Transparent Flexible Active Faraday Cage Enables In Vivo Capacitance Measurement in Assembled Microsensor

Area of Science:

• Electrical Engineering
• Biomedical Engineering
• Sensor Technology

Background:

• Capacitive micro-sensors (accelerometers, gyroscopes, pressure sensors) are vital in modern electronics.
• In vivo applications of capacitive sensing face significant errors from stray capacitance.
• Accurate internal body measurements require mitigation of these capacitive interference effects.

Purpose of the Study:

• To propose and validate a novel solution for eliminating stray capacitance in in vivo capacitive micro-sensors.
• To enhance the precision and reliability of internal physiological measurements.
• To enable accurate real-time monitoring of pressure and other variables within the human body.

Main Methods:

• Development of a transparent, thin, flexible Faraday cage surrounding the capacitive sensor.
• Simultaneous application of active sensing voltage to the sensor's electrode and the Faraday cage.
• Experimental testing involving full sensor immersion in water to quantify stray capacitance reduction.

Main Results:

• The proposed Faraday cage effectively shields the capacitive sensor from external electrical interference.
• Stray capacitance was reduced by a factor of 10 during in vivo measurement simulations (full immersion in water).
• The transparent nature of the cage facilitates accurate sensor assembly and alignment.

Conclusions:

• The transparent thin flexible Faraday cage is a viable and effective solution to mitigate stray capacitance in in vivo capacitive micro-sensors.
• This technology significantly improves the accuracy of internal body measurements, paving the way for more reliable biosensors.
• The method offers a practical approach to enhance the performance of implantable sensing devices.