W-band active loads and switching front-end MMICs for radiometer calibration

A millimeter-wave monolithic integrated circuit consisting of a W-band (75-100 GHz) single-pole-five-throw (SP5T) switch and multiple internal active and passive loads for radiometer calibration was designed and manufactured in a low noise 50 nm GaAs metamorphic high electron mobility transistor technology. This highly compact and integrated front-end device for radiometer systems is capable of ultra fast switching between two identical input ports (e.g. for polarimetric applications) and three internal calibration references. It allows an accurate multi-load calibration with noise temperatures between 220 and 1750 K at the output of the device. Compared to conventional calibration methods this marks a substantial advantage in terms of size, mass, power consumption, complexity, and repetition rate.