 percent by weight and 60 percent by weight, for example between 10 percent by weight and 55 percent by weight, on a dry weight basis.

[0235] The plant material content of the aerosol-generating substrate may be between 20 percent by weight and 65 percent by weight, for example between 20 percent by weight and 60 percent by weight, for example between 20 percent by weight and 55 percent by weight, on a dry weight basis.

[0236] The plant material content of the aerosol-generating substrate may be between 25 percent by weight and 65 percent by weight, for example between 25 percent by weight and 60 percent by weight, for example between 25 percent by weight and 55 percent by weight, on a dry weight basis.

[0237] The plant material content of the aerosol-generating substrate may be between 30 percent by weight and 65 percent by weight, for example between 30 percent by weight and 60 percent by weight, for example between 30 percent by weight and 55 percent by weight, on a dry weight basis.

[0238] The plant material content of the aerosol-generating substrate may be between 40 percent by weight and 65 percent by weight, for example between 40 percent by weight and 60 percent by weight, for example between 40 percent by weight and 55 percent by weight, on a dry weight basis.

[0239] The plant material content of the aerosol-generating substrate may be between 45 percent by weight and 65 percent by weight, for example between 45 percent by weight and 60 percent by weight, for example between 45 percent by weight and 55 percent by weight, on a dry weight basis.

[0240] The plant material content of the aerosol-generating substrate may be between 46 percent by weight and 50 percent by weight, on a dry weight basis. The plant content of the aerosolgenerating substrate may be between 47 percent by weight and 49 percent by weight, on a dry weight basis.

[0241] The plant material may, for example, comprise tobacco or non-tobacco plant material or a mixture of tobacco and non-tobacco plant material. For example, a proportion of non-tobacco plant material may be added to tobacco material to provide a particular flavour profile. A proportion of tobacco may, for example, be replaced with a non-tobacco plant material.

[0242] The tobacco content may be 100 percent of the plant material content of the aerosolgenerating substrate, on a dry weight basis. In other words, the tobacco content of the aerosolgenerating substrate may be between 5 percent by weight and 65 percent by weight, on a dry weight basis. The non-tobacco plant material content may be 100 percent of the plant material content of the aerosol-generating substrate, on a dry weight basis. In other words, the non-tobacco plant content of the aerosol-generating substrate may be between 5 percent by weight and 65 percent by weight, on a dry weight basis.

[0243] Alternatively, the tobacco material content may be at least 75 percent, for example at least 80 percent, for example at least 85 percent, for example at least 90 percent of the plant material content of the aerosol-generating substrate, on a dry weight basis.

[0244] The tobacco material content may be less than or equal to 99 percent, for example less than or equal to 98 percent, for example less than or equal to 95 percent of the plant material content of the aerosol-generating substrate, on a dry weight basis.

[0245] The tobacco material content may be between 75 percent and 99 percent, for example between 75 percent and 98 percent, for example between 75 percent and 95 percent of the plant material content of the aerosol-generating substrate, on a dry weight basis.

[0246] The tobacco material content may be between 80 percent and 99 percent, for example between 80 percent and 98 percent, for example between 80 percent and 95 percent of the plant material content of the aerosol-generating substrate, on a dry weight basis.

[0247] The tobacco material content may be between 85 percent and 99 percent, for example between 85 percent and 98 percent, for example between 85 percent and 95 percent of the plant material content of the aerosol-generating substrate, on a dry weight basis.

[0248] The tobacco material content may be between 90 percent and 99 percent, for example between 90 percent and 98 percent, for example between 90 percent and 95 percent of the plant material content of the aerosol-generating substrate, on a dry weight basis.

[0249] The non-tobacco plant material content may be at least 1 percent, for example at least 2 percent, for example at least 5 percent, for example at least 10 percent of the plant material content of the aerosol-generating substrate, on a dry weight basis.

[0250] The non-tobacco plant material content may be less than or equal to 25 percent, for example less than or equal to 20 percent, for example less than or equal to 15 percent of the plant material content of the aerosol-generating substrate, on a dry weight basis.

[0251] The non-tobacco plant material content may be between 1 percent and 25 percent, for example between 1 percent and 20 percent, for example between 1 percent and 15 percent of the plant material content of the aerosol-generating substrate, on a dry weight basis.

[0252] The non-tobacco plant material content may be between 2 percent and 25 percent, for example between 2 percent and 20 percent, for example between 2 percent and 15 percent of the plant material content of the aerosol-generating substrate, on a dry weight basis. The non-tobacco plant material content may be between 5 percent and 25 percent, for example between 5 percent and 20 percent, for example between 5 percent and 15 percent of the plant material content of the aerosol-generating substrate, on a dry weight basis.

[0253] The non-tobacco plant material content may be between 10 percent and 25 percent, for example between 10 percent and 20 percent, for example between 10 percent and 15 percent of the plant material content of the aerosol-generating substrate, on a dry weight basis.

[0254] By adjusting the amount of plant material in the aerosol-generating substrate it may be advantageously possible to adjust the density of the aerosol-generating substrate. Furthermore, by adjusting the amount of plant material in the aerosol-generating substrate, as well as the relative proportion of the plant material to the aerosol former, it may be possible to tune the delivery of certain compounds, such as flavour compounds, into the aerosol generated from the aerosol-generating substrate upon heating.

[0255] The plant material may be provided in any suitable form, for example particulate (i.e., ground particles) or shredded. Preferably, the plant material is particulate.

[0256] The plant particles may include a combination of tobacco particles and non-tobacco particles. Alternatively, the plant particles may be substantially free from tobacco material such that the aerosol-generating substrate is tobacco free.

[0257] The plant particles may have an average particle size of at least 25 microns. Preferably, the plant particles have an average particle size of at least 30 microns. More preferably, the plant particles have an average particle size of at least 35 microns. Even more preferably, the plant particles have an average particle size of at least 40 microns.

[0258] Use of plant particles having an average particle size of 25 microns or more may help control how easily the tobacco particles may be dispersed and kept in suspension within the aerosol former, which helps in providing an homogenous distribution of plant particles throughout the aerosol-generating substrate.

[0259] The plant particles may have an average size of less than or equal to 250 microns. Preferably, the plant particles have an average size of less than or equal to 200 microns. More preferably, the plant particles have an average size of less than or equal to 180 microns. Even more preferably, the plant particles have an average size of less than or equal to 160 microns. Most preferably, the plant particles have an average size of less than or equal to 140 microns.

[0260] The plant particles may have an average size of from 30 microns to 200 microns, preferably from 35 microns to 200 microns, more preferably from 40 microns to 200 microns. In other embodiments, the plant particles have an average size of from 30 microns to 180 microns, preferably from 35 microns to 180 microns, more preferably from 40 microns to 180 microns. In further embodiments, the plant particles have an average size of from 30 microns to 160 microns, preferably from 35 microns to 160 microns, more preferably from 40 microns to 160 microns. In yet other embodiments, the plant particles have an average size of from 30 microns to 140 microns, preferably from 35 microns to 140 microns, more preferably from 40 microns to 140 microns.

[0261] Advantageously, using plant particles having an average size within the ranges described above has a beneficial impact on flowability and malleability of the aerosol-generating substrate, and may also enable some desirable control over porosity of the formed aerosol-generating substrate, which helps in release of the aerosol species during use.

[0262] The plant particles may have a D90 value of less than or equal to 300 microns. This expression means that 90 percent of plant particles in the aerosol-generating substrate have a size of less than or equal to 300 microns. For a population of particles, the D90 value may be determined by analysing the particle size distribution. In more detail, looking at a particle size distribution curve, the D90 value can be determined by identifying the point on the curve below which 90 percent of the particles fall.

[0263] Preferably, the plant particles have a D90 value of less than or equal to 275 microns. More preferably, the plant particles have a D90 value of less than or equal to 250 microns. Even more preferably, the plant particles have a D90 value of less than or equal to 200 microns.

[0264] The plant particles may have a D90 value of at least 35 microns. Preferably, the plant particles have a D90 value of at least 40 microns. More preferably, the plant particles have a D90 value of at least 45 microns. Even more preferably, the plant particles have a D90 value of at least 50 microns.

[0265] The particle size distribution may be determined by laser diffraction. For example, the particle size distribution may be determined by laser diffraction using a Malvern Mastersizer 3000 laser diffraction particle size analyser in accordance with the manufacturer’s instructions.

[0266] Using plant particles having a D90 value falling within the ranges described above has the benefit that a regular particle distribution is achieved in the aerosol-generating substrate. This may facilitate controlling the porosity of the aerosol-generating substrate, which helps in release of the aerosol during use. Additionally, this helps ensure that a consistent aerosol can be generated from the aerosol-generating substrate upon heating.

[0267] Where the aerosol-generating substrate comprises plant particles from two or more different plants, the plant particles from each plant may have a different average size and particle size distribution to the plant particles from the other plant or plants. For example, where the aerosol-generating substrate comprises tobacco particles and non-tobacco particles, the D90 value of the non-tobacco particles may be higher than the D90 value of the tobacco particles.

[0268] Preferably, the aerosol-generating substrate comprises tobacco particles having a D90 value of between 35 microns and 100 microns, or between 40 microns and 80 microns, or between 50 microns and 70 microns. Alternatively or additionally, the aerosol-generating substrate preferably comprises nontobacco particles having a D90 value of between 50 microns and 250 microns, or between 75 microns and 200 microns, or between 100 microns and 200 microns, or between 100 microns and 150 microns.

[0269] In examples for which the plant material is provided in shredded form, the shredded plant material forming the cut filler may have an average cut width of at least 0.75 millimetres. Preferably, the shredded plant material has an average cut width of at least 0.8 millimetres, more preferably at least 0.85 millimetres, more preferably at least 0.9 millimetres.

[0270] Preferably, the shredded plant material forming the cut filler has an average cut width of less than or equal to 2 millimetres, more preferably less than or equal to 1.75 millimetres, more preferably less than or equal to 1.5 millimetres, more preferably less than or equal to 1.25 millimetres.

[0271] For example, the shredded plant material may have an average cut width of between 0.75 millimetres and 2 millimetres, or between 0.8 millimetres and 1.75 millimetres, or between 0.85 millimetres and 1.5 millimetres, or between 0.9 millimetres and 1.25 millimetres. In one preferred embodiment, the shredded plant material has an average cut width of approximately 1 millimetre.

[0272] Preferably, the cut filler comprises at least 25 percent of plant leaf lamina, more preferably, at least 50 percent of plant leaf lamina, still more preferably at least 75 percent of plant leaf lamina and most preferably at least 90 percent of plant leaf lamina.

[0273] The aerosol-generating substrate may comprise the plant material and the aerosol former in a ratio of between approximately 0.1 :1 and approximately 3.5:1.

[0274] The ratio of the plant material to the aerosol former may be less than approximately 2.5:1 , for example less than approximately 1.5:1.

[0275] The ratio of the plant material to the aerosol former may be at least approximately 0.5:1 , for example at least approximately 0.75:1 .

[0276] The ratio of the plant material to the aerosol former may be approximately 1 :1.

[0277] The aerosol-generating substrate of the aerosol-generating article may comprise a binder, which acts to improve the binding of the plant material in the aerosol-generating substrate and optimise the structural integrity of the aerosol-generating substrate.

[0278] The binder may comprise a cellulose binder. The cellulose binder may comprise one or more of hydroxypropyl methylcellulose (HPMC), methylcellulose (MC), ethylcellulose (EC), hydroxyethyl methyl cellulose (HEMC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC) and hydroxypropyl cellulose (HPC).

[0279] The aerosol-generating substrate of the aerosol-generating article may have a cellulose binder content of at least 1 percent by weight, for example at least 2 percent by weight, for example at least 3 percent by weight, on a dry weight basis. The cellulose binder content of the aerosol-generating substrate may be less than or equal to 10 percent by weight, on a dry weight basis.

[0280] The cellulose binder content of the aerosol-generating substrate may be between 1 percent by weight and 10 percent by weight, for example between 2 percent by weight and 10 percent by weight, for example between 3 percent by weight and 10 percent by weight, on a dry weight basis.

[0281] The binder may comprise a non-cellulose binder. The non-cellulose binder may comprise one or more of agar, guar gum, xanthan gum, Arabic gum, locust bean gum, pectin, carrageenan, starch and alginate.

[0282] The aerosol-generating substrate of the aerosol-generating article may have a non- cellulose binder content of at least 0.2 percent by weight, for example at least 0.4 percent by weight, for example at least 0.6 percent by weight, for example at least 0.8 percent by weight, on a dry weight basis.

[0283] The non-cellulose binder content of the aerosol-generating substrate may be less than or equal to 2 percent by weight, for example less than or equal to 1.8 percent by weight, for example less than or equal to 1.6 percent by weight, for example less than or equal to 1.4 percent by weight, on a dry weight basis.

[0284] The non-cellulose binder content of the aerosol-generating substrate may be between 0.2 percent by weight and 2 percent by weight, for example between 0.2 percent by weight and 1.8 percent by weight, for example between 0.2 percent by weight and 1 .6 percent by weight, for example between 0.2 percent by weight and 1.4 percent by weight, on a dry weight basis.

[0285] The non-cellulose binder content of the aerosol-generating substrate may be between 0.4 percent by weight and 2 percent by weight, for example between 0.4 percent by weight and 1.8 percent by weight, for example between 0.4 percent by weight and 1 .6 percent by weight, for example between 0.4 percent by weight and 1.4 percent by weight, on a dry weight basis.

[0286] The non-cellulose binder content of the aerosol-generating substrate may be between 0.6 percent by weight and 2 percent by weight, for example between 0.6 percent by weight and 1.8 percent by weight, for example between 0.6 percent by weight and 1 .6 percent by weight, for example between 0.6 percent by weight and 1.4 percent by weight, on a dry weight basis.

[0287] The non-cellulose binder content of the aerosol-generating substrate may be between 0.8 percent by weight and 2 percent by weight, for example between 0.8 percent by weight and 1.8 percent by weight, for example between 0.8 percent by weight and 1 .6 percent by weight, for example between 0.8 percent by weight and 1.4 percent by weight, on a dry weight basis.

[0288] The binder may comprise a cellulose binder and a non-cellulose binder. The binder may comprise one or more of HPMC, MC, EC, HEMC, HEC, CMC and HPC, and one or more of agar, guar gum, xanthan gum, Arabic gum, locust bean gum, pectin, carrageenan, starch and alginate. The binder may, for example, comprise HPMC and agar.

