Halo Transmit Coil Layout for Low-Interference Wireless Power

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Solution Overview

Problem

Inductive wireless power transfer (IWPT) systems face interference risks between magnetic fields and electronic components, particularly in the central area of the receiver coil, which complicates simultaneous data communication and power transfer.

Innovation Solution

A specially wound transmitter coil with a halo antenna structure comprising an outer and inner winding, where the inner winding generates a magnetic field opposite to the outer winding to cancel out central magnetic field interference, allowing for reduced magnetic field intensity in the central area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a conventional transmit coil is used for inductive wireless power transfer, then power transmission efficiency is high, but magnetic field interference with electronic components in the central area increases

Engineering Contradiction:
Improvepower transmission efficiencyVSAvoidmagnetic field interference
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The transmit coil is segmented into two distinct windings: an outer winding for generating the magnetic field required for power transmission, and an inner winding for reducing the magnetic field intensity in the central area. This segmentation allows each winding to perform its specific function independently, resolving the contradiction between maintaining power transmission efficiency and reducing magnetic field interference with electronic components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The magnetic field characteristics are made non-uniform across different spatial regions. The outer winding generates a strong magnetic field for effective power transmission at the coil edges, while the inner winding creates a opposing magnetic field in the central area to reduce interference. This local differentiation of magnetic field quality allows simultaneous optimization of power transfer and electronic component protection.

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If the magnetic field intensity in the central area is reduced, then interference with electronic components decreases, but power transmission capability may be compromised

Engineering Contradiction:
Improvemagnetic field interferenceVSAvoidpower transmission capability
Core Design Contradiction:
Object-affected harmful factorsVSPower

Solution Approach 1:

The coil structure is divided into functional segments with distinct roles: the outer winding segment handles power transmission by generating the primary magnetic field, while the inner winding segment handles interference reduction by generating an opposing field in the central area. This functional segmentation ensures that power transmission capability is maintained through the outer winding while the inner winding selectively reduces central area interference.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The inner winding generates a magnetic field that opposes the outer winding's field in the central area. What appears to be a reduction in overall magnetic field strength is actually a strategic conversion: the harmful central magnetic field interference is converted into a beneficial protective effect, while the outer winding maintains sufficient field strength for power transmission at the coil periphery.

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

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 halo antenna structure minimizes magnetic field interference in the central area, enabling simultaneous inductive wireless power transfer and data communication without mutual interference.

Implementation Method 1

a first (outer) winding for generating the magnetic field

Methodology Applied
Scientific EffectMagnetic induction: Electromagnetic Induction

Implementation Method 2

a second (inner) winding for reducing the magnetic field intensity of the magnetic field in a central area of the transmit coil

Methodology Applied
Scientific EffectMagnetic induction: Electromagnetic Induction

Data Source

PatentEP4700808A1Inductive wireless power transfer device and system using same
Publication Date: 2026.02.25 STICHTING IMEC NEDERLAND
  • EP4700808A1 patent drawingFigure 1A~1B
  • EP4700808A1 patent drawingFigure 2
  • EP4700808A1 patent drawingFigure 3

AI summary

Inductive wireless power transfer device comprising a transmit coil for generating a magnetic field with a magnetic field intensity suitable for power transmission through magnetic induction, wherein the transmit coil comprises at least one halo antenna structure (100) comprising a first winding (101) for generating the magnetic field and a second winding (102) for reducing the magnetic field intensity of the magnetic field in a central area of the transmit coil.