A single-chip 53 GHz radiometer front-end MMIC for geostationary atmospheric measurements

A multi-functional single-chip 53 GHz radiometer front-end MMIC has been designed in a commercial GaAs mHEMT technology and evaluated by probed measurements. To the best of the authors´ knowledge, this is the first multi-functional MMIC ever presented intended for a radiometer application. Thus, the presented MMIC represents the future in radiometer front-end design, enabling a new generation of radiometers with lower cost, weight and DC power consumption. The MMIC is intended to be used in a demonstrator for a future geostationary synthetic thinned aperture radiometer for satellite-based environmental studies of the earth. Measured results for conversion gain, RF and IF bandwidths, image rejection ratio, 1-dB compression point, input referred third order intercept point (IIP3), LO saturation, and noise figure are presented and discussed. A study of the influence of benzocyclobutene (BCB) as a dielectric coating used for surface passivation on the measured RF performance is also performed. Furthermore, the very important issue of phase stability versus temperature and time was also investigated.