[0289] Relative permittivity, which may be referred to as dielectric constant, is the permittivity of a material expressed as a ratio with the electric permittivity of a vacuum. In other words, the relative permittivity of a material is the ratio of the capacitance of a capacitor using the material as a dielectric (an electrical insulator that can be polarised by an applied electric field) compared with a similar capacitor that has a vacuum as its dielectric. The relative permittivity values described herein are defined based on measurements to the substrate carried out at room temperature with a very low frequency (VLF), preferably below 1kHz, e.g. as defined in the international standard IEC 62631-2-1 :2018.

[0290] The aerosol-generating substrate of the aerosol-generating article may have an initial relative permittivity prior to heating (an unheated relative permittivity) and a subsequent relative permittivity after heating (a post-heating relative permittivity) for a given period of time.

[0291] The given period of time may be at least 30 seconds and less than one hour.

[0292] Controlling the relative permittivity of the aerosol-generating substrate may enable the adjustment of the heating profile or operation for an aerosol-generating substrate that is heated using dielectric heating. An aerosol-generating substrate having a porous or foam-like structure, and thus a high volume percentage of air, may have a relatively low relative permittivity, for example.

[0293] The initial or unheated relative permittivity may be at least 3.7.

[0294] The initial or unheated relative permittivity may be less than, for example less than 7, for example, less than 5, for example less than 4.2.

[0295] The initial or unheated relative permittivity may be in a range between 3.7 and 10, for example between 3.7 and 7, for example between 3.7 and 5, for example between 3.7 and 4.2.

[0296] The subsequent or post-heating relative permittivity may be at least 2, for example at least 2.2, for example at least 2.3.

[0297] The subsequent or post-heating relative permittivity may be less than 2.8.

[0298] The subsequent or post-heating relative permittivity may be in a range between 2 and 2.8, for example between 2.2 and 2.8, for example between 2.3 and 2.8.

[0299] The relative permittivity range may allow for an improved heating operation, because the variation from full substrate to empty substrate is relatively high, which may lead to an improved determination of a property of the aerosol-generating substrate, such as the substrate depletion, and hence to an improved heating control. A decrease in the relative permittivity of the substrate is indicative for a decrease of the capacity of the electrode arrangement due to a reduction of a share of an aerosol generating material, such as a liquid filler or aerosolization agents or materials (e.g. water, propylene glycol or glycerin), compared to a share of a carrier material, such as a tobacco-based material, in the solid aerosol-generating substrate during the heating operation. A change on the capacitance in turn may lead to a change in a measurable resonant frequency of the oscillation circuit. The relative permittivity range could be further increased by using liquid filler or aerosolization agents or materials (e.g. water, propylene glycol or glycerin) in the substrate that may have a substantially higher relative permittivity than the tobacco-based material, for example.

[0300] The aerosol-generating substrate of the aerosol-generating article may comprise an active agent and / or a flavourant. The aerosol-generating substrate may comprise a cellulose-based strengthening agent. The aerosol-generating substrate may comprise an active agent and / or a flavourant, and a cellulose-based strengthening agent.

[0301] The active agent of the aerosol-generating substrate may comprise nicotine, for example exogenous nicotine. The term “exogenous” refers to nicotine that is added to the aerosolgenerating substrate as a distinct component from any nicotine that is intrinsically present in the plant material, for example, where the plant material comprises tobacco. Exogenous nicotine may be included in the aerosol-generating substrate where the plant material is solely or largely nontobacco plant material. The term “nicotine” encompasses nicotine, a nicotine base or a nicotine salt. In embodiments in which the aerosol-generating substrate comprises a nicotine base or a nicotine salt, the amounts of nicotine recited herein are the amount of free base nicotine or amount of protonated nicotine, respectively.

[0302] The aerosol-generating substrate may comprise a natural nicotine or a synthetic nicotine.

[0303] The aerosol-generating substrate may comprise less than or equal to 2 percent nicotine by weight, on a dry weight basis. The aerosol-generating substrate may comprise at least 0.5 percent nicotine, for example at least 1 percent nicotine by weight, on a dry weight basis.

[0304] The aerosol-generating substrate may comprise between 0.5 percent and 2 percent nicotine by weight, on a dry weight basis.

[0305] The aerosol-generating substrate may comprise between 1 percent and 2 percent nicotine by weight, on a dry weight basis.

[0306] In examples, the aerosol-generating substrate may comprise approximately 1.5 percent nicotine by weight, on a dry weight basis.

[0307] In an example, the mass of aerosol-generating substrate within the aerosol-generating article may be 5 milligrams.

[0308] Such an aerosol-generating article may have a nicotine content of at least 0.025 milligrams, for example at least 0.05 milligrams.

[0309] The nicotine content of the aerosol-generating article may be less than or equal to 0.1 milligrams, for example less than or equal to 0.075 milligrams.

[0310] The nicotine content may be between 0.025 milligrams and 0.1 milligrams, for example between 0.025 milligrams and 0.075 milligrams. The nicotine content may be between 0.05 milligrams and 0.1 milligrams, for example between 0.05 milligrams and 0.075 milligrams.

[0311] In an example, the mass of aerosol-generating substrate within the aerosol-generating article may be 50 milligrams.

[0312] Such an aerosol-generating article may have a nicotine content of at least 0.25 milligrams, for example at least 0.5 milligrams.

[0313] The nicotine content of the aerosol-generating article may be less than or equal to 1.0 milligram, for example less than or equal to 0.75 milligrams.

[0314] The nicotine content may be between 0.25 milligrams and 1.0 milligram, for example between 0.25 milligrams and 0.75 milligrams.

[0315] The nicotine content may be between 0.5 milligrams and 1.0 milligram, for example between 0.5 milligrams and 0.05 milligrams.

[0316] In an example, the mass of aerosol-generating substrate within the aerosol-generating article may be 100 milligrams.

[0317] Such an aerosol-generating article may have a nicotine content of at least 0.5 milligrams, for example at least 1.0 milligrams.

[0318] The nicotine content of the aerosol-generating article may be less than or equal to 2.0 milligrams, for example less than or equal to 1.5 milligrams.

[0319] The nicotine content may be between 0.5 milligrams and 2.0 milligram, for example between 0.5 milligrams and 1.5 milligrams.

[0320] The nicotine content may be between 1.0 milligram and 2.0 milligram, for example between 1.0 milligrams and 1.5 milligrams.

[0321] In an example, the mass of aerosol-generating substrate within the aerosol-generating article may be 140 milligrams.

[0322] Such an aerosol-generating article may have a nicotine content of at least 0.7 milligrams, for example at least 1 .4 milligrams.

[0323] The nicotine content of the aerosol-generating article may be less than or equal to 2.8 milligrams, for example less than or equal to 2.1 milligrams.

[0324] The nicotine content may be between 0.7 milligrams and 2.8 milligrams, for example between 0.7 milligrams and 2.1 milligrams.

[0325] The nicotine content may be between 1.4 milligrams and 2.8 milligrams, for example between 1.4 milligrams and 2.1 milligrams.

[0326] The aerosol-generating substrate may further comprise one or more carboxylic acids. Advantageously, where the active agent comprises nicotine, including one or more carboxylic acids in the aerosol-generating substrate may create a nicotine salt. The carboxylic acid may comprise one or more of lactic acid, levulinic acid, benzoic acid, fumaric acid or acetic acid. Preferably, the carboxylic acid is at least one of fumaric acid, lactic acid or levulinic acid.

[0327] The aerosol-generating substrate may have a carboxylic acid content of at least 0.5 percent by weight, preferably at least 1 percent by weight, more preferably at least 2 percent by weight, on a dry weight basis.

[0328] The aerosol-generating substrate may have a carboxylic acid content of less than or equal to 10 percent by weight, preferably less than or equal to 8 percent by weight, more preferably less than or equal to 8 percent by weight, on a dry weight basis.

[0329] For example, the aerosol-generating substrate may comprise between about 0.5 percent by weight and about 10 percent by weight of the acid, or between about 1 percent by weight and about 8 percent by weight of the acid, or between about 2 percent by weight and about 6 percent by weight of the acid, on a dry weight basis.

[0330] The active agent and / or the flavourant of the aerosol-generating substrate may comprise a plant material, for example a non-tobacco plant material.

[0331] The non-tobacco plant material may comprise one or more of: tea (such as black tea), rosehip seeds, apple fibres, lemon balm stems, coffee, star anise, rooibos, lavender, clove, peppermint, chamomile, rosemary, eucalyptus, ginger, dill seed, thyme, oregano and cumin.

[0332] Additionally, or alternatively, the active agent of the aerosol-generating substrate may comprise one or more cannabinoid compounds. The one or more cannabinoid compounds may be selected from the group consisting of: tetrahydrocannabinol (THC), tetrahydrocannabinolic acid (THCA), cannabidiol (CBD), cannabidiolic acid (CBDA), cannabinol (CBN), cannabigerol (CBG), cannabigerol monomethyl ether (CBGM), cannabivarin (CBV), cannabidivarin (CBDV), tetrahydrocannabivarin (THCV), cannabichromene (CBC), cannabicyclol (CBL), cannabichromevarin (CBCV), cannabigerovarin (CBGV), cannabielsoin (CBE), cannabicitran (CBT) and combinations thereof.

[0333] The flavourant of the aerosol-generating substrate may comprise one or more of: one or more essential oils such as eugenol, peppermint oil and spearmint oil; one or both of menthol and eugenol; one or both of anethole and linalool.

[0334] The cellulose-based strengthening agent of the aerosol-generating substrate may comprise a fibrous cellulose based strengthening agent.

[0335] Advantageously, the present inventors have found that a fibrous cellulose based strengthening agent is particularly effective at increasing the tensile strength of an aerosolgenerating substrate.

[0336] The fibrous cellulose based strengthening agent may comprise an exogenous source of fibres. In other words, the fibrous cellulose based strengthening agent may be provided in addition to any tobacco material that may be provided. Suitable exogenous fibres for inclusion in the fibrous cellulose based strengthening agent may include fibres formed from a non-tobacco fibrous material, including but not limited to: cellulose fibres, soft-wood fibres, hard-wood fibres, jute fibres and combinations thereof.

[0337] The cellulose-based strengthening agent of the aerosol-generating substrate may comprise microcrystalline cellulose.

[0338] Advantageously, the present inventors have found that microcrystalline cellulose may be a cellulose based strengthening agent that is particularly effective at increasing the tensile strength of an aerosol-generating substrate.

[0339] The cellulose-based strengthening agent of the aerosol-generating substrate may comprise cellulose powder. Advantageously, the present inventors have found that cellulose powder may be a cellulose based strengthening agent that is particularly effective at increasing the tensile strength of an aerosol-generating substrate.

[0340] The aerosol-generating substrate of the aerosol-generating article may have a cellulose- based strengthening agent content of at least 0.3 percent by weight, for example at least 0.5 percent by weight, for example at least 1 percent by weight, for example at least 5 percent by weight, for example at least 10 percent by weight, on a dry weight basis.

[0341] The cellulose-based strengthening agent content of the aerosol-generating substrate may be less than or equal to 50 percent by weight, for example less than or equal to 40 percent by weight, for example less than or equal to 30 percent by weight, for example less than or equal to 20 percent by weight, on a dry weight basis.

[0342] The cellulose-based strengthening agent content of the aerosol-generating substrate may be between 0.3 percent by weight and 50 percent by weight, for example between 0.3 percent by weight and 40 percent by weight, for example between 0.3 percent by weight and 30 percent by weight, for example between 0.3 percent by weight and 20 percent by weight, on a dry weight basis.

[0343] The cellulose-based strengthening agent content of the aerosol-generating substrate may be between 0.5 percent by weight and 50 percent by weight, for example between 0.5 percent by weight and 40 percent by weight, for example between 0.5 percent by weight and 30 percent by weight, for example between 0.5 percent by weight and 20 percent by weight, on a dry weight basis.

[0344] The cellulose-based strengthening agent content of the aerosol-generating substrate may be between 1 percent by weight and 50 percent by weight, for example between 1 percent by weight and 40 percent by weight, for example between 1 percent by weight and 30 percent by weight, for example between 1 percent by weight and 20 percent by weight, on a dry weight basis.

[0345] The cellulose-based strengthening agent content of the aerosol-generating substrate may be between 5 percent by weight and 50 percent by weight, for example between 5 percent by weight and 40 percent by weight, for example between 5 percent by weight and 30 percent by weight, for example between 5 percent by weight and 20 percent by weight, on a dry weight basis.

[0346] The cellulose-based strengthening agent content of the aerosol-generating substrate may be between 10 percent by weight and 50 percent by weight, for example between 10 percent by weight and 40 percent by weight, for example between 10 percent by weight and 30 percent by weight, for example between 10 percent by weight and 20 percent by weight, on a dry weight basis.

[0347] The aerosol-generating article may be configured for use with a dielectric heating aerosolgenerating device.

[0348] It will be appreciated that any combination of the mass of aerosol-generating substrate within the volume of the substrate plug of the aerosol-generating article, the total mass of aerosolgenerating substrate within the aerosol-generating article, the bulk density of the formed aerosolgenerating substrate unit, the porosity of the formed aerosol-generating substrate, the shape or form of the aerosol-generating article, the shape or form of the internal volume of the substrate plug and / or the composition and / or chemistry and / or shape or form of the aerosol-generating substrate may be adapted in order to optimise the aerosol performance of the aerosol-generating article.

[0349] According to an aspect of the invention there is provided an aerosol-generating system. The aerosol-generating system may comprise an aerosol-generating device and an aerosolgenerating article according to any of the preceding aspects of the invention. The aerosolgenerating device of the aerosol-generating system may be configured to dielectrically heat the aerosol-generating substrate of the aerosol-generating article.

[0350] The aerosol-generating device of the aerosol-generating system may comprise a cavity that is configured to receive the aerosol-generating article and an electromagnetic field generator that is configured to generate an electromagnetic field in the cavity. The electromagnetic field generator may comprise a solid state radio frequency transistor and is configured to generate a radio frequency electromagnetic field in the cavity.

