Broadband high-resolution receivers for the sub-millimetre region

This paper describes the main features of high performance heterodyne receivers for the sub-millimetre frequency range. The great interest in the use of these receivers for scientific observations dictates that high performances in the areas of frequency resolution, sensitivity and tuneability are mandatory. The parallel interest in eventual space application of such receivers due to the high attenuation of the atmosphere to submillimetre waves also motivates technological efforts to minimize the mass and power consumption and maximize the reliability and automation of such systems. The implications of these constraints on hardware choices are examined especially in terms of input mixers, local oscillators and back-end spectrum analysers. Recent technological advances leading to improved performances of these components are described as well as work presently in progress on the realization of a fully automated, high-resolution, high-sensitivity receiver working in the 300¿500 GHz band. Details of the applications potential of such systems are discussed with special emphasis on the importance of space-borne heterodyne receiver systems.