A 211.4-to-234.8 GHz 25.6-dB Differential Amplifier With Compact Terminal Multi-Coupled and Auxiliary Interstage-Coupled Matching Networks

This paper presents a 220-GHz five-stage differential amplifier in IHP SG13G2 0.13-lm BiCMOS technology. The differential amplifier employs multi-coupling inductors and transmission lines at the inter-stage to perform high-gain, high-robustness and miniaturization. The compact multi-coupling inductors used in the Gm-boosting technique and noise reduction technique consists of three inductors connected to the base, emitter, and collector of the transistor, respectively. Meanwhile, the inductors are coupled between stages by auxiliary coupled-transmission-lines (CTLs) to expand bandwidth and improve gain. The proposed differential amplifier provides a measured peak gain of 25.6-dB at 222.5 GHz with a 3-dB bandwidth of 23.4 GHz from 211.4-234.8 GHz and a simulated noise figure (NF) of 14.1 dB at 220 GHz. Furthermore, the stability condition indicates that the amplifier is unconditionally stable in all frequency bands. The circuit occupies a small area of 0.3 mm2 including bond pads and consumes a moderate power of 63.2 mW from a 3.3 V supply.