Compact, High-Isolation 110-140-GHz SPST and SPDT Switches Using a 250-nm InP HBT Process

A low insertion-loss (IL) and high isolation (ISO) single-pole single-throw (SPST) and single-pole double-throw (SPDT) is demonstrated in 250-nm Indium Phosphide (InP) heterojunction bipolar transistor (HBT). The switch employs a 90° hybrid coupler with independent reflective loads to break tradeoffs in IL and ISO ratio. Measurement results of the implemented SPST show IL of 0.77-2.7 dB and ISO of 22.5-40dB in 110–140 GHz. Measured results of the proposed SPDT show 1.42-3.8 dB IL and ISO of 33.8-53 dB in 110–132 GHz.