120-GHz-band Low-noise Amplifier with 14-ps Group-delay Variation for 10-Gbit/s Data Transmission

This paper presents a 120-GHz-band low-noise amplifier (LNA) for a receiver microwave monolithic integrated circuit (MMIC), which is used for a 10-Gbit/s wireless link. The LNA was designed for low-noise performance, a high gain, and low group-delay variation. To achieve enough stability with low-noise performance and low group-delay variation, we introduce a new stabilizing circuit consisting of two coplanar-waveguide stubs. The LNA MMIC was fabricated using 0.1-mum-gate InP high-electron-mobility transistors (HEMTs). We integrated the LNA into a WR-8 (90-140 GHz) waveguide module and evaluated it. The LNA module achieved an averaged noise figure of 5.6 dB, a gain of > 19.5 dB, and group-delay variation of < 14 ps from 117.5 to 132.5 GHz.