A Flexible Passive Wireless Permeation Sensor for Implantable Biomedical Electronics

Biological fluids permeation can lead to the failure of implantable biomedical electronics and endanger patient health. Real-time monitoring of fluids permeation is critical to the safe operation of electronics. In this paper, we propose a flexible passive wireless permeation sensor for implantable biomedical electronics. The proposed sensor system is realized based on the principle of magnetic coupling and LC resonance. It is composed of a sensing front end and readout circuit, enabling wireless permeation detection and do not need internal power supply. The sensing front end is made from flexible printed circuit (FPC) material and the maximum implant depth can reach 15.24 mm. When the sensor is fully coupled without offset, the sensing sensitivity achieves 2720 mV/mm. The footprint of the implant sensor is 314.16 mm². Moreover, it has high sensitivity to the permeation of different body fluids and can be well adapted to multifarious implantation environments. This paper shows the potential of passive wireless method in permeation detection of the implantable biomedical electronics.