RFID Receiver Power Prioritization Using Field Strength Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing RFID systems lack an effective method to quantify and maximize received RF field strength as a function of induced current, which is essential for optimizing power transfer and impedance matching, especially in power-sensitive environments.
Innovation Solution
A sensing system for RFID systems that includes a tank circuit with selectively variable impedance and a detector circuit to quantify RF field strength, allowing the RFID reader to dynamically adjust impedance to maximize power transfer with minimal power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage quantization is used to match tank circuit frequency to transmission frequency, then frequency matching is achieved, but received power maximization is not effectively achieved because voltage quantization is indirectly related to received signal field strength
Solution Approach 1:
The patent changes the measurement parameter from voltage quantization to current quantization. The field strength detector quantizes the current induced in the tank circuit, which is directly proportional to received signal field strength. This parameter change enables direct optimization of received power while maintaining frequency matching capability.
2Power
If dynamic impedance variation is implemented to maximize received power, then power transfer is optimized, but power loss increases due to additional circuit complexity
Solution Approach 1:
The patent implements a self-service mechanism where the field strength detector automatically quantizes received signal strength and feeds back control signals to the impedance controller. The system self-adjusts tank circuit impedance without external intervention, maximizing received power while minimizing power loss through automated optimization.
Solution Approach 2:
The patent establishes a feedback loop where the field strength detector continuously monitors current quantization and sends control signals back to the impedance controller. This feedback mechanism enables real-time impedance adjustment to maintain optimal power transfer while minimizing energy loss.
3Power
If current quantization is implemented to directly measure field strength, then received power can be maximized, but device complexity increases due to additional detector circuitry
Solution Approach 1:
The patent merges the field strength detection function with the existing RFID tag circuitry. The field strength detector is integrated into the tag's existing structure, sharing components with the tank circuit and impedance control mechanisms. This consolidation enables current quantization and power optimization while minimizing additional device complexity.
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 system effectively quantizes RF field strength, enabling the RFID reader to selectively vary impedance and maximize received power, even in challenging environments, by using a field strength detector to adjust the tank circuit's operating characteristics.
Implementation Method 1
the amplitude modulated ('AM') signal broadcast by the reader in an RFID system will be electromagnetically coupled to a conventional antenna, and a portion of the current induced in a tank circuit is extracted by a regulator to provide operating power for all other circuits
Data Source
AI summary
A method includes transmitting, by a radio frequency identification (RFID) reader, a series of RF signals to a plurality of RF receiver circuits in a time sequence. The first RF signal commands the plurality of RF receiver circuits to remain silent when received signal strength of the first RF signal corresponds to a power level greater than a first power level. The method further includes receiving one or more sets of responses from one or more sets of RF receiver circuits of the plurality of RF receiver circuits in response to the series of RF signals. The method further includes determining an area of interest based on the one or more sets of responses, determining a set of power levels corresponding to the area of interest, and transmitting a second series of RF signals to the plurality of RF receiver circuits in a second time sequence.