Gap Waveguide Wireless Charging With Bandgap Field Confinement

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Solution Overview

Problem

Existing wireless power transfer technologies suffer from low efficiency and electromagnetic field leakage, especially in applications requiring large power delivery over distances, such as charging electric vehicles, due to the need for close proximity between coils and potential radiation hazards.

Innovation Solution

A wireless power transfer system based on gap waveguides, utilizing a charging plate and a gap waveguide base that enables efficient power transfer without ohmic contact, using a ridge or aperture gap waveguide structure with a bandgap structure to confine electromagnetic fields, allowing for high efficiency and separation distances of a few centimeters to tens of centimeters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If inductive power transfer or capacitive power transfer is used for wireless charging, then power can be delivered wirelessly, but efficiency is low due to electromagnetic field leakage and requirement for small physical separation

Engineering Contradiction:
Improvepower transfer efficiencyVSAvoidelectromagnetic field leakage
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an electromagnetic field as an intermediary carrier to transfer power wirelessly from the transmitting coil to the receiving coil. The field acts as a mediator that enables contactless power transfer while the bandgap structure controls its propagation to minimize leakage and maximize efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the physical parameters of the system by introducing a bandgap structure with specific periodicity and dimensions. This structure modifies the electromagnetic field distribution, creating regions of high and low field intensity that improve power transfer efficiency while containing field leakage through careful parameter selection.

Inventive Principle:
Principle #35Parameter changes

2Power

If inductive power transfer is used, then wireless power delivery is achieved, but electromagnetic field leakage increases harmful radiation effects

Engineering Contradiction:
Improvewireless power delivery capabilityVSAvoidradiation effects
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The patent converts the potentially harmful electromagnetic field leakage into a beneficial contained field distribution. The bandgap structure transforms what would be radiative loss into directed field confinement, where the field that could have leaked harmful radiation is instead channeled efficiently to the receiving coil.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The electromagnetic field serves as an intermediary that transfers power without direct contact, eliminating the need for physical connectors while the bandgap structure ensures this intermediary remains contained and does not become a source of harmful radiation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Loss of energy

If gap waveguide structure with bandgap structure is used, then power transfer efficiency is improved and field leakage is reduced, but device complexity increases

Engineering Contradiction:
Improvepower transfer efficiencyVSAvoidwaveguide structure complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent segments the waveguide structure into distinct functional components: the main waveguide path, the bandgap structure with periodic elements, and the coupling regions. This segmentation allows each component to be optimized independently for its specific function while maintaining overall system efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses parameter changes in the bandgap structure (periodicity, element dimensions, spacing) to achieve the desired field confinement and power transfer characteristics. By carefully selecting these parameters, the system achieves high efficiency without requiring overly complex structural designs.

Inventive Principle:
Principle #35Parameter changes

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

The system achieves up to 100% theoretical efficiency in power transfer with minimal losses, providing contactless power delivery suitable for electric vehicles and mobile platforms, while avoiding electromagnetic interference and radiation issues.

Implementation Method 1

a gap waveguide base that includes... a bandgap structure next to the waveguiding structure along at least two opposing lateral sides of the waveguiding structure, the bandgap structure having a periodicity prohibiting propagation of the electromagnetic field from the lateral sides of the waveguiding structure

Methodology Applied
Scientific EffectBandgap structure: Photonic Crystal

Implementation Method 2

a conductive waveguiding structure coupled to the adaptor to receive an input electromagnetic field from the external power source, the waveguiding structure configured to facilitate propagation of the electromagnetic field along a longitudinal axis of the gap waveguide base

Methodology Applied
Scientific EffectWaveguide: Waveguide

Implementation Method 3

Together, the charging plate and the gap waveguide base provides a complete WPT system... enables wireless transfer of electric power from the power source (to which the gap waveguide base is coupled) to the charging plate

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4275261B1Contactless transmission line for wireless power transfer
Publication Date: 2025.11.05 HUAWEI TECH CANADA CO LTD
  • EP4275261B1 patent drawingFigure 1
  • EP4275261B1 patent drawingFigure 2
  • EP4275261B1 patent drawingFigure 3

AI summary

A system for wireless power transfer (WPT) is described. The WPT system may be used for charging of electric vehicles or other mobile platforms. The WPT system includes a gap waveguide base including a conductive waveguiding structure and a bandgap structure along at least the lateral sides of the waveguiding structure. The WPT system also includes a charging plate separate from the gap waveguide base. The charging plate includes a conductive plate having a receiving structure for receiving the electromagnetic field from the gap waveguide base through an air gap. The disclosed WPT system enables propagation of an electromagnetic field through the air gap, including electromagnetic fields in the very high frequency (VHF) band.