Minimizing a Wireless Passive LC-Tank Sensor to Monitor Bladder Pressure: A Simulation Study

Area of Science:

• Biomedical Engineering
• Sensor Technology
• Wireless Communication

Background:

• Continuous bladder monitoring is crucial for managing various medical conditions.
• Existing monitoring systems may be invasive or lack long-term usability.
• Wireless passive sensors offer a promising alternative for unobtrusive monitoring.

Purpose of the Study:

• To characterize a wireless passive LC-tank sensor system for continuous bladder monitoring.
• To propose and simulate a specific system design, including coil geometries and circuitry.
• To determine the operational limits and requirements for an implantable version of the sensor.

Main Methods:

• Spatial mapping of coupling coefficients via simulation, varying coil distance and sensor translation.
• Simulation of two interrogation schemes: auto-balancing bridge and a simplified implantable circuit.
• Analysis of noise limits, required Analog-to-Digital Converter (ADC) resolution, and system performance using Monte Carlo simulations.

Main Results:

• Coupling coefficients were mapped as a function of spatial parameters.
• The theoretical noise limit of the analog circuitry was determined.
• The simplified implantable system requires a 14-bit ADC and can tolerate a 27 dB carrier SNR.
• Successful operation was demonstrated for distances up to 12mm (coupling coefficient > 0.005).

Conclusions:

• The proposed wireless passive LC-tank sensor system is feasible for continuous bladder monitoring.
• The system demonstrates robust performance within specified operational ranges and noise tolerances.
• The simulation results provide critical design parameters for developing an implantable bladder monitoring device.