Abstract
Bio-implantable pressure sensors are of great significance for many life-threatening clinical applications that require real-time monitoring of the internal pressure of the human body. Wireless and bioresorbable capacitive pressure sensors overcome the shortcomings of the traditional, resistance-based pressure sensors (e.g., leading to infections and restrictions of natural body motion movements), but they have low sensitivity. One effective way to improve the sensitivity is to increase the volume of the dielectric (air) cavity. Analytic models are established in this paper for the deformation of the electrodes in the wireless and bioresorbable capacitive pressure sensor, and the models show explicitly the sensitivity dependence on the sensor geometry and material properties. The models show that the pressure increase in the air cavity overwhelms the bending stiffness of the electrodes, therefore dominating the deflection of the electrode in capacitors. The traditional strategy to reduce the initial separation between electrodes is not suitable. Instead, increasing the initial volume of the air cavity provides an effective strategy to improve the sensitivity of the bio-implantable wireless pressure sensors.