[0351] The aerosol-generating system may comprise a first electrode, a second electrode and a controller that is configured to connect to each of the first electrode and the second electrode, wherein the first electrode, the second electrode and a portion of the aerosol-generating substrate of the aerosol-generating article form a capacitor, and wherein the controller is configured to supply an alternating voltage to the first electrode and the second electrode for dielectrically heating the aerosol-generating substrate.

[0352] The aerosol-generating device may comprise the controller.

[0353] The aerosol-generating device may comprise the first electrode and the second electrode.

[0354] The aerosol-generating article may comprise the first electrode and the second electrode. The aerosol-generating article may be configured such that the aerosol-generating substrate is disposed between the first electrode and the second electrode.

[0355] The frequency of the alternating voltage supplied to the first electrode and the second electrode may be between 10 megahertz and 100 megahertz.

[0356] The aerosol-generating device may comprise a power source, wherein the power source is configured to supply power of between approximately 10 Watts and approximately 60 Watts to the first electrode and the second electrode.

[0357] Dielectric heating is very efficient, which enables a reduction in the reservoir of substances in the aerosol from aerosol-generating articles that are heated using dielectric heating methods. The substrate may comprise less than 20 percent glycerin. The substrate may comprise less than 1 .5 percent nicotine. Despite comprising reduced amounts of glycerin and / or nicotine, the more efficient and more homogeneous heating achieved using dielectric heating may result in comparable or even identical levels of aerosol generated by heating substrate with more aerosol former and nicotine using convective or conductive heating methods. Dielectric heating methods may enable the mass of substrate to be reduced without negatively impacting the aerosol performance of the aerosol-generating article. This also enables the mass of substrate per volume to be reduced, for example to below 0.3 milligrams per cubic millimetre.

[0358] Increased porosity substrates have an increased surface area to mass ratio, and therefore present more surface area for evaporation of volatiles. Increased porosity allows airflow to circulate through the substrate and collect the aerosol generated by dielectric heating. The surface area may also be increased by using foam or crimped substrates or by using a pouch with cut filler.

[0359] A long, thin aerosol-generating article may provide an improved sensory performance by filtering the aerosol.

[0360] As used herein, the term “aerosol-generating substrate” refers to a substrate capable of releasing upon heating volatile compounds, which can form an aerosol.

[0361] As used herein, the term “aerosol-generating article” refers to an aerosol-generating article for producing an aerosol comprising an aerosol-generating substrate that is intended to be heated rather than combusted in order to release volatile compounds that can form an aerosol.

[0362] As used herein, the term “aerosol-generating device” refers to a device comprising a heating element that interacts with the aerosol-generating substrate of the aerosol-generating article to generate an aerosol.

[0363] As used herein, the term “aerosol-generating system” refers to a combination of an aerosolgenerating device and one or more aerosol-generating articles for use with the device. An aerosolgenerating system may include additional components, such as a charging unit for recharging an on-board electric power supply in an electrically operated or electric aerosol-generating device. As used herein, the term “rod” is used to denote a generally cylindrical element of substantially circular, oval or elliptical cross-section.

[0364] As used herein, the term “longitudinal” refers to the direction corresponding to the main longitudinal axis of the aerosol-generating article, which extends between upstream and downstream ends of the aerosol-generating article.

[0365] As used herein, the terms “upstream” and “downstream” describe the relative positions of elements or portions of elements, of the aerosol-generating article in relation to the direction in which the aerosol is transported through the aerosol-generating article during use. During use, air is drawn through the aerosol-generating article in the longitudinal direction.

[0366] As used herein, the term “planar” refers to a feature generally formed in a single Euclidean plane and not wrapped around or otherwise conformed to fit a curved or other non-planar shape. A planar surface may extend in two dimensions in a single Euclidean plane. A planar object may extend in two dimensions in a single Euclidean plane substantially more than in a third dimension perpendicular to the plane. More specifically, a planar object may extend in a first dimension and a second dimension perpendicular to the first dimension at least two, five or ten times further than the object extends in a third dimension perpendicular to the first and second dimensions.

[0367] As used herein, the term “length” denotes the dimension of a component of the aerosolgenerating article in the longitudinal direction. For example, it may be used to denote the dimension of the rod or of the elongate tubular elements in the longitudinal direction, from the component’s furthest upstream point to the components furthest downstream point. It may be used, for example, to denote the dimension of aerosol-generating substrate or of any elements in the longitudinal direction.

[0368] As used herein, the term “width” refers to a maximum dimension of the aerosol-generating article or a component of the aerosol-generating article in the lateral direction.

[0369] As used herein, the term “lateral” refers to a direction that is perpendicular to the transverse direction and the longitudinal direction. For example, a direction from a first side wall to a second side wall of the aerosol-generating article.

[0370] As used herein, the term “thickness” is used to describe the minimum dimension between opposite, substantially parallel surfaces of a solid aerosol-generating substrate, for example a solid aerosol-generating film.

[0371] As used herein, the term “transverse” refers to the direction that is perpendicular to the longitudinal axis. Any reference to the “cross-section” of the aerosol-generating article or a component of the aerosol-generating article refers to the transverse cross-section unless stated otherwise.

[0372] As used herein, the “density” of the aerosol-generating substrate in the aerosol-generating article refers to the mass of aerosol-generating substrate within the internal volume of the substrate plug of the aerosol-generating article. The “mass” of the aerosol-generating substrate does not include the mass of any wrapping material circumscribing the aerosol-generating substrate. The “internal volume” of the substrate plug does not include the volume of any wrapping material circumscribing the aerosol-generating substrate.

[0373] As used herein, the terms “aerosol-generating substrate density” and “substrate density” refers to the density of the aerosol-generating substrate itself, i.e. the mass of the aerosolgenerating substrate material within the volume of the formed aerosol-generating substrate unit.

[0374] As used herein, the term “aerosol former” may refer to any suitable known compound or mixture of compounds that, in use, facilitates formation of an aerosol. The aerosol may be a dense and stable aerosol. The aerosol may be substantially resistant to thermal degradation at the operating temperature of the aerosol-generating substrate or aerosol-generating article.

[0375] As used herein, the term “aerosol former content” may refer to aerosol former content in percent on a dry weight basis, unless otherwise specified.

[0376] As used herein with reference to the present invention, the term “flexible” is used to describe the ability of a material, in particular of the outer wall of the substrate compartment of the pouch of the aerosol-generating article, to bend easily without breaking. That is, the flexible outer wall of the substrate compartment of the pouch of the aerosol-generating article has the ability to bend easily without breaking allowing the aerosol-generating article to conform to the shape of a heating chamber of an aerosol-generating device when the aerosol-generating article is received therein.

[0377] As used herein with reference to the present invention, the term “air permeable” refers to the ability of a material, in particular of the outer wall of the substrate compartment of the pouch of the aerosol-generating article, to allow air to pass bidirectionally through the material. That is, the air permeable outer wall of the substrate compartment of the pouch of the aerosol-generating article may allow air to pass through the outer wall into the substrate compartment, mix with aerosol generated within the substrate compartment and then pass back through the outer wall to be inhaled by a user.

[0378] As used herein, the term “usage session” refers to an operational period of the aerosolgenerating system having a finite duration. A usage session may be a specific type of event that can be performed by the aerosol-generating system. A usage session may be initiated by the action of a user. A usage session may be terminated after a predetermined period of time has elapsed from the initiation of the usage session. A usage session may be terminated after a monitored parameter has reached a threshold during the usage session.

[0379] As used herein, the term “homogenised plant material” encompasses any plant material, for example tobacco material, formed by the agglomeration of particles of plant. For example, sheets or webs of homogenised plant material for the aerosol-generating substrates of the present invention may be formed by agglomerating particles of plant material obtained by pulverising, grinding or comminuting plant material. The homogenised plant material may be produced by casting, extrusion, paper making processes or any other suitable processes known in the art.

[0380] As used herein, the term “sheet” describes a laminar element having a width and length substantially greater than the thickness thereof.

[0381] As used herein, the term “strand” describes an elongate element of material having a length that is substantially greater than the width and thickness thereof. The term “strand” should be considered to encompass strips, shreds and any other homogenised plant material having a similar form.

[0382] As used herein, the term “cut filler” is used to describe a blend of shredded plant material, such as tobacco plant material, including, in particular, one or more of leaf lamina, processed stems and ribs, homogenised plant material.

[0383] As used herein, the term “film” is used to describe a solid aerosol-generating substrate having a thickness that is substantially less than the width or length thereof.

[0384] As used herein, the term “textured” is used to describe a solid aerosol-generating film that has been crimped, embossed, debossed, perforated or otherwise deformed. Textured solid aerosol-generating film may comprise a plurality of spaced apart indentations, protrusions, perforations or a combination thereof.

[0385] As used herein with reference to the invention, the term “crimped” is intended to be synonymous with the term “creped” and is used to describe a solid aerosol-generating film having a plurality of substantially parallel ridges or corrugations.

[0386] The invention is defined in the claims. However, below there is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

[0387] EX1 . An aerosol-generating article for producing an inhalable aerosol upon heating, the aerosol-generating article comprising a substrate plug defining an internal volume, the internal volume comprising an aerosol-generating substrate, wherein a mass of the aerosol-generating substrate within the internal volume of the substrate plug is less than or equal to 0.3 milligrams per cubic millimetre and wherein the aerosol-generating article comprises less than or equal to 140 milligrams of aerosol-generating substrate.

[0388] EX2. The aerosol-generating article of example EX1 , wherein the mass of the aerosolgenerating substrate within the internal volume of the substrate plug is less than or equal to 0.2 milligrams per cubic millimetre.

[0389] EX3. The aerosol-generating article of example EX1 or example EX2, wherein the mass of the aerosol-generating substrate within the internal volume of the substrate plug is less than or equal to 0.1 milligrams per cubic millimetre. EX4. The aerosol-generating article of example EX1 , example EX2 or example EX3, wherein the mass of the aerosol-generating substrate within the internal volume of the substrate plug is at least 0.005 milligrams per cubic millimetre.

[0390] EX5. The aerosol-generating article of any one of examples EX1 to EX4, wherein the mass of the aerosol-generating substrate within the internal volume of the substrate plug is at least 0.01 milligrams per cubic millimetre.

[0391] EX6. The aerosol-generating article of any one of examples EX1 to EX5, wherein the mass of the aerosol-generating substrate within the internal volume of the substrate plug is at least 0.02 milligrams per cubic millimetre.

[0392] EX7. The aerosol-generating article of any one of examples EX1 to EX6, wherein the mass of the aerosol-generating substrate within the internal volume of the substrate plug is at least 0.04 milligrams per cubic millimetre.

[0393] EX8. The aerosol-generating article of any one of examples EX1 to EX7, wherein the mass of the aerosol-generating substrate within the internal volume of the substrate plug is at least 0.05 milligrams per cubic millimetre.

[0394] EX9. The aerosol-generating article of any one of examples EX1 to EX8, wherein the aerosol-generating article comprises less than or equal to 120 milligrams of aerosol-generating substrate.

[0395] EX10. The aerosol-generating article of any one of examples EX1 to EX9, wherein the aerosol-generating article comprises less than or equal to 110 milligrams of aerosol-generating substrate.

[0396] EX11. The aerosol-generating article of any one of examples EX1 to EX10, wherein the aerosol-generating article comprises less than or equal to 100 milligrams of aerosol-generating substrate.

[0397] EX12. The aerosol-generating article of any one of examples EX1 to EX11 , wherein the aerosol-generating article comprises less than or equal to 90 milligrams of aerosol-generating substrate.

[0398] EX13. The aerosol-generating article of any one of examples EX1 to EX12, wherein the aerosol-generating article comprises less than or equal to 80 milligrams of aerosol-generating substrate.

[0399] EX14. The aerosol-generating article of any one of examples EX1 to EX13, wherein the aerosol-generating article comprises at least 5 milligrams of aerosol-generating substrate.

[0400] EX15. The aerosol-generating article of any one of examples EX1 to EX14, wherein the aerosol-generating article comprises at least 10 milligrams of aerosol-generating substrate.

[0401] EX16. The aerosol-generating article of any one of examples EX1 to EX15, wherein the aerosol-generating article comprises at least 20 milligrams of aerosol-generating substrate. EX17. The aerosol-generating article of any one of examples EX1 to EX16, wherein the aerosol-generating article comprises at least 30 milligrams of aerosol-generating substrate.

[0402] EX18. The aerosol-generating article of any one of examples EX1 to EX17, wherein the aerosol-generating article comprises at least 50 milligrams of aerosol-generating substrate.

[0403] EX19. An aerosol-generating article for producing an inhalable aerosol upon heating, the aerosol-generating article comprising a substrate plug defining an internal volume, the internal volume comprising an aerosol-generating substrate, wherein a mass of the aerosol-generating substrate within the internal volume of the substrate plug is less than or equal to 0.5 milligrams per cubic millimetre and wherein the aerosol-generating article comprises less than or equal to 100 milligrams of aerosol-generating substrate.

[0404] EX20. The aerosol-generating article of example EX19, wherein the mass of the aerosolgenerating substrate within the internal volume of the substrate plug is less than or equal to 0.4 milligrams per cubic millimetre.

[0405] EX21. The aerosol-generating article of example EX19 or example EX20, wherein the mass of the aerosol-generating substrate within the internal volume of the substrate plug is less than or equal to 0.3 milligrams per cubic millimetre.

[0406] EX22. The aerosol-generating article of example EX19, example EX20 or example EX21, wherein the mass of the aerosol-generating substrate within the internal volume of the substrate plug is less than or equal to 0.2 milligrams per cubic millimetre.

[0407] EX23. The aerosol-generating article of any one of examples EX19 to EX22, wherein the mass of the aerosol-generating substrate within the internal volume of the substrate plug is less than or equal to 0.1 milligrams per cubic millimetre.

[0408] EX24. The aerosol-generating article of any one of examples EX19 to EX23, wherein the mass of the aerosol-generating substrate within the internal volume of the substrate plug is at least 0.005 milligrams per cubic millimetre.

[0409] EX25. The aerosol-generating article of any one of examples EX19 to EX24, wherein the mass of the aerosol-generating substrate within the internal volume of the substrate plug is at least 0.01 milligrams per cubic millimetre.

[0410] EX26. The aerosol-generating article of any one of examples EX19 to EX25, wherein the mass of the aerosol-generating substrate within the internal volume of the substrate plug is at least 0.02 milligrams per cubic millimetre.

