RFID Reader Leakage Cancellation Using Baseband IQ Control
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Solution Overview
Problem
Existing RFID readers face challenges in quickly and effectively removing self-jamming signals due to transmission signal leakage, which degrades reception quality and increases reading time, especially in UHF frequency bands, and require complex circuitry that is difficult to implement digitally.
Innovation Solution
A digital leakage canceling device for RFID readers that utilizes a coupling unit, RF/Analog transceiving unit, leakage cancellation controller, and attenuation and amplification unit to convert transmission leakage signals into baseband IQ signals, calculate phase and magnitude, and cancel them using dual leakage cancellation amplifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a typical general RFID receiver uses a phase variant generation circuit and amplitude adjustment summation circuit to remove self-jamming signals, then the self-jamming signal removal is achieved, but the reading time increases and recognition distance is reduced
Solution Approach 1:
The patent replaces the conventional analog circuit-based self-jamming cancellation system with a digital signal processing system. The digital leakage canceling device uses digital circuits to generate anti-phase signals and perform summation, substituting the mechanical/analog phase variant generation circuit and amplitude adjustment summation circuit with digital equivalents that operate faster and enable parallel processing, thereby reducing reading time while maintaining self-jamming removal capability
Solution Approach 2:
The patent changes the operational parameters from analog domain to digital domain. By converting the signal processing to digital, the system achieves faster processing speeds and improved timing characteristics. The digital implementation allows for precise control of phase and amplitude parameters through digital signal processing algorithms, enabling rapid cancellation of self-jamming signals without extending reading time
2Length of stationary object
If the transmission signal intensity is increased to read tags at distance, then the recognition distance is improved, but the transmission signal leakage increases and degrades reception quality
Solution Approach 1:
The patent applies preliminary anti-action by generating an anti-phase leakage cancellation signal before the leaked transmission signal interferes with the reception signal. The digital leakage canceling device creates a cancellation signal that is equal in magnitude but opposite in phase to the expected leakage signal, and combines it with the reception signal in advance. This preliminary counteraction neutralizes the harmful leakage effect, allowing high-power transmission for extended recognition distance without degradation of reception quality
Solution Approach 2:
The patent introduces a digital leakage canceling device as an intermediary between the transmission and reception paths. This intermediary component processes the transmission signal to generate a leakage cancellation signal, which acts as a mediator to counterbalance the harmful leakage. The digital signal processing unit serves as an intermediate processing stage that separates the transmission and reception functions, enabling high-power transmission while protecting the sensitive reception function from leakage interference
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 enables rapid and effective removal of transmission leakage, enhancing RFID recognition distance and reducing signal degradation, thus improving reading efficiency and reducing circuit complexity.
Implementation Method 1
an RF/Analog transceiving unit converting the transmission leakage signal into a baseband IQ signal
Implementation Method 2
converting the transmission leakage signal into a baseband IQ signal
Data Source
AI summary
The present invention discloses a digital leakage canceling device of an RFID reader and a method thereof. The device includes: a coupling unit configured to couple an antenna signal and a power amplifier signal; an RF/Analog transceiving unit configured to convert a transmission leakage signal generated in the coupling unit into a baseband IQ signal and generate a transmission leakage removal signal as an IQ code to cancel the transmission leakage; a leakage cancellation controller configured to receive the converted baseband IQ signal, calculate a magnitude and a phase of the signal, and output a leakage cancellation control signal; and an attenuation and amplification unit configured to attenuate a magnitude of the coupled signal, amplify an RF transmission signal output from the RF/Analog transceiving unit using a built-in power amplifier, and transmit the amplified signal to the coupling unit.