Heating module for an aerosol-generating device with a movable dielectric heater arrangement

Abstract

The present invention provides a heating module (700) for an aerosol-generating device (120). The heating module (700) comprises a heating chamber (140) and a dielectric heater arrangement (712) movable relative to the heating chamber (140). The heating chamber (140) comprises a first heating zone (HZ1) and a second heating zone (HZ2) arranged in a distance to the first heating zone (HZ1). The dielectric heater arrangement (712) comprises at least two electrodes (310, 315) for generating an alternating electric field. Each of the at least two electrodes (310, 315), in operation, moves as part of the dielectric heater arrangement (712) to heat an aerosol-generating substrate (110) received in the first heating zone (HZ1) when arranged at the first heating zone (HZ1) and to heat an aerosol-generating substrate (110) received in the second heating zone (HZ2) when arranged at the second heating zone (HZ2), by the alternating electric field formed between the at least two electrodes (130, 135).

Description

[0001] Heating module for an aerosol -generating device with a movable dielectric heater arrangement

[0002] The present invention relates to a heating module for an aerosol-generating device or aerosol-generating system, specifically to a heating module with a movable dielectric heater arrangement designed for segmented heating of an aerosol-generating substrate.

[0003] Known electrically operated aerosol-generating systems typically heat an aerosolgenerating substrate through conduction, radiation, or convection, with Joule heating being the most commonly used method. Inductive heating has also been explored, utilizing eddy currents to generate heat. However, these conventional heating methods often result in non-uniform heating, where the region closest to the heating element reaches higher temperatures faster than more distant areas, leading to inconsistent aerosol generation.

[0004] Also, segmented heating systems have been developed, employing multiple heating elements arranged along the aerosol-generating substrate. These heating elements are activated in a controlled manner to achieve stepwise heating to heat solely when a puff is being taken, with the goal to provide for a puff-on-demand or response-to-draw heating regime and operation, similar to the puff-on-demand or response-to-draw operations of e-vapor products or electronic cigarettes.

[0005] Additionally, dielectric heating has been proposed as a means to achieve more uniform heating of the aerosol-generating substrate. While dielectric heating offers advantages in heat distribution, existing implementations suffer from inefficiencies, require complex circuitry, and pose challenges in achieving precise temperature regulation.

[0006] Typically, there are two types of dielectric heating approaches known: the resonant cavity or transmission line type dielectric heater approach and the load capacitor dielectric heater approach. In contrast to the resonant cavity or transmission line type dielectric heaters, where an electric field is generated by coupling of an electromagnetic wave to a resonant cavity and / or transmission line, the load capacitor dielectric heater comprises at least two electrodes subjected to an high-frequency alternating voltage with an aerosol-generating substrate arranged therebetween, configured to generate a high frequency alternating electric field to heat the aerosol-generating substrate.

[0007] In the food processing industry, certain load capacitor dielectric heating approaches have been used for heavy machinery that involve a moving electrode relative to a larger static electrode. However, while moving electrode designs may enable zoned heating, their use at high frequencies above 100 MHz, which are typical for portable aerosol-generating systems, becomes impractical due to increased capacitance and / or changing stray inductance and capacitance, making stable and efficient heating difficult to achieve. Alternative solutions utilizing arrays of selectable dielectric heaters require sophisticated high frequency power switching, adding cost and complexity.In the context of the present disclosure, the aerosol-generating device and / or the aerosolgenerating system may be a portable device and / or system. It may be battery powered. Particularly, the aerosol-generating device and / or the aerosol-generating system may be pocket-size, hand-held, suitable for one-hand use and / or may weigh less than 300 grams, preferably less than 200 grams. It may be shaped and / or sized to fit snugly into a user’s hand. It may be carried in jacket and / or trouser pockets. Particularly, the aerosol-generating device and / or the aerosolgenerating system may be configured to provide aerosol for human inhalation and / or human consumption, particularly inhalation and / or consumption through the mouth.

[0008] It would be desirable to provide a heating module that dielectrically heats an aerosolgenerating substrate with greater efficiency, for example to achieve a zoned heating or puff-on-demand heating regime, while still being suitable for compact or handheld applications.

[0009] According to a first aspect, there is provided a heating module for an aerosol-generating device. The heating module comprises a heating chamber and a dielectric heater arrangement movable relative to the heating chamber. The heating chamber comprises a first heating zone and a second heating zone arranged in a distance to the first heating zone. The dielectric heater arrangement comprises at least two electrodes for generating an alternating electric field. Each of the at least two electrodes, in operation, moves as part of the dielectric heater arrangement to heat an aerosol-generating substrate received in the first heating zone when arranged at the first heating zone and to heat an aerosol-generating substrate received in the second heating zone when arranged at the second heating zone, by the alternating electric field formed between the at least two electrodes.

[0010] The at least two electrodes may form a uniform movable unit together with the dielectric heater arrangement. In embodiments, the dielectric heater arrangement may comprise a holding structure (or carrying structure) configured to hold the at least two electrodes in a spatial arrangement. The spatial arrangement of the at least two electrodes relative to each other may remain unchanged during movement. In other words, the movement of the electrodes may not affect the distance between the at least two electrodes. Under such premise, a strength of the alternating electric field generated by the at least two electrodes may be affected by a voltage and frequency of the alternating current supplied to the at least two electrodes only, thereby facilitating heat control of the aerosol-generating substrate.

[0011] The alternating electric field generated by the at least two electrodes may be in the radio frequency (RF) range, preferably within the ultra-high frequency (UHF) range, specifically between 100 MHz and 5 GHz, preferably between 200 MHz and 2 GHz, and even more preferably between 300 MHz and 1 GHz.

[0012] The aerosol-generating substrate in the first and second heating zones may form distinct sections or partially overlapping sections of a continuous substrate housed within the heating chamber. This holistic aerosol-generating substrate may be shaped like a long rod, tape, or band.The dielectric heater arrangement may comprise an oscillation circuit configured to power the at least two electrodes. The oscillation circuit, in operation, may move with the movable dielectric heater arrangement.

[0013] Each of the oscillation circuit and the at least two electrodes, in operation, may move as part of the dielectric heater arrangement to heat an aerosol-generating substrate received in the first heating zone when arranged at the first heating zone and to heat an aerosol-generating substrate received in the second heating zone when arranged at the second heating zone, by the alternating electric field formed between the at least two electrodes.

[0014] The use of a uniform movable dielectric heating arrangement (DHA) that includes most or preferably all high frequency, radio frequency (RF) side components may prevent creation of variable operating conditions during heating (e.g., due to changing parasitic capacitances and inductances) that could impact the functioning of the dielectric heater.

[0015] The oscillation circuit may be configured to operate the at least two electrodes at radio frequency (RF), preferably within the ultra-high frequency (UHF) range, specifically between 100 MHz and 2 GHz, and preferably between 300 MHz and 1 GHz.

[0016] The oscillation circuit may comprise a switching unit with a feedback loop connected between an input and an output of the switching unit. The feedback loop may comprise a load capacitor formed by the at least two electrodes and one or more inductors.

[0017] The heating chamber may have a main extension direction in a longitudinal direction. The heating chamber may have an elongated shape, preferably a tubular shape, extending in the main extension direction. Preferably, the heating chamber and the heating module and / or the aerosolgenerating device may share the same main extension direction.

[0018] The dielectric heater arrangement may be movable relative to the heating chamber along the longitudinal direction and / or along a rotational direction around the longitudinal direction. Specifically, the dielectric heater arrangement may perform linear movement along the longitudinal direction, rotational movement around longitudinal direction and / or around an outer circumference the heating chamber or heating chamber structure, or both.

[0019] The second heating zone may be offset from the first heating zone, in particular offset in the longitudinal and / or rotational direction. While in some examples, the first heating zone and the second heating zone may be fully distinct or non-overlapping, there may be other examples where the first heating zone and the second heating zone partially overlap.

[0020] The displacement mechanism may be configured to displace the dielectric heater arrangement relative to the heating chamber in the longitudinal direction and / or in the rotational direction by a guide movement.

[0021] The guide movement / motion may refer to a controlled linear and / or rotational movement regulated by a controller of the heating module or the aerosol-generating device. In a non-limiting example, the controller may be configured to control the displacement mechanism and thedielectric heater arrangement (in particular, the switch unit of the oscillation circuit) under continuous motion (velocity) around or along the heating chamber while regulating the heating power delivered to the electrodes. In other embodiments, the dielectric heater arrangement may be moved in intervals. That is, the at least two electrodes may be moved to the first heating zone, stop there, activate heating, stop heating, and move to the second heating zone.

[0022] The displacement mechanism may comprise a motor and a transmission arrangement configured to translate rotational motion from the motor into the guide movement of the dielectric heater arrangement. The motor may be a stepper motor.

[0023] The transmission arrangement may comprise a drive gear coupled to the motor and configured to rotate the dielectric heater arrangement around the longitudinal axis by engaging with a mating, specifically meshing, internal gear connected to the dielectric heater arrangement. The internal gear may be formed in a carrier structure, such as a disk, that securely holds the dielectric heater arrangement, and / or or forms part thereof.

[0024] Alternatively or additionally, the transmission arrangement may include any one of a belt, a screw drive, a rack drive and / or a worm drive to cause the guide movement in the longitudinal direction.

[0025] The transmission arrangement may include a drive gear coupled to the motor, and a sleeve with a mating, particularly meshing, internal gear. The sleeve may have a main extension direction in the longitudinal direction. The internal gear may extend in a helix along the longitudinal direction. The drive gear may be configured to engage with the internal gear of the sleeve to cause the guide movement in both the rotational direction and translation direction.

[0026] A carrier structure may be movable relative to the heating chamber. The dielectric heater arrangement is attached to the carrier structure or comprises the carrier structure. The carrier structure and the dielectric heater arrangement form a uniform unit that is movable relative to the heating chamber. The carrier structure may include a planarly extending plate, preferably in form of a disk. The carrier structure may comprise an internal gear engaging with a drive gear coupled to the motor in order to rotate the carrier structure. The disk as used herein may refer to a circular and flat object.

[0027] The carrier structure may hold the at least two electrodes to a distance to each other.

[0028] The dielectric element, or dielectric filler in some embodiments, may be arranged between the at least two electrodes. A relative permittivity of the dielectric element may be lower than a relative permittivity of the carrier structure.

[0029] The dielectric element may be any of a space, a volume or a coating provided on the carrier structure.

[0030] The heating chamber may include an interior volume of a heating chamber structure for accommodating an aerosol-generating substrate. The interior volume may be hermetically sealed from the dielectric heater arrangement.The term “hermetically sealed” as used herein may mean airtight, preventing the passage of aerosol particles and / or vapor. In other words, the interior volume may form a sealed space relative to other parts of the heating module / aerosol-generating device while having a fluidic inlet and outlet. The goal may be that no vapor or aerosol particles can enter into the space where the dielectric heater and the movable parts are, by virtue of the arrangement of the heating chamber. Particularly, the interior volume may be hermetically sealed and thus hermetically isolated from the carrier structure and / or the displacement mechanism.