[0411] EX27. The aerosol-generating article of any one of examples EX19 to EX26, wherein the mass of the aerosol-generating substrate within the internal volume of the substrate plug is at least 0.04 milligrams per cubic millimetre. EX28. The aerosol-generating article of any one of examples EX19 to EX27, wherein the mass of the aerosol-generating substrate within the internal volume of the substrate plug is at least 0.05 milligrams per cubic millimetre.

[0412] EX29. The aerosol-generating article of any one of examples EX19 to EX28, wherein the aerosol-generating article comprises less than or equal to 90 milligrams of aerosol-generating substrate.

[0413] EX30. The aerosol-generating article of any one of examples EX19 to EX29, wherein the aerosol-generating article comprises less than or equal to 80 milligrams of aerosol-generating substrate.

[0414] EX31. The aerosol-generating article of any one of examples EX19 to EX30, wherein the aerosol-generating article comprises at least 5 milligrams of aerosol-generating substrate.

[0415] EX32. The aerosol-generating article of any one of examples EX19 to EX31 , wherein the aerosol-generating article comprises at least 10 milligrams of aerosol-generating substrate.

[0416] EX33. The aerosol-generating article of any one of examples EX19 to EX32, wherein the aerosol-generating article comprises at least 20 milligrams of aerosol-generating substrate.

[0417] EX34. The aerosol-generating article of any one of examples EX19 to EX33, wherein the aerosol-generating article comprises at least 30 milligrams of aerosol-generating substrate.

[0418] EX35. The aerosol-generating article of any one of examples EX19 to EX34, wherein the aerosol-generating article comprises at least 50 milligrams of aerosol-generating substrate.

[0419] EX36. An aerosol-generating article for producing an inhalable aerosol upon heating, the aerosol-generating article comprising at least 10 milligrams and less than 100 milligrams of aerosol-generating substrate, wherein the aerosol-generating article has an internal volume of at least 1 cubic centimetre.

[0420] EX37. The aerosol-generating article of example EX36, wherein the aerosol-generating article comprises at least 20 milligrams of aerosol-generating substrate.

[0421] EX38. The aerosol-generating article of example EX36 or example EX37, wherein the aerosol-generating article comprises at least 40 milligrams of aerosol-generating substrate.

[0422] EX39. The aerosol-generating article of example EX36, example EX37 or example EX38, wherein the aerosol-generating article comprises at least 60 milligrams of aerosol-generating substrate.

[0423] EX40. The aerosol-generating article of any one of examples EX36 to EX39, wherein the aerosol-generating article comprises at least 70 milligrams of aerosol-generating substrate.

[0424] EX41. The aerosol-generating article of any one of examples EX36 to EX40, wherein the aerosol-generating article comprises less than 90 milligrams of aerosol-generating substrate.

[0425] EX42. The aerosol-generating article of any one of examples EX36 to EX41 , wherein the aerosol-generating article comprises less than 80 milligrams of aerosol-generating substrate. EX43. The aerosol-generating article of any one of examples EX36 to EX42, wherein the aerosol-generating article volume is at least 1.25 cubic centimetres.

[0426] EX44. The aerosol-generating article of any one of examples EX36 to EX43, wherein the aerosol-generating article volume is at least 1.5 cubic centimetres.

[0427] EX45. The aerosol-generating article of any one of examples EX36 to EX44, wherein the aerosol-generating article volume is less than or equal to 3 cubic centimetres.

[0428] EX46. The aerosol-generating article of any one of examples EX36 to EX45, wherein the aerosol-generating article volume is less than or equal to 2.5 cubic centimetres.

[0429] EX47. The aerosol-generating article of any one of examples EX36 to EX46, wherein the aerosol-generating article comprises at least 3 milligrams of aerosol-generating substrate per cubic centimetre of the aerosol-generating article volume.

[0430] EX48. The aerosol-generating article of any one of examples EX36 to EX47, wherein the aerosol-generating article comprises at least 6 milligrams of aerosol-generating substrate per cubic centimetre of the aerosol-generating article volume.

[0431] EX49. The aerosol-generating article of any one of examples EX36 to EX48, wherein the aerosol-generating article comprises at least 10 milligrams of aerosol-generating substrate per cubic centimetre of the aerosol-generating article volume.

[0432] EX50. The aerosol-generating article of any one of examples EX36 to EX49, wherein the aerosol-generating article comprises at least 20 milligrams of aerosol-generating substrate per cubic centimetre of the aerosol-generating article volume.

[0433] EX51 . The aerosol-generating article of any one of examples EX36 to EX50, wherein the aerosol-generating article comprises less than 100 milligrams of aerosol-generating substrate per cubic centimetre of the aerosol-generating article volume.

[0434] EX52. The aerosol-generating article of any one of examples EX36 to EX51 , wherein the aerosol-generating article comprises less than 80 milligrams of aerosol-generating substrate per cubic centimetre of the aerosol-generating article volume.

[0435] EX53. The aerosol-generating article of any one of examples EX36 to EX52, wherein the aerosol-generating article comprises less than 60 milligrams of aerosol-generating substrate per cubic centimetre of the aerosol-generating article volume.

[0436] EX54. The aerosol-generating article of any one of examples EX1 to EX53, wherein the aerosol-generating substrate has a density of less than or equal to 0.55 grams per cubic centimetre.

[0437] EX55. The aerosol-generating article of example EX54, wherein the aerosol-generating substrate density is less than or equal to 0.50 grams per cubic centimetre.

[0438] EX56. The aerosol-generating article of example EX54 or example EX55, wherein the aerosol-generating substrate density is less than or equal to 0.45 grams per cubic centimetre. EX57. The aerosol-generating article of example EX54, example EX55 or example EX56, wherein the aerosol-generating substrate density is less than or equal to 0.40 grams per cubic centimetre.

[0439] EX58. The aerosol-generating article of any one of examples EX54 to EX57, wherein the aerosol-generating substrate density is at least 0.01 grams per cubic centimetre.

[0440] EX59. The aerosol-generating article of any one of examples EX54 to EX58, wherein the aerosol-generating substrate density is at least 0.05 grams per cubic centimetre.

[0441] EX60. The aerosol-generating article of any one of examples EX54 to EX59, wherein the aerosol-generating substrate density is at least 0.10 grams per cubic centimetre.

[0442] EX61. The aerosol-generating article of any one of examples EX54 to EX60, wherein the aerosol-generating substrate density is at least 0.20 grams per cubic centimetre.

[0443] EX62. The aerosol-generating article of any one of examples EX54 to EX61 , wherein the aerosol-generating substrate density is at least 0.30 grams per cubic centimetre.

[0444] EX63. The aerosol-generating article of any one of examples EX54 to EX62, wherein the aerosol-generating substrate density is at least 0.33 grams per cubic centimetre.

[0445] EX64. The aerosol-generating article of any one of examples EX1 to EX63, wherein the aerosol-generating substrate has a porosity of at least 60 percent.

[0446] EX65. The aerosol-generating article of example EX64, wherein the aerosol-generating substrate porosity is at least 70 percent.

[0447] EX66. The aerosol-generating article of example EX64 or example EX65, wherein the aerosol-generating substrate porosity is at least 75 percent.

[0448] EX67. The aerosol-generating article of example EX64, example EX65 or example EX66, wherein the aerosol-generating substrate is at least 80 percent.

[0449] EX68. The aerosol-generating article of any one of examples EX64 to EXE67, wherein the aerosol-generating substrate porosity is less than or equal to 98 percent.

[0450] EX69. The aerosol-generating article of any one of examples EX64 to EX68, wherein the aerosol-generating substrate porosity is less than or equal to 97 percent.

[0451] EX70. The aerosol-generating article of any one of examples EX64 to EX69, wherein the aerosol-generating substrate porosity is less than or equal to 95 percent.

[0452] EX71. The aerosol-generating article of any one of examples EX1 to EX70, wherein the aerosol-generating substrate comprises an aerosol former.

[0453] EX72. The aerosol-generating article of example EX71, wherein the aerosol-generating substrate has an aerosol former content of at least 5 percent by weight, on a dry weight basis.

[0454] EX73. The aerosol-generating article of example EX71 or example EX72, wherein the aerosol former content of the aerosol-generating substrate is at least 15 percent by weight, on a dry weight basis. EX74. The aerosol-generating article of any one of examples EX71 to EX73, wherein the aerosol former content of the aerosol-generating substrate is at least 25 percent by weight, on a dry weight basis.

[0455] EX75. The aerosol-generating article of any one of examples EX71 to EX74, wherein the aerosol former content of the aerosol-generating substrate is at least 35 percent by weight, on a dry weight basis.

[0456] EX76. The aerosol-generating article of any one of examples EX71 to EX75, wherein the aerosol former content of the aerosol-generating substrate is at least 45 percent by weight, on a dry weight basis.

[0457] EX77. The aerosol-generating article of any one of examples EX71 to EX76, wherein the aerosol former content of the aerosol-generating substrate is less than or equal to 80 percent by weight, on a dry weight basis.

[0458] EX78. The aerosol-generating article of any one of examples EX71 to EX77, wherein the aerosol former content is less than or equal to 60 percent by weight, on a dry weight basis.

[0459] EX79. The aerosol-generating article of any one of examples EX71 to EX778, wherein the aerosol former content is less than or equal to 50 percent by weight, on a dry weight basis.

[0460] EX80. The aerosol-generating article of any one of examples EX71 to EX79, wherein the aerosol former comprises glycerin or propylene glycol, or a mixture of glycerin and propylene glycol.

[0461] EX81. The aerosol-generating article of example EX71, wherein the aerosol former comprises glycerin.

[0462] EX82. The aerosol-generating article of example EX81 , wherein the aerosol-generating article has a glycerin content of at least 0.25 milligrams.

[0463] EX83. The aerosol-generating article of example EX81 or example EX82, wherein the glycerin content is at least 0.75 milligrams.

[0464] EX84. The aerosol-generating article of any one of examples EX81 to EX83, wherein the glycerin content is at least 1.25 milligrams.

[0465] EX85. The aerosol-generating article of any one of examples EX81 to EX84, wherein the glycerin content is at least 1.75 milligrams.

[0466] EX86. The aerosol-generating article of any one of examples EX81 to EX85, wherein the glycerin content is less than or equal to 4 milligrams.

[0467] EX87. The aerosol-generating article of any one of examples EX81 to EX86, wherein the glycerin content is less than or equal to 3 milligrams.

[0468] EX88. The aerosol-generating article of any one of examples EX81 to EX87, wherein the glycerin content is less than or equal to 2.5 milligrams. EX89. The aerosol-generating article of any one of examples EX81 to EX88, wherein the glycerin content is less than or equal to 2.25 milligrams.

[0469] EX90. The aerosol-generating article of example EX81 , wherein the aerosol-generating article has a glycerin content of at least 2.5 milligrams.

[0470] EX91 . The aerosol-generating article of example EX90, wherein the glycerin content is at least 7.5 milligrams.

[0471] EX92. The aerosol-generating article of example EX90 or example EX91 , wherein the glycerin content is at least 12.5 milligrams.

[0472] EX93. The aerosol-generating article of any one of examples EX90 to EX92, wherein the glycerin content is at least 17.5 milligrams.

[0473] EX94. The aerosol-generating article of any one of examples EX90 to EX93, wherein the glycerin content is less than or equal to 40 milligrams.

[0474] EX95. The aerosol-generating article of any one of examples EX90 to EX94, wherein the glycerin content is less than or equal to 30 milligrams.

[0475] EX96. The aerosol-generating article of any one of examples EX90 to EX95, wherein the glycerin content is less than or equal to 25 milligrams.

[0476] EX97. The aerosol-generating article of any one of examples EX90 to EX96, wherein the glycerin content is less than or equal to 22.5 milligrams.

[0477] EX98. The aerosol-generating article of example EX81 , wherein the aerosol-generating article has a glycerin content of at least 5 milligrams.

[0478] EX99. The aerosol-generating article of example EX98, wherein the glycerin content is at least 15 milligrams.

[0479] EX100. The aerosol-generating article of example EX98 or example EX99, wherein the glycerin content is at least 25 milligrams.

[0480] EX101. The aerosol-generating article of any one of examples EX98 to EX100, wherein the glycerin content is at least 35 milligrams.

[0481] EX102. The aerosol-generating article of any one of examples EX98 to EX101 , wherein the glycerin content is less than or equal to 80 milligrams.

[0482] EX103. The aerosol-generating article of any one of examples EX98 to EX102, wherein the glycerin content is less than or equal to 60 milligrams.

[0483] EX104. The aerosol-generating article of any one of examples EX98 to EX103, wherein the glycerin content is less than or equal to 55 milligrams.

[0484] EX105. The aerosol-generating article of any one of examples EX98 to EX104, wherein the glycerin content is less than or equal to 45 milligrams.

[0485] EX106. The aerosol-generating article of example EX81 , wherein the aerosol-generating article has a glycerin content of at least 7 milligrams. EX107. The aerosol-generating article of example EX106, wherein the glycerin content is at least 21 milligrams.

[0486] EX108. The aerosol-generating article of example EX106 or example EX107, wherein the glycerin content is at least 35 milligrams.

[0487] EX109. The aerosol-generating article of any one of examples EX106 to EX108, wherein the glycerin content is at least 49 milligrams.

[0488] EX110. The aerosol-generating article of any one of examples EX106 to EX109, wherein the glycerin content is less than or equal to 112 milligrams.

[0489] EX111. The aerosol-generating article of any one of examples EX106 to EX110, wherein the glycerin content is less than or equal to 84 milligrams.

[0490] EX112. The aerosol-generating article of any one of examples EX106 to EX111, wherein the glycerin content is less than or equal to 70 milligrams.

[0491] EX113. The aerosol-generating article of any one of examples EX106 to EX112, wherein the glycerin content is less than or equal to 63 milligrams.

[0492] EX114. The aerosol-generating article of any one of examples EX71 to EX113, wherein the aerosol-generating substrate comprises a binder.

[0493] EX115. The aerosol-generating article of example EX114, wherein the binder comprises a cellulose binder.

[0494] EX116. The aerosol-generating article of example EX115, wherein the cellulose binder comprises one or more of hydroxypropyl methylcellulose (HPMC), methylcellulose (MC), ethylcellulose (EC), hydroxyethyl methyl cellulose (HEMC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC) and hydroxypropyl cellulose (HPC).

