Self-Adaptive RFID Resonator for High-Q Power and Fast Communication
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Solution Overview
Problem
RFID tags face challenges in achieving high Q operation for efficient energy transfer and communication due to limited tag Q values, which result in narrow frequency bands and insufficient bandwidth for communication, making them susceptible to environmental detuning and manufacturing variations.
Innovation Solution
The implementation of a self-adaptive resonator that separates powering and communication cycles, using a high Q resonator to derive power and switch to a conventional linear resonator for communication, along with a tuning circuit and negative feedback to maintain high Q behavior and extend range while enabling fast communication responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a high Q resonator is used to improve energy transfer efficiency, then the voltage step up increases, but the frequency band becomes very narrow making the system susceptible to environmental detuning
Solution Approach 1:
The patent applies dynamics by making the resonator frequency可调 (adjustable) to track the reader frequency. The resonator is designed with variable capacitance or inductance that can be dynamically tuned during operation, allowing the system to maintain high Q operation at the optimal frequency while adapting to environmental changes and reader frequency variations.
Solution Approach 2:
The patent changes the resonant frequency parameter of the tag resonator to match the reader frequency. By adjusting the resonator's electrical parameters (capacitance or inductance), the system maintains resonance at the desired frequency, thereby preserving energy transfer efficiency while adapting to different operating conditions.
2Loss of energy
If a high Q resonator is used to increase voltage step up, then power transfer efficiency improves, but the bandwidth for communication becomes insufficient
Solution Approach 1:
The patent uses a dynamically可调 resonator that can operate at high Q for power transfer, then quickly adjust its frequency or coupling to provide sufficient bandwidth for communication. The resonator's adjustable nature allows it to optimize for power transfer during the powering phase and then provide adequate bandwidth during the communication phase.
3Length of stationary object
If the resonator Q is increased to extend tagging range, then the voltage step up increases, but the resonance width drops proportionally
Solution Approach 1:
The patent employs a dynamically可调 resonator that maintains high Q for extended range while being able to adapt its frequency to match the reader. The adjustable resonator can achieve the necessary voltage step up for long-range operation while tracking the reader frequency to maintain resonance, thereby extending tagging range without sacrificing adaptability.
4Loss of energy
If a self-adaptive resonator is used to achieve high Q operation, then power derivation efficiency improves, but the system complexity increases
Solution Approach 1:
The patent implements a self-adaptive resonator that automatically tracks the reader frequency without requiring complex external control systems. The resonator uses feedback from the reader field to automatically adjust its frequency, achieving high Q operation and efficient power derivation while minimizing the need for additional control circuitry and reducing overall system complexity.
Solution Approach 2:
The self-adaptive resonator incorporates feedback mechanisms that use the reader's electromagnetic field as a reference to automatically tune the resonator frequency. This feedback-based approach enables the resonator to maintain high Q operation and track reader frequency changes automatically, achieving efficient power derivation without requiring complex external control systems.
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 approach allows for extended range and improved tolerance to environmental detuning, enabling efficient power derivation and fast communication while maintaining high Q operation for both powering and communication phases.
Implementation Method 1
RFID generally employs resonance in order to increase the efficiency of energy transfer from the reader to the tag. This is achieved through the resonant recycling of energy that results in voltage step up in the tag when subject to the reader powering field.
Implementation Method 2
The self-adaptive resonator is used to derive power from the reader field
Implementation Method 3
The resonator is first used to derive power from a field generated by a RFID reader
Data Source
AI summary
We describe RFID tags that incorporate a nonlinear resonator that self-adapts to the driving frequency of a reader. More particularly we describe an RF tag for sending data to a tag reader by modulating energy drawn from an RF field of said tag reader, the tag comprising: an antenna; a resonant circuit coupled to said antenna to resonate at a frequency of said RF field; a local power store to store power extracted from said RF field; a modulation system to modulate one or both of the resonance amplitude and a relative phase of a signal in said resonant circuit with respect to said RF field; and a feedback circuit coupled to said resonant circuit and to said local power store to control one or both of said resonance amplitude and said relative phase to control transients in said resonance amplitude caused by said modulation.