Low Insertion Loss, Reflective-Load Switches Operating in D-Band and G-Band

article presents the analysis and design of a reflective-switch topology for frequency bands above 100 GHz. The switches employ a 90? hybrid coupler with independent reflective loads to break tradeoffs in conventional switches design in terms of insertion loss (IL) and isolation (ISO). Prototypes of a single-pole-single-throw (SPST) and single-pole-double-throw (SPDT) at the D-band and G-band are demonstrated in a 250-nm indium phosphide (InP) heterojunction bipolar transistor (HBT) process. The InP HBT-based switch provides low insertion loss (IL) and high ISO through independent tuning on the switches. Measurement results of the implemented D-band SPST show the IL of 0.77-2.7 dB and ISO of 22.5-40 dB in 110-140 GHz. Measured results of the proposed D-band SPDT show 1.4-3.8-dB IL and ISO of 33.8-53 dB in 110-132 GHz. Implemented G-band SPST shows the measured IL of 1.7-3.1 dB and the ISO of 27.4-42 dB in 190-220 GHz. The proposed SPDT offers 2.3-5.8-dB IL and ISO of 25.3-31 dB in 190-220 GHz.