[0495] EX117. The aerosol-generating article of example EX115 or example EX116, wherein the aerosol-generating substrate has a cellulose binder content of at least 1 percent by weight, on a dry weight basis.

[0496] EX118. The aerosol-generating article of example EX117, wherein the cellulose binder content is at least 2 percent by weight, on a dry weight basis.

[0497] EX119. The aerosol-generating article of example EX117 or example EXE118, wherein the cellulose binder content is at least 3 percent by weight, on a dry weight basis.

[0498] EX120. The aerosol-generating article of example EX117, example EX118 or example EX119, wherein the cellulose binder content is less than or equal to 10 percent by weight, on a dry weight basis.

[0499] EX121. The aerosol-generating article of any one of examples EX117 to EX120, wherein the binder comprises a non-cellulose binder. EX122. The aerosol-generating article of example EX121 , wherein the non-cellulose binder comprises one or more of agar, guar gum, xanthan gum, Arabic gum, locust bean gum, pectin, carrageenan, starch and alginate.

[0500] EX123. The aerosol-generating article of example EX121 or example EX122, wherein the aerosol-generating substrate has a non-cellulose binder content of at least 0.2 percent by weight, on a dry weight basis.

[0501] EX124. The aerosol-generating article of example EX123, wherein the non-cellulose binder content is at least 0.4 percent by weight, on a dry weight basis.

[0502] EX125. The aerosol-generating article of example EX123 or example EX124, wherein the non-cellulose binder content is at least 0.6 percent by weight, on a dry weight basis.

[0503] EX126. The aerosol-generating article of example EX123, example EX124 or example EX125, wherein the non-cellulose binder content is at least 0.8 percent by weight, on a dry weight basis.

[0504] EX127. The aerosol-generating article of any one of examples EX123 to EX126, wherein the non-cellulose binder content is less than or equal to 2 percent by weight, on a dry weight basis.

[0505] EX128. The aerosol-generating article of any one of examples EX123 to EX127, wherein the non-cellulose binder content is less than or equal to 1.8 percent by weight, on a dry weight basis.

[0506] EX129. The aerosol-generating article of any one of examples EX123 to EX128, wherein the non-cellulose binder content is less than or equal to 1.6 percent by weight, on a dry weight basis.

[0507] EX130. The aerosol-generating article of any one of examples EX123 to EX129, wherein the non-cellulose binder content is less than or equal to 1.4 percent by weight, on a dry weight basis.

[0508] EX131. The aerosol-generating article of any one of examples EX71 to EX130, wherein the aerosol-generating substrate comprises an active agent and / or a flavourant, and a cellulose- based strengthening agent.

[0509] EX132. The aerosol-generating article of example EX131 , wherein the active agent comprises nicotine.

[0510] EX133. The aerosol-generating article of example EX132, wherein the nicotine comprises nicotine, a nicotine base or a nicotine salt.

[0511] EX134. The aerosol-generating article of example EX132 or example EX133, wherein the nicotine comprises a natural nicotine or a synthetic nicotine. EX135. The aerosol-generating article of any one of examples EX132 to EX134, wherein the aerosol-generating article comprises at least 0.5 percent nicotine by weight, on a dry weight basis.

[0512] EX136. The aerosol-generating article of any one of examples EX132 to EX135, wherein the aerosol-generating article comprises at least 1.0 percent nicotine by weight, on a dry weight basis.

[0513] EX137. The aerosol-generating article of any one of examples EX132 to EX136, wherein the aerosol-generating article comprises less than or equal to 2.0 percent nicotine by weight, on a dry weight basis.

[0514] EX138. The aerosol-generating article of any one of examples EX132 to EX137, wherein the aerosol-generating article comprises less than or equal to 1.5 percent nicotine by weight, on a dry weight basis.

[0515] EX139. The aerosol-generating article of any one of examples EX132 to EX134, wherein the aerosol-generating article has a nicotine content of at least 0.025 milligrams

[0516] EX140. The aerosol-generating article of example EX139, wherein the nicotine content is at least 0.05 milligrams.

[0517] EX141. The aerosol-generating article of example EX139 or example EX140, wherein the nicotine content is less than or equal to 0.1 milligrams.

[0518] EX142. The aerosol-generating article of any one of examples EX139 to EX141 , wherein the nicotine content is less than or equal to 0.075 milligrams.

[0519] EX143. The aerosol-generating article of any one of examples EX132 to EX134, wherein the aerosol-generating article has a nicotine content of at least 0.25 milligrams.

[0520] EX144. The aerosol-generating article of example EX143, wherein the nicotine content is at least 0.5 milligrams.

[0521] EX145. The aerosol-generating article of example EX143 or example EX144, wherein the nicotine content is less than or equal to 1.0 milligram.

[0522] EX146. The aerosol-generating article of any one of examples EX143 to EX145, wherein the nicotine content is less than or equal to 0.75 milligrams.

[0523] EX147. The aerosol-generating article of any one of examples EX132 to EX134, wherein the aerosol-generating article has a nicotine content of at least 0.5 milligrams.

[0524] EX148. The aerosol-generating article of example EX147, wherein the nicotine content is at least 1.0 milligrams.

[0525] EX149. The aerosol-generating article of example EX147 or example EX148, wherein the nicotine content is less than or equal to 2.0 milligram.

[0526] EX150. The aerosol-generating article of any one of examples EX147 to EX149, wherein the nicotine content is less than or equal to 1.5 milligrams. EX151. The aerosol-generating article of any one of examples EX132 to EX134, wherein the aerosol-generating article has a nicotine content of at least 0.7 milligrams.

[0527] EX152. The aerosol-generating article of example EX151 , wherein the nicotine content is at least 1.4 milligrams.

[0528] EX153. The aerosol-generating article of example EX151 or example EX152, wherein the nicotine content is less than or equal to 2.8 milligram.

[0529] EX154. The aerosol-generating article of any one of examples EX151 to EX153, wherein the nicotine content is less than or equal to 2.1 milligrams.

[0530] EX155. The aerosol-generating article of any one of examples EX131 to EX154, wherein the active agent comprises one or more cannabinoid compounds selected from the group consisting of: tetrahydrocannabinol (THC), tetrahydrocannabinolic acid (THCA), cannabidiol (CBD), cannabidiolic acid (CBDA), cannabinol (CBN), cannabigerol (CBG), cannabigerol monomethyl ether (CBGM), cannabivarin (CBV), cannabidivarin (CBDV), tetrahydrocannabivarin (THCV), cannabichromene (CBC), cannabicyclol (CBL), cannabichromevarin (CBCV), cannabigerovarin (CBGV), cannabielsoin (CBE), cannabicitran (CBT) and combinations thereof.

[0531] EX156. The aerosol-generating article of any one of examples EX131 to EX155, wherein the flavourant comprises one or more of: one or more essential oils such as eugenol, peppermint oil and spearmint oil; one or both of menthol and eugenol; one or both of anethole and linalool.

[0532] EX157. The aerosol-generating article of any one of examples EX131 to EX156, wherein the cellulose-based strengthening agent comprises a fibrous material.

[0533] EX158. The aerosol-generating article of example EX156, wherein the fibrous material comprises a non-tobacco fibrous material.

[0534] EX159. The aerosol-generating article of example EX158, wherein the non-tobacco fibrous material comprises one or more of cellulose fibres, soft-wood fibres, hard-wood fibres, jute fibres.

[0535] EX160. The aerosol-generating article of example EX158, wherein the non tobacco fibrous material comprises cellulose fibres.

[0536] EX161. The aerosol-generating article of any one of examples EX131 to EX160, wherein the cellulose-based strengthening agent comprises microcrystalline cellulose.

[0537] EX162. The aerosol-generating article of any one of examples EX131 to EX161 , wherein the cellulose-based strengthening agent comprises cellulose powder.

[0538] EX163. The aerosol-generating article of any one of examples EX131 to EX162, wherein the aerosol-generating substrate has a cellulose-based strengthening agent content of at least 0.3 percent by weight, on a dry weight basis.

[0539] EX164. The aerosol-generating article of example EX163, wherein the cellulose-based strengthening agent content is at least 0.5 percent by weight, on a dry weight basis. EX165. The aerosol-generating article of example EX163 or example EX164, wherein the cellulose-based strengthening agent content is at least 1 percent by weight, on a dry weight basis.

[0540] EX166. The aerosol-generating article of example EX163, example EX164 or example EX165, wherein the cellulose-based strengthening agent content is at least 5 percent by weight, on a dry weight basis.

[0541] EX167. The aerosol-generating article of any one of examples EX163 to EX166, wherein the cellulose-based strengthening agent content is at least 10 percent by weight, on a dry weight basis.

[0542] EX168. The aerosol-generating article of any one of examples EX163 to EX167, wherein the cellulose-based strengthening agent content is less than or equal to 50 percent by weight, on a dry weight basis.

[0543] EX169. The aerosol-generating article of any one of examples EX163 to EX168, wherein the cellulose-based strengthening agent content is less than or equal to 40 percent by weight, on a dry weight basis.

[0544] EX170. The aerosol-generating article of any one of examples EX163 to EX169, wherein the cellulose-based strengthening agent content is less than or equal to 30 percent by weight, on a dry weight basis.

[0545] EX171. The aerosol-generating article of any one of examples EX163 to EX170, wherein the cellulose-based strengthening agent is less than or equal to 20 percent by weight, on a dry weight basis.

[0546] EX172. The aerosol-generating article of any one of examples EX71 to EX171 , wherein the aerosol-generating substrate comprises a plant material.

[0547] EX173. The aerosol-generating article of example EX1172, wherein the plant material comprises a non-tobacco plant material.

[0548] EX174. The aerosol-generating article of example EX173, wherein the non-tobacco plant material comprises one or more of: tea (such as black tea), rosehip seeds, apple fibres, lemon balm stems, coffee, star anise, rooibos, lavender, clove, peppermint, chamomile, rosemary, eucalyptus, ginger, dill seed, thyme, oregano and cumin.

[0549] EX175. The aerosol-generating article of example EX172, example EX173 or example EX174, wherein the non-tobacco plant material comprises a cannabinoid compound.

[0550] EX176. The aerosol-generating article of example EX175, wherein the cannabinoid compound is a naturally derived cannabinoid compound.

[0551] EX177. The aerosol-generating article of example EX175, wherein the cannabinoid compound is a synthetically derived cannabinoid compound.

[0552] EX178. The aerosol-generating article of example EX175, example EX176 or example EX177, wherein the cannabinoid compound selected from the group consisting of: tetrahydrocannabinol (THC), tetrahydrocannabinolic acid (THCA), cannabidiol (CBD), cannabidiolic acid (CBDA), cannabinol (CBN), cannabigerol (CBG), cannabigerol monomethyl ether (CBGM), cannabivarin (CBV), cannabidivarin (CBDV), tetrahydrocannabivarin (THCV), cannabichromene (CBC), cannabicyclol (CBL), cannabichromevarin (CBCV), cannabigerovarin (CBGV), cannabielsoin (CBE), cannabicitran (CBT) and combinations thereof.

[0553] EX179. The aerosol-generating article of any one of examples EX172 to EX178, wherein the plant material comprises tobacco.

[0554] EX180. The aerosol-generating article of example EX179, wherein the tobacco comprises tobacco material from one or more of: Bright tobacco, dark tobacco, aromatic tobacco and filler tobacco.

[0555] EX181. The aerosol-generating article of any one of examples EX172 to EX178, wherein the aerosol-generating substrate has a plant material content of at least 5 percent by weight, on a dry weight basis.

[0556] EX182. The aerosol-generating article of example EX181 , wherein the aerosol-generating substrate has a plant material content of at least 10 percent by weight, on a dry weight basis.

[0557] EX183. The aerosol-generating article of example EX181 or example EX182, wherein the aerosol-generating substrate has a plant material content of at least 20 percent by weight, on a dry weight basis.

[0558] EX184. The aerosol-generating article of example EX181 , example EX182 or example EX183, wherein the plant material content is at least 25 percent by weight, on a dry weight basis.

[0559] EX185. The aerosol-generating article of any one of examples EX181 to EX184, wherein the plant material content is at least 30 percent by weight, on a dry weight basis.

[0560] EX186. The aerosol-generating article of any one of examples EX181 to EX185, wherein the plant material content is at least 40 percent by weight, on a dry weight basis.

[0561] EX187. The aerosol-generating article of any one of examples EX181 to EX186, wherein the plant material content is at least 45 percent by weight, on a dry weight basis.

[0562] EX188. The aerosol-generating article of any one of examples EX181 to EX187, wherein the plant material content is less than or equal to 65 percent weight, on a dry weight basis.

[0563] EX189. The aerosol-generating article of any one of examples EX181 to EX188, wherein the plant material content is less than or equal to 60 percent weight, on a dry weight basis.

[0564] EX190. The aerosol-generating article of any one of examples EX181 to EX189, wherein the plant material content is less than or equal to 55 percent by weight, on a dry weight basis.

[0565] EX191. The aerosol-generating article of any one of examples EX181 to EX190, wherein aerosol-generating substrate comprises the plant material and the aerosol former in a ratio of between approximately 0.1 :1 and approximately 3.5:1. EX192. The aerosol-generating article of example EX191 , wherein the ratio of the plant material to the aerosol former is less than approximately 2.5:1.

[0566] EX193. The aerosol-generating article of example EX191 or example EX192, wherein the ratio of the plant material to the aerosol former is less than approximately 1.5:1.

[0567] EX194. The aerosol-generating article of example EX191 , example EX192 or example EX193, wherein the ratio of the plant material to the aerosol former is at least approximately 0.5:1 .

[0568] EX195. The aerosol-generating article of any one of examples EX191 to EX194, wherein the ratio of the plant material to the aerosol former is at least approximately 0.75:1 .

[0569] EX196. The aerosol-generating article of any one of examples EX191 to EX195, wherein the ratio of the plant material to the aerosol former is approximately 1 :1.

[0570] EX197. The aerosol-generating article of any one of examples EX1 to EX196, wherein the internal volume of the substrate plug of the aerosol-generating article has a first end, a second end, a width and a length extending between the first end and the second end, wherein a longitudinal axis of the internal volume is defined between the first end and the second end of the internal volume, and wherein the width of the internal volume corresponds to a maximum dimension of the internal volume in a direction that is orthogonal to the longitudinal axis of the longitudinal volume.

