Radiometer instruments for space applications

In this paper, the challenges and various aspects in designing non-cryogenic space radiometers are discussed in general, both from a system level perspective as well as on a subsystem and technology level. Specifically two recent European radiometer instruments, the Geosounder interferometer and the STEAMR limbsounder are described in depth. Other concurrent radiometer subsystems under development at Omnisys, e.g the SWI 600/1200 GHz mixer/lna front end for JUICE and 875 GHz receiver for ISMAR are also briefly touched up on, highlighting different performance aspects of subsystem components.