GaAs MMIC fabrication for the RF MEMS power sensor with both detection and non-detection states

This paper presents the GaAs MMIC fabrication for the coupled RF MEMS power sensor with an impedance matching structure for improving the microwave performance, a capacitance compensating structure for obtaining the wideband response, and two shunt capacitive MEMS switches for achieving the conversion of the detection and non-detection state. In the fabrication process, we focus on discussing three key techniques of the fabrication such as the release of the MEMS membrane and switches, the protection of thermopiles and the process of the backside cavity, and propose the effects of these techniques on the power sensor. The validity of the fabrication is analyzed by the experiments, with the reflection and insertion losses of less than −17 dB and 0.8 dB in the detection state as well as that of less than −19 dB and 0.6 dB in the non-detection state, and the good power handing capability. Furthermore, the measured resistance of the thermopiles of the power sensor is about 172 kΩ, which corresponds to the calculated signal-to-noise ratio of 2.5 × 106 W−1.