[0031] The heating chamber structure may form a cylindrical body with a main axis extending in the longitudinal direction.

[0032] The heating chamber structure may comprise walls made of a relatively low-dielectric but relatively high temperature-resistive material, for example quartz glass or Polyetheretherketone (PEEK). For example, a relative permittivity (also called dielectric constant) of the walls may be made of a material with relative permittivity ranging from 2 to 20, preferably from 3 to 6.

[0033] The walls of the heating chamber structure may be substantially transparent to the radio frequency (RF) alternating electric field. This may allow the RF electric field to traverse the wall while allowing the interior volume of the heating chamber that receives the to-be-heated substrate to be hermetically sealed from the dielectric heating arrangement.

[0034] In embodiments, the walls of the heating chamber structure may be made of at least one of Parylene N, Parylene D, polyetherimide (PEI) and PEEK.

[0035] The heating chamber structure may be configured as a cup, preferably cylindrical cup, and / or may include a receiving opening for removably inserting an aerosol-generating article, or at least a part thereof, including the aerosol-generating substrate, or the substrate itself. In a variant, the heating chamber structure can have an oval, rectangular, or oblong cross-sectional shape seen in an insertion direction and longitudinally extending along or across the insertion direction. A cover, such as a lid, for closing the receiving opening may be attached to the heating chamber. The heating chamber may be integrally formed with walls of the housing of the aerosolgenerating device.

[0036] The heating chamber structure may be configured as a cylindrical cup that is inserted into an opening of a housing of the heating module or aerosol-generating device. The cylindrical cup may be closed with a bottom end and an opening at an upper end opposite to the bottom end, designed to receive the substrate or at least a portion of the aerosol-generating article, which includes the substrate.

[0037] The heating chamber may be configured to accommodate a solid aerosol-generating substrate.

[0038] The cylindrical cup may incorporate a flange structure that extends radially outward, forming a contact surface that ensures a hermetic seal against the inner surface of the housing. This design may create an interior volume that is hermetically isolated from the dielectric heaterarrangement and the electrode displacement mechanism. The cylindrical cup may be secured within the upper opening of the housing through a friction fit, a form fit, or an additional locking mechanism. In some embodiments, the heating chamber structure and the housing may form an integral unit. A gap, such as an air gap or vacuum space, may be formed between cylindrical walls of the housing and the cylindrical cup due to the flange structure. The electrodes and a portion of the carrier structure may be movably accommodated within said gap, allowing for a rotational movement and / or linear movement.

[0039] The heating module may comprise or at least be connected to a DC power supply movable relative to the dielectric heater arrangement. The DC power supply may be non-movably attached relative to the heating chamber structure. The DC power supply may be configured to provide power for operating the dielectric heater arrangement, in particular the electrodes, specifically the oscillation circuit.

[0040] An electrical interface may be provided between the DC power supply and the dielectric heater arrangement. The electrical interface may comprise flexible electric interconnection elements. The flexible electric interconnection elements may comprise one or more of cables, flex PCBs, or expandable conductive elements like coils.

[0041] Alternatively, the electrical interface between the DC power supply and the dielectric heater arrangement may comprise a sliding power connector. The sliding power connector may comprise two electrical tracks electrically insulated from each other, and sliding electrical contacts configured to engage with a respective one of the two electric tracks during a relative movement between DC power supply and the dielectric heater arrangement. Such a configuration may allow for the DC power supply and the dielectric heater arrangement to be able to rotate more than one full rotation relative to each other. The electrical tracks may be in form of concentrically rings insulated from each other. In an alternative, the sliding electrical contacts may be formed as parallel tracks. Specifically, the electrical tracks may parallelly extend along the longitudinal direction. The sliding electrical contacts may comprise one or more of: pins, spring elements (leaf spring, coil spring), pogo pins, tabs, or legs.

[0042] The heating module or the aerosol-generating device may comprise a housing accommodating the heating chamber, in particular the heating chamber structure, and the dielectric heater arrangement. The heating chamber structure may be attached to or formed by the housing. The dielectric heater arrangement may be movably supported within the housing.

[0043] A ball bearing may be mounted on the housing and configured to provide a movable support for the dielectric heater arrangement within the housing.

[0044] An air gap or vacuum space may be arranged between the housing and the heating chamber structure. The at least two electrodes in operation may move, preferably rotate or linearly displace, relative to the heating chamber and / or heating chamber structure within said air gap or vacuum space.The at least two electrodes may include any of two electrode tabs or cylindrical segments with a main extension direction in the longitudinal direction. Specifically, the at least two electrodes may form plate-shaped tabs angled towards each other to form tangents of a circle around the longitudinal direction.

[0045] The at least two electrodes may be arranged at an angular distance around the longitudinal direction. The angular distance between the at least two electrodes may be less than 2 millimeters, preferably less than 1 .5 millimeters.

[0046] An angular distance between the respective centers of the electrodes may be less than 180 degrees, preferably in a range from 5 to 90 degrees, and more preferably from 10 to 45 degrees.

[0047] The at least two electrodes may include two parallelly-arranged electrode plates.

[0048] The at least two electrodes may include circular bands arranged at a longitudinal distance from each other.

[0049] A distance between the at least two electrodes may be less than 2 millimeters, preferably less than 1 .5 millimeters.

[0050] The at least two electrodes may be controlled to move from the first heating zone to the second heating zone while generating an alternating electric field for the dielectric heating during presence of a puff. For example, during a puff, specifically upon detection of the puff, the at least two electrodes may be continuously moved to a non-depleted section of the substrate while generating the alternating electric field. The at least two electrodes may be positioned before the puff starts and may move slowly along the substrate during the puff, while the oscillation circuit powers the electrodes to generate an alternating electric field to heat and aerosolize the substrate. The movement speed or field intensity may vary based on the puff strength. The at least two electrodes may stop the movement once the puff ends.

[0051] Alternatively, the at least two electrodes may be controlled to move from the first heating zone to the second heating zone before a puff occurs. For example, the at least two electrodes may be positioned at a non-depleted location of the substrate, and during the puff, specifically upon detection of the puff, the oscillation circuit may power the electrodes to generate an alternating electric field to heat and aerosolize the substrate at said non-depleted location. Once the puff ends, the at least two electrodes may be moved to the next non-depleted location. In other words, this control may ensure that the electrodes either move or generate heat, but not perform both actions simultaneously. A rotary encoders may be used for precise positioning of the electrodes.

[0052] According to a second aspect of the invention, there may be provided an aerosol-generating device comprising the heating module according to the first aspect, wherein the heating module is configured to generate aerosol by heating the aerosol-generating substrate through an alternating electric field formed between the at least two electrodes.According to a third aspect of the invention, there may be provided an aerosol-forming device comprising: a device body; a dielectric heater arrangement movably arranged in the device body, the dielectric heater arrangement including an oscillator and at least two electrodes for heating a substrate by an RF electric field formed at the at least two electrodes; a carrier structure linearly and / or rotatably movable relative to the device body, the dielectric heater arrangement attached to the carrier structure; a motor fixed to the device body, configuration to perform a linear and / or rotation motion of the carrier structure relative to the device body; and a heating chamber or heating chamber structure arranged in the device body for removably accommodating at least a portion of an aerosol-forming article, wherein departing a motion to the carrier structure moves an electric field generated by the dielectric heating arrangement along a substrate of the aerosolforming article.

[0053] The heating chamber or heating chamber structure may form an interior volume that isolates the heating chamber from the dielectric heater arrangement, the carrier structure, and the motor. The heating chamber or heating chamber structure may include a receiving opening for removably inserting the aerosol-forming article.

[0054] The at least two electrodes may include two electrode tabs or cylindrical segments. The at least two electrodes may include two parallelly-arranged electrode plates.

[0055] The aerosol-forming device may be the aerosol-generating device according to the second aspect. According to a fourth aspect of the invention, there may be provided an aerosolgenerating system comprising an aerosol-generating article accommodating an aerosolgenerating substrate, and the aerosol-generating device according to the second aspect, wherein the aerosol-generating device is configured to receive at least a part of the aerosol-generating article that accommodates the aerosol-generating substrate.

[0056] 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.

[0057] Example Ex1 . A heating module for an aerosol-generating device comprising a heating chamber comprising a first heating zone and a second heating zone, wherein the second heating zone is arranged in a distance to the first heating zone, and a dielectric heater arrangement movable relative to the heating chamber, wherein the dielectric heater arrangement comprises at least two electrodes for generating an alternating electric field, each, in operation, moving as part of the dielectric heater arrangement to heat an aerosol-generating substrate received in the first heating zone when arranged at the first heating zone and to heat an aerosol-generating substrate received in the second heating zone when arranged at the second heating zone, by the alternating electric field formed between the at least two electrodes.

[0058] Example Ex2. The heating module according to the preceding example, wherein the dielectric heater arrangement comprises an oscillation circuit configured to power the at least twoelectrodes, wherein the oscillation circuit, in operation, moves with the movable dielectric heater arrangement.

[0059] Example Ex3. The heating module according to the preceding example, wherein the oscillation circuit comprises a switching unit with a feedback loop connected between an input and an output of the switching unit, wherein the feedback loop comprises a load capacitor formed by the at least two electrodes and one or more inductors.

[0060] Example Ex4. The heating module according to any one of the preceding examples, wherein the heating chamber, in particular a heating chamber structure defining the heating chamber, has a main extension direction in a longitudinal direction, wherein the dielectric heater arrangement is movable relative to the heating chamber along the longitudinal direction and / or along a rotational direction around the longitudinal direction.

[0061] Example Ex5. The heating module according to the preceding example, a displacement mechanism configured to displace the dielectric heater arrangement relative to the heating chamber in the longitudinal direction and / or in the rotational direction by a guide movement.

[0062] Example Ex6. The heating module according to the preceding example, wherein the displacement mechanism comprises a motor and a transmission arrangement configured to translate a rotational motion from the motor into the guide movement of the dielectric heater arrangement.

[0063] Example Ex7. The heating module according to the preceding example, wherein the transmission arrangement comprises a drive gear coupled to the motor and configured to rotate the dielectric heater arrangement around the longitudinal axis by engaging with a mating internal gear connected to the dielectric heater arrangement.

[0064] Example Ex8. The heating module according to example Ex6 or example Ex7, wherein the transmission arrangement includes any one of a belt, a screw drive, a rack drive and / or a worm drive to cause guide movement in the longitudinal direction.

[0065] Example Ex8.1 . The heating module according to any one of examples Ex6 to Ex8, wherein the transmission arrangement includes a drive gear coupled to the motor, and a sleeve extending in the longitudinal direction comprising a meshing internal gear extending in a helix along the longitudinal direction, wherein the drive gear is configured to engage with the meshing internal gear of the sleeve to cause guide movement in the rotational direction and translation direction.

[0066] Example Ex9. The heating module according to any one of the preceding examples, comprising a carrier structure is movable relative to the heating chamber, wherein the dielectric heater arrangement is attached to the carrier structure.

