A Tricoupled Resonant-Based Terahertz Switch Utilizing Tail-Transmission-Line with Ultra-Low Insertion Loss and Intrinsic ESD-Protection

This letter presents a cell-based single-pole single-throw (SPST) switch adopting tricoupled resonant topology. Due to the inherent characteristics of the physically isolated structure and the introduction of isolation-enhanced tail-transmission-lines, the switch features low insertion loss (IL), high linearity, and electrostatic discharge (ESD) self-protection. Implemented in 0.13- μ m SiGe BiCMOS process, the switch achieves a minimum IL of 1.35 dB @ 228 GHz, 17–23 dB isolation from 200 to 250 GHz, and >8 kV HBM ESD pulse, which is suitable for millimeter-wave and terahertz wireless communication and imaging systems. The chip occupies a core area of 0.0078 mm ² and exhibits the highest figure of merit among similar SPST switches.