Characteristics of low-k RF MEMS capacitive switches on gallium arsenide substrate

This paper details the fabrication and performance of a low-k RF MEMS capacitive switch on gallium arsenide (epsiv r =12.9) substrate. The switch is fabricated using GaAs MMIC compatible MEMS specific surface micromachining techniques. The switch posses a movable metallic bridge which pulls down onto a metal/dielectric sandwich to form a capacitive contact. The bridge consists of a proof mass which is supported by meander-type flexures that essentially result in a low effective spring constant of the suspended structure and thus a lower actuation voltage is required to pull the bridge down. The fabricated switch has low insertion loss of 0.5 dB with good isolation of 25.5 dB at 26.5 GHz and the actuation voltage lies in 10-20 V range.