Adjustable RFID Tag Resonant Frequency for Range Optimization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional RFID systems face reduced tag identification rates and increased system latency due to the need to hop between frequencies, which decreases the range of RFID tags operating at off-resonant frequencies, leading to suboptimal performance.
Innovation Solution
An RFID system with a variable radio frequency source and adjustable impedance blocks in RFID tags that allow the reader to dynamically change the resonant frequency of tags to match optimal communication frequencies, enhancing range and identification efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the RFID system operates at a single resonant frequency to maximize tag range, then tag identification rate is improved, but the system cannot comply with FCC frequency hopping requirements
Solution Approach 1:
The patent applies dynamics by making the tag resonant frequency adjustable rather than fixed. The tag impedance block can be dynamically reconfigured to change the resonant frequency, allowing the tag to adapt to different carrier frequencies used by the reader during frequency hopping operations
Solution Approach 2:
The patent changes the resonant frequency parameter of the tag by adjusting the impedance block configuration. This allows the tag to match different carrier frequencies (e.g., 902 MHz, 904 MHz, 906 MHz) used by the reader, maintaining optimal communication performance across frequency-hopped channels
2Adaptability or versatility
If the RFID system hops to off-resonant frequencies to comply with FCC regulations, then frequency diversity is achieved, but tag range decreases and system performance degrades
Solution Approach 1:
The dynamic adjustment of tag resonant frequency allows the tag to track the reader's carrier frequency throughout the frequency hopping sequence. This maintains the tag at or near resonance regardless of which frequency the reader is currently using, preserving tag range and identification performance
Solution Approach 2:
The system uses feedback mechanisms where the reader transmits pilot tones or training sequences that enable the tag to determine the current carrier frequency, and the tag adjusts its impedance block accordingly to maintain resonance with the active carrier frequency
3Ease of manufacture
If the RFID tag uses a fixed resonant frequency design, then manufacturing simplicity is maintained, but the system cannot adapt to frequency hopping causing increased latency
Solution Approach 1:
The patent introduces a dynamically reconfigurable impedance block that can switch between different resonant frequency configurations. This allows the tag to quickly adapt to frequency changes without requiring complex manufacturing, using relatively simple switched capacitor or inductor circuits
Solution Approach 2:
The tag is pre-configured with multiple impedance block settings corresponding to different resonant frequencies. During operation, the appropriate pre-configured setting is activated based on the current carrier frequency, enabling rapid adaptation without complex real-time calculations
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 increases RFID tag identification rates and system efficiency by ensuring communication at frequencies that maximize tag range, thereby reducing system latency and improving overall performance.
Implementation Method 1
The resonant frequency is that frequency at which the interrogation RF signal from the RFID reader 110, for example, causes the largest electrical response in the RFID tag 120
Data Source
AI summary
A radio frequency identification (RFID) system includes a plurality of RFID tags each having adjustable tag resonant frequency, and an RFID reader configured to transmit interrogation and change frequency RF signals. The interrogation and change frequency RF signals are transmitted at the current tag resonant frequency. The plurality of RFID tags modify the tag resonant frequency to a new tag resonant frequency in response to the change frequency RF signals. RFID tag identification rates may be enhanced by interrogating the plurality of RFID tags at the tag resonant frequency for a dwell time, receiving response RF signals, determining a new tag resonant frequency, and transmitting a change frequency RF signal that causes the RFID tags to change the tag resonant frequency to the new tag resonant frequency. The new resonant frequency may be based on the number of received responses.