Microwave Aerosol Heater With Faraday Cage for Uniform Heating

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Solution Overview

Problem

Existing aerosol generating apparatuses face issues with slow heating due to contact-based methods and shallow energy penetration, leading to non-uniform heating and thermal strain in device components.

Innovation Solution

An aerosol-generating apparatus using a microwave heater and a Faraday cage assembly to irradiate aerosol-generating materials, allowing non-contact heating with deeper energy penetration and uniform heating, while preventing microwave transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If resistive heating or inductive heating is used, then heating can be achieved, but heating speed is slow and energy penetration is shallow

Engineering Contradiction:
Improveheating speedVSAvoidenergy penetration depth
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The patent replaces contact-based mechanical heating systems (resistive heating elements or inductive coils) with a microwave heating system. The microwave generator emits electromagnetic waves that directly penetrate and heat the aerosol-generating material through dielectric heating, eliminating the need for physical contact and enabling deeper, more uniform energy penetration throughout the material volume.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the heating mechanism from low-frequency electrical or magnetic fields to high-frequency microwave radiation (typically 2.45 GHz). This parameter change in electromagnetic frequency enables much faster heating rates and deeper penetration into the aerosol-generating material, transforming the heating process from surface-level to volumetric heating.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If contact-based heating methods are used, then heating can be achieved, but heating uniformity is poor

Engineering Contradiction:
Improveheating uniformityVSAvoidheating system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex contact-based heating systems with a microwave heating system that inherently provides uniform volumetric heating. The microwave fields penetrate throughout the material simultaneously, heating all regions uniformly without the gradient issues associated with contact heating, where heat must conduct from the surface inward.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent transitions from surface-based heating (two-dimensional heat transfer at the material surface) to volumetric heating (three-dimensional energy distribution throughout the material). Microwave radiation penetrates and deposits energy throughout the entire volume of the aerosol-generating material, achieving uniform heating without requiring complex multi-element heating systems.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Temperature

If heating elements are used, then heating can be achieved, but thermal strain occurs due to repeated thermal expansion and contraction

Engineering Contradiction:
Improveheating capabilityVSAvoiddevice reliability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent replaces physical heating elements that undergo thermal cycling with a microwave generation system. The microwave generator produces electromagnetic waves that heat the material without the generator components themselves experiencing repeated thermal expansion and contraction, thereby eliminating the reliability issues associated with thermal fatigue in heating elements.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces microwave electromagnetic radiation as an intermediary between the power source and the aerosol-generating material. Instead of directly heating the heating elements, the microwave field acts as a mediator that transfers energy wirelessly to the material, preventing thermal strain in the device components while maintaining effective heating capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Object-affected harmful factors

If a Faraday cage assembly is added to prevent microwave transmission, then microwave containment is improved, but device complexity increases

Engineering Contradiction:
Improvemicrowave radiation containmentVSAvoidapparatus structure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent integrates the Faraday cage structure to serve multiple functions: it contains microwave radiation within the heating chamber, provides structural support for the apparatus, and may serve as a shielding enclosure for electronic components. This multi-functionality reduces the need for separate containment structures, thereby limiting the increase in overall device complexity despite the addition of microwave safety features.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables faster, uniform, and instantaneous heating without thermal strain, reducing the need for heating elements and improving heating efficiency.

Implementation Method 1

a microwave heater configured to receive power supplied from a power source to irradiate the receptacle with microwave radiation therewith to heat an aerosol-generating material

Methodology Applied
Scientific EffectMicrowave radiation: Microwave Radiation

Implementation Method 2

irradiate the aerosol-generating material with microwave radiation when the consumable is held within the receptacle thereby to irradiate the aerosol-generating material

Methodology Applied
Scientific EffectDielectric heating: Dielectric Heating

Implementation Method 3

A Faraday cage assembly is provided for preventing the transmission therethrough of microwave radiation emitted within the receptacle by the microwave heater

Methodology Applied
Scientific EffectFaraday cage effect: Faraday Cage

Data Source

PatentEP4646949A1Aerosol generating apparatus comprising a microwave heater and a faraday cage
Publication Date: 2025.11.12 IMPERIAL TOBACCO LTD
  • EP4646949A1 patent drawingFigure 1
  • EP4646949A1 patent drawingFigure 2~3b
  • EP4646949A1 patent drawingFigure 4~5

AI summary

An aerosol-generating device (90) comprises a receptacle (94) configured to hold an aerosol-generating material. A microwave heater (96) is disposed within the receptacle (94) and configured to receive power supplied from a power source (92) to irradiate the receptacle with microwave radiation therewith to heat the aerosol-generating material to generate an aerosol for delivery to a user. A Faraday cage assembly (94, 100) prevents the transmission therethrough of microwave radiation emitted within the receptacle (94) by the microwave heater (96). The Faraday cage assembly comprises an array of through-openings (101) via which said aerosol is deliverable to a user from within the receptacle.