A Ten-Beam $Ka$ -Band Radiometric Receiver Using Custom Designed InP MMICs at Cryogenic Temperatures

Large ground-based radio telescopes are increasingly being equipped with multibeam feed systems to enable simultaneous observation of a larger part of the sky. The aim of the One Centimetre Receiver Array-f project, part of the European Commission funded FARADAY Programme, was to develop a high-quality science instrument to survey the sky at 1-cm wavelength, while developing technologies that would be applicable to future development of systems with 100 beams or more. A complete ten-beam Ka-band radiometer system is described, together with measured results at cryogenic temperatures. Performance compares well with that obtained with similar (non monolithic microwave integrated circuit) instruments produced for the Wilkinson microwave anisotropy probe and Planck satellites.