[0067] Example Ex9.1 . The heating module according to example Ex9, wherein the carrier structure includes a planarly extending plate, preferably in form of a disk or plate.

[0068] Example Ex9.2. The heating module according to example Ex9 or example Ex9.1 , wherein the carrier structure holds the at least two electrodes to a distance to each other.Example Ex9.3. The heating module according to any one of examples Ex9 to Ex9.2, wherein a dielectric element is arranged between the at least two electrodes, wherein a relative permittivity of the dielectric element is lower than a relative permittivity of the carrier structure.

[0069] Example Ex9.4. The heating module according to example Ex9.3, wherein the dielectric element is any of a space, a volume or a coating provided on the carrier structure.

[0070] Example Ex10. The heating module according to any one of the preceding examples, wherein the heating chamber is an interior volume of the heating chamber structure for accommodating an aerosol-generating substrate, wherein the interior volume is hermetically sealed from the dielectric heater arrangement.

[0071] Example Ex10.1 . The heating module according to example Ex10, wherein the heating chamber structure forms a cylindrical body with a main axis extending in the longitudinal direction.

[0072] Example Ex10.2. The heating module according to example Ex10 or example Ex10.1, wherein the interior volume is hermetically isolated from the carrier structure and / or the displacement mechanism.

[0073] Example Ex10.3. The heating module according to any one of examples Ex10 to Ex10.2, wherein the heating chamber structure comprises walls made of a relatively low-dielectric but relatively high temperature-resistive material, for example quartz glass or PEEK.

[0074] Example Ex10.4. The heating module according to any one of examples Ex10 to Ex10.3, wherein the heating chamber structure includes a receiving opening for removably inserting an aerosol-generating article including the aerosol-generating substrate.

[0075] Example Ex10.5. The heating module according to any one of examples Ex10 to Ex10.4, a cover, such as a lid, for closing the receiving opening.

[0076] Example Ex11. The heating module according to any one of the preceding examples, comprising a DC power supply movable relative to the dielectric heater arrangement, wherein the DC power supply is configured to provide power for operating the dielectric heater arrangement.

[0077] Example Ex12. The heating module according to the preceding example, wherein an electrical interface between the DC power supply and the dielectric heater arrangement comprises flexible electric interconnection elements.

[0078] Example Ex12.1 . The heating module according to the preceding example, wherein the flexible electric interconnection elements comprise one or more of cables, flex PCBs, expandable conductive elements like coils.

[0079] Example Ex13. The heating module according to example Ex11, wherein an electrical interface between the DC power supply and the dielectric heater arrangement comprises a sliding power connector.

[0080] Example Ex13.1 . The heating module according to the preceding example, wherein the sliding power connector includes two electric tracks electrically insulated from each other, andsliding electrical contacts configured to engage with a respective one of the two electric tracks during a relative movement between DC power supply and the dielectric heater arrangement.

[0081] Example Ex13.1 .1 . The heating module according to the preceding example, wherein the electrical tracks are concentrically rings insulated from each other.

[0082] Example Ex13.1 .2. The heating module according to example Ex13.1, wherein the electrical tracks are parallel tracks.

[0083] Example Ex13.2. The heating module according to any one of examples Ex13.1 to Ex13.1.2, wherein the sliding electrical contacts comprise one or more of: pins, spring elements (leaf spring, coil spring), pogo pins, tabs, or legs.

[0084] Example Ex14. The heating module according to any one of the preceding examples, comprising a housing accommodating the heating chamber and the dielectric heater arrangement, wherein the heating chamber is attached to or formed by the housing, and wherein the dielectric heater arrangement is movably supported within the housing.

[0085] Example Ex14.1. The heating module according to the preceding example, wherein a ball bearing is mounted on the housing and configured to provide movable support for the dielectric heater arrangement within the housing.

[0086] Example Ex14.2. The heating module according to example Ex14 or example Ex14.1, wherein an air gap or vacuum space is arranged between the housing and the heating chamber, wherein the at least two electrodes in operation are moving, preferably rotating or linearly displacing, within said air gap or vacuum space.

[0087] Example Ex15. The heating module according to any one of the preceding examples, wherein the at least two electrodes include any of two electrode tabs or cylindrical segments with a main extension direction in the longitudinal direction.

[0088] Example Ex15.1. The heating module according to the preceding example, wherein the at least two electrodes are arranged at an angular distance around the longitudinal axis.

[0089] Example Ex15.2. The heating module according to example Ex15 or example Ex15.1, wherein the angular distance between the respective centers of the electrodes is less than 180 degrees, preferably in a range from 5 to 90 degrees, and more preferably from 10 to 45 degrees.

[0090] Example Ex15.3. The heating module according to any one of examples Ex1 to Ex15.2, wherein the at least two electrodes include two parallelly-arranged electrode plates.

[0091] Example Ex15.4. The heating module according to any one of examples Ex1 to Ex15.3, wherein the at least two electrodes include circular bands arranged at a longitudinal distance from each other.

[0092] Example Ex16. The heating module according to any one of the preceding examples, wherein the at least two electrodes are controlled to move from the first heating zone to the second heating zone while generating an alternating electric field for the dielectric heating during presence of a puff.Example Ex17. The heating module according to any one of examples Ex1 to Ex15.4, wherein the at least two electrodes are controlled to move from the first heating zone to the second heating zone before a puff occurs.

[0093] Example Ex18. The aerosol-generating device comprising the heating module according to any one of the preceding examples, wherein the heating module is configured to generate aerosol by heating the aerosol-generating substrate through an alternating electric field formed between the at least two electrodes.

[0094] Example Ex19. An aerosol-generating system comprising an aerosol-generating article accommodating the aerosol-generating substrate, and the aerosol-generating device according to the preceding example, wherein the aerosol-generating device is configured to receive at least a part of the aerosol-generating article that accommodates the aerosol-generating substrate.

[0095] The term "heating module" as used herein may refer to a component of an aerosolgenerating device, which heats an aerosol-generating substrate, such as a Heat-not-Burn (HnB) device or an electronic cigarette. It may be interchangeably connected or mounted within the device and can act as an aerolizer or vaporizer, depending on whether it is configured to heat a solid or liquid substrate. In some cases, it functions as a preheater positioned upstream of an aerolizer or vaporizer, warming the substrate without generating significant aerosol or vapor.

[0096] The term "aerosol" may refer to a suspension of tiny solid or liquid particles in the air.

[0097] The term "vapor" may refer to a gaseous state of an evaporated liquid aerosol-generating substrate, which later cools and condenses into an aerosol for inhalation.

[0098] The invention will be further described, by way of example only, with reference to the accompanying drawings in which:

[0099] Figure 1 is a schematic illustration of a dielectric heating aerosol-generating system according to embodiments of the disclosure;

[0100] Figure 2 is a schematic illustration of an oscillation circuit for use in the dielectric heating aerosol-generating system of Figure 1 , according to embodiments of the disclosure;

[0101] Figure 3A is a schematic illustration of an oscillation circuit showing two different phaseshifting elements, one exemplarily implemented as a resonance circuit, one exemplarily implemented as a capacitive element, to achieve a 180° phase shift;

[0102] Figure 3B is a schematic illustration of an oscillation circuit showing two different phaseshifting elements, one exemplarily implemented as a resonant circuit having parallel resonance properties, one exemplarily implemented as a capacitive element, to achieve a 180° phase shift;

[0103] Figure 4 illustrates an oscillation circuit diagram according to embodiments of the disclosure; Figures 5A-F illustrate how a Quartz-mimicking or Quartz equivalent circuit may be derived, as a non-limiting example of a parallel-resonant circuit, according to embodiments of the disclosure;Figure 6 illustrates a frequency analyzer plot of a parallel resonant circuit showing the effect of the switching frequency on the phase shift and impedance of a parallel resonant circuit;

[0104] Figures 7A to 9 illustrate different variants of a heating module for use in the dielectric heating aerosol-generating system of Figure 1 , according to embodiments of the disclosure, having a rotationally movable dielectric heating arrangement for segmented heating of the aerosol-generating substrate;

[0105] Figures 10 to 12 illustrate different variants of a heating module for use in the dielectric heating aerosol-generating system of Figure 1 , according to embodiments of the disclosure, having a linearly movable dielectric heating arrangement for segmented heating of the aerosolgenerating substrate; and

[0106] Figure 13 illustrates two different variants of a heating module for use in the dielectric heating aerosol-generating system of Figure 1, according to embodiments of the disclosure, having a linearly movable dielectric heating arrangement or linearly and rotationally movable dielectric heating arrangement for segmented heating of the aerosol-generating substrate.

[0107] The above and other features and advantages of example embodiments will become more apparent by describing in detail, example embodiments with reference to the attached drawings. However, specific structural and functional details disclosed herein are merely representative for purposes of describing example embodiments. Example embodiments may, however, be embodied in many alternate forms and should not be construed as limited to only the embodiments set forth herein. Accordingly, while example embodiments are capable of various modifications and alternative forms, embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit example embodiments to the particular forms disclosed, but to the contrary, example embodiments are to cover all modifications, equivalents, and alternatives falling within the scope of example embodiments. Like numbers refer to like elements throughout the description of the Figures.

[0108] Figure 1 is a schematic illustration of a dielectric heating aerosol-generating system 100 according to an embodiment of the disclosure. The system 100 comprises an aerosol-generating article 105 comprising an aerosol-generating substrate 110 and an aerosol-generating device 120 for heating the aerosol-generating substrate 110. The aerosol-generating device 120 comprises a housing 125 for hand-held operation, for example designed to snugly fit in a user’s hand.

[0109] The housing 125 accommodates a dielectric heating element formed by an electrode arrangement comprising a first electrode 130 and a second electrode 135 separated by a heating chamber 140 for removably receiving the article 105. The heating chamber 140 and the article 105 are sized such that the aerosol-generating substrate 110 is in contact or in close proximity to both the first electrode 130 and the second electrode 135 when received within the heating chamber 140. Moreover, the first electrode 130 and the second electrode 135 can form part of afeedback loop of an oscillation circuit 150 via a first electrical contact 160 and a second electrical contact 165. In the shown embodiment, the electrodes 130, 135 are in direct contact with the aerosol-generating article 105 having the aerosol-generating substrate 110, thereby holding the aerosol-generating substrate 110 in place.

[0110] In some embodiments, the width of the article 105 comprising the aerosol-generating substrate 110 is slightly greater than a diameter of the heating chamber, such that the distal end of the aerosol-generating substrate 110 is slightly compressed. In some embodiments, the article 105, in an initial, uncompressed form has a width between 2-20% larger than the diameter of the heating chamber. This may reduce or prevent the build-up of air between the first electrode 130 and the second electrode 135 when the aerosol-generating article 105 is received in the heating chamber 140, and decrease a distance between first and second electrodes 130, 135 for dielectric heating, thereby improving dielectric properties of a load capacitor CL and the accuracy of any measurements or determinations of the dielectric properties of the aerosol-generating substrate 110 performed by the aerosol-generating device 120.

