Design and Implementation of Stoppers to Capacitive RF MEMS Switch For Low Frequency Applications

Abstract

This work presents the fixed-fixed type capacitive RF MEMS switch. The device additionally includes nonuniform meanders which can reduce the actuation voltage of the device. The switch accomplishes 0.5-1.5μN of applied force for actuation voltages of 6.9-7.9 V. The simulated and calculated spring steady is 1.49N/m to evaluate the actuation voltage the concept of stoppers is introduced in this work. Incorporating stoppers and meanders to the proposed device is to improve the RF performance. The proposed switch produces perfect electromagnetic behavior low insertion and high isolation with the addition of stoppers at the thickness of 1.2μm for 3μm air gap and aluminum nitride as dielectric layer followed by silicon nitride, silicon dioxide and Kapton polyimide in the device. The switch performance undergoes two conditions here with the addition and without inclusion of the stoppers. The RF Performance of the device with the stoppers, are lower insertion, better return losses and higher isolation are -0.07dB, -82 dB, -69dB at the 8- 8.1GHz frequency having Al3N4 as dielectric film followed by Si3N4 as-0.06dB, -77dB and -71dB then SiO2 as-0.06dB,-87dB, -71dB finally, Kapton polyimide as -0.06dB, -77dB,-76dB at 8- 8.5Ghz frequency. The S-parameter analysis like isolation, return loss and insertion loss are carried using FDTD tool CST which gives good performance.