Variable-Frequency Transponder for Medical Object Detection
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Solution Overview
Problem
Existing methods for detecting wirelessly detectable objects in medical settings, such as surgical sponges and instruments, face challenges in identifying specific objects within a group and maintaining detection accuracy, especially when obstacles are present or under interference, and often require manual, time-consuming processes prone to errors.
Innovation Solution
A wirelessly detectable object system utilizing a passive variable-frequency transponder circuit powered by an interrogation signal, which generates a variable-frequency response signal to produce a characteristic signature, allowing for unique identification and robust detection, even through obstacles, using a combination of inductors, varactor diodes, and capacitors to vary the frequency of the response signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional RFID transponders are used to identify specific objects, then object identification capability is improved, but detection range is reduced and detection through obstacles is inhibited
Solution Approach 1:
The patent changes the frequency parameter of the response signal dynamically. The transponder modulates its response signal frequency based on the strength of the received interrogation signal, allowing it to operate effectively at lower frequencies that penetrate obstacles better while maintaining identification capability through frequency modulation patterns.
Solution Approach 2:
The system dynamically adjusts the response signal frequency in real-time based on signal strength conditions. This dynamic adaptation allows the transponder to optimize between identification accuracy and detection range/obstacle penetration by varying operational parameters during the interrogation process.
2Device complexity
If transponders transmit identifiers at fixed frequencies, then identification is simplified, but detection accuracy under interference is reduced
Solution Approach 1:
The transponder varies the frequency parameter of its response signal dynamically during each interrogation cycle. This frequency variation creates a distinctive modulation pattern that enables reliable identification even in noisy environments, as the frequency-modulated signal can be distinguished from constant-frequency interference.
Solution Approach 2:
The system employs periodic frequency modulation of the response signal during each interrogation cycle. This periodic variation creates a recognizable pattern that enhances detection reliability under interference, allowing the receiver to distinguish the transponder signal from background noise through pattern recognition.
3Device complexity
If manual counting procedures are used to track objects, then system complexity is reduced, but productivity and accuracy are worsened
Solution Approach 1:
The transponder automatically responds to interrogation signals without requiring manual intervention. Each transponder independently modulates its response frequency based on received signal strength, enabling automated tracking and counting of objects, which significantly improves productivity while maintaining manageable system complexity through simple passive operation.
4Use of energy by moving object
If transponders operate at constant frequency, then power consumption is minimized, but ability to produce unique identification signature is reduced
Solution Approach 1:
The transponder changes the frequency parameter of its response signal dynamically during each interrogation cycle. This frequency modulation creates a unique identification signature for each transponder while maintaining passive operation that minimizes power consumption, as the frequency variation is achieved through natural signal strength-dependent modulation rather than active frequency synthesis.
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
Enables accurate and efficient detection of specific objects, reducing the risk of errors and manual labor, while maintaining detection capability through obstacles and minimizing interference, thus improving the reliability of tracking objects during medical procedures.
Implementation Method 1
a passive variable-frequency transponder circuit that is communicatively coupled to the at least one antenna, the passive variable-frequency transponder circuit powered by an interrogation signal received via the at least one antenna from an external source
Implementation Method 2
The passive variable-frequency transponder circuit may include at least one inductor and at least one varactor diode, the varactor diode which has a variable capacitance that depends at least in part on a control voltage
Data Source
AI summary
Methods and apparatus are disclosed for detecting a wirelessly detectable object. The wirelessly detectable object may include an antenna and a passive variable-frequency transponder circuit that is communicatively coupled to the antenna. The passive variable-frequency transponder circuit is powered by an interrogation signal received from an external source, and returns via the antenna a wireless response signal having a frequency that varies over a single interrogation cycle. Such variation may be based upon a decaying control voltage that controls the value(s) of one or more components in the passive variable-frequency transponder circuit and/or a switch that selectively couples and decouples components in the passive variable-frequency transponder circuit. The variable frequency may provide a characteristic signature for the wireless response signal that may be used to identify the wirelessly detectable object.