RFID Transponder Ground Plane Openings for Near-Field Encoding

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Solution Overview

Problem

RFID transponders with ground plane structures that isolate the antenna from the reader antenna's radiation prevent encoding, as the reader antenna cannot couple with the transponder's antenna when positioned below the ground plane.

Innovation Solution

A dielectric spacer layer is introduced between the antenna element and the ground plane, featuring openings such as slots or grooves, allowing for near-field communication and enabling encoding by creating a pathway for RF signals through the ground plane.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a ground plane is used to provide shielding and stable reference potential, then electromagnetic shielding and signal stability are improved, but coupling with reader antenna positioned below the ground plane is blocked

Engineering Contradiction:
Improvesignal stabilityVSAvoidencoding capability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The ground plane is segmented by introducing openings (slots or grooves) that divide the continuous ground plane into separate regions. This segmentation allows RF signals to pass through the ground plane via near-field coupling while maintaining the ground plane's shielding and reference potential functions in other areas.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A dielectric spacer layer is introduced as an intermediary element between the antenna element and the ground plane. This spacer layer creates a controlled impedance environment and enables near-field communication paths through the ground plane openings, facilitating signal coupling without direct contact.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the ground plane is made continuous for optimal shielding, then electromagnetic shielding is improved, but near-field communication through the ground plane is blocked

Engineering Contradiction:
Improveelectromagnetic shieldingVSAvoidnear-field communication
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The continuous ground plane is segmented by creating openings (slots or grooves) that allow near-field RF signals to pass through. The segmentation is strategically designed to maintain shielding effectiveness in directions where electromagnetic interference is most problematic while creating pathways for intended near-field communication.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the ground plane are given different properties: areas with openings provide near-field communication pathways, while areas without openings maintain strong shielding. This local differentiation allows the ground plane to simultaneously perform both shielding and signal transmission functions in different locations.

Inventive Principle:
Principle #3Local quality

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 solution allows for successful encoding of RFID transponders even when the reader antenna is positioned opposite the antenna, enhancing coupling and enabling efficient encoding and end-use functionality on both conductive and non-conductive surfaces.

Implementation Method 1

A dielectric spacer layer (7) is arranged between the antenna element (2) and the ground plane (4). The ground plane (4) comprises at least one opening (6) that extends through the ground plane (4) for enabling near field communication through the ground plane (4)

Methodology Applied
Scientific EffectNear-field communication: Electromagnetic Induction

Data Source

PatentEP3207504B1RFID transponder
Publication Date: 2024.07.24 CONFIDEX OY
  • EP3207504B1 patent drawingFigure 1
  • EP3207504B1 patent drawingFigure 2
  • EP3207504B1 patent drawingFigure 3

AI summary

An RFID transponder (100), comprising a printable surface (1), an antenna element (2), an IC (3), and a ground plane (4) arranged under the antenna element (2). The ground plane (4) comprises one or more opening(s) (6) through said ground plane (4) for enabling near field communication through the ground plane (4).