Antenna Impedance Adjustment for Access Control Credential Detection
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Solution Overview
Problem
Existing credential readers face issues with high power consumption, reduced credential detection range, and high false detection rates due to environmental factors and component variations, which are exacerbated by calibration limitations and design variations in lock hardware.
Innovation Solution
The implementation of a credential reader system with an antenna circuit that adjusts impedance based on I and Q values from received signals, allowing for dynamic calibration and reduced false detections while maintaining sensitivity, using a processor to execute instructions and adjust antenna impedance in response to false detection signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the range of allowable impedance values is increased to reduce false detections, then false detection rate decreases, but credential detection sensitivity is reduced and effective range is significantly reduced
Solution Approach 1:
The patent implements dynamic impedance adjustment by continuously monitoring I and Q values and automatically tuning the antenna circuit impedance to maintain optimal detection parameters. This dynamic adaptation allows the system to maintain high sensitivity while rejecting false detections, as the impedance is continuously optimized rather than fixed at a conservative value that would reduce sensitivity.
Solution Approach 2:
The system changes the impedance parameter of the antenna circuit based on monitored I and Q values. By adjusting impedance dynamically according to actual operating conditions and signal characteristics, the system can maintain optimal detection sensitivity while filtering out false detections, rather than using a fixed wide impedance range that would reduce sensitivity.
2Measurement precision
If credential detection sensitivity is maintained at high levels, then credential detection range is improved, but false detection rate increases due to environmental factors and component variations
Solution Approach 1:
The patent employs feedback mechanisms by monitoring I and Q values from the received signals and using this information to adjust impedance settings. This closed-loop feedback allows the system to distinguish between genuine credential signals and false detections caused by environmental factors or component variations, maintaining high sensitivity while improving reliability through continuous optimization based on actual signal characteristics.
3Reliability
If impedance adjustment mechanisms are added to dynamically calibrate antenna circuit, then false detection rate decreases and detection reliability improves, but device complexity increases
Solution Approach 1:
The patent implements self-service by enabling the antenna circuit to automatically monitor its own I and Q values and perform self-adjustment of impedance parameters without external intervention. This self-calibrating capability reduces false detections and improves reliability while minimizing the need for additional complex external calibration equipment or manual adjustment mechanisms.
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 reduces false detection rates, conserves power, and maintains the credential detection range by dynamically adjusting antenna impedance, thereby enhancing the reliability and efficiency of access control systems.
Implementation Method 1
an antenna circuit having an antenna to transmit and to receive a signal
Implementation Method 2
demodulating the received modified energizing signal to determine an I value and a Q value of the received modified energizing signal
Implementation Method 3
adjusting a component of the antenna circuit as a function of one of the I value and the Q value
Data Source
AI summary
An access control device including a credential reader circuit structured to enter a standby mode, awaken from the standby mode, and receive data from a nearby credential, and a credential detection circuit. The credential detection circuit includes a memory configured to store program instructions, an antenna circuit, and a processor electrically coupled to the antenna circuit and to the credential reader circuit, wherein the processor configured to execute the stored program instructions to: transmit an energizing signal; receive a modulated energizing signal with the antenna circuit; transmit an activation signal to the credential reader circuit in response to the received modulated energizing signal, wherein the received modulated energizing signal includes I and Q values; receive a false detection signal from the credential reader circuit; and adjust an impedance of the antenna circuit.