W-band SPST transistor switches

A single-pole, single-throw (SPST) transistor switch has been developed, Three types of switches, that is, GaAs MESFET, AlGaAs-GaAs HEMT, and pseudomorphic HEMT (PM-HEMT), have been fabricated, and the performances at W-band are compared. To reduce on-state resistance and off-state capacitance, gate length was varied as a parameter. Moreover, an inductance for resonance was installed in parallel to the off-state capacitance between source and drain to obtain a high isolation, A relatively low insertion loss of 1.6 dB and a high isolation over 20 dB at W-band have been obtained from the 0.8-μm gate length PM-HEMT.