[0571] EX198. The aerosol-generating article of example EX197, wherein the internal volume of the substrate plug of the aerosol-generating article comprises one or more cavities or chambers.

[0572] EX199. The aerosol-generating article of example EX197 or example EX198, wherein the internal volume is quadrilateral in cross section.

[0573] EX200. The aerosol-generating article of example EX197, example EX198 or example EX199, wherein the internal volume is cuboidal in cross section.

[0574] EX201. The aerosol-generating article of any one of example EX197 to EX200, wherein the internal volume is parallelepiped in cross section.

[0575] EX202. The aerosol-generating article of example EX197 or example EX198, wherein the internal volume is circular in cross section.

[0576] EX203. The aerosol-generating article of example EX197 or example EX198, wherein the internal volume is oval in cross section.

[0577] EX204. The aerosol-generating article of example EX197 or example EX198, wherein the internal volume is elliptical in cross section.

[0578] EX205. The aerosol-generating article of example EX197 or example EX198, wherein the internal volume is spherical.

[0579] EX206. The aerosol-generating article of any one of examples EX197 to EX205, wherein the length of the internal volume is at least 3 millimetres. EX207. The aerosol-generating article of any one of example EX197 to EX206, wherein the length of the internal volume is at least 10 millimetres.

[0580] EX208. The aerosol-generating article of any one of examples EX197 to EX207, wherein the length of the internal volume is at least 15 millimetres.

[0581] EX209. The aerosol-generating article of any one of examples EX197 to EX207, wherein the length of the internal volume is less than or equal to 30 millimetres.

[0582] EX210. The aerosol-generating article of any one of examples EX197 to EX209, wherein the length of the internal volume is less than or equal to 28 millimetres.

[0583] EX211. The aerosol-generating article of any one of examples EX197 to EX210, wherein the length of the internal volume is less than or equal to 16 millimetres.

[0584] EX212. The aerosol-generating article of any one of examples EX197 to EX211 , wherein the width of the internal volume is at least 1 millimetre.

[0585] EX213. The aerosol-generating article of any one of examples EX197 to EX212, wherein the width of the internal volume is at least 4 millimetres.

[0586] EX214. The aerosol-generating article of any one of examples EX197 to EX213, wherein the width of the internal volume is at least 5 millimetres.

[0587] EX215. The aerosol-generating article of any one of examples EX197 to EX214, wherein the width of the internal volume is at least 6 millimetres.

[0588] EX216. The aerosol-generating article of any one of examples EX197 to EX215, wherein the width of the internal volume is less than or equal to 15 millimetres.

[0589] EX217. The aerosol-generating article of any one of examples EX197 to EX216, wherein the width of the internal volume is less than or equal to 12 millimetres.

[0590] EX218. The aerosol-generating article of any one of examples EX197 to EX217, wherein the width of the internal volume is less than or equal to 10 millimetres.

[0591] EX219. The aerosol-generating article of any one of examples EX197 to EX218, wherein the width of the internal volume is less than or equal to 8 millimetres.

[0592] EX220. The aerosol-generating article of any one of examples EX197 to EX219, wherein the thickness of the internal volume is at least 0.1 millimetres.

[0593] EX221. The aerosol-generating article of any one of examples EX197 to EX220, wherein the thickness of the internal volume is at least 0.5 millimetres.

[0594] EX222. The aerosol-generating article of any one of examples EX197 to EX221 , wherein the thickness of the internal volume is at least 1 millimetre.

[0595] EX223. The aerosol-generating article of any one of examples EX197 to EX222, wherein the thickness of the internal volume is at least 2 millimetres.

[0596] EX224. The aerosol-generating article of any one of examples EX197 to EX223, wherein the thickness of the internal volume is less than or equal to 10 millimetres. EX225. The aerosol-generating article of any one of examples EX197 to EX224, wherein the thickness of the internal volume is less than or equal to 4 millimetres.

[0597] EX226. The aerosol-generating article of any one of examples EX197 to EX225, wherein the volume of the internal volume is less than or equal to 4500 cubic millimetres.

[0598] EX227. The aerosol-generating article of any one of examples EX197 to EX226, wherein the volume of the internal volume is less than or equal to 1680 cubic millimetres.

[0599] EX228. The aerosol-generating article of any one of examples EX197 to EX227, wherein the volume of the internal volume is less than 320 cubic millimetres.

[0600] EX229. The aerosol-generating article of any one of examples EX197 to EX228, wherein the volume of the internal volume is at least 0.3 cubic millimetres.

[0601] EX230. The aerosol-generating article of any one of examples EX197 to EX229, wherein the volume of the internal volume is at least 20 cubic millimetres.

[0602] EX231. The aerosol-generating article of any one of examples EX197 to EX230, wherein the volume of the internal volume is at least 110 cubic millimetres.

[0603] EX232. The aerosol-generating article of any one of examples EX1 to EX231 , comprising an upstream end and a downstream end, wherein the internal volume is positioned between the upstream end and the downstream end of the aerosol-generating article.

[0604] EX233. The aerosol-generating article of example EX232, wherein the aerosol-generating article comprises a downstream element.

[0605] EX234. The aerosol-generating article of example EX233, wherein the downstream element comprises one or more of: a mouthpiece element, an aerosol-cooling element, a hollow tubular segment, a filter and a support element.

[0606] EX235. The aerosol-generating article of example EX233 or example EX234, wherein the downstream element is positioned between the internal volume and the downstream end of the aerosol-generating article.

[0607] EX236. The aerosol-generating article of any one of examples EX233 to EX235, wherein the aerosol-generating article comprises an upstream element.

[0608] EX237. The aerosol-generating article of example EXE236, wherein the upstream element comprises an upstream plug.

[0609] EX238. The aerosol-generating article of example EX236 or example EX237, wherein the upstream element is positioned between internal volume and the upstream end of the aerosolgenerating article.

[0610] EX239. The aerosol-generating article of any one of examples EX1 to EX238, wherein the aerosol-generating substrate has an unheated relative permittivity of at least 3.7.

[0611] EX240. The aerosol-generating article of example EX239, wherein the unheated relative permittivity of the aerosol-generating substrate is less than 10. EX241. The aerosol-generating article of example EX239 or example EX240, wherein the unheated relative permittivity of the aerosol-generating substrate is less than 7.

[0612] EX242. The aerosol-generating article of example EX239, example EX240 or example EX241 , wherein the unheated relative permittivity of the aerosol-generating substrate is less than 5.

[0613] EX243. The aerosol-generating article of any one of examples EX239 to EXE242, wherein the unheated relative permittivity of the aerosol-generating substrate is less than 4.2.

[0614] EX244. The aerosol-generating article of any one of examples EX239 to EX243, wherein the post-heating relative permittivity of the aerosol-generating substrate is at least 2.

[0615] EX245. The aerosol-generating article of any one of examples EX1 to EX244, wherein the aerosol-generating article is flat.

[0616] EX246. The aerosol-generating article of any one of examples EX1 to EX245, wherein the aerosol-generating article is planar.

[0617] EX247. The aerosol-generating article of any one of examples EX1 to EX244, wherein the aerosol-generating article is rod-shaped.

[0618] EX248. The aerosol-generating article of any one of examples EX1 to EX244, wherein the aerosol-generating article is spherical.

[0619] EX249. The aerosol-generating article of any one of examples EX1 to EX244, wherein the aerosol-generating article is a rolling tape.

[0620] EX250. The aerosol-generating article of any one of examples EX1 to EX249, wherein the aerosol-generating article is configured for use with a dielectric heating aerosol-generating device.

[0621] EX251. An aerosol-generating system comprising an aerosol-generating device and the aerosol-generating article of any one of examples EX1 to EX250, wherein the aerosol-generating device is configured to dielectrically heat the aerosol-generating substrate of the aerosolgenerating article.

[0622] EX252. The aerosol-generating system of example EX251 , wherein the aerosol-generating device comprises a dielectric or microwave heating element that is configured to heat the aerosolgenerating substrate of the aerosol-generating article.

[0623] EX253. The aerosol-generating system of example EX251 or example EX252, wherein the aerosol-generating device comprises a cavity that is configured to receive the aerosol-generating article and an electromagnetic field generator that is configured to generate an electromagnetic field in the cavity.

[0624] EX254. The aerosol-generating system of example EX253, wherein the electromagnetic field generator comprises a solid state radio frequency transistor and is configured to generate a radio frequency electromagnetic field in the cavity. EX255. The aerosol-generating system of example EX251 or example EX252, comprising a first electrode, a second electrode and a controller that is configured to connect to each of the first electrode and the second electrode, wherein the first electrode, the second electrode and a portion of the aerosol-generating substrate of the aerosol-generating article form a capacitor, and wherein the controller is configured to supply an alternating voltage to the first electrode and the second electrode for dielectrically heating the aerosol-generating substrate.

[0625] EX256. The aerosol-generating system of example EX255, wherein the aerosolgenerating device comprises the controller.

[0626] EX257. The aerosol-generating system of example EX255 or example EX256, wherein the aerosol-generating device comprises the first electrode and the second electrode.

[0627] EX258. The aerosol-generating system of example EX255 or example EX256, wherein the aerosol-generating article comprises the first electrode and the second electrode.

[0628] EX259. The aerosol-generating system of any one of examples EX255 to EX258, wherein the aerosol-generating article is configured such that the aerosol-generating substrate is disposed between the first electrode and the second electrode.

[0629] EX260. The aerosol-generating system of any one of examples EX255 to EX259, wherein the frequency of the alternating voltage supplied to the first electrode and the second electrode is between 10 megahertz and 100 megahertz.

[0630] EX261. The aerosol-generating system of any one of examples EX255 to EX260, comprising a power source, wherein the power source is configured to supply power of between approximately 10 Watts and approximately 60 Watts to the first electrode and the second electrode.

[0631] Examples will now be further described with reference to the figures in which:

[0632] Figure 1 is a schematic cross-sectional diagram of an embodiment of an aerosol-generating article;

[0633] Figure 2a is a schematic view of an aerosol-generating article according to another embodiment;

[0634] Figure 2b is an alternative schematic view of the aerosol-generating article of Figure 2a;

[0635] Figure 3a is perspective side view of an aerosol-generating article according to another embodiment;

[0636] Figure 3b is a schematic lateral cross-sectional view of the aerosol-generating article of Figure 3a;

[0637] Figure 4a is a schematic side view of an aerosol-generating article according to another embodiment;

[0638] Figure 4b is a schematic cross-sectional view of the aerosol-generating article of Figure 4a; Figure 5 illustrates a partially transparent view of a further embodiment of an aerosolgenerating article;

[0639] Figure 6 is a schematic illustration of a dielectric heating system;

[0640] Figure 7 is a schematic illustration of an aerosol-generating system according to the invention; and

[0641] Figure 8 is a schematic illustration of another dielectric heating system.

[0642] Examples of aerosol-generating articles according to the present invention will now be described with reference to Figures 1 to 5.

[0643] Aerosol-generating articles according to the present invention produce an inhalable aerosol upon heating. Examples of heating devices and systems for heating the aerosolgenerating articles will be described with reference to Figures 6 to 8.

[0644] Aerosol-generating articles according to the invention comprise a substrate plug defining an internal volume, for example a cavity or chamber, which includes an aerosol-generating substrate 20, 280, 31. The mass of the aerosol-generating substrate within the internal volume of the substrate plug is less than or equal to 0.3 milligrams per cubic millimetre. The aerosolgenerating article includes less than or equal to 140 milligrams of aerosol-generating substrate. Example 1

[0645] An example of a suitable composition for forming an aerosol-generating substrate for use in aerosol-generating articles in accordance with the invention is set out in Table 1 below:

[0646] All amounts are shown as percentages by weight, on a dry weight basis, based on the total weight of the aerosol-generating substrate.

[0647] In order to make the substrate, the HPMC is dispersed in the glycerin. The agar is added and dispersed in the HPMC and glycerin slurry. Water is mixed into the slurry. Tobacco is added to the slurry, which is then stirred and dried by lyophilisation.

[0648] In this way, a one-piece aerosol-generating substrate unit may be produced. The aerosolgenerating substrate unit may be formed by drying the slurry in a mould (i.e. casting) or by forming a piece of aerosol-generating substrate material and cutting it to the desired size and shape. The aerosol-generating unit is thus formed as a one-piece porous structure.

[0649] The one-piece aerosol-generating substrate unit may be self-supporting. In other words, the properties of the one-piece aerosol-generating substrate unit may be such that, even if the one-piece aerosol-generating substrate unit is formed by casting a slurry onto a support surface, the one-piece aerosol-generating substrate unit can be separated from the support surface.

[0650] When incorporated into an aerosol-generating article and heated by dielectric heating (which is described below), an aerosol is generated containing a comparable amount of nicotine as obtained from known aerosol-generating substrates in either cylindrical or planar aerosolgenerating articles, despite the total mass of aerosol-generating substrate in the aerosolgenerating article being less than that used previously.

[0651] Further advantageously, the aerosol-generating substrate of the present invention generates less carbon monoxide than is generated from the known aerosol-generating substrates.

[0652] Example 2

[0653] Another suitable composition for forming an aerosol-generating substrate 20, 280, 31 according to the invention is set out in Table 2 below:

[0654] All amounts are shown as percentages by weight, on a dry weight basis, based on the total weight of the aerosol-generating substrate 20, 280, 31 .

[0655] In order to make the porous aerosol-generating substrate 20, 280, 31 , HPMC is dispersed in glycerin. Agar is added and dispersed in the HPMC and glycerin slurry. Water is mixed into the slurry. The plant material (black tea), nicotine and lactic acid are added to the slurry, which is stirred and dried, for example by lyophilisation.

[0656] In this way, a one-piece aerosol-generating substrate unit may be produced. The aerosolgenerating substrate unit may be formed by drying the slurry in a mould (i.e. casting) or by forming a piece of aerosol-generating substrate material and cutting it to the desired size and shape. The aerosol-generating unit is thus formed as a one-piece porous structure.

