MEMS near-DC to RF capacitive series switches

This paper presents a novel type of RF-MEMS capacitive series switch. Its insertion loss and isolation can be separately optimised. Moreover, its actual performances closely fit the theoretical characteristics allowing an accurate and precise design. We will present electromechanical and high frequency simulations as well as C-V and S-parameters measurements clearly showing the improved characteristics of the new "boosted switch". We demonstrate the design flexibility, e.g. arbitrary and precise choice of the up- and down-capacitances in the respective ranges [0.1-0.3 pF] and [1-30 pF]. Insertion Loss lower than 0.3 dB (including 1 μm thick, 2*400 μm long Al feeding line losses) and Isolation higher than 10 dB in the frequency range 1-10 GHz have been measured. The capacitance ratio C_down/C_up, fixed at 11 for the conventional design in our technology, has been boosted up to 600 with the new structure using the same materials and comparable dimensions.