Mobile Handheld Antenna With Real-Time Impedance Tuning
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Solution Overview
Problem
In operating rooms, manual counting and tracking of surgical tools are time-consuming, error-prone, and resource-intensive, and existing mobile RFID tag readers face interference from environmental objects, leading to unreliable readings.
Innovation Solution
A mobile tag reader system with a real-time antenna tuning circuit that adjusts impedance in response to nearby objects, using an array of controllable elements to maintain stable power return loss and ensure reliable RFID tag communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a mobile reader is used instead of a stationary container reader, then handling time of tools is dramatically reduced and productivity is improved, but the antenna becomes more susceptible to interference from environmental objects causing unreliable readings
Solution Approach 1:
The patent implements real-time dynamic impedance tuning of the antenna by adjusting circuit components while the mobile reader is in operation. This allows the antenna to adapt its electrical characteristics to compensate for changing environmental conditions and interference from nearby objects, maintaining reliable RFID communication despite the mobile platform's vulnerability to environmental factors.
Solution Approach 2:
The system changes the electrical parameters of the antenna, specifically its impedance, in real-time based on detected interference conditions. By adjusting parameters such as capacitance and inductance through variable components, the antenna maintains optimal performance across varying environmental conditions encountered during mobile operation.
2Device complexity
If the antenna impedance is fixed, then the device complexity is reduced, but the antenna cannot compensate for impedance changes caused by nearby objects leading to unreliable tag reading
Solution Approach 1:
The antenna circuit transitions from a fixed impedance design to a dynamic impedance tuning system. Variable capacitors and inductors are incorporated into the antenna circuit, controlled by a microcontroller that adjusts these components in real-time to maintain optimal impedance matching despite environmental interference, thereby improving reliability without excessive complexity.
Solution Approach 2:
The system implements a feedback mechanism where the microcontroller monitors RFID reading quality and environmental conditions, then adjusts the antenna impedance accordingly. This closed-loop control ensures the antenna maintains optimal performance by continuously adapting to changing conditions, with the feedback signal guiding the impedance adjustment process.
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 enables efficient, error-free tracking of surgical tools by maintaining reliable RFID communication despite environmental interference, reducing handling time and improving patient safety and operational efficiency.
Implementation Method 1
a real-time antenna tuning circuit to adjust the impedance of the antenna in the mobile part to overcome interference caused by the influence of objects near the antenna
Data Source
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AI summary
A tag reader, including: a. a mobile part having an antenna for positioning near a group of tags, transmitting a power signal to the tags and receiving a response from the tags; wherein the antenna has an internal impedance that increases or decreases responsive to objects located in its vicinity; b. a reader base for providing the power signal to the mobile part and for storing and analyzing information read from tags; and c. a real-time antenna tuning circuit for adjusting the impedance of the antenna; wherein the mobile part, reader base and real time antenna tuning circuit are wired together to transfer the power signal from the reader base to the antenna through the real-time antenna tuning circuit, and wherein the real-time antenna tuning circuit monitors the power signal and adjusts the impedance of the antenna responsive to a determination in real-time of power return loss from the antenna.