Reliability of RF MEMS capacitive and ohmic switches for space redundancy configurations

In this paper Radio Frequency micro-electromechanical system (RF MEMS) switches in coplanar waveguide configuration designed for redundancy space applications have been analyzed within an European Space Agency contract, to demonstrate their reliability in terms of microwave performances when subjected to DC actuations up to one million cycles. The experimental results obtained by means of on-wafer measurements on shunt capacitive and ohmic series RF-MEMS single-pole-single-throw (SPST) switches demonstrate isolation and insertion loss better than −20 and −0.4 dB respectively after 10⁶ cycles, up to a frequency of 20 GHz, making them suitable for space reliable applications. Based on these building blocks, two configurations of SPDT switches making use of the developed SPST devices have been fabricated and experimentally investigated. Both the topologies exhibit good performances in terms of transmission and isolation parameters, fulfilling the mechanical requirements expected for redundancy logic purposes. Preference for the SPDT based on two shunt capacitive RF MEMS switches is obtained, in agreement with the proposed space application.