Design and simulation of a RF MEMS shunt capacitive switch with low actuation voltage, low loss and high isolation

According to contact type, RF MEMS switches are generally classified into two categories: Capacitive switches and Metal-to-Metal ones. The capacitive switches are capable to tolerate a higher frequency range and more power than M-to-M switches. This paper presents a cantilever shunt capacitive RF MEMS switch with characteristics such as low trigger voltage, high capacitive ratio, short switching time and high isolation. In this switch, aluminum bridge is used because of its high Young’s modulus and low density which help reduction of switching time. Also aluminum has a good electrical conductivity which increases isolation. The proposed switch is designed on a Coplanar Waveguide line (CPW) with impedance of 50Ω. Also,  is used as dielectric layer. 24 holes have been placed on the bridge surface to reduce the squeeze film damping and to increase the switching speed. Actuation voltage is 5.2v and capacitive ratio (CR) is 231. RF analysis is done in HFSS Software. The results show the isolation level as -27dB, insertion loss as -0.2dB and return loss as -22dB at 17GHz. Also, the switching time is 32us.