A wireless pressure sensor design using a microwave cavity resonator

A wireless pressure sensor based on a microwave cavity resonator is proposed herein. A metallic post is located at the center of the cavity to form an evanescent-mode tunable resonator and the resonant frequency depends on the air gap between the cavity cap and the post. When the cavity has a deformation resulted from external pressure, the resonant frequency is shifted. A slot antenna is integrated with this pressure sensor for wireless detection without occupying any additional volume. Simulation results show that the pressure sensor operates from 12.55 to 10.50 GHz corresponding to applied pressure from 0 to 100 psi. This proposed wireless passive pressure sensor is suitable for applications where physical contact or active elements are hard to be implemented.