[0111] The aerosol-generating substrate 110 may comprise tobacco-based or non-tobacco based materials having an aerosol forming material therein and one or more active agents or ingredients, such as nicotine, pharmaceutical, botanicals, flavorants, liquid substrates with one or more active agents or ingredients, or a combination thereof.

[0112] The aerosol-generating substrate 110 can also be a liquid aerosol-generating substrate and thereby the aerosol-generating article 105 can be in the form of a cartridge, capsule, pouch, token, or liquid container, and the electrodes 130, 135 can be configured as a wicking element, liquid transfer element, or capillary element for liquid transfer. For example, it is possible that first and second electrodes 130, 135 are arranged to have a liquid transfer element therebetween to expose the liquid transfer element to the alternating electric field, or first and second electrodes 130, 135 itself form a capillary structure that is part of the aerosol-generating article 105 or reaches into an inner volume of the aerosol-generating article 105 that can heat and vaporize a liquid aerosol-generating substrate 110 located in the inner volume. The first and second electrodes 130, 135 can be configured to move together along the liquid transfer element, for example a wicking element, for example but not limited to a longitudinally extending liquid transfer element. For example, the first and second electrodes 130, 135 can be embodied as parallelly arranged plates separated by a distance that forms a capillary channel, for example in a range between 0.1 mm to 2 mm, preferably 1 mm to 2 mm, depending on the desired capillary strength or rise. The first and second electrodes 130, 135 can be arranged as two matrices or arrays of pin-like, rod-like, or tab-like electrodes with opposite polarity, the two matrices or arrays interposed between each other, forming a capillary structure therebetween, for example with an average distance between neighboring pin-like electrodes being in a range between 0.1 mm to 2 mm, depending on the desired capillary strength or rise. In another variant, the wicking elementcan be a separate element that is interposed between two electrodes 130, 135, for example flat or slightly curved electrodes 130, 135.

[0113] The aerosol-generating device 120 further comprises a power supply 170 (DC power supply) and a controller 180 electrically coupled to the oscillation circuit 150. In addition, for puff-on-demand operation, a puff sensor (not shown) is arranged to detect a puff by a user, preferably arranged to be in operative communication with the controller 180. For example, the puff sensor can be a pressure or a flow sensor arranged to be in fluidic communication with an upstream airflow path that leads to the substrate 110 of the article 105 when inserted into the heating chamber 140. The puff sensor can be configured to deliver data that is indicative of a puff start, puff end, and puff intensity to the controller 180. Controller 180 can be configured to control the dielectric heating power provided by oscillation circuit 150. Instead of a puff sensor, a manual puff actuation device can also be used, for example via a user interface, such as a button or touch-sensitive screen, In this embodiment, the power supply 170 can be a rechargeable lithium ion battery, for example with one or more lithium ion battery cells, and the aerosol-generating device 120 comprises a power connector that enables the aerosol-generating device 120 to be connected to a mains power supply for recharging the power supply. Providing the aerosolgenerating device 120 with a power supply, such as a battery, enables the aerosol-generating device 120 to be portable and used outdoors or in locations in which a mains power supply is not available.

[0114] In use, power is supplied to the oscillation circuit 150 from the power supply 170 when a user activates the aerosol-generating device 120. In this embodiment, the aerosol-generating device 120 is activated by a user pressing an activation button (not shown) that can be provided on an external surface of the aerosol-generating device 120. It will be appreciated that in other embodiments, the aerosol-generating device 120 may be activated in another manner, such as on detection of a user drawing on a mouthpiece (not shown) by a puff sensor provided on the mouthpiece, or a user holding the aerosol-generating device 120, or by the user inserting an aerosol-generating article 105 to the aerosol-generating device. When power is supplied to the oscillation circuit 150, the oscillation circuit 150 generates an alternating electric field across the first and second electrodes 130, 135 to dielectrically heat the aerosol-generating substrate 110 in the heating chamber 140, releasing volatile compounds.

[0115] The controller 180 may cause dielectric heating of the aerosol-generating substrate 110 that is located between the two electrodes 130, 135 with an average dielectric heating power density in a range between 1 W / cm3to 25W / cm3, preferably between 1 ,5W / cm3and 15W / cm3per volume of substrate material during a time period of less than 15 minutes. In particular, during a heat-up phase, the average dielectric heating power density may be controlled or set to be in a range between 7W / cm3to 25W / cm3, preferably between 8W / cm3to 20W / cm3. During a target heating phase (also called maintenance heating phase) during consumption, the averagedielectric heating power density is in a range between 1W / cm3to 7W / cm3, preferably between 1W / cm3to 5W / cm3. In a non-limiting example, these power densities may be used in heat-not-burn applications.

[0116] In yet another exemplary embodiment, the aerosol-generating system 100 may be configured to provide a power density between the pair of opposing electrodes 130, 135 of between 35W / cm3and 35kW / cm3. The aerosol-generating system 100 may be configured to provide a power density between the pair of opposing electrodes 130, 135 of between 50W / cm3and 10 kW / cm3, between 50W / cm3and 2.5kW / cm3or between 50W / cm3and 1 ,25kW / cm3. The aerosol-generating system 100 may be configured to provide a power density between the pair of opposing electrodes 130, 135 of between 170W / cm3and 2.5kW / cm3, between 250W / cm3and 2.5kW / cm3or between 500W / cm3and 2.5kW / cm3. Preferably, the aerosol-generating system 100 may be configured to provide a power density between the pair of opposing electrodes 130, 135 of between 1 kW / cm3and 2kW / cm3. In a non-limiting example, these power densities may be used for heating and vaporizing liquids during a puff in a puff-on-demand application.

[0117] The aerosol-generating system 100 is also configured for measuring a dielectric property of the aerosol-generating article 105 or the aerosol-generating substrate 110 using the electrodes 130, 135 that are employed for dielectric heating of the aerosol-generating substrate 110. In some examples, the first and second electrodes 130, 135 can be used for dielectric measurements, either during the heating process (for example during the pre-heating phase or the main heating phase) or separately to the heating process. In this embodiment, the aerosol-generating system 100 can be configured to determine the presence of the aerosol-generating article 105 between the first electrode 130 and the second electrode 135. The aerosol-generating system 100 can be configured to measure a dielectric property, for example an instant value, timely-evolution, or change of a dielectric property, for example to determine whether the aerosol-generating article 105 meets specific criteria or is an authentic substrate. The aerosol-generating system 100 in this example is also configured to control the heating of the aerosol-generating substrate 110 based on the measured dielectric property of the aerosol-generating article 105.

[0118] In one exemplary embodiment, the material composition of the substrate 110 of the aerosolgenerating article 105 that can be dielectrically heated by the aerosol-generating device 120 can include tobacco powder or tobacco cut filler.

[0119] As used herein, the term “cut filler” is used to describe to 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. Preferably, the cut filler comprises at least 25% of plant leaf lamina, more preferably, at least 50% of plant leaf lamina, still more preferably at least 75% of plant leaf lamina and most preferably at least 90% of plant leaf lamina.

[0120] The cut filler suitable to be used in the present invention generally may a resemble cut filler used for conventional smoking articles. The cut width of the cut filler preferably is between 0.3millimeters and 2.0 millimeters, more preferably, the cut width of the cut filler is between 0.5 millimeters and 1 .2 millimeters and most preferably, the cut width of the cut filler is between 0.6 millimeters and 0.9 millimeters.

[0121] The aerosol-generating substrate 110 of the aerosol-generating article 105 may comprise an aerosol former. Where the aerosol-generating substrate 110 comprises cut filler, the cut filler may be soaked with the aerosol former. Soaking the cut filler can be done by spraying or by other suitable application methods. Preferably, the aerosol former comprises one or more of glycerine, for example vegetable glycerine (VG), and / or propylene glycol (PG). The aerosol former may consist of glycerine or propylene glycol or of a combination of glycerine and propylene glycol. The aerosol-generating substrate 110 may comprise any amount of aerosol former.

[0122] For example, in case a solid aerosol-generating substrate 110 is used, it may comprise between 5 weight percent aerosol former and 25 weight percent aerosol former. For example, the aerosol-generating substrate 110 may comprise between 10 weight percent aerosol former and 20 weight percent aerosol former, or between 15 weight percent aerosol former and 20 weight percent aerosol former. Preferably, the aerosol-generating substrate 110 comprises about 18 weight percent aerosol former. The weight percentages of aerosol former are given as a dry weight basis of the cut filler, with the balance being tobacco.

[0123] The aerosol-generating substrate 110 may have a density of no more than 0.45 grams per cubic centimetre, no more than 0.4 grams per cubic centimetre, no more than 0.36 grams per cubic centimetre, no more than 0.3 grams per cubic centimetre, or no more than 0.25 grams per cubic centimetre. The aerosol-generating substrate 110 may have a density of at least 0.1 grams per cubic centimetre. For example, the aerosol-generating substrate 110 may have a density of at least 0.15 grams per cubic centimetre, at least 0.2 grams per cubic centimetre, or at least 0.28 grams per cubic centimetre.

[0124] The aerosol-generating substrate 110 can have different shapes, for example a cuboid shape, rectangular parallelepiped shape, pouch-shaped, or may be cylindrically shaped, for example a solid or a hollow cylinder having a cylindrical inner opening, and is preferably substantially cylindrically shaped.

[0125] Suitable aerosol-generating substrates and articles comprising cut filler include those described in W02022 / 074240 and / or W02022 / 074158, these references herewith incorporated by reference in their entirety.

[0126] In another exemplary embodiment, the material composition of the aerosol-generating substrate 110 of the aerosol-generating article 105 that can be dielectrically heated by the aerosol-generating device 120 can include reconstituted tobacco, such as one or more sheets of homogenized tobacco material made by a cast leaf process. Where the aerosol-generating substrate 110 comprises homogenised tobacco material, the tobacco material preferably comprises particulate tobacco obtained by grinding or otherwise comminuting tobacco leaf lamina.Such a homogenised tobacco material may have a tobacco content of at least about 40% by weight on a dry weight basis or of at least about 50% by weight on a dry weight basis. In other embodiments, the homogenised tobacco material may have a tobacco content of about 70% or more by weight on a dry weight basis, such as between 70% and 80% by weight on a dry weight basis.

[0127] In yet another exemplary embodiment, the aerosol-generating substrate 110 can include a plurality of tobacco beads or granules. The beads or granules may comprise tobacco, an aerosol former and a hydrocolloid binder.

[0128] The aerosol-generating substrate 110 may comprise one or more intrinsic binders, that are tobacco endogenous binders, one or more extrinsic binders, that are tobacco exogenous binders, or a combination thereof to help agglomerate the particulate tobacco. Alternatively, or in addition, the aerosol-generating substrate 110 may comprise other additives including, but not limited to, tobacco and non-tobacco fibres, aerosol- formers, humectants, plasticisers, flavourants, fillers, aqueous and non-aqueous solvents and combinations thereof.

