EVALUATION OF LC RESONANT PRESSURE SENSOR FOR SMART STENT APPLICATION

This paper aims to project the design and evaluation of inductor capacitor (LC) pressure sensor for smart stent application. The sensor was fabricated through ultraviolet (UV) patterning process using SU-8 polymer material because of its biocompatibility and suitability to fabricate small patterns. In the second phase of the research illustrates the measurement of pressure difference of blood and wireless monitoring inside the coronary artery having a stent implant equipped with LC resonant pressure sensor. This rectangular shaped pressure sensor (with and area of 4 x 4 mm^2), consists of an inductive coil and a capacitive plate, which exactly matches with the radio frequency-identification (RFID) design. The LC pressure sensor circuit is able to communicate with external antenna by matching the resonance frequency of both circuits. The fabricated sensor has 1.3 pF capacitance, 100 nH inductance with the resonance frequency about 440 MHz. The fabricated sensor is placed in a small vacuum chamber and the chamber pressure is controlled by using a syringe pump. The change of 100 MHz in the resonance frequency is observed in a pressure range of 0 to 16 kPa. Through a series of experimental analysis, it has been perceived that the discussed sensor can effectively measure pressure difference inside the vacuum and the change in resonance frequency can be further detected by using wireless equipment. The sensor can be widely used in the applications to effectively monitor the pressure difference of blood inside the human coronary artery.