Advanced Manufacturing of Passive Wireless High-Temperature Pressure Sensor Using 3-D Laser Machining

Recent radio-frequency resonance-based hightemperature sensors have enable the next generation of passive wireless sensing for harsh environments, such as inside of jet engines. A novel manufacturing technique for an evanescentmode-resonator-based and antenna-integrated wireless passive pressure sensor is proposed therein. This technique employs a planar PCB manufacturing tool to laser etch a 3-D structure on an alumina substrate. A laser machining study is conducted to find etch consistency and fine-tune laser etching parameters. The wireless passive pressure sensor is tested through various mechanical and thermal loads to measure its performance. The sensor is proven to work in the range of $25^{\circ}\mathrm{C} -1700^{\circ}\mathrm{C}$, sensing pressures of 0 psi to 163 psi with resonances within the frequency range of 6.33 GHz--6.7 GHz.