220–325 GHz high‐isolation SPDT switch in InP DHBT technology

Abstract

A broadband single‐pole‐double‐throw (SPDT) switch is presented covering 220–325 GHz in 800 nm transferred substrate InP DHBT technology. The SPDT switch configuration employs shunt‐topology. The circuit achieves an isolation of >36 dB within the band with very low DC power of 9 mW, benefitting from the low intrinsic capacitance of the transistors. This is the highest reported isolation for wideband SPDT switches covering 220–325 GHz. This three‐stage SPDT switch also demonstrates the highest isolation of 12 dB per stage in this frequency range.