A space-qualified, hermetically-sealed, Ka-band LNA with 2.0dB noise figure

Abstract

A space-qualified, hermetically-sealed, Ka-Band LNA with 2.0dB typical noise figure and greater than 38dB of temperature compensated gain has been built tested, and integrated into commercial satellite payloads. Noise figures as low as 1.7dB at 25deg C, have been recorded. A novel matching technique was used to minimize noise figure. This involved designing the LNA input stage with the waveguide to microstrip transition as part of the matching circuitry. In this way, input loss was minimized. Additionally, some tuning elements at the input enhanced the consistency of the design by allowing for device and assembly variations. This paper will describe the design and performance of the LNA. This will include a physical description, LNA design drivers and approach, waveguide to microstrip design, production LNA performance, and some ideas for future improvements. To the author's knowledge, this is the lowest Ka-Band noise figure reported, from a hermetically-sealed, commercial space module currently in production.