[0657] The one-piece aerosol-generating substrate unit may be self-supporting. In other words, the properties of the one-piece aerosol-generating substrate unit may be such that, even if the one-piece aerosol-generating substrate unit is formed by casting a slurry onto a support surface, the one-piece aerosol-generating substrate unit can be separated from the support surface. When incorporated into an aerosol-generating article 10, 100, 200, 400, 4000, 602, 718 and heated by resistive or induction heating, an aerosol is generated containing a comparable amount of nicotine as obtained from known aerosol-generating substrates in either cylindrical or planar aerosol-generating articles, despite the mass of aerosol former in the aerosol-generating substrate 20, 280, 31 in the present invention being less than the weight of aerosol former in known aerosol-generating substrates.

[0658] Further advantageously, the aerosol-generating substrate of the present invention generates less carbon monoxide than is generated from known aerosol-generating substrates.

[0659] Example 3

[0660] A further composition for forming an aerosol-generating substrate 20, 280, 31 according to the invention is set out in Table 3 below:

[0661] All amounts are shown as percentages by weight, on a dry weight basis, based on the total weight of the aerosol-generating substrate 20, 280, 31 .

[0662] In order to make the porous aerosol-generating substrate 20, 280, 31 , HPMC is dispersed in glycerin. Agar is added and dispersed in the HPMC and glycerin slurry. Water is mixed into the slurry. The tobacco and clove (i.e. a mixture of tobacco and non-tobacco plant material) are added to the slurry, which is stirred and dried, for example by lyophilisation.

[0663] In this way, a one-piece aerosol-generating substrate unit may be produced. The aerosolgenerating substrate unit may be formed by drying the slurry in a mould (i.e. casting) or by forming a piece of aerosol-generating substrate material and cutting it to the desired size and shape. The aerosol-generating unit is thus formed as a one-piece porous structure.

[0664] The one-piece aerosol-generating substrate unit may be self-supporting. In other words, the properties of the one-piece aerosol-generating substrate unit may be such that, even if the one-piece aerosol-generating substrate unit is formed by casting a slurry onto a support surface, the one-piece aerosol-generating substrate unit can be separated from the support surface.

[0665] When incorporated into an aerosol-generating article 10, 100, 200, 400, 4000, 602, 718 and heated by resistive or induction heating, an aerosol is generated containing a comparable amount of nicotine as obtained from known aerosol-generating substrates in either cylindrical or planar aerosol-generating articles, despite the mass of aerosol former in the aerosol-generating substrate 20, 280, 31 in the present invention being less than the weight of aerosol former in known aerosol-generating substrates.

[0666] Further advantageously, the aerosol-generating substrate of the present invention generates less carbon monoxide than is generated from known aerosol-generating substrates.

[0667] Example 4

[0668] An alternative composition for forming an aerosol-generating substrate 20, 280, 31 according to the invention is set out in Table 4 below:

[0669] All amounts are shown as percentages by weight, on a dry weight basis, based on the total weight of the aerosol-generating substrate 20, 280, 31 .

[0670] In order to make the porous aerosol-generating substrate 20, 280, 31 , HPMC is dispersed in glycerin. Agar is added and dispersed in the HPMC and glycerin slurry. Water is mixed into the slurry. The cellulose-based strengthening agent, nicotine and acid are added to the slurry, which is stirred and dried, for example by lyophilisation.

[0671] In this way, a one-piece aerosol-generating substrate unit may be produced. The aerosolgenerating substrate unit may be formed by drying the slurry in a mould (i.e. casting) or by forming a piece of aerosol-generating substrate material and cutting it to the desired size and shape. The aerosol-generating unit is thus formed as a one-piece porous structure.

[0672] The one-piece aerosol-generating substrate unit may be self-supporting. In other words, the properties of the one-piece aerosol-generating substrate unit may be such that, even if the one-piece aerosol-generating substrate unit is formed by casting a slurry onto a support surface, the one-piece aerosol-generating substrate unit can be separated from the support surface.

[0673] When incorporated into an aerosol-generating article 10, 100, 200, 400, 4000, 602, 718 and heated by resistive or induction heating, an aerosol is generated containing a comparable amount of nicotine as obtained from known aerosol-generating substrates in either cylindrical or planar aerosol-generating articles, despite the mass of aerosol former in the aerosol-generating substrate 20, 280, 31 in the present invention being less than the weight of aerosol former in known aerosol-generating substrates.

[0674] Further advantageously, the aerosol-generating substrate of the present invention generates less carbon monoxide than is generated from known aerosol-generating substrates. The aerosol-generating substrate may be used in aerosol-generating articles having different forms, as described with particular reference to Figures 1 to 5.

[0675] The aerosol-generating articles may be heated using dielectric heating devices (which will be described with reference to Figures 6 to 8), which are more efficient and ensure uniform heating of the aerosol-generating substrate. Features of the aerosol-generating substrate and the aerosol-generating article may be modified in order to optimise the performance of the aerosol-generating article and a user’s experience thereof.

[0676] Any combination of the mass of aerosol-generating substrate within the volume of the substrate plug, or cavity or chamber, the total mass of aerosol-generating substrate within the aerosol-generating article, the bulk density of the aerosol-generating substrate, the porosity of the aerosol-generating substrate, the shape and / or form of the aerosol-generating article, the shape and / or form of the internal volume of the substrate plug or cavity or chamber and / or the aerosolgenerating substrate composition or chemistry and / or shape and / or form may be adjusted or varied in order to optimise the performance of the aerosol-generating article and a user’s experience thereof.

[0677] Figure 1 illustrates an aerosol-generating article 10 according to an embodiment of the invention. The aerosol-generating article 10 comprises four elements arranged in coaxial alignment: an aerosol-generating substrate 20, a support element 30, an aerosol-cooling element 40, and a mouthpiece 50. These four elements are arranged sequentially and are circumscribed by an outer wrapper 60 to form the aerosol-generating article 10. The aerosol-generating article 10 has a proximal or mouth end 70, which a user inserts into his or her mouth during use, and a distal end 80 located at the opposite end of the aerosol-generating article 10 to the mouth end 70.

[0678] In use air is drawn through the aerosol-generating article by a user from the distal end 80 to the mouth end 70. The distal end 80 of the aerosol-generating article 10 may also be described as the upstream end of the aerosol-generating article 10 and the mouth end 70 of the aerosolgenerating article 10 may also be described as the downstream end of the aerosol-generating article 10. Elements of the aerosol-generating article 10 located between the mouth end 70 and the distal end 80 can be described as being upstream of the mouth end 70 or, alternatively, downstream of the distal end 80.

[0679] The aerosol-generating substrate 20 is located at the extreme distal or upstream end of the aerosol-generating article 10. In the embodiment illustrated in Figure 1 , aerosol-generating substrate 20 comprises a gathered sheet of crimped homogenised tobacco material circumscribed by a wrapper. The crimped sheet of homogenised tobacco material comprises comprising glycerin as an aerosol-former.

[0680] The support element 30 is located immediately downstream of the aerosol-generating substrate 20 and abuts the aerosol-generating substrate 20. In the embodiment shown in Figure 1 , the support element is a hollow cellulose acetate tube. The support element 30 locates the aerosol-generating substrate 20 at the extreme distal end 80 of the aerosol-generating article 10. The support element 30 also acts as a spacer to space the aerosol-cooling element 40 of the aerosol-generating article 10 from the aerosol-generating substrate 20.

[0681] The aerosol-cooling element 40 is located immediately downstream of the support element 30 and abuts the support element 30. In use, volatile substances released from the aerosolgenerating substrate 20 pass along the aerosol-cooling element 40 towards the mouth end 70 of the aerosol-generating article 10. The volatile substances may cool within the aerosol-cooling element 40 to form an aerosol that is inhaled by the user. In the embodiment illustrated in Figure 1 , the aerosol-cooling element comprises a crimped and gathered sheet of polylactic acid circumscribed by a wrapper 90. The crimped and gathered sheet of polylactic acid defines a plurality of longitudinal channels that extend along the length of the aerosol-cooling element 40.

[0682] The mouthpiece 50 is located immediately downstream of the aerosol-cooling element 40 and abuts the aerosol-cooling element 40. In the embodiment illustrated in Figure 1 , the mouthpiece 50 comprises a conventional cellulose acetate tow filter of low filtration efficiency.

[0683] To assemble the aerosol-generating article 10, the four elements described above are aligned and tightly wrapped within the outer wrapper 60. In the embodiment illustrated in Figure 1 , the outer wrapper is a conventional cigarette paper. As shown in Figure 1 , an optional row of perforations is provided in a region of the outer wrapper 60 circumscribing the support element 30 of the aerosol-generating article 10.

[0684] In the embodiment illustrated in Figure 1 , a distal end portion of the outer wrapper 60 of the aerosol-generating article 10 is circumscribed by a band of tipping paper (not shown).

[0685] The aerosol-generating article 10 illustrated in Figure 1 is designed to engage with an aerosol-generating device comprising a heating element in order to be smoked or consumed by a user. In use, the heating element of the aerosol-generating device heats the aerosol-generating substrate 20 of the aerosol-generating article 10 to a sufficient temperature to form an aerosol, which is drawn downstream through the aerosol-generating article 10 and inhaled by the user.

[0686] As shown in Figures 2a and 2b, the pouch 100 according to the invention comprises a container formed from a porous material for containing an aerosol-generating substrate 102. In this example, the pouch has a circular cross-section profile and is in the form of a cylinder. The porous material may be a mesh-like material formed by either weaving or cutting and then extending. Suitable materials include the natural fibres Sisal and Ramie.

[0687] In use, the pouch is heated in an aerosol-generating device to generate an aerosol.

[0688] Figure 3a illustrates a perspective side view of an aerosol-generating article 200 according to another embodiment of the present invention. The aerosol-generating article 200 includes a first planar layer 110 extending in a first plane and a second planar layer 120 extending in a second plane, the second plane being parallel to and spaced from the first plane. A thickness of the aerosol-generating article 200 extends in a z dimension in a direction perpendicular to the first plane and the second plane. The aerosol-generating article 200 comprises an aerosol-generating substrate. In one embodiment, the aerosol-generating article 200 may consist substantially of aerosol-generating substrate. In another embodiment, the aerosol-generating substrate may be one of a plurality of component parts of the aerosol-generating article 200. The aerosol-generating substrate may be enclosed within an interior of the aerosol-generating article 200. The aerosolgenerating substrate may at least partially define an exterior of the aerosol-generating article 200; for example, one or both of the first and second planar layers 110, 120 may comprise or consist of aerosol-generating substrate. A suitable aerosol-generating substrate may be homogenised tobacco. The aerosol-generating article 200 has a length, extending in an x dimension, of 80 millimetres, a width, extending in a y dimension, of 15 millimetres, and a height (which may also be referred to as the thickness), extending in a z dimension, of 3.6 millimetres. The thickness of the aerosol-generating article is defined by the distance between an upper surface of the aerosolgenerating article, in this example that is an upper surface of the first planar layer 110, and a lower surface of the aerosol-generating article, in this example that is a lower surface of the second planar layer 120. The aerosol-generating article 200 comprises a cavity 270. The cavity 270 is defined between the first planar layer 110 and the second planar layer 120. A height of the cavity 270 is defined by the distance between a lower surface of the first planar layer 110 and an upper surface of the second planar layer 120. The height of the cavity is greater than 50 percent of the thickness of the article. The height of the cavity is greater than 1 .8 millimetres, for example about 2.5 millimetres. The width of the cavity is about 12 mm. The aerosol-generating article 200 comprises an aerosol-generating substrate. In this embodiment, the first planar layer 110 and the second planar layer 120 each comprise a sheet of homogenised tobacco and an external layer. The external layer of the first planar layer 110 forms the upper surface of the first planar layer 110 and the external layer of the second planar layer 120 forms the lower surface of the second planar layer 120. Each external layer comprises a sheet of paper. An air flow path 230 is defined through the aerosol-generating article 200 between the upper and lower planar layers 110, 120. The air flow path 230 extends between opposed first and second ends 201 , 202 of the aerosol-generating article 200. The first end 201 may define a distal end of the aerosol-generating article 200, and the second end 202 may define a proximal end of the aerosol-generating article. The air flow path 230 may be directed towards a mouth of a user to allow a user to inhale aerosol generated in consequence of heating of aerosol-generating substrate of the aerosol-generating article 200. An air flow passage is defined through the aerosol-generating article 200 between an air flow inlet 240 and an air flow outlet 260 (shown in Figure 3b). The air flow passage extends through the cavity and is configured to allow, in use, air to flow from the air inlet 240, through the cavity and out of the air outlet 260. The air flow inlet 240 is defined by an inlet width and an inlet height, in which the inlet width is greater than 80 percent of the aerosol-generating article 200 width, and the inlet height is greater than 25 percent of the aerosol-generating article 200 height. The airflow path is defined through the aerosol-generating article 200 from the air inlet 240, through the cavity, and to the air outlet, in which a resistance to draw (RTD) of the aerosol-generating article 200, along the airflow path between the air inlet 240 and the air outlet 260, is less than 20 millimetres H2O. Figure 3b illustrates a schematic lateral cross-sectional view of the aerosol-generating article of Figure 3a. Figure 3b shows an internal cross-section of the aerosol-generating article. In use, when a user puffs on the air outlet 260, air is drawn into the aerosol-generating article 200 through the air flow inlet 240, and along the air flow passage. The air flows through the cavity 270 to the air flow outlet 260. Aerosol-generating substrate 280 is positioned on either side of the cavity 270. In addition, aerosol-generating substrate 280 may be located within the cavity 270. In use, as the aerosol-generating article is heated by an external heater, the aerosol-generating substrate 280 in the aerosol-generating article 200 is heated and the aerosol-formers are vaporised. The vapours are entrained in air flow in the airflow passage as the user puffs on the air outlet 260. The vapours cool in the air flow and condense to form an aerosol, the aerosol may then be inhaled by the user.

[0689] An aerosol-generating article 400 in accordance with an embodiment of the present invention is illustrated schematically in Figure 4a. The aerosol-generating article 400 is substantially spherical and has a maximum dimension DMAX, which corresponds to a diameter of the aerosol-generating article 400, of 10.8 millimetres. As shown in Figure 4b, the aerosolgenerating article comprises an inner core 402 of an aerosol-generating substrate and an outer shell 404 encapsulating the inner core 402 of aerosol-generating substrate. A thickness of the outer shell 404 is 0.8 millimetres, that is 7.4 percent of the maximum dimension DMAX.

