Microwave-Safe HF RFID Tag Structure to Prevent Arcing
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Solution Overview
Problem
Current RFID tags cannot withstand the high-field emissions of microwave ovens and often damage the food items they are attached to, necessitating removal before cooking.
Innovation Solution
A microwave-safe RFID tag design featuring a split ring conductor, a coil antenna conductor, and a dielectric between them, with a gap in the antenna conductor to prevent arcing, allowing the tag to be securely attached to food items and read during microwave cooking without damaging them.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional RFID tag is placed in a microwave oven, then the RFID tag can provide data for controlling the cooking process, but the RFID tag will be destroyed and may damage the food item
Solution Approach 1:
The antenna conductor is divided into multiple segments with gaps between them, preventing continuous current flow that would cause arcing. The split ring conductor is also segmented, creating discrete sections that reduce electromagnetic stress concentration and prevent the tag from overheating or being destroyed during microwave exposure.
Solution Approach 2:
A dielectric material is introduced as an intermediary between the antenna conductor and the split ring conductor. This dielectric layer isolates the two conductors, preventing direct electrical contact and reducing the risk of arcing while maintaining the necessary electromagnetic coupling for RFID functionality.
2Ease of operation
If the RFID tag remains attached to the food item during microwave cooking, then convenience is improved, but the food item may be damaged by arcing
Solution Approach 1:
The antenna conductor is divided into multiple segments with gaps between them, preventing continuous current flow that would cause arcing. The split ring conductor is also segmented, creating discrete sections that reduce electromagnetic stress concentration and prevent the tag from overheating or being destroyed during microwave exposure.
Solution Approach 2:
A dielectric material is introduced as an intermediary between the antenna conductor and the split ring conductor. This dielectric layer isolates the two conductors, preventing direct electrical contact and reducing the risk of arcing while maintaining the necessary electromagnetic coupling for RFID functionality.
3Reliability
If a continuous conductor design is used in the RFID tag, then electromagnetic coupling is improved, but arcing occurs during microwave exposure
Solution Approach 1:
The antenna conductor is divided into multiple segments with gaps between them, preventing continuous current flow that would cause arcing. The split ring conductor is also segmented, creating discrete sections that reduce electromagnetic stress concentration and prevent the tag from overheating or being destroyed during microwave exposure.
Solution Approach 2:
A dielectric material is introduced as an intermediary between the antenna conductor and the split ring conductor. This dielectric layer isolates the two conductors, preventing direct electrical contact and reducing the risk of arcing while maintaining the necessary electromagnetic coupling for RFID 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
Enables the RFID tag to operate within microwave ovens without damaging the food items, providing data for controlling cooking processes and ensuring safety by preventing arcing and excessive heating.
Implementation Method 1
a path connects the split ring conductor formed on one side of the dielectric and the antenna conductor formed on an opposite side of the dielectric, so that the split ring conductor acts as a HF bridge between a center and an edge of the antenna conductor
Implementation Method 2
a dielectric positioned between the antenna conductor and the split ring conductor
Implementation Method 3
the antenna conductor comprises a gap and the RFID chip is positioned in the gap
Data Source
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AI summary
A high-field emission tolerant RFID tag device that may be secured to a product to be cooked, heated, reheated and/or thawed in a heating apparatus such as, but not limited to, a microwave oven and that does not need to be removed from the product before initiating the heating process. The RFID device is microwave safe and does not damage the product or food item to which it is attached during the microwave process, and may contain data to control the microwave process. The microwave safe RFID tag comprises a split ring (or shield) conductor formed on one side of a substrate (or dielectric), a coil antenna conductor formed on an opposite side of the substrate, and a RFID chip. The split ring conductor capacitively couples to the coil antenna conductor via the dielectric and a gap in the split ring conductor prevents arcing.