230-GHz SPDT Switch with 60-GHz Bandwidth and 20 dB Dynamic Ratio Utilizing Double-Shunt Topology in SiGe BiCMOS

This paper presents the analysis and design of a single-pole double-throw (SPDT) switch in 130-nm SiGe BiCMOS technology with an operating frequency from 200 GHz to 260 GHz. The switch design is based on the λ/4-shunt topology, and optimized for a high dynamic ratio by introducing a double shunt transistor with increased internal impedance level for matching. The tradeoff between insertion loss (IL), isolation, dynamic ratio and bandwidth is discussed. The switch achieves an IL of 4.6 dB to 6.0 dB, isolation of 15 dB to 26.3 dB, and consumes 0.12-mW DC power in measurements. With a dynamic ratio of 20 dB in the frequency band of 220 GHz, the switch shows a comparable performance to the designs in III-V technologies. To the best of the authors’ knowledge, the presented SPDT switch achieves the highest operating frequency in silicon-based process.