A Transformer-Based $V$ -Band SPDT Switch

This letter presents a novel transformer-based 58-85 GHz single-pole double-throw (SPDT) switch structure, verified in a 65-nm CMOS process. A four-way transformer-based combiner implements the input impedance transformation resulting in significant chip area reduction to 0.015 mm
²
, which is smaller than one tenth of the conventional SPDT switch based on λ/4 transmission lines. The designed SPDT switch achieves 1.8-dB insertion loss, 22-30 dB isolation and >10 dB return loss over 58-85 GHz band with input-referred P1dB compression point of 10 dBm at 66 GHz. The good performance validates the application of the newly invented structure for the challenging millimeter-wave frequency switches in integrated systems.