Abstract
A dc 6
GHz single-pole double-throw (SPDT) switching circuit that employs lateral metal-contact micromachined switches is investigated. The lateral metal-contact switch consists of a set of quasi-finite ground coplanar waveguide (FGCPW) transmission lines and a high-aspect-ratio cantilever beam. A single-pole single-throw (SPST) lateral micromachined switch has an insertion loss of 0.08
dB and a return loss of 32
dB at 5
GHz. The isolation is 32
dB at 5
GHz. The measured insertion loss of the SPDT switching circuit is below 0.75
dB, whereas the return loss is higher than 19
dB at 5
GHz. The isolation at 5
GHz is 33
dB. Pull-in voltage of the switch is 23.3
V and switching time is 35
μs. The size of the SPDT switching circuit is 1.2
mm
×
1.5
mm. A main advantage of this circuit structure is simple fabrication process with high yield (>90%) based on the deep reactive ion etching (DRIE) technique of silicon-on-insulator (SOI) wafer and shadow mask technology.