Smart Card Printed Circuit with SMD Capacitor Resonance Tuning

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Solution Overview

Problem

The fabrication of dual interface smart cards is complex due to the need for separate integration of wire antennas and printed circuits, which is challenging with non-plastic materials and requires compliance with EMVCo standards. Additionally, existing solutions are not compatible with various IC chips having different capacitances.

Innovation Solution

A printed circuit with integrated contact and contactless features, incorporating one or more SMD capacitors to adjust the resonance frequency, allowing compatibility with different IC chips and materials, including non-plastic ones, while meeting EMVCo standards.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wire antennas are integrated separately from printed circuits, then contactless communication functionality is achieved, but device complexity and manufacturing complexity increase

Engineering Contradiction:
Improvecontactless communication functionalityVSAvoidintegration complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the wire antenna and printed circuit into a single integrated module, eliminating the need for separate integration processes. The antenna is fabricated directly on the printed circuit substrate using conductive traces, merging two previously separate components into one unified structure that reduces manufacturing complexity while maintaining contactless communication functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated module serves multiple functions simultaneously: it provides both contactless communication through the antenna and electrical contact through the printed circuit traces. This multi-functional design eliminates the need for separate wire antenna integration and simplifies the overall device architecture while maintaining both communication modes.

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

2Reliability

If wire antennas are embedded in prelam bodies, then contactless functionality is provided, but ease of manufacture decreases especially with non-plastic materials

Engineering Contradiction:
Improvecontactless communication capabilityVSAvoidembedding difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces the mechanical embedding process of wire antennas into prelam bodies with a printed circuit fabrication process. Instead of physically inserting and securing wire antennas, the antenna is created using standard PCB techniques (conductive traces on substrate), which is much easier to manufacture and compatible with various materials including non-plastic substrates.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the fundamental approach from mechanical wire embedding to printed circuit trace formation. This parameter change in the manufacturing method makes the process compatible with diverse materials (wood, ceramic, metal, plastic) and eliminates the difficulties associated with wire embedding in non-plastic materials.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If fixed capacitance values are used in printed circuits, then manufacturing is simplified, but adaptability to different IC chips decreases

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidchip compatibility
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent implements adjustable capacitance values in the printed circuit using SMD capacitors that can be selected or tuned based on the specific IC chip requirements. This dynamic adjustment capability allows the same printed circuit design to work with multiple chip types having different capacitance specifications, maintaining manufacturing simplicity while achieving broad adaptability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention enables parameter changes in the circuit capacitance by using selectable SMD capacitor values. This allows optimization of the resonance frequency for different IC chips without requiring complete redesign of the printed circuit, thus maintaining ease of manufacture while achieving versatility across different chip types.

Inventive Principle:
Principle #35Parameter changes

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 simplifies the manufacturing process by integrating contact and contactless features into a single printed circuit, ensuring compatibility with various IC chips and materials, and achieving optimal performance in EMVCo L1 PICC Analog tests.

Implementation Method 1

the printed circuit further includes one or more SMD capacitors, each having a predefined capacitance, which allows to tune the resonance frequency of the printed circuit so as to match a predefined resonance frequency

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP4441655B1Printed circuit with surface mount capacitor for integration into a smart card
Publication Date: 2025.06.18 LINXENS HOLDING SAS
  • EP4441655B1 patent drawingFigure 1
  • EP4441655B1 patent drawingFigure 2
  • EP4441655B1 patent drawingFigure 3

AI summary

The present disclosure refers to a printed circuit for integration in a smart card, wherein the printed circuit comprises a printed circuit substrate of dielectric material, an antenna having a resonance frequency, one or more contact pads forming an external contact pattern, and at least one surface mount (SMD) capacitor connected to the antenna so as to adjust its resonance frequency, in order to match a predefined resonance frequency, for instance a resonance frequency comprised within the range defined in ISO 14443 standards. The present disclosure also refers to a module comprising the above-indicated printed circuit and an IC chip and to a corresponding smart card.