[0690] Figure 5 shows a transparent view of another aerosol-generating article 4000. The aerosolgenerating article 4000 comprises a housing 4001. The housing 4001 comprises an aerosolgenerating substrate sheet 31. The housing 4001 of the aerosol-generating article 4000 is a substantially closed housing 4001 configured to retain the aerosol-generating substrate sheet 31 in the housing 4001. More precisely, the housing 4001 comprises a first compartment 4002 and a second compartment 4003 for respectively receiving at least a portion of the aerosol-generating substrate sheet 31. The aerosol-generating substrate sheet 31 may be stored as a bobbin in the first compartment 4002. The first compartment 4002 may be provided with a circular pin 32, around which the aerosol-generating substrate sheet 31 is initially wound. The second compartment 4003 is a waste compartment 25 for storing the portion of aerosol-generating substrate sheet 31 that has been aerosolized. The internal volume of the second compartment 4003 is greater than the volume of the first compartment 4002. The aerosol-generating article 4000 further comprises an access port 4004 provided between the first compartment 4002 and the second compartment 4003. The access port 4004 is only visible by transparency in the view of Figure 5 and is therefore showed by dotted lines. The access port 4004 is in fluid communication with an inside of the housing 4001 . In the example shown in Figure 5, the aerosolgenerating article 4000 is free of a mouthpiece. In such examples, a mouthpiece may be provided on an aerosol-generating device. The housing 4001 is formed such that the first compartment 4002 is joined to the second compartment 4003 by means of a tunnel 4005. A length 4007 of the tunnel 4005 extending between the first compartment 4002 and the second compartment 4003 may be comprised between 2 millimetres and 40 millimetres. In the non-limitative example of Figure 5, a transversal cross-section of the tunnel is rectangular. The access port 4004 is provided on a wall of the tunnel 4005. An opposite wall of the tunnel 4005 is provided with two air inlet slots 4006. The two air inlet slots 4006 overlies a portion of the access port 4044. The aerosolgenerating article 4000 further comprises a moving mechanism configured to move the aerosolgenerating substrate sheet 31 from the first compartment 4002 to the second compartment 4003. The moving mechanism is arranged inside the tunnel 4005. In the non limitative example illustrated by Figure 5, the moving mechanism comprises a first pair of rollers 4008, 4009 arranged in the tunnel 4005 between the access port 4004 and the first compartment 4002. The moving mechanism further comprises a second pair of rollers 4010, 4011 arranged in the tunnel 4005 between the second compartment 4003 and the access port 4004. The rollers 4008, 4009; 4010, 4011 may be friction rollers configured to engage and move the aerosol-generating substrate sheet 31 by friction. The moving mechanism is configured to move the aerosolgenerating substrate sheet 31 from the first compartment 4002 to the second compartment 4003 in the direction of transportation 312. The aerosol-generating substrate sheet 31 is configured to pass between the rollers 4008, 4009 of the first pair of rollers. The aerosol-generating substrate sheet 31 is also configured to pass between the rollers 4010, 4011 of the second pair of rollers. At least one of the rollers of each pair of rollers 4008, 4009; 154010, 4011 is configured to engage a respective drive of an aerosol-generating device 3000, when the aerosol-generating article 4000 is inserted in the receptacle 3004 of the aerosol-generating device. The engagement of the rollers of the aerosol-generating article 4000 with a respective drive of the aerosol-generating device enables transmitting the torque of a respective drive to at least one of the rollers 4008, 4009; 4010, 4011. Advantageously, the tunnel 4005 may be further provided with an opening 4012 for receiving a sensor. The opening 402 is provided between the first pair of rollers 4008, 4009 and the first compartment 4002.

[0691] Figure 6 is a schematic illustration of a system for heating using radio frequency electromagnetic radiation, sometimes referred to as dielectric heating or microwave heating. The system comprises a radio frequency signal generator 510, power amplifier 512 connected to the signal generator to amplify the radio frequency signal, and antennae 516 positioned inside the heating cavity 514, the antennae connected to an output of the power amplifier 512. The output of the amplifier is fed back to the signal generator to provide closed-loop control. An object 518 which is to be heated is placed in the cavity 514 and subjected to radiofrequency electromagnetic radiation. Polar molecules within the object 518 align with the oscillating electromagnetic field and so are agitated by the electromagnetic field as it oscillates. This causes an increase in temperature of the object 518. This kind of heating has the advantage that it is uniform throughout the object (provided that the polar molecules are uniformly distributed). It also has the advantage of being a non-contact form of heating, which does not require conduction or convection of heat from high temperature heating element.

[0692] In embodiments of the present invention, a solid state radiofrequency (RF) transistor may be used to perform both the signal generation and power amplification functions illustrated in Figure 6. However, it would be possible to implement the embodiments described using an RF transistor for the signal generation and a separate electronic component or components to provide for the power amplification.

[0693] Figure 7 is a schematic illustration of a heat-not-burn aerosol-generating system 600. The system 600 comprises an aerosol-generating article 602 received within the housing 604 of an aerosol-generating device. The aerosol-generating device comprises a power source 606, such as a lithium ion battery, control circuitry 608, an RF electromagnetic field generator 610 comprising a solid state RF transistor, and a substrate cavity 612 in which the aerosol-generating article 602 is received. The RF electromagnetic field generator 610 is provided with power from the battery 606 under the control of the control circuitry 608 to generate radio frequency electromagnetic radiation within the substrate cavity 612. Surrounding the substrate cavity 612, and positioned between the RF electromagnetic field generator and the substrate cavity, is a radiation containment cavity 614, through which the electromagnetic radiation generated by the RF electromagnetic field generator travels before reaching the substrate cavity 612.

[0694] The substrate cavity 612 is a generally cylindrical, blind cavity having an open end and a closed end, and a sidewall extending between the open end and the closed end. The aerosolgenerating article is inserted into the substrate cavity through its open end. Both the substrate cavity 612 and the radiation containment cavity 614 have external walls formed from suitable metal material, such as aluminium, that is opaque to the RF radiation. This concentrates the electromagnetic field in the substrate cavity and prevents leakage of radiation from the device. In order to allow for radiation to pass from the radiation containment cavity into the substrate cavity, slots 616 are formed in the external walls of the substrate cavity 612. In the example shown in Figure 7, a slot is formed in the wall at the closed end of the substrate cavity and a further two slots are formed in the sidewall of the substrate cavity.

[0695] The aerosol-generating article 602 in this embodiment has the look and feel of a cigarette. It comprises a mouthpiece end on which the user can puff to draw aerosol out of the aerosolgenerating system. Opposite the mouthpiece end, the aerosol-generating article holds an aerosolgenerating substrate. In this embodiment, the aerosol-generating substrate comprises reconstituted tobacco together with an aerosol former, such as glycerol, and water. The mouthpiece may comprise a filter.

[0696] The aerosol-generating device is designed to be a portable, hand-held device which the user can easily hold in one hand. The housing 604 may be formed of a suitable plastics material, such as polyetheretherketone (PEEK). Airflow inlets (not shown) may be provided in the housing to allow air to be drawn into the device, through the substrate cavity 612 and out through the mouthpiece of the aerosol-generating article 602.

[0697] In operation, after an aerosol-generating article 602 is placed in the substrate cavity 612, the device is activated. RF radiation from the electromagnetic field generator is then directed into the substrate cavity and causes dielectric heating of the aerosol-generating substrate. In this example, the frequency of the electromagnetic field is between 900 MHz and 2.4 GHz. The temperature inside the substrate cavity can be regulated using a feedback control mechanism, as described in WO2021 / 013477, the contents of which are incorporated by reference. The temperature inside the substrate cavity 612 can be sensed, or another parameter indicative of the temperature inside the substrate cavity can be sensed, to provide a feedback signal to the control circuitry 608. The control circuitry 608 then adjusts the frequency or amplitude, or both the frequency and the amplitude, of the electromagnetic field in order to maintain the temperature inside the substrate cavity 612 within a desired temperature range.

[0698] As previously described, the walls of the substrate cavity 612 and the radiation containment cavity 614 are made from a material which is not transparent to RF radiation. For example, aluminium, stainless steel, silver and gold can be used. The walls of the substrate cavity 612 are ideally polished surfaces to improve reflection of the RF radiation. It is also desirable to minimise the escape of RF radiation through the mouthpiece end of the aerosol-generating article 602. For that purpose, a radiation shielding element may be included within the aerosol-generating article 602. It will be appreciated that the aerosol-generating article 602 may be provided in any form and that the substrate cavity 612 may be configured to receive aerosol-generating articles in any form, including, but not limited to, the aerosol-generating articles 10, 100, 200, 400, 4000, as described above.

[0699] Figure 8 is a schematic illustration of a system for dielectrically heating an aerosolgenerating substrate using radio frequency (RF) electromagnetic radiation according to an embodiment of the present disclosure. The system comprises an oscillation circuit 710 including a radio frequency (RF) signal generator 711 and a phase shift network 712. The oscillation circuit is controlled by a controller (not shown). The system further comprises a first electrode 715 connected to a first output of the phase shift network 712, and a second electrode 716 connected to a second output of the phase shift network 712. The second electrode 716 is spaced apart from the first electrode 715 to define an article cavity 714 between the first electrode 715 and the second electrode 716. The article cavity 714 is configured to receive an aerosol-generating article 718. An aerosol-generating article 718, which is to be heated, is placed in the article cavity 714 and subjected to radio frequency electromagnetic radiation between the first electrode 715 and the second electrode 716. Polar molecules within the aerosol-generating article 718 align with the oscillating electromagnetic field and so are agitated by the electromagnetic field as it oscillates. This causes an increase in temperature of the aerosol-generating article 718. This kind of heating has the advantage that it is uniform throughout the aerosol-generating article 718 (provided that the polar molecules are uniformly distributed). It also has the advantage of reducing the likelihood of combustion of the substrate in contact with the first electrode 715 and the second electrode 716 compared to a conventional heating element that transfers heat to the substrate via conduction. In this embodiment, the first electrode 715 and the second electrode 716 are spaced apart by a separation distance of 3 millimetres, and the length of the first and second electrodes is about 40 millimetres, resulting in a ratio of the length of the first electrode to the separation distance of 13.3.

[0700] It will be appreciated that the separation distance between the first and second electrodes in any of these embodiments may be between about 2 millimetres and about 9 millimetres, in accordance with the disclosure, and the ratio between the length of the electrodes and the separation distance may be between about 10.5 and about 19.5.

[0701] It will also be appreciated that in some embodiments, the first electrode 715 and the second electrode 716 may be part of separate components of the system, for example, one of the first electrode 715 and the second electrode 716 may form a part of the article 718, in these embodiments. In these embodiments, the separation distance is configured to be between about 2 millimetres and about 9 millimetres, and the ratio is configured to be between about 10.5 and about 19.5, when the aerosol-generating article is received in the article cavity. The system may include a controller, for example as described in WO2022 / 184783, the contents of which are incorporated herein by reference.

[0702] It will be appreciated that the aerosol-generating article 718 may be provided in any form and that the article cavity 714 may be configured to receive aerosol-generating articles in any form, including, but not limited to, the aerosol-generating articles 10, 100, 200, 400, 4000, as described above.

[0703] For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances 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 enumerated herein. In this context, therefore, a number A is understood as A ± 10% of A. Within this context, a number A may be considered to include numerical values that are within general standard error for the measurement of the property that the number A modifies. The number A, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which A deviates does not materially affect the basic and novel characteristic(s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein.

Claims

CLAIMS1 . An aerosol-generating article for producing an inhalable aerosol upon heating, the aerosol-generating article comprising a substrate plug defining an internal volume, the internal volume comprising an aerosol-generating substrate, wherein a mass of the aerosol-generating substrate within the internal volume of the substrate plug is less than or equal to 0.3 milligrams per cubic millimetre and wherein the aerosol-generating article comprises less than or equal to 140 milligrams of aerosol-generating substrate.

2. An aerosol-generating article for producing an inhalable aerosol upon heating, the aerosol-generating article comprising a substrate plug defining an internal volume, the internal volume comprising an aerosol-generating substrate, wherein a mass of the aerosol-generating substrate within the internal volume of the substrate plug is less than or equal to 0.5 milligrams per cubic millimetre and wherein the aerosol-generating article comprises less than or equal to 100 milligrams of aerosol-generating substrate.

3. The aerosol-generating article according to claim 1 or claim 2, wherein the mass of the aerosol-generating substrate within the internal volume of the substrate plug is at least 0.05 milligrams per cubic millimetre.

4. The aerosol-generating article of any one of claims 1 to 3, wherein the mass of the aerosol-generating substrate within the internal volume of the substrate plug is at least 0.1 milligrams per cubic millimetre.

5. The aerosol-generating article according to any one of claims 1 to 4, comprising at least 10 milligrams of aerosol-generating substrate.

6. The aerosol-generating article according to any one of claim 1 to 5, wherein the internal volume is between 0.3 cubic millimetres and 4500 cubic millimetres.

7. An aerosol-generating article for producing an inhalable aerosol upon heating, the aerosol-generating article comprising at least 10 milligrams and less than 100 milligrams of aerosol-generating substrate, wherein the aerosol-generating article has an internal volume of at least 1 cubic centimetre.

8. The aerosol-generating article according to any one of claims 1 to 7, comprising at least 30 milligrams of aerosol-generating substrate.

9. The aerosol-generating article according to any one of claim 1 to 8, comprising less than or equal to 90 milligrams of aerosol-generating substrate.

10. The aerosol-generating article according to any one of claim 1 to 9, wherein the aerosol-generating substrate comprises an aerosol former and the aerosol-generating article has an aerosol former content of between 7 milligrams and 112 milligrams.

11. The aerosol-generating article according to claim 10, wherein the aerosol former content is between 35 milligrams and 70 milligrams.

12. The aerosol-generating article according to any one of claim 1 to 11, wherein the aerosol-generating substrate comprises an active agent.

13. The aerosol-generating article according to claim 12, wherein the active agent is nicotine and the aerosol-generating article has a nicotine content of between 0.7 milligrams and 2.8 milligrams.

14. The aerosol-generating article of any one of claims 1 to 13, wherein the aerosolgenerating article is flat.

15. An aerosol-generating system comprising an aerosol-generating device and the aerosol-generating article of any one of claims 1 to 14, wherein the aerosol-generating device comprises a dielectric or microwave heating element that is configured to heat the aerosolgenerating substrate of the aerosol-generating article.

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