Design and Development of Monolithic Subsystems for Satellite Applications

This paper presents the performance of a set of microwave monolithic integrated circuits (MMICs) developed for application in a 6/4-GHz satellite repeater. These include a 6-GHz low-noise amplifier, a broadband feedback amplifier, a dual-gate FET module with on-chip TTL compatible switch driver, and a broadband digital (programmable) attenuator. The low-noise amplifier is a two-stage cascade with measured gain of 21 dB and noise figure of 1.7 dB at 6 GHz. The feedback amplifier is also a cascaded two-stage with a measured gain of 9 dB + 0.5 dB across 2-6 GHz bandwidth. The measured on-state gain and on-to-off isolation of the dual-gate FET switch are 10 dB and 50 dB, respectively, over a frequency range of 3-7 GHz. The digital attenuator has 15.5-dB dynamic range and a resolution of 0.5 dB with excellent phase tracking characteristics over a measured range of 0.05 GHz to 14 GHz. The feedback amplifier and FET switch modules were developed for use at the C-band satellite up-link (6 GHz) and down-link (4 GHz) bands. The digital attenuator was developed for use in both the C-band and the 14/11-GHz Ku-band satellite transponders.