Flexible RFID Antenna with Inductor Substrate
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Solution Overview
Problem
RFID tags used in UHF band systems face disconnection issues when folded or bent due to narrow conductor lines and stress concentration around the wireless IC chip, leading to reliability concerns.
Innovation Solution
A wireless communication device with a flexible base material film and a flexible antenna conductor featuring radiation elements facing each other through a slit, connected by an inductor substrate with an inductance element, which eliminates narrow conductor lines and ensures reliable impedance matching, preventing disconnection upon folding or bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If narrow conductor lines are used in the antenna structure, then the antenna size is reduced, but disconnection occurs when folded or bent
Solution Approach 1:
The patent applies this principle by using a flexible substrate as the base material for the antenna structure. The flexible substrate allows the antenna to be bent and folded without causing disconnection, while maintaining a compact form factor. The conductor patterns are formed on this flexible substrate, enabling the antenna to adapt to curved surfaces and folding conditions without compromising connection reliability.
Solution Approach 2:
The patent uses composite materials by combining the flexible substrate with conductor patterns and dielectric layers to create a multi-layered antenna structure. This composite construction provides both mechanical flexibility for bending and electrical conductivity for signal transmission, resolving the contradiction between size reduction and connection reliability.
2Ease of manufacture
If the wireless IC chip is mounted on a pad with lead wiring lines, then the chip can be connected to the radiation element, but stress concentration occurs at the joint portion causing disconnection
Solution Approach 1:
The patent merges the wireless IC chip mounting function with the antenna structure by integrating the chip directly onto the flexible substrate that forms part of the antenna assembly. This eliminates the separate pad and lead wiring line structure, distributing stress across the flexible substrate rather than concentrating it at discrete connection points, thereby improving joint portion reliability while maintaining ease of manufacture.
3Volume of moving object
If the antenna structure includes a loop portion with narrow line width, then the antenna can be made compact, but fold lines form during cleaning or folding causing disconnection
Solution Approach 1:
The patent applies this principle by replacing the rigid loop portion with narrow lines with a flexible substrate-based antenna structure. The flexible substrate inherently accommodates folding and bending without forming permanent fold lines that would cause disconnection, while still achieving compactness through the flexibility and conformability of the material.
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 provides a highly reliable wireless communication device that maintains connectivity even when folded or bent, ensuring effective impedance matching and reducing the likelihood of disconnection.
Implementation Method 1
The inductance element provided in the inductor substrate preferably achieves impedance matching between the wireless IC element and the flexible antenna conductor
Data Source
AI summary
A wireless communication device includes a flexible base material film, a flexible antenna conductor that is provided in substantially the entire region of one main surface of the flexible base material film and that includes a first radiation element and a second radiation element facing each other through a slit, an inductor substrate that is connected to the first radiation element and the second radiation element so as to extend across the slit, the inductor substrate including an inductance element, and a wireless IC element that is connected in parallel to the inductance element and that is mounted in the inductor substrate. The wireless IC element is connected to the first radiation element and the second radiation element so as to extend across the slit.