Planar RFID Transponder with Integrated Matching Network

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Solution Overview

Problem

Existing RFID transponders in the UHF band are not compact, completely planar, and reproducible, leading to limited range and poor power adjustment, with complex and expensive structures that are difficult to modify for different frequency ranges or chip types.

Innovation Solution

A compact, completely planar RFID transponder design featuring an integrated matching network within the antenna structure, using a loop antenna with conductive connections and structured metallization to form capacitances that complex conjugate match the impedance of the chip, allowing for maximum range and power adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional PIFA antennas are used with folded layers and conductive adhesive films, then the RFID transponder can be manufactured, but the structure becomes complex and expensive with limited range

Engineering Contradiction:
ImproverangeVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the antenna structure with the matching network into a single integrated planar design. The matching network is formed by structured metallization patterns directly on the dielectric substrate, eliminating the need for separate folded layers and conductive adhesive films. This integration simplifies the overall structure while improving manufacturing reproducibility and extending the operational range through optimized impedance matching.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention transitions from a three-dimensional folded layer structure to a completely planar two-dimensional design. The antenna and matching network are both realized as flat metallization patterns on a single dielectric substrate, eliminating vertical folding and achieving a truly planar configuration that simplifies manufacturing and improves reproducibility.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If conventional folded antenna structures are used, then the RFID transponder can be assembled, but modification for different chips or frequency ranges becomes difficult

Engineering Contradiction:
Improveadaptability to different chips and frequenciesVSAvoidmodification difficulty
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a dynamic and reconfigurable matching network using structured metallization that can be easily adjusted for different frequency ranges and chip types. The planar metallization patterns can be modified through standard PCB design techniques, allowing flexible adaptation without requiring complex structural changes or reassembly procedures.

Inventive Principle:
Principle #15Dynamics

3Reliability

If conventional antenna structures are used, then the RFID transponder can be manufactured, but the manufacturing reproducibility is poor leading to short ranges

Engineering Contradiction:
ImproverangeVSAvoidmanufacturing reproducibility
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention achieves superior manufacturing reproducibility by transitioning to a completely planar structure that can be manufactured using standard PCB fabrication techniques. The metallization patterns are deposited and etched in a single planar process, eliminating the variability introduced by multi-step folding and assembly operations. This results in consistent impedance matching and reliable performance across production batches.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 solution results in a transponder with enhanced range and power adjustment capabilities, achieving a completely planar and reproducible design that is cost-effective and adaptable to various frequency bands and chip types.

Implementation Method 1

The structuring of the first metallization on the first surface is designed in such a way that two electrically conductive connections are formed on the first surface... which forms at least a section of a matching network, by means of which the input impedance of the antenna is complex conjugate to the impedance of the chip is adjusted

Methodology Applied
Scientific EffectImpedance matching: Capacitance

Implementation Method 2

The RFID transponder according to the invention also has a dielectric carrier element, which is covered at least in sections on a first surface with a structured first metallization and on one of the first surfaces opposite, second surface is covered at least in sections with a second metallization

Methodology Applied
Scientific EffectDielectric insulation: Dielectric

Implementation Method 3

The antenna is an antenna having at least one winding; in particular, a loop antenna can advantageously be used which, as is known to those skilled in the art, consists of or includes an (almost completely) closed electrical conductor loop

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Data Source

PatentEP2256673B1RFID transponder for mounting on metal and production method for same
Publication Date: 2013.11.06 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP2256673B1 patent drawingFigure 1
  • EP2256673B1 patent drawingFigure 2
  • EP2256673B1 patent drawingFigure 3a~3b

AI summary

The invention relates to an RFID transponder comprising: an antenna, a chip comprising at least one transmitting and receiving circuit and a memory, a dielectric carrier element which is at least partially covered on a first surface with a structured first metallization and which is at least partially covered on a second surface opposite the first surface with a second metallization, wherein the first and the second metallization are electrically conductively connected to each other and thereby form the antenna, wherein the first metallization is structured such that it forms two electrical connections of the antenna arranged on the first surface of the dielectric carrier element.and wherein the chip can be electrically contacted or is contacted via these two connections and can be placed or arranged on the first surface and/or at least sectionally integrated into this surface, and a matching network formed at least partially by the structuring of the first metallization, which conjugates the input impedance of the antenna to the impedance of the chip.