Optimisation of millimetre wave amplifiers for satellite based radiometer

STFC / RAL Space has been involved in the development of an extensive variety of satellite mission payloads operating across a wide range of the electromagnetic spectrum. The RAL Space Millimetre-wave Technology Group (MMTG) has undertaken the development of instrumentation in support of spaceborne earth observation. Most recently, the MMTG is contributing towards a next generation of weather monitoring satellites that will utilise state-of-the-art low-noise amplifier (LNA) technology as the first reception stage of heterodyne receivers. This contribution describes the performance optimisation of an LNA used in a 183GHz receiver chain. Device optimisation includes variation in impedance transformation between waveguide and LNA millimetre-wave integrated circuit (MMIC), and under different MMIC DC bias conditions, to achieve required performance. Extensive and accurate LNA measurements have been made and, in addition to the optimisation procedures used, example results will be presented, described and discussed.