HF RFID Tag Coil Layout for Induction Sealing Interference
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Solution Overview
Problem
High Frequency (HF) RFID tags face failure due to voltage induction during induction sealing and interference from metallic sealing foils, which hinder their performance without requiring additional shielding materials.
Innovation Solution
The RFID tag is partitioned into a main coil for semiconductor operations and an auxiliary coil acting as a resonator, both on separate regions of a dielectric substrate, with no galvanic connection, to manage induced voltages and eddy currents, using magnetic coupling for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional RFID tag is used in induction sealing arrangement, then the tag can be integrated into the container, but the voltage induced in the antenna coil during induction sealing exceeds the safe working limit of the semiconductor chip
Solution Approach 1:
The antenna coil is divided into two separate coils: a main coil for RFID communication and an auxiliary coil for induction sealing. This segmentation allows each coil to be optimized for its specific function, with the auxiliary coil handling the induction sealing voltage while the main coil remains protected for RFID operations.
Solution Approach 2:
The auxiliary coil acts as an intermediary element that interfaces between the induction sealing system and the RFID tag. It absorbs the high voltage induced during induction sealing, protecting the semiconductor chip and main coil from damage while enabling the RFID tag to function within the induction sealing arrangement.
2Loss of information
If an HF RFID tag is placed inside the container, then the consumer can verify authenticity and gather product information, but the metallic sealing foil generates eddy currents that hinder the proper performance of the RFID tag
Solution Approach 1:
By separating the antenna into main and auxiliary coils with distinct functions, the system can maintain RFID communication effectiveness while the auxiliary coil manages the interaction with metallic sealing foil, reducing eddy current interference.
Solution Approach 2:
The auxiliary coil is designed with specific geometric parameters and is tuned to resonate at the induction sealing frequency, which allows it to counteract the eddy currents generated by the metallic sealing foil and maintain RFID tag performance.
3Reliability
If shielding material like ferrite is used to protect the RFID tag, then the tag performance is improved, but additional costs are incurred
Solution Approach 1:
The auxiliary coil serves dual purposes: it enables induction sealing functionality and simultaneously provides shielding against eddy currents from the metallic sealing foil. This self-service approach eliminates the need for separate ferrite shielding materials, reducing costs while maintaining performance.
Solution Approach 2:
The auxiliary coil is designed to perform multiple functions: inducing voltage during induction sealing, shielding the main coil from eddy currents, and resonating at the operating frequency to enhance RFID performance. This multi-functionality replaces what would traditionally require multiple separate components including ferrite shielding.
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 maintains safe voltage levels for the semiconductor chip and provides shielding against eddy currents, improving read range and performance in induction sealing environments.
Implementation Method 1
the auxiliary coil operates as a resonator tuned to a certain frequency to provide shielding against the deleterious effect of the metal seal
Implementation Method 2
using magnetic coupling for enhanced performance
Implementation Method 3
The Induction sealing apparatus generates a strong time-varying (nominally sinusoidal) magnetic field that can penetrate the plastic or glass container and generate eddy currents on the metallic foil in the liner
Implementation Method 4
generate eddy currents on the metallic foil in the liner. The heat generated in the foil melts the low melting point wax-like substance
Data Source
AI summary
A Radio Frequency Identification Device (RFID) tag capable of withstanding electrical stress from induction sealing arrangement and provide shielding against the metallic seal required for induction sealing includes an antenna coil partitioned into a main coil and an auxiliary coil. Both the coils are collocated on two separate overlapping or non-overlapping regions of a dielectric substrate without any galvanic connection therebetween. The main coil is operatively connected with semiconductor chip on the dielectric substrate for necessary RFID activities, while the auxiliary coil operates as a resonator tuned to a certain resonating frequency that enables the auxiliary coil to act as a virtual open circuit to induction sealing frequency and help the semiconductor chip to withstand the electrical stress from induction sealing. The auxiliary coil carries a current during interrogation of the tag by an RFID Reader which provides shielding against eddy currents on the metal seal for induction sealing.