Microwave Calibration Targets for Earth Observation and Planetary Science Missions

Microwave radiometers are invaluable tools for remote sensing. The relation between the radiometer output quantity and the brightness temperature of the observed object is established by calibrating the radiometer with blackbody calibration targets. The geometries, microwave absorbing materials, and thermal aspects associated with OBCTs are discussed based on examples from recent missions of the European Space Agency, such as the MetOp-SG, the Arctic Weather Satellite, and the Jupiter Icy Moons Explorer, which carry instruments operating at millimeter and sub-millimeter wavelengths. The features of an internal calibration subsystem are discussed based on a W-band technology demonstrator.