A fixed-fixed beam MEMS microwave power sensor fabricated on GaAs substrate

This paper presents the design, fabrication, and measurements of a fixed-fixed beam MEMS microwave power sensor. The sensor measures microwave power coupled from CPW transmission line by a MEMS membrane and then measured by the thermopiles. Since the fabrication process is fully compatible with the GaAs process, the power sensor could be embedded into monolithic microwave integrated circuit (MMIC) conveniently. From the measured S-parameters, the average sensitivity of the MEMS microwave power sensor in X-band is 77.56 ¿V.mW^-1 and the insertion loss is lower than 4 dB with the reflection loss is below -12 dB. In addition, the measurements under amplitude modulation (AM) signals prove that the modulation index influences the output DC voltage directly.