Direct Detection Polarimetric Radiometer

The major problem in microwave radiometry is weakness of the signal. This causes a low signal to noise ratio. To attain the required temperature sensitivity it is necessary to integrate the signal for a long time. It has