Tire RFID Patch Antenna for Flexible Pressure and Temperature Sensing

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Solution Overview

Problem

Existing RFID devices for tires face challenges in monitoring tire conditions such as temperature and pressure while maintaining flexibility and avoiding mechanical damage, with potential safety risks and performance issues due to integration with elastic and flexible tire materials.

Innovation Solution

A multilayer RFID sensor device with a patch-type antenna, comprising a bottom ground plane, intermediate dielectric substrate, and top conductive patches, integrated with sensors for temperature and pressure monitoring, designed to be flexible and compatible with tire materials, allowing integration without causing mechanical damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an RFID tag is embedded in a tire, then tire identification and condition monitoring are enabled, but mechanical damage to the tire or cords may occur during manufacturing and operation

Engineering Contradiction:
Improvetire identification and condition monitoringVSAvoidmechanical damage to tire or cords
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies this principle by using a flexible printed circuit board (FPC) as the substrate for the RFID tag, allowing the tag to conform to the tire's curved surface and flex with the tire during manufacturing and operation. The FPC's flexibility prevents mechanical damage while maintaining functional integrity, directly resolving the contradiction between enabling monitoring and avoiding harm to the tire structure.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent transitions from traditional planar RFID tag designs to a three-dimensional conformal structure that wraps around the tire's inner liner. This dimensional adaptation allows the tag to integrate with the tire's geometry without creating stress concentration points that would cause cord breakage or delamination, while still providing reliable identification and monitoring capabilities.

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

2Object-affected harmful factors

If the RFID device is made flexible to match tire properties, then integration without damage is achieved, but remote reading distance may be reduced

Engineering Contradiction:
Improvemechanical damage avoidanceVSAvoidremote reading distance
Core Design Contradiction:
Object-affected harmful factorsVSLength of stationary object

Solution Approach 1:

The patent combines multiple antenna elements (including meander-line, spiral, or planar inverted-F antenna configurations) into a single integrated RFID tag structure on the FPC. This merging of antenna functions increases the effective radiating area and electromagnetic coupling efficiency, compensating for the flexibility-induced reading distance reduction while maintaining the flexible form factor needed for tire integration.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If sensors are integrated into the RFID chip, then temperature and pressure monitoring are enabled, but device complexity increases

Engineering Contradiction:
Improvetemperature and pressure monitoringVSAvoidsensor integration complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements multi-functionality by integrating temperature sensors, pressure sensors, and RFID identification capabilities into a single unified device. The FPC-based platform supports multiple sensor types and RFID frequencies, allowing one device to perform diverse monitoring functions that would otherwise require separate systems, thereby reducing overall system complexity despite the added capabilities.

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

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 RFID sensor device provides real-time monitoring of tire conditions, enhancing safety and performance by minimizing mechanical interference and ensuring reliable operation in harsh electromagnetic environments.

Implementation Method 1

a patch-type antenna, differently from known solutions that are typically based on single-layer dipole-like antennas... for radiation and receiving of electromagnetic fields

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 2

an intermediate dielectric substrate arranged on the bottom ground plane... one or more top conductive patches arranged on the intermediate dielectric substrate

Methodology Applied
Scientific EffectDielectric insulation: Dielectric

Data Source

PatentEP4157650B1Improved RFID sensor device with patch-type antenna for tires
Publication Date: 2025.08.27 BRIDGESTONE EURO NV SA
  • EP4157650B1 patent drawingFigure 1
  • EP4157650B1 patent drawingFigure 2
  • EP4157650B1 patent drawingFigure 3

AI summary

The invention concerns an RFID sensor device (1, 2, 3) for tires, designed to be embedded/integrated, at least partially, in/into, or applied to, a tire (4) and comprising a patch-type antenna that includes a multilayer structure comprising: a bottom ground plane (10, 20, 30); an intermediate dielectric substrate (11, 21, 31) arranged on the bottom ground plane (10, 20, 30); and one or more top conductive patches (12, 13, 22, 32) arranged on the intermediate dielectric substrate (11, 21, 31) and covering partially or completely said intermediate dielectric substrate (11, 21, 31), wherein said bottom ground plane (10, 20, 30) and said one or more top conductive patches (12, 13, 22, 32) are short-circuited or capacitively coupled. The RFID sensor device (1, 2, 3) further comprises: a rigid or flexible board (15, 25, 33) arranged on said one or more top conductive patches (12, 13, 22, 32) and/or the intermediate dielectric substrate (11, 21, 31); an RFID chip (16, 26, 34) installed on the rigid/flexible board (15, 25, 33) and connected/coupled to said one or more top conductive patches (12, 13, 22, 32); a temperature sensor integrated into, or connected to, said RFID chip (16, 26, 34); and a pressure sensor (17, 27, 35) installed on the rigid/flexible board (15, 25, 33) and connected to the RFID chip (16, 26, 34). The bottom ground plane (10, 20, 30) is formed: by conductive textile/fabric/thread/fiber/yarn elements/layers or by a metal weft/net/mesh; or at least partially by conductive and/or metal elements/layers of the tire (4). The intermediate dielectric substrate (11, 21, 31) is made at least partially of rubber, or is formed at least partially by dielectric and/or rubber elements/layers of the tire (4).