mm-Wave Through-Load Switch for in-situ Vector Network Analyzer on a 55-nm BiCMOS Technology

In this paper, an innovative millimeter-wave (mm-wave) through-load switch for in-situ reflectometers and on-wafer calibration is proposed. This two-port device can switch between two states: (i) a through connection or (ii) a 50 Ω load for both of its ports. The through-load switch is composed of a 3-dB directional coupler and two nMOS transistors controlled through a biasing voltage applied to their gate. Measurement results of a 120-GHz 3-dB directional coupler are provided up to 145 GHz together with EM simulations and circuit-level simulations up to 220 GHz of the through-load switch. A wide bandwidth is obtained, from 73 GHz to 179 GHz, with limited insertion loss of 2 dB.