A Magnetic-Polymer-Based Passive Pressure Sensor Realized with a Foldable Parylene Substrate

In this work, we propose a wireless passive pressure sensor, which is designed for monitoring cardiovascular pressure. The device consists of an LC tank and a magnetic polymer film with tapered microstructures. The LC tank includes a micromachined parallel-plate capacitor and an inductor coil connected in series. External pressure applied on the magnetic polymer film changes the LC tank's resonant frequency, which can be wirelessly retrieved using the phase-dip technique. The corresponding relationship between the resonant frequency and the applied pressure is presented. The pressure sensitivity of the proposed device is about 0.113 MHz/mmHg in the pressure range of 0-300 mmHg. The measured results also showed that the proposed sensing mechanism has a wide range of linearity of pressure sensing.