Dual System RFID Tag Rectifier Impedance Optimization
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Solution Overview
Problem
Typical RFID tags face challenges in achieving both high bandwidth and strong return link signals due to conflicting requirements between charge pump and diode rectifiers, particularly in HF transponders, where low minimum input voltage is needed for bandwidth but high voltage swing is required for a strong return link.
Innovation Solution
A combined system using a charge pump rectifier and a diode-based rectifier working on the same antenna and frequency, where the charge pump rectifier system adjusts the operating point of the diode rectifier system to achieve low minimum voltage for high bandwidth and strong return link signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a charge pump rectifier is used to achieve low minimum input voltage for high bandwidth, then bandwidth is improved, but return link signal strength deteriorates
Solution Approach 1:
The rectifier system is segmented into two independent rectifier circuits: a charge pump rectifier optimized for bandwidth and a diode rectifier optimized for return link signal strength. Each rectifier operates independently to address different performance requirements, resolving the contradiction between bandwidth and signal strength.
Solution Approach 2:
Different parts of the system are assigned different functional qualities: the charge pump rectifier provides low minimum input voltage characteristics for bandwidth optimization, while the diode rectifier provides high voltage swing characteristics for return link optimization. Each component is optimized for its specific local function.
2Reliability
If a diode rectifier is used to achieve high voltage swing for strong return link, then return link signal strength is improved, but bandwidth deteriorates
Solution Approach 1:
The system divides the rectification function into two separate circuits with different topologies. The diode rectifier is segmented as a dedicated circuit for return link optimization, while the charge pump rectifier handles bandwidth requirements, eliminating the need to compromise either performance metric.
Solution Approach 2:
The dual rectifier system provides multi-functionality by simultaneously supporting both bandwidth optimization and return link optimization through two independent rectification paths. The system can utilize both rectifiers together to achieve comprehensive performance.
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 configuration enables RFID tags to operate efficiently with a low minimum voltage for high bandwidth and strong return link signals, improving overall system performance by optimizing input impedance and signal strength.
Implementation Method 1
A dual rectifier system is disclosed, which includes a charge pump rectifier and a diode rectifier
Implementation Method 2
The reader is a device that has one or more antennas that emit radio waves and receive signals back from the RFID tag
Data Source
Figure 1~2
Figure 3~5
AI summary
A Radio Frequency Identification (RFID) tag is disclosed. The RFID tag includes an antenna to receive an input AC signal and a tuning system coupled with the antenna to optimize signal strength of the input AC signal. The tuning system includes a charge pump rectifier. A diode rectifier is included and is coupled with the antenna to receive the input AC signal after the tuning system optimizes the signal strength by tuning input impedance of the antenna.