Stretchable RFID Tag with Folded Substrate and Spiral Antenna
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Solution Overview
Problem
Conventional RFID antennas attached to human skin are prone to breaking due to flexing or stretching, as they often have high stress concentration points that lead to damage when subjected to skin movement.
Innovation Solution
A radio frequency identification (RFID) tag with a stretchable substrate and an antenna featuring a spiral geometry with a radius of curvature greater than 0.1 mm and less than 5 mm, along with a dielectric layer and electrically conductive ink to prevent contact with the antenna loops, ensuring flexibility and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional RFID antennas are used with rigid structures, then manufacturing precision is improved, but flexibility and reliability deteriorate due to breaking when subjected to skin movement
Solution Approach 1:
The patent applies this principle by using a flexible substrate instead of rigid structures to support the RFID antenna. The substrate can bend and stretch with skin movement, preventing the antenna from breaking while maintaining manufacturing precision through controlled flexibility in the material selection and design.
Solution Approach 2:
The patent implements dynamics by designing the antenna structure to be adaptable and flexible rather than rigid. The antenna can dynamically adjust to skin movements through its flexible mounting and structural design, allowing it to maintain reliability under varying mechanical conditions.
2Adaptability or versatility
If the antenna radius of curvature is reduced to increase flexibility, then adaptability to skin movement is improved, but stress concentration increases leading to breaking
Solution Approach 1:
The patent applies this principle by optimizing the antenna's radius of curvature to be greater than 0.1 mm. This controlled curvature allows the antenna to flex and adapt to skin movements while distributing mechanical stress evenly across the structure, preventing stress concentration and breaking.
3Ease of manufacture
If terminals are exposed for electrical connection, then ease of manufacture is improved, but risk of contact with conductive materials increases causing short circuits
Solution Approach 1:
The patent implements this principle by introducing a dielectric layer as an intermediary between the exposed terminals and any surrounding conductive materials. This dielectric barrier allows electrical connections to be made to the exposed terminals while preventing accidental short circuits with adjacent conductive structures.
Data Source
AI summary
A radio frequency identification tag including a stretchable substrate folded along a fold line to form top and bottom stretchable fold portions is described. Each fold portion has major top and bottom surfaces with the major top surface of the bottom fold portion facing the major bottom surface of the top fold portion. An antenna having a spiral form is disposed on the major top surface of the top fold portion. First and second terminals are disposed on the major top surface of the top fold portion and are in electrical communication with respective first and second ends of the antenna. A meandering electrode is disposed on the major bottom surface of the bottom fold portion and has first and second electrode ends making crimp connections with the respective first and second terminals.