Coil Antenna Layout Around Magnets Without RF Loss

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Solution Overview

Problem

Magnets adjacent to coils in electronic devices can decrease RF performance, necessitating a spacing that increases the device width, which is undesirable.

Innovation Solution

A housing structure is designed with magnets positioned non-overlappingly to coils, allowing coils to be wound around perpendicular axes without overlapping magnets, ensuring RF performance without increasing device width.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If multiple coil antennas are disposed close to each other, then the overall device size is reduced, but it becomes difficult to distinguish between adjacent coils and determine which coil a detected object is above

Engineering Contradiction:
Improvedevice sizeVSAvoidcoil identification difficulty
Core Design Contradiction:
Volume of moving objectVSDifficulty of detecting and measuring

Solution Approach 1:

Each coil antenna is assigned a unique identification value that distinguishes it from adjacent coils. This local identifier allows the system to maintain compact spacing while still enabling clear identification of which specific coil is detecting an object, resolving the contradiction between small size and coil distinguishability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system determines the identification value of the coil associated with a detected object by analyzing signal characteristics and providing feedback about which coil is active. This feedback mechanism enables precise coil identification even when coils are disposed close together, maintaining both compact size and detection accuracy.

Inventive Principle:
Principle #23Feedback

2Device complexity

If a single coil antenna is used, then the device structure is simple, but the ability to detect multiple objects simultaneously and determine their positions is limited

Engineering Contradiction:
Improveantenna structure complexityVSAvoidmulti-object detection capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The single coil antenna is segmented into multiple independent coil antennas, each capable of independent operation and identification. This segmentation enables simultaneous detection of multiple objects at different positions while maintaining relatively simple individual coil structures, resolving the contradiction between structural simplicity and multi-object detection capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple coil antennas are configured to perform the same detection function but with unique identification values, allowing the system to detect multiple objects simultaneously. Each coil serves the universal function of object detection while its unique identifier enables position differentiation, achieving multi-object detection without excessive complexity.

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

3Volume of moving object

If coil antennas are disposed close to each other, then space is saved, but signals from adjacent coils may interfere with each other

Engineering Contradiction:
Improvedevice volumeVSAvoidsignal interference
Core Design Contradiction:
Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

Each coil antenna is assigned a unique identification value that allows the system to distinguish and process signals from different coils separately. This local differentiation enables close spacing of coils while preventing signal interference through identification-based signal separation.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system uses feedback mechanisms to determine which specific coil is detecting an object by analyzing signal characteristics. This feedback allows the system to identify the source coil even when multiple coils are closely spaced, thereby managing signal interference and enabling compact coil arrangement.

Inventive Principle:
Principle #23Feedback

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

Maintains RF performance of coils while preventing device width expansion by strategically arranging magnets and coils within the housing.

Implementation Method 1

a coil antenna for transmitting/receiving a signal

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4258478B1Electronic device having plurality of coil antennas
Publication Date: 2026.04.29 SAMSUNG ELECTRONICS CO LTD
  • EP4258478B1 patent drawingFigure 1
  • EP4258478B1 patent drawingFigure 2
  • EP4258478B1 patent drawingFigure 3A

AI summary

An electronic device in various embodiments comprises: a housing having a front surface, a rear surface, and lateral surfaces for encompassing the front surface and the rear surface; first and second magnets which do not overlap with each other and are positioned inside the housing when viewed from the rear surface; a first coil which is positioned between the first magnet and the second magnet to not overlap with each other when viewed from the rear surface, and which has a structure wound several times around a first axis that is perpendicular to the rear surface; and a second coil which is positioned inside the housing to overlap with the first coil and to not overlap with the first magnet and the second magnet when viewed from the rear surface, and which has a structure passing between the first magnet and the second magnet.