[0129] Suitable extrinsic binders for inclusion in the aerosol-generating substrate 110 are known in the art and include, but are not limited to: gums such as guar gum, xanthan gum, arabic gum and locust bean gum; cellulosic binders such as hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose and ethyl cellulose; polysaccharides such as starches, organic acids, such as alginic acid, conjugate base salts of organic acids, such as sodium-alginate, agar and pectins; and combinations thereof. For example, the aerosol-generating substrate 110 may comprise between 1% and 5% extrinsic binder by weight on a dry weight basis, such as between 1.5% and 3.5% extrinsic binder by weight on a dry weight basis, preferably about 2% extrinsic binder by weight on a dry weight basis. Preferably, the extrinsic binder is guar gum.

[0130] Suitable non-tobacco fibres for inclusion in the aerosol-generating substrate 110, to strengthen the material, are known in the art and include, but are not limited to: cellulose fibers; soft-wood fibres; hard-wood fibres; jute fibres and combinations thereof. For example, the aerosol-generating substrate 110 may comprise between 2% and 6% non-tobacco fibres by weight on a dry weight basis, such as between 3% and 5% non-tobacco fibres by weight on a dry weight basis, preferably about 4% non-tobacco fibres by weight on a dry weight basis. Preferably, the non-tobacco fibres are cellulose fibres.

[0131] The aerosol-generating substrate 110 may comprise an aerosol former. Preferably, the aerosol former comprises one or more of glycerine, for example VG (Vegetable Glycerine), and PG (Propylene Glycol). The aerosol former may consist of glycerine or propylene glycol or of a combination of glycerine and propylene glycol. The aerosol-generating substrate 110 may comprise any amount of aerosol former. For example, the aerosol-generating substrate 110 may comprise between 5 weight percent aerosol former and 25 weight percent aerosol former. For example, the aerosol-generating substrate 110 may comprise between 10 weight percent aerosolformer and 20 weight percent aerosol former, or between 15 weight percent aerosol former and 20 weight percent aerosol former. Preferably, the aerosol-generating substrate 110 comprises about 18 weight percent aerosol former. The weight percentages of aerosol former are given as a dry weight basis of the aerosol-generating substrate 110.

[0132] The aerosol-generating substrate 110 can have different shapes, for example a cuboid shape, rectangular parallelepiped shape, pouch-shaped, cylindrically or substantially cylindrically shaped, or may have a shape of a hollow cylinder, or substantially a hollow cylinder.

[0133] In yet another exemplary embodiment, the aerosol-generating substrate 110 can be a nontobacco-based substrate and / or a substantially tobacco free substrate. The aerosol-generating substrate 110 may be a cellulose-based substrate, for example as described in W02020 / 207733, WO2023 / 126494, and / or WO2022 / 248378, these references herewith incorporated by reference in their entirety.

[0134] Figure 2 is a schematic illustration of an oscillation circuit 250 for use in the aerosolgenerating system 100 of Figure 1 , according to an embodiment of the disclosure. The oscillation circuit 250 comprises a switching unit 260 interconnected with a resonator feedback loop 270 to provide for a self-oscillating signal to the switching unit 260. The switching unit 260 comprises a single transistor, such as a bipolar junction transistor (BJT) or a field effect transistor (FET).

[0135] The oscillation circuit 250 can further comprise a choke 280 that acts on an input to the feedback loop 270 to provide for a stimulation signal, for example a stimulation voltage. The oscillation circuit 250 also comprises a biasing unit 290 acting on the feedback loop 270 for providing a variable or controllable biasing signal, for example a biasing voltage for setting the operating conditions. In the variant shown, the feedback signal can be described as a voltage. An output voltage UOUT of the switching unit 260 is coupled to the feedback loop 270 providing a feedback switching signal in the form of an input voltage UIN to the switching unit 260. The configuration of the feedback loop 270 is such that the output signal, e.g. the output voltage UOUT of the switching unit 260 can undergo a phase change and arrives inverted at the input voltage UIN of the switching unit 260 for resonant oscillation. In other configurations, a current could be used as the feedback signal with the switching unit 260 comprising a BJT.

[0136] The feedback loop 270 is configured to be self-oscillating and will oscillate at or close to a given resonance frequency determined by the values of the passive components of the feedback loop 270. The feedback loop 270 is configured to provide a 180° phase shift from the output voltage UOUT to input voltage UIN of the switching unit 260 for oscillation, and in addition, the transistor T is configured for inverting operation.

[0137] As shown in Figures 3a and 3b, the feedback loop 270 includes a resonant circuit 272 comprising the load capacitor CL providing for a first 90° phase shift or quarter wave shift to the feedback signal. The feedback loop 270 further includes a capacitive element 274 providing for a second 90°phase shift or quarter wave shift to the feedback signal, such that the feedback signalreaching the input of the switching unit 260 is inverted and phase-shifted by 180°. The switching unit 260 is itself configured for inverted switching operation to provide the 180° phase shift between the input voltage UIN and the output voltage UOUT of the switching unit 260.

[0138] The resonant circuit 272 comprises the first and second electrodes 130, 135, together forming the load capacitor CL. When the aerosol-generating substrate 110 is situated between the first and second electrodes 130, 135, it forms part of the load capacitor CL. Importantly, the load capacitor CL is formed in the feedback loop 270, and not at a separate output or part of a separate circuitry that is connected to the switching unit 260. This enables a high-frequency oscillating voltage to be created across the electrodes of the load capacitor CL, which is needed for sufficient and efficient dielectric heating of the aerosol-generating substrate 110, without having an additional output or circuit to the already resonating feedback loop 270, which would create unnecessary losses and circuit complexity. The resonant circuit 272 may comprise a series resonator circuit or a parallel resonator circuit, examples of which are described in greater detail below.

[0139] Figure 4 illustrates an oscillation circuit 350 according to a non-limiting, exemplary embodiment of the disclosure. The oscillation circuit 350 comprises a switching unit 260 in the form of a transistor T having an intrinsic capacitance Ci. Moreover, the transistor T is configured for inverting operation, for example as an inverting common source FET, MOSFET, or a common emitter BJT. The source terminal of the transistor T can be coupled to a DC power supply via a choke 280. Between the gate terminal and source terminal of the transistor T extends a feedback loop 270. The feedback loop 270 comprises the resonant circuit 272 including the load capacitor CL having the first and second electrodes 130, 135 separated by the aerosol-generating substrate 110. In the variant shown, the resonator circuit 272 is also connected to ground via a delay line D and a capacitor C2 connected in series to the delay line DL. The oscillation circuit 350 further comprises a biasing unit 290 coupled to the gate terminal of the transistor T via the delay line DL. As shown in Figure 4, the biasing unit 290 is electrically connected between the delay line DL and the capacitor C2, so that the biasing unit 290 is somewhat isolated from the high oscillation frequency of the feedback loop 270. The delay line D could be placed elsewhere, for example somewhere else in the feedback loop 270.

[0140] The delay line D is a time delay element, for example an element that has inductive behavior, for slowing down the arriving voltage wave from the feedback loop 270 during a period of the oscillation. This allows to tune the resonant circuit 272 to a desired switching and oscillation frequency, to move the oscillation frequency away from the natural resonant frequency given by the resonant circuit 272. This ensures that oscillation circuit 350 remains in a predefined frequency operating range to provide for the requisite inverted or 90° phase shifted feedback and also to make sure that the feedback loop 270 has a low impedance to provide for a high gain, as described in greater detail below.The oscillation circuit 350 is shown with electrical contacts 160, 165 that are arranged on each side of the load capacitor CL. In some embodiments, the first and second electrodes 130, 135 may be removable from the oscillation circuit 350. The electrical contacts 160, 165 provide an electrical connection between the first and second electrodes 130, 135 and the feedback loop 270. In embodiments where the load capacitor CL is fixed within the feedback loop 270, for example, such that an aerosol-generating substrate 110 can be inserted and removed to and from a heating chamber 140 formed in between the first and second electrodes 130, 135, the electrical contacts 160, 165 provide electrical connections from the first and second electrodes 130, 135 to the next components in the feedback loop 270, e.g. inductors Li and L2.

[0141] With respect to the power supply voltage, a DC power supply voltage is provided, that is preferably in a range that is suitable for battery operation with one or more standard battery cells. Preferably, the DC power supply voltage is below 14V. For example, it is possible to operate the oscillation circuit 350 on a single battery cell, for example an 18650 battery cell (Li-Ion), or a similar battery cell, that provides for 3.2V to 3.9V. However, more preferably, a voltage of one battery cell of an exemplary 3.5V to 7V for power supply can be boosted, for example by a DC-DC converter (e.g. a boost circuit), or a voltage doubler. Alternatively or in addition, two or more battery cells can be used in series, or other configurations or arrangements that allows to increase a voltage from one or more battery cells can be used. It is also possible to have a controllable output voltage (e.g. DC-DC converter, on-off duty cycle controller, voltage regulator), to control the temperature of heating by a change to the DC supply voltage, or to boost the voltage (for example to 10-12V) for maximum power at the preheating stage, to speed up the preheating stage with the goal to reach the aerosolization temperature quickly. Control of the DC supply voltage is one way that makes it possible to rapidly change heating power despite the oscillation circuit 350 freely oscillating.

[0142] A capacitor Ci is arranged in parallel to the transistor T and therefore in parallel with the intrinsic capacitor of the transistor T (e.g. a field effect transistor). This facilitates a less voltagedependent oscillation and frequency, stabilizes the oscillation, and also improves the overall dielectric heating efficiency. Capacitance of the capacitor Ci is chosen to be larger than the maximal intrinsic capacitor Ci of transistor T at the operating conditions, so that the variation of the intrinsic transistor based on frequency, temperature, etc. has much less or negligible influence on the feedback loop 270. For example, in a non-limiting embodiment, the value can be in a range between 2pF to 100pF, more preferably in a range between 5pF and 50pF.

[0143] A capacitive element 274 comprises a capacitor C2arranged at the output or end of the resonant circuit 272. In one embodiment, capacitive element 274 comprises more than one capacitor. As described above, the capacitive element 274 has the function of providing a 90° phase shift to the feedback voltage of the feedback loop 270 with minimized losses or other undesired effects, and it therefore needs to have a high-quality factor or Q factor, preferably above1000 at 100MHz. The capacitance value for C2 of the capacitive element 274 should be relatively high as compared to Ci, for example in a range between 500pF to 100nF, more preferably between 1nF and 50nF, which leads to a low impedance of the capacitive element 274. In a variant, the capacitive element 274 can be implemented as a RC network to provide for the 90° phase shift, for example using two single-resistor-capacitor networks, having two capacitors in the feedback loop 270, each capacitor connected to ground via a resistor.

[0144] The resonant circuit 272, together with the capacitive element 274, provides for a 180° phase shift and a voltage gain from the output voltage UOUT to the input voltage UIN, and the transistor T (for example a FET, preferably an LDMOS) is configured for inverting operation, thereby also providing for another 180° phase shift. This results in a resonant or close-to resonant oscillation and an amplified voltage UL across the electrodes 130 and 135 of the load capacitor CL, as compared to the DC supply voltage. When operating close to resonance, the resonant circuit 272 behaves inductively, having a high Q factor. Furthermore, the feedback loop 270 is impedance-matched with the transistor T, at an impedance of approximately 500mQ to 8Q, preferably around 2Q, to provide for a high gain, leading to an increased voltage across the load capacitor CL. Also, preferably, this gain is achieved without the use of an additional voltage or current amplifying passive element, such as a tapped inductor or a transformer located in the circuit that forms the feedback loop 270, as such passive elements are difficult and lossy to operate and design at frequencies greater than 50 MHz. Preferably, the impedances of the resonant circuit 272 and the capacitor C2 add up to match the impedance of the transistor T, more preferably the resonant circuit 272 is substantially impedance-matched with the transistor T.

[0145] The combination of the capacitor Ci, the feedback loop 270 with the resonant circuit 272 and the capacitive element 274 can also be described as a bandpass filter or Pi or TT network that generates a 180° phase shift. In the illustrated embodiment, the resonant circuit 272 of the feedback loop 270 is not connected to ground, but is suspended with ends at each capacitor Ci and C2, thereby not having a direct ground connection at either end of resonant circuit 272, reducing stray elements and ground influences for more predictable operation.

[0146] At the operating frequency, the resonant circuit 272 including the load capacitor CL acts as an inductive load providing a first 90° phase shift, also referred to as a quarter-wave phase shift, and the capacitive element 274 exemplarily including a high quality factor capacitor C2 connected to ground, provides for a second 90° phase shift or quarter-wave phase shift.

[0147] The oscillation circuit 350 can be described or characterized as a Pierce oscillation circuit with a modified feedback loop 270, where the physical Quartz element is replaced by a Quartzmimicking or Quartz electric equivalent circuit to provide for an inverting feedback to the switching unit 260 that also operates in an inverted mode. In some embodiments, the resonant circuit 272 can be based on other resonant feedback loop oscillation circuit configurations, for example, but not limited to, the use of a Colpitts or Hartley type oscillator, using an inverting transistor T. Inother embodiments, the circuit feeding the load capacitor CL with electrodes 130, 135 with a high-frequency alternative voltage could include a signal oscillator, an RF amplifier, and an optionally an impedance matching circuit to connect to the load capacitor, or the load capacitor can be part of the impedance matching circuit.

[0148] Figures 5A to 5F illustrate how a Quartz-mimicking or Quartz equivalent circuit may be derived using a variant of a parallel resonator circuit PRC, that can serve as an exemplary and non-limiting embodiment as a resonant circuit 272. A Quartz-mimicking or Quartz equivalent circuit can have a parallel resonance at a given frequency. This can be seen as a circuit with two branches, one representing the mechanical oscillation and one representing the electric behavior, as illustrated in Figures 5A and 5B. The mechanical oscillation is represented by a first branch having the load capacitor CL and an inductor LTOT. The electric oscillation is represented by a second branch arranged in parallel to the first branch, having a capacitor CE. This configuration leads to a series connection of two capacitors CL and CE (seen around the loop formed by the two branches) so that the capacitor CE will decrease the overall capacitive value of the equivalent circuit. Also, this circuit provides an inductive phase shift of about 90° within certain defined frequency range.

[0149] Referring now to Figure 5C, one branch of the parallel resonator circuit PRC comprises an inductor LTOT and the load capacitor CL connected in series of the first branch. This branch can be improved by splitting the LTOT into two inductors Li and L2on each side of the load capacitor CL, as shown in Figure 5D, to provide a split inductor or split-coil design and a more symmetric application of the voltage UL across the load capacitor CL, thereby improving dielectric heating efficiency. However, in some variants, only one inductor is used. To provide for parallel resonance, the capacitor CE of the second branch can be replaced with an inductor (as shown in Figure 5F) due to the capacitor CE‘S minimal capacitive effect on the capacitor CL.

[0150] In a non-limiting example starting from the split inductors Li and L2of the resonant circuit 272 of Figure 5D, the inductors Li and L2can be mutually magnetically coupled to form a mutual inductance M, thereby forming the parallel circuit branch or second branch of the resonant circuit 272, as shown in Figure 5E. The mutual magnetic coupling can be achieved by the close proximity of the two inductors Li and L2with alignment of winding axis of the coils, or by use of a mutual magnetic core, or both. This has the advantage of providing a parallel-resonator circuit PRC without the use of additional wires for the second branch, and without additional windings or separate magnetic cores for a second parallelly-arranged inductor. This also allows for a symmetric arrangement that favors and facilitates the inductive coupling of the two inductors Li, L2and the balancing of the voltage UL over the load capacitor CL. The symmetry of the two branches in either direction with first branch Li - CL - L2and the second branch with an inductor LE, representing the two mutual inductance values, facilitates the symmetrical balancing of thevoltage over the electrodes of the load capacitor CL, which consequently reduces losses created at the load capacitor CL. This split inductor principle can also be referred to as a split coil resonator.

[0151] The resonant circuit 272 could also be implemented as shown in Figure 5F, where the mutual inductance M (seen two times due to the mutuality) is replaced by a separate inductive element, for example the inductor LE.

[0152] The values of components in this resonant circuit 272 are preferably chosen to be in the following exemplary and non-limiting ranges. The LTOT can be a range between 10nH to 50nH, more preferably between 15nH and 40nH, which is the equivalent of Li plus L2, LE could be in a range between 7nH and 30nH, more preferably between 10nH and 20nH, and the value of the load capacitor can be in a range between 0.5pF to 5pF, more preferably between 1 pF to 3pF.

[0153] The resonant circuit 272 can be configured as another type of tank circuit providing for the 90° phase shift in a given frequency range. In one embodiment, the resonant circuit 272 can be implemented as a series resonant circuit, having the load capacitor CL connected in series with one or more inductive elements, configured to provide for an inductive response or 90° phase shift in a given frequency range that is suitable for dielectric heating.

[0154] To have a proper inverting effect and a 180° phase shift on the feedback loop 270 between UIN and UOUT, the oscillation circuit 350 must remain in a frequency operating range where the behavior of the feedback loop 270 is highly inductive. In the example comprising a parallel resonator circuit (PRC), the series resonance frequency fsER (resonant frequency) is relatively close to the parallel resonance frequency fpAR (antiresonant frequency). If the oscillation frequency fs of the PRC exceeds the parallel resonance frequency fPAR, the feedback loop 270 will act capacitively and not provide the necessary phase inversion to the loop 270. Furthermore, the equivalent impedance of the circuit will increase to an extent that is too high for efficient dielectric heating as not providing for the requisite gain.

[0155] Oscillations in the feedback loop 270 will be naturally drawn towards the parallel resonance (antiresonant) frequency of the resonant circuit 272. However, the addition of the delay line D can introduce a slight time delay limiting the oscillation frequency below the parallel resonance frequency. Figure 6 shows a frequency analyzer plot of an exemplary resonant circuit 272, specifically a plot of a parallel resonator circuit PRC showing the relationship between the oscillation frequency (with a series resonance at 855 MHz and a parallel resonance at 1.246 GHz), the phase shift across the PRC (with a relatively flat inductive 90° frequency response between the two resonant frequencies) and the effective impedance of the PRC. More specifically, it can be seen from Figure 6 that the 90° phase shift starts dropping before the parallel resonance frequency fPAR is reached. After the parallel resonance frequency f PAR, the phase shift response drops below 0° to capacitive behavior and the impedance is very high, e.g. 2.4kQ. The ideal operating frequency range is closer to the series resonance frequency fsER where the phase shift is still 90° and the impedance response is low, preferably an impedance that is less than 2Q, morepreferably less than 1Q. The parallel resonance frequency fpAR can be above 1GHz, e.g. 1GHz to 1.5GHz, while the actual switching frequency fs can be below 1GHz, and this lower switching frequency is caused by the delay line D .

[0156] Ideally, the oscillation frequency fs should be set to be below the parallel resonance frequency fpAR but above the series resonance frequency fsER, to make sure that two conditions are fulfilled, firstly (i) that the resonant circuit 272 behaves inductively to provide a 90° phase shift, and secondly (ii) to make sure that the impedance of the resonant circuit 272 (an therefore the feedback loop 270) is low, as illustrated in the graphs of Figure 6. For example, a resulting impedance of the feedback loop 270 at the oscillation frequency fs of the oscillation circuit can be in a range of approximately 100mQ to 2Q. Preferably, the delay line DL is configured such that the oscillation frequency fs is closer to the series resonance frequency fsER than to the parallel resonance frequency fPAR, thereby maintaining a low resonant circuit impedance while operating at a frequency range where the resonant circuit provides the 90° phase shift. The time delay caused by the delay line D needs to be relatively short, as the series resonance and the parallel resonance of a parallel oscillating circuit PRC are close to each other, relative to the overall frequency range. Preferably, the delay caused by the delay line D that acts of the feedback loop 270 should be in a range between 5% to 35% of the period of the parallel resonance frequency fpAR, providing that the above two conditions (i) and (ii) are fulfilled. In an embodiment, the delay caused by the delay line D that acts on the feedback loop 270 is in a range between 35% and 90% of a difference between the period of the parallel resonance frequency fpAR and the period of the series resonance frequency fsER, again providing that the above two conditions (i) and (ii) are fulfilled, more preferably a range between 50% and 85%. For example, taking the illustration of Figure 6 and as a non-limiting numerical example, assuming that a parallel resonance frequency fpAR is at 1.25 GHz, therefore having a period of 800ps (picoseconds), and a series resonance is frequency fsER at 855MHZ, and therefore a period of 1169ps, there is a difference of 369ps between the period of fpAR and fsER. The time delay caused by the delay line D can be in the above range, for example at 70% of the period difference between fPAR and fsER, thereby being 258ps, thereby making sure that the feedback loop 270 has the desired inductive behavior and low impedance that is necessary to provide inverting feedback at high gain.

[0157] Preferably, the delay line DL is implemented as a meandering conductive element having dominantly inductive behavior, for example a meandering element having from two (2) to twelve (12) meandering branches, more preferably from three (3) to eight (8) meandering branches. Such implementations exhibit minimal stray inductive and capacitive behavior. Various delay line structures can be used to provide the desired function, for example an Omega-shaped coil, single planar coil, flat inductor, wavy line, zig-zag line, or a sawtooth line. It is also possible to provide the required delay line functionality by a specific transmission line design. For example, it is possible that the physical element of the delay line D is implemented as a conductor in a printedcircuit board, for example implemented as a microstrip patch antenna. In some embodiments, a low-pass filter may be used as the delay line D , however this will have an impact on the shape of the oscillating voltage, whereas a delay line D that provides for a short time delay by inductive effect will not impact the wave shape. In the embodiment illustrated in Figure 4, the delay line DL is placed between the feedback loop output of the resonant circuit 272 and the capacitive element 274, but other arrangements are also possible.

[0158] The oscillation circuit described herein is exemplary only, and other types of oscillation circuits can be used, for example other types of resonant oscillator circuits where the load capacitor for causing the dielectric heating is part of the resonant feedback loop, or signal oscillators that are connected to an amplifier and an impedance matching circuit to apply an RF voltage to the electrodes for causing the alternating electric field for dielectric heating. Forced oscillators or forced oscillation circuits may also be used. The given embodiments of the oscillation circuits of Figure 4 are therefore merely exemplary and not intended to limit the invention.

[0159] Dielectric heating arrangement

[0160] Figures 7 to 13 schematically show embodiments of a heating module 700 for the aerosolgenerating device 120 using a movable dielectric heating arrangement 712 for zoned or sectional (i.e. segmented) heating of the aerosol-generating substrate 110. That is, unlike the embodiments where the aerosol-generating substrate 110 is heated by a statically positioned electrode arrangement relative to the heating chamber 140, sized and designed to heat the entire or nearly the entire substrate simultaneously, the following configurations allow for zoned or sectional heating of the aerosol-generating substrate 110 by an alternating electric field moving along the heating chamber 140. The movement of the dielectric heating arrangement 712 relative to the heating chamber 140 can be a rotational movement, linear movement, or a combination of both.

[0161] The heating chamber 140 is a receiving space for receiving the substrate 110 or at least a part of the article 105 having the substrate 110, and for heating the substrate 110. In the herein preferred embodiments, the heating chamber 140 forms an interior volume of a rigid heating chamber structure 141. The heating chamber structure 141 is configured to removably receive an aerosol-generating article 105 or substrate 110 via an opening of the housing 125 and to support or hold same in place when received. The heating chamber structure 141 can be integrally formed with the housing 125, or is a separate unit movably or non-movably arranged in the housing 125.

[0162] The heating chamber structure 141 may have the form of a cup, for example but not limited to a cylindrical cup, as shown in Figures 7A and 9. The heating chamber structure 141 has a sleeve portion 142, for example but not limited a cylindrical or tubular element, with walls made of a material with relatively low relative permittivity but relatively high temperature-resistive material, for example but not limited to PEI, PEEK or quartz glass. The heating chamber structure 141 further comprises a bottom end 143 for closing an open bottom end of the sleeve portion 142.In the embodiment shown in Figures 7 to 8, the heating chamber structure 141 is embodied as a cylindrical carrier element for holding the first and second electrodes 130, 135. As shown in Figure 7A, the first and second electrodes 130, 135 are integrally formed with the sleeve portion 142. In other examples, the electrodes 130, 135 could be attached onto the sleeve portion 142, either on an inner surface of the sleeve portion 142 directed towards the heating chamber 140 or on an outer surface thereof. In these embodiments, the cylindrical carrier element is operable to move, for example rotate, relative to the housing 125 and together with the electrodes 130, 135.

[0163] In a variant of the heating chamber structure 141 as shown in Figure 9 by contrast, the heating chamber structure 141 is secured and thus not movably attached to the housing 125, and the electrodes 130, 135 can move relative to the heating chamber structure 141.

[0164] A. Rotational Movement

[0165] Figures 7A to 9 show an embodiment where the dielectric heating arrangement 712 can be rotated along a rotational direction R around a main direction (longitudinal direction L) of the heating chamber 140, enabling the alternating electric field generated by the first and second electrodes 130, 135 to rotate around the heating chamber 140, thereby heating the aerosolforming substrate 110 at different heating zones HZ1 to HZ3 via HZ2, as shown in Figure 7B.

[0166] As shown in Figure 7A, the aerosol-generating device 120 is composed of two units, a first unit 710 and a second unit 720, that are moved relative to each other during operation, preferably heating operation. The first unit 710 comprises the dielectric heating arrangement 712 and a carrier structure 714 carrying the dielectric heating arrangement 712. In the present example, the carrier structure 714 is disk- or plate-shaped. The disk may have a diameter that is smaller than an inner diameter of the housing 125. In the present example, the first unit 710 further comprises the heating chamber structure 141 .

[0167] The dielectric heating arrangement 712 comprises at least the first and second electrodes 130, 135 that are non-movably attached to each other by the carrier structure 714. Besides the first and second electrodes 130, 135, other RF components that operate under radio frequency are attached to the carrier structure 714 to form a uniformly movable RF arrangement. These RF components include some or all components of the oscillation circuit 150, 250, 350, specifically the switching unit 260 and the two inductors Li and L2, or alternatively just one inductor L. The electrodes 130, 135 forming the load capacitor CL and the two inductors Li and L2are connected between an input and an output of the switching unit 260 to form a feedback loop 270. In other examples, an oscillator may be used to generate an alternating electric signal that is applied to the load capacitor CL via the two inductors Li and L2. With this arrangement, not only the electrodes 130, 135 will be moving relative to the substrate 110, but all the components of the RF circuit will be moving with the electrodes 130, 135, such that the RF circuit does not undergo any geometric changes that would impact the operation of the oscillation circuit 150, 250, 350. Theswitching unit 260, inductors Li and L2, and the interconnections therebetween can be filled with a non-conductive filler, or can be encapsulated by a shielding structure, or both.

[0168] The second unit 720 comprises the housing 125, and other electrical components of the aerosol-generating device 120 not operated at radio frequency, including the power supply 170 and the controller 180, and in some configurations, a DC / DC converter 172 or other power control unit that can be connected between the power supply 170 and the switching unit 260.

[0169] Figure 7C shows a variant where the electrodes 130, 135 protrude upwardly from the rotatable carrier structure 714 as shown in Figure 7A, but contrary to the embodiment shown in Figures 7A and 7B, where the electrodes are arranged in an angular (azimuth) distance to each other, the electrodes 130, 135 are arranged at a radial distance from each other along the same radial direction. The surfaces of the electrodes 130, 135 can be arranged to be parallel to each other. In terms of the aerosol-forming substrate 110, it has a hollow cylinder (as shown in Figure 7B but with somewhat thinner walls), where the first electrode 130 would turn around the outer circumference of the substrate 110, while the second electrode 135 would turn around the inner circumference of the substrate 110. When an RF alternating voltage is applied to the electrodes 130, 135, the electric field would be substantially homogeneous between the two parallelly-arranged electrodes, heating through the tubular or cylindrical substrate wall.

[0170] A displacement mechanism 800 is arranged between the first and second units 710, 720 configured to displace the dielectric heater arrangement 712 relative to heating chamber 140 in the rotational direction R by a guide movement.

[0171] As illustrated in Figures 8A and 8B, the displacement mechanism 800 comprises a motor 810, for example a stepper motor, and a transmission arrangement 820 configured to translate rotational motion from the motor 810 into the rotational movement of the dielectric heater arrangement 712. The transmission arrangement 820 comprises a drive gear 822 coupled to the motor 810 and configured to rotate the dielectric heater arrangement 712 via engagement with a mating internal gear 824. In the preset example, the internal gear 824 is formed within the carrier structure 714. In other examples, the internal gear 824 is firmly connected to the carrier structure 714, for example by welding, brazing, snap-lock, screw attachment, etc. In the present example, the motor 810 and the drive gear 822 form part of the second unit 720, while the internal gear 824 formed within the carrier structure 714 is part of the first unit 710. Specifically, a ball bearing 830, for example but not limited to a cylindrical roller bearing, or other rotational bearing structure like rotating or swivel washer can be mounted at the inner bottom of the housing 125, providing a rotational support for the dielectric heater arrangement 712. This support can facilitated through a center support axis 840 that extends along the longitudinal direction L and connects to the carrier structure 714.

[0172] The power supply 170 forms part of the second unit 720 and is connected to the dielectric heater arrangement 712 by an electrical interface 850. In a first variant, as shown in Figure 8A,the electrical interface 850 includes a sliding power connector 852 with two concentrical electric tracks 853 (853a, 853b) which are electrically insulated from each other. It also comprises sliding contacts 854 (854a, 854b), each configured to slidably engage with one of the respective electric tracks 853 during rotation of the dielectric heater arrangement 712. The electrical tracks 853 form concentric rings around the longitudinal direction L attached to or integrated on the carrier structure 714. The sliding electrical contacts 854 are shaped as pins, spring elements (leaf spring, coil spring), pogo pins, tabs, or legs. The sliding electrical contacts 854 are held by a contact holder 855. The contact holder 855 electrically connects the sliding electrical contacts 854 to a plus (+) and minus (-) poles of the power supply 170. Such configuration of the electrical interface 850 allows for the first unit 710 to be able to rotate freely more than one full rotation without limitations. In a second variant, as shown in Figure 8B, the electrical interface 850 includes flexible electric interconnection elements 856 (856a, 856b). These are, in the present example, implemented as cables or wires, for example but not limited to cables or wires having an elongated and / or coiled wire surrounded by an electrical insulator, having a length and / or arrangement that allows for a rotational motion between the first unit 710 and the second unit 720. In such variant, the first unit 710 may not spin more than one full rotation.

[0173] Because the electric connection between the first unit 710 and the second unit 720 is solely a DC power supply connection, as illustrated above, the relative motion departed between the first and second units 710, 720 does only affect the DC electric connection, which is much less fragile and less subject to change that could impact the operation, as compared to the RF oscillation circuit 150, 250, 350 that powers the electrodes 130, 135,

[0174] In the present variant, the electrodes 130, 135 form cylindrical segments arranged at an angular distance around the longitudinal axis L. In other examples, the electrodes 130, 135 are formed as plate-shaped tabs angled towards each other to form tangents of a circle around the main axis. In the example shown in Figures 7A and 7B, an angular distance a between the respective centers of the electrodes 130, 135 is roughly 30 degrees. Notably, the number of electrodes 130, 135 is not limited to two. Despite, any number of electrodes 130, 135 greater than two could be used, as long as there are in pairs. Some of them may be connected in parallel, and / or electrode pairs may be formed that are controlled independently of others. However, the variant is not limited to such an electrode arrangement. Any other electrode arrangements as disclosed herein may be used. Preferably, a distance (in the present variant angular distance d) between electrodes 130, 135 is less than 2mm, preferably less than 1.5mm.

[0175] Figure 9 shows an upper part of an aerosol-generating device 120 according to an embodiment, with a variant of the heating chamber structure 141 , where the heating chamber structure 141 is configured as a cylindrical cup 940 that incorporates a flange structure 942 that extends radially outward, forming a contact surface that ensures a hermetic seal, for example together with a washer or a seal ring, against the inner surface of the housing 125. This designcreates an interior volume of the heating chamber structure 141 , called heating chamber 140, that is hermetically separated from the dielectric heater arrangement 712 and the electrode displacement mechanism 800. The cylindrical cup 940 is secured within an upper opening 126 of the housing 125 through a friction fit, form fit, press-fit, thread, adhesion, or an additional locking mechanism. In some embodiments, the heating chamber 140 and the housing 125 form an integral unit.

[0176] A gap 943 is formed between the cylindrical walls of the housing 125 and the cylindrical cup 940. Within this gap 943, the electrodes 130, 135, along with, in this example, the sleeve portion 142 in form of a cylindrical carrier element , are rotatable movably accommodated, allowing for the rotational movement, and in some examples, linear movement. With an aerosol-generating substrate 110 inserted into the heating chamber that is formed by cylindrical cup 940, the electrodes 130, 135 can be positioned to heat a segment of the cylindrical aerosol-forming substrate 110 by subjecting it to an RF electric field that traverses the cylindrical cup 940.

[0177] In the present variant, the electrodes 130, 135 include two parallelly-arranged electrode plates with the substrate 110 arranged therebetween. However, the variant is not limit to such an electrode arrangement. Any other electrode arrangements as disclosed herein may be used.

[0178] B. Linear Movement

[0179] Figures 10 to 13 show embodiments where the dielectric heating arrangement 712 can be moved along the main direction (longitudinal direction L) of the heating chamber 140, enabling the alternating electric field generated by the first and second electrodes 130, 135 to move along the heating chamber 140, thereby heating the aerosol-forming substrate 110 at different heating zones HZ1 to HZ3 via HZ2, as shown in Figure 10. In the present non-limiting example, the heating chamber 140 is sealed or insulated from the interior of device 120, by a heating chamber structure 141 which interior volume is solely connected to the external environment via an air inlet 1001 and mouthpiece outlet 1002. The heating occurs by the electric field traversing the low-dielectric walls of the heating chamber structure 141 .

[0180] In contrast to the transmission arrangement 820 depicted in Figures 8A and 8B, rotational movement of the motor 810 is converted into linear movement.

[0181] In a first variant illustrated in Figures 10 and 11 , the transmission arrangement comprises a belt 1022 tensioned between two axes along the longitudinal direction L and extending parallel to the heating chamber 140. The belt 1022 is firmly connected to the carrier structure 714. The belt 1022 is configured to move linearly upon activation of the motor 810. The belt 1022 further comprises two parallel electric tracks 1053 (1053a, 1053b), which are structured to engage with the sliding electrical contacts 854 (854a, 854b) during the linear movement of the belt 1022. This engagement establishes an electrical connection that supplies electrical power to the dielectric heating arrangement 712.In a second variant illustrated in Figure 12, a screw drive mechanism (screw drive 1222) instead of the belt 1022 is used to convert rotational motion of the motor 810 into linear movement. The screw drive 1222 comprises a threaded shaft 1223 and a mating component (nut 1224) firmly connected to the carrier structure 714. The nut 1224 and the carrier structure 714 carrying the dielectric heating arrangement 712 with the electrodes 130, 135 move linearly upon activation of the motor 810. In such a configuration, the electrical interface 850 includes flexible electric interconnection elements 856, for example cables or wires. For the embodiment shown in Figure 10, electric tracks 1053 and sliding electric contacts 854 can also be replaced by flexible interconnection with cables or wires, nut 1224 and carrier structure 714 can be linearly guided with a track structure (not shown) that can extend along the direction L, to make sure that the rotation of threaded shaft 1223 does not rotate the nut 1224.

[0182] In a third configuration shown in Figure 13, a rack drive mechanism 1322 (also called rack gear or rack drive) replaces the screw drive 1222 to convert the rotational motion of motor 810 into linear movement to move electrodes up or down in the direction L passed a substrate 110 that can be located inside the heating chamber 140. The rack gear 1322 comprises a drive gear 1323, for example a rotating pinion gear, and a linearly movable rack 1324 with a meshing internal gear, which is firmly attached to the carrier structure 714. When the motor 810 is activated, the rotation of the drive gear 1323 drives the rack 1324, causing the carrier structure 714, which supports the dielectric heating arrangement 712 with the electrodes 130, 135, to move linearly up and down along the direction L.

[0183] In the present variant, the electrodes 130, 135 include circular bands arranged in a longitudinal distance from each other, for a cylindrical aerosol-forming substrate 110 that is located in a cylindrical heating chamber 140. However, the variant is not limit to such an electrode arrangement. Any other electrode arrangements as disclosed herein may be used.

[0184] A dielectric element 1310 is positioned between the electrodes 130 and 135, with a relative permittivity lower than that of the carrier structure 714. In this example, the dielectric element 1310 is an air gap integrated into the carrier structure 714. The carrier structure 714 may be composed of, PEI, PEEK (Polyetheretherketone), or low dielectric glass such as Quartz glass. In a preferred embodiment, PEEK is used which typically has a relative permittivity ranging from 3.1 to 3.8, depending on its formulation and the frequency of the applied electric field. In contrast, air has a relative permittivity close to 1, which is significantly lower than that of PEEK. This lower relative permittivity of the dielectric element 1310 helps to concentrate the electric field inward.

[0185] Another aspect, which could be implemented, for example, in the embodiment shown in Figure 13, is the provision of a heating chamber structure 141 that separates the dielectric heating arrangement 712 from the heating chamber 140, by the virtue of the RF electric field generated by the electrodes 130, 135 able to traverse the walls of the heating chamber structure 141 without the need of having any heating electrodes on the walls of heating chamber structure 141 , or insidethe substrate 110 itself. In this way, a hermetic sealing of the heating chamber 140 relative to the electrodes 130, 135 and other electrical components of the aerosol-generating device 120 can be achieved.

[0186] In another aspect, the aerosol-forming article 105 can be inserted to heating chamber 140 in various ways, for example by insertion to the front by pivoting mouthpiece 1003 away to free up the insertion opening.

[0187] C. Combination of both linear and rotational movement.

[0188] In another embodiment, the transmission arrangement is provided to convert the rotational motion of the motor 810 into both linear movement along and rotary movement of the dielectric heating arrangement 712 around the longitudinal direction L. In such configuration, the rack drive mechanism 1322 includes, for example, a sleeve with a helical internal gear, instead of the linearly movable rack 1324, as further indicated with dashed lines in Figure 13. In such configuration, the electrodes 130, 135 may be formed as cylindrical segments, tabs or parallelly-arranged electrode plates.

[0189] The herein presented embodiments may be used to perform a puff-on-demand operation for aerosolization of substrate material. For example, the electrodes 130, 135 forming an electrode pair can be moved to a location of the substrate 110 that has not yet been depleted, and during a puff, that can be detected by a puff sensor or puff detector that is in operative connection with the controller 180 of the aerosol-generating device 120, the oscillation circuit 150, 250, 350 can be powered to generate the alternating electric field between the electrodes 130, 135 and to dielectrically heat and aerosolize the aerosolisable material at the given location of the substrate 110. Once the puff has stopped, the electrodes 130, 135 can be moved to the next location of the substrate material that has not yet been depleted, ready for the next puff. For precise positioning of the electrodes, rotary encoders (not shown) that are coupled with motor 810 could be used.

[0190] Another puff-on-demand aerosolization could involve the moving of the electrodes 130, 135 during a puff, to make sure that the electrodes 130, 135 are constantly moved to a non-depleted section of the substrate 110 while they are causing the alternating electric field for dielectric heating. For example, electrodes 130, 135 can be positioned at a given location of the substrate 110 before the puff has started, and upon detecting the puff by the puff sensor or puff detector, the electrodes 130, 135 are slowly moved along the substrate 110, for example at a speed in a range between 0.1 mm per second to 1.5 mm per second, and simultaneously, the oscillation circuit 150, 250, 350 can be powered to generate the alternating electric field between the electrodes 130, 135 and to dielectrically heat and aerosolize the aerosolisable material at a moving location along the substrate 110. It is also possible that the speed of motion or the intensity of the alternating electric field is varied based on a puff strength, e.g. at a moment where the puff is stronger, the electrodes move faster or the alternating electric field is made strongeras compared to a moment where the puff is weaker. Once the puff has stopped, both the moving of electrodes 130, 135 can be stopped from moving, and at the same time the electrodes 130, 135 are stopped from being supplied by an RF voltage by the oscillation circuit 150, 250, 350, controlled by the controller 180 of device 120.

Claims

Claims1. A heating module for an aerosol-generating device comprisinga heating chamber comprising a first heating zone and a second heating zone, wherein the second heating zone is arranged in a distance to the first heating zone, anda dielectric heater arrangement movable relative to the heating chamber,wherein the dielectric heater arrangement comprises at least two electrodes for generating an alternating electric field, each, in operation, moving as part of the dielectric heater arrangement to heat an aerosol-generating substrate received in the first heating zone when arranged at the first heating zone and to heat an aerosol-generating substrate received in the second heating zone when arranged at the second heating zone, by the alternating electric field formed between the at least two electrodes,wherein the dielectric heater arrangement comprises an oscillation circuit configured to power the at least two electrodes, wherein the oscillation circuit, in operation, moves with the movable dielectric heater arrangement.

2. The heating module according to the preceding claim, wherein the oscillation circuit comprises a switching unit with a feedback loop connected between an input and an output of the switching unit, wherein the feedback loop comprises a load capacitor formed by the at least two electrodes and one or more inductors.

3. The heating module according to any one of the preceding claims, wherein the heating chamber has a main extension direction in a longitudinal direction, wherein the dielectric heater arrangement is movable relative to the heating chamber along the longitudinal direction and / or along a rotational direction around the longitudinal direction.4 The heating module according to the preceding claim, a displacement mechanism configured to displace the dielectric heater arrangement relative to the heating chamber in the longitudinal direction and / or in the rotational direction by a guide movement.

5. The heating module according to the preceding claim, wherein the displacement mechanism comprises a motor and a transmission arrangement configured to translate a rotational motion from the motor into the guide movement of the dielectric heater arrangement.

6. The heating module according to the preceding claim, wherein the transmission arrangement comprises a drive gear coupled to the motor and configured to rotate the dielectric heater35 / 36arrangement around the longitudinal axis by engaging with a mating internal gear connected to the dielectric heater arrangement.

7. The heating module according to claim 5 or claim 6, wherein the transmission arrangement includes any one of a belt, a screw drive, a rack drive and / or a worm drive to cause guide movement in the longitudinal direction.

8. The heating module according to any one of the preceding claims, comprising a carrier structure is movable relative to the heating chamber, wherein the dielectric heater arrangement is attached to the carrier structure.

9. The heating module according to any one of the preceding claims, wherein the heating chamber is an interior volume of a heating chamber structure for accommodating an aerosol-generating substrate, wherein the interior volume is hermetically sealed from the dielectric heater arrangement.

10. The heating module according to any one of the preceding claims, comprising a DC power supply movable relative to the dielectric heater arrangement, wherein the DC power supply is configured to provide power for operating the dielectric heater arrangement.11 . The heating module according to the preceding claim, wherein an electrical interface between the DC power supply and the dielectric heater arrangement comprises flexible electric interconnection elements.

12. The heating module according to claim 10, wherein an electrical interface between the DC power supply and the dielectric heater arrangement comprises a sliding power connector.

13. The heating module according to any one of the preceding claims, comprising a housing accommodating the heating chamber and the dielectric heater arrangement, wherein the heating chamber is attached to or formed by the housing, and wherein the dielectric heater arrangement is movably supported within the housing.

14. The heating module according to any one of the preceding claims, wherein the at least two electrodes include any of two electrode tabs or cylindrical segments with a main extension direction in the longitudinal direction.

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