Broadband High-Performance SPDT Switch Based on Phase-Change-Material From DC to 200 GHz

This letter presents two single-pole, double-throw (SPDT) switches (SPDT-1 and SPDT-2) that use phase-change material (PCM)-based switching devices with matching networks to compensate for the high-frequency parasitic effects and a low-impedance transmission line as a novel bias circuit, operating from 0 (dc) to 200 GHz. SPDT-1 uses a series-only architecture to achieve extremely low loss, with measured insertion loss below 0.6 dB up to 60 GHz and 2.2 dB up to 200 GHz and measured isolation higher than 35.5 dB up to 60 GHz and 14.2 dB up to 200 GHz. SPDT-2 has an extra shunt switching device to achieve high isolation performance, with measured insertion loss below 0.6 dB up to 60 GHz and 2.9 dB up to 200 GHz and measured isolation higher than 37.6 dB up to 60 GHz and 25.6 dB up to 200 GHz. The measured results indicated that the proposed switches outperformed existing radio frequency (RF) switches in the terahertz (THz) frequency band. To the best of the authors’ knowledge, this study is the first to develop PCM-based SPDT switches that can operate at frequencies of up to 200 GHz.