Bistatic RF Switch Matrix for Incontinence Pad Validation
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Solution Overview
Problem
Existing wireless incontinence detection systems face signal-to-interference ratio issues due to strong interfering signals from the antenna and biological tissue, leading to communication channel degradation and difficulty in detecting weak signals from RFID tags.
Innovation Solution
The system employs a bistatic RF switch matrix with multiple antennae configurations for efficient energy transmission and data reception, using a frequency hopping scheme and ceramic patch antennae to improve signal isolation and prevent conductive paths from patient fluids, coupled with remote validation and encryption for secure data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a monostatic architecture with hybrid directional coupler is used for wireless communication, then the system structure is simplified, but the signal-to-interference ratio deteriorates due to strong coupling between transmitter and receiver ports
Solution Approach 1:
The patent divides the single antenna into separate transmit and receive antennas (spatial segmentation), physically isolating the transmitter and receiver paths to eliminate mutual coupling interference while maintaining wireless communication functionality
Solution Approach 2:
The patent introduces a circulator as an intermediary component that directs signal flow between the transmitter, antennas, and receiver, enabling isolation between transmit and receive paths while allowing simultaneous operation
2Ease of manufacture
If the antenna impedance deviates from transmission line characteristic impedance, then the matching is simplified, but the reflected power creates strong interference that overwhelms the weak backscattered signal
Solution Approach 1:
The patent converts the harmful reflected power into a beneficial indicator by using it to detect pad validation status, transforming the interference problem into a useful diagnostic function
Solution Approach 2:
The circulator acts as an intermediary that isolates the receiver from reflected power, preventing the strong reflected signals from overwhelming the weak backscattered RFID signals
3Measurement precision
If RFID systems are placed in close proximity to patient's body, then the detection sensitivity is improved, but communication channel degradation occurs due to interaction with biological tissue and body fluids
Solution Approach 1:
The patent uses backscattered RFID technology where the RFID tag modulates the reflected electromagnetic signal, allowing wireless communication without direct electrical contact with the patient, thus maintaining detection capability while avoiding tissue interaction issues
4Duration of action of moving object
If forward power coupling and reflected power are present in the receiver, then the system operates continuously, but the receiver experiences overload and intermodulation distortion that impacts performance
Solution Approach 1:
The circulator serves as an intermediary component that directs transmitted power away from the receiver input, preventing forward power coupling and reflected power from causing receiver overload and distortion while allowing continuous operation
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 enhances the signal-to-interference ratio, improves communication reliability, and prevents false positives from patient fluids, ensuring accurate detection and secure data handling.
Implementation Method 1
a passive radio frequency identification (RFID) tag... establish a first antenna of the plurality of antennae as a transmit antenna that may be used to wirelessly energize the passive RFID tag and to establish a second antennae of the plurality of antennae as a receive antenna that may be used to read backscattered data that may be emitted from the passive RFID tag
Data Source
AI summary
An incontinence detection pad has an RFID tag in which an authentication code, such as an electronic product code (EPC), is stored. A reader in wireless communication with the RFID tag of the incontinence detection pad verifies that the incontinence detection pad is an authorized detection pad. Thus, unauthorized incontinence detection pads that do not have the proper authentication code are not able to be used in an incontinence detection system.