A New Double-Bridge RF MEMS Switch with Low Actuation Voltage and High Isolation

This paper presents a new dual beam RF MEMS capacitive shunt switch with low voltage, low loss and high isolation for K-band applications. In this design, we have proposed the step structure to reduce the air gap between the bridge and the signal line, thus the actuation voltage is reduced to 2.9V. Furthermore, to reach more isolation, we used Aluminum Nitride (AlN) as a dielectric layer instead of conventional dielectric materials such as 􀜵􀝅􀝋􀬶 and 􀜵􀝅􀬷􀜰􀬸which has more 􀟝􀯥 led to increase the down-state capacitance and increase the isolation of switch. The results show that the switch in up position involve 􀜵􀬵􀬵 less than -10 dB from 1 to 40 GHZ and 􀜵􀬶􀬵 more than - 0.72 dB from 1 to 22 GHZ. In down state, switch has an excellent isolation at the frequency range of K-band. The maximum isolation of -58 dB is obtained at resonance frequency of 27 GHZ. Furthermore, we used the 􀟨-match circuit to improve the reflection and isolation of switch. In this case, the double-bridge switch has the return loss of around -12 dB at the range of 1-31 GHZ. The insertion loss of switch is less than -0.8 dB at the range of 1-27 GHZ. The isolation around -40 dB is obtained at the range of 15-40 GHZ. The proposed dual beam switch is the wideband and lowloss switch that appropriate for applications of K-band frequencies