RFID Tag Antenna Harmonic Resonance Melting
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Solution Overview
Problem
RFID tags attached to food products risk ignition when exposed to high-frequency electromagnetic waves from microwave ovens, as the metal antenna patterns can cause discharge, heat generation, and sublimation, leading to potential fires.
Innovation Solution
The design of RFID tags with an antenna pattern featuring a narrow line width at harmonic current concentration portions, which undergoes harmonic resonance and subsequent melting or sublimation when exposed to microwave heating, thereby interrupting heat generation and preventing ignition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal antenna pattern is used in the RFID tag, then communication function is improved, but ignition risk increases when exposed to microwave heating
Solution Approach 1:
The antenna pattern is divided into multiple segments with varying line widths. The narrow line width portions (0.1-0.5mm) are strategically placed at harmonic resonance current concentration points, while wider portions maintain communication efficiency. This segmentation allows the antenna to function during normal operation but automatically disconnect at critical points during microwave heating.
Solution Approach 2:
Different portions of the antenna pattern have different line widths to serve different functions. The narrow portions (0.1-0.5mm) are designed to melt and disconnect under microwave heating conditions, while wider portions maintain signal transmission during normal RFID operation. This local differentiation resolves the contradiction between communication reliability and ignition prevention.
2Object-affected harmful factors
If the antenna pattern line width is reduced to prevent ignition, then safety is improved, but communication signal strength deteriorates
Solution Approach 1:
The antenna is segmented into narrow portions (0.1-0.5mm) at harmonic resonance points and wider portions elsewhere. The narrow segments are sufficient to prevent ignition by melting under microwave heating, while the wider segments maintain adequate signal strength for normal RFID communication, thus resolving the contradiction between safety and signal strength.
Solution Approach 2:
The antenna pattern employs local quality variation with different line widths at different locations. Narrow sections (0.1-0.5mm) provide safety by preventing ignition through controlled melting, while wider sections maintain communication power. This localized differentiation optimizes both safety and signal strength simultaneously.
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
This configuration effectively prevents ignition and combustion of the RFID tag and attached products by interrupting harmonic resonance and heat generation, ensuring safe operation during microwave heating.
Implementation Method 1
the narrow portion of the antenna pattern or the base material on which the narrow portion of the antenna pattern is arranged is melted and cut due to temperature rise
Implementation Method 2
heat generation and sublimation of metal material due to overcurrent flowing through the metal material part
Implementation Method 3
heat is intensively generated at the harmonic current concentration portion due to Joule heat
Implementation Method 4
harmonic resonance occurs at the wireless communication device with the microwave for electromagnetic wave heating
Data Source
AI summary
An RFID tag is provided as a wireless communication device for transmitting and receiving a communication signal. The RFID tag includes a base material, antenna patterns formed on the base material, and an RFIC package that is a feeder circuit connected to the antenna patterns. In the antenna patterns, a line width at a harmonic current concentration portion where a current is strong at a frequency of harmonic resonance higher than a resonance frequency at a frequency of the communication signal is narrower than a line width at another portion of the antenna pattern.