Flexible RFID Antenna Coil with Opposing Winding

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Solution Overview

Problem

Existing RFID antenna coils mounted on circuit boards face challenges in achieving consistent sensitivity due to variable mounting positions, requiring intricate adjustments and resulting in inconsistent performance.

Innovation Solution

The design incorporates a flexible board wound around two flat magnetic cores with opposing coil winding directions, a fixed non-winding portion, and strategically placed connecting conductors to ensure consistent magnetic flux guidance and sensitivity, regardless of mounting position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If segments are fixed separately on the board, then the antenna coil can be assembled, but the fixing positions require fine adjustment and many steps to achieve consistent distance

Engineering Contradiction:
Improveease of mountingVSAvoidfixing position precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent combines multiple segments and the board into a single integrated antenna coil structure. The conductor continuously connects all segments through the board, forming one unified component that is mounted as a whole rather than assembling separate segments, thereby eliminating the need for fine adjustment of individual segment positions

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The board serves multiple functions: it acts as both the substrate for mounting and as part of the antenna structure itself. The conductor on the board performs dual roles as both electrical connection and antenna element, eliminating the need for separate adjustment mechanisms

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

2Ease of operation

If the distance between segments varies with fixing positions, then mounting becomes simpler, but antenna sensitivity becomes inconsistent

Engineering Contradiction:
Improvemounting simplicityVSAvoidantenna sensitivity consistency
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

By merging all segments and the board into one integrated antenna coil, the invention ensures that the relative positions of all segments are fixed by the rigid board structure, maintaining consistent segment spacing and reliable antenna sensitivity while allowing simple mounting of the entire assembly

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The board is pre-configured with conductors that establish fixed geometric relationships between segments before mounting. This preliminary arrangement of conductors on the board ensures consistent segment positioning is built into the structure itself, eliminating the need for post-mounting adjustment

Inventive Principle:
Principle #10Preliminary action

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

This configuration stabilizes antenna sensitivity, enhances flux concentration, and improves communication efficiency by maintaining consistent performance across different mounting configurations.

Implementation Method 1

When the magnetic flux passes through the coil axes of the coils of the segments 102a and 102b, voltages are induced in the coils, and communication is allowed

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

magnetic flux perpendicular to the board is bent about 90° after entering the non-winding portion, and is then guided to the first segment 102a and the second segment 102b

Methodology Applied
Scientific EffectMagnetic flux guidance: Magnetic Field

Data Source

PatentEP2040202B1Antenna coil to be mounted on substrate and antenna device
Publication Date: 2011.09.07 MURATA MFG CO LTD
  • EP2040202B1 patent drawingFigure 1(A)~1(B)
  • EP2040202B1 patent drawingFigure 2
  • EP2040202B1 patent drawingFigure 3(A)~3(B)

AI summary

In an antenna coil (2) including a first magnetic core (4a), a second magnetic core (4b), and a flexible board (5), coil conductors are provided on a surface of the flexible board (5). By winding the flexible board (5) around the first magnetic core (4a) and the second magnetic core (4b), a first coil portion (2a) is formed around the first magnetic core (4a), and a second coil portion (2b) is formed around the second magnetic core (4b). The winding direction of the second coil portion (2b) is opposite to that of the first coil portion (2a). The first coil portion (2a) and the second coil portion (2b) are connected to form one coil as a whole.