Transponder Antenna Composite Conductor for Bending Stress

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Solution Overview

Problem

Transponder cards with conventional copper antennas are prone to breaking due to bending and torsional stresses, as the metallic antennas are exposed to high mechanical stresses when the cards are flexed, leading to potential antenna failure.

Innovation Solution

A composite conductor is used, which includes a structural device bonded to the conductor, enhancing its tensile strength and flexibility, allowing it to absorb bending and torsional stresses more effectively, thereby increasing the rupture strength and mechanical elongation at break.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a conventional copper antenna is used in a transponder card, then the antenna can be firmly connected to the antenna substrate, but the antenna is prone to breaking due to bending and torsional stresses

Engineering Contradiction:
Improvetensile strength of antennaVSAvoidresistance to breakage under mechanical stress
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies composite materials by bonding a structural device to the copper conductor to form a composite conductor. The structural device provides enhanced mechanical strength and flexibility, while the copper conductor maintains electrical conductivity. This composite structure resolves the contradiction by combining materials with complementary properties to achieve both firm connection and resistance to breakage under bending and torsional stresses.

Inventive Principle:
Principle #40Composite materials

2Reliability

If a metallic antenna is used in a transponder card, then the antenna provides good electrical conductivity, but the antenna is exposed to high tensile, compressive or bending stresses when the card bends

Engineering Contradiction:
Improveelectrical conductivity of antennaVSAvoidmechanical strength under bending stress
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent uses composite materials to create a composite conductor that combines a copper conductor (providing electrical conductivity) with a structural device (providing mechanical strength). The structural device is bonded to the conductor to form a unified structure that maintains electrical performance while withstanding bending and torsional stresses during card flexing.

Inventive Principle:
Principle #40Composite materials

3Adaptability or versatility

If the transponder card is made from stretchable plastic materials, then the card is flexible and can be carried in purses, but the metallic antenna inside is exposed to high mechanical stresses

Engineering Contradiction:
Improveflexibility of transponder cardVSAvoidintegrity of antenna under mechanical stress
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies composite materials by creating a composite conductor that combines a flexible copper conductor with a structural device that provides mechanical strength. This composite structure allows the transponder card to maintain flexibility for carrying in purses while the structural device protects the antenna from breaking during constant body movements and card flexing.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP2095303B1Transponder unit
Publication Date: 2012.06.13 SMARTRAC IP
  • EP2095303B1 patent drawingFigure 1~2
  • EP2095303B1 patent drawingFigure 3~9

AI summary

The invention relates to a transponder unit (10), in particular for transponder cards, identification documents or the like, having at least one chip (15) and at least one antenna (11), wherein the antenna is formed from a metal conductor which is arranged on an antenna substrate (14) and is permanently connected to the latter, and wherein the conductor is provided with a structure device which is integrally connected to the conductor and is intended to form a composite conductor (12) such that the composite conductor has a higher tensile stress or a higher elongation at break than the conductor.