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

This 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 theD-band andG-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 implementedD-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 proposedD-band SPDT show 1.4–3.8-dB IL and ISO of 33.8–53 dB in 110–132 GHz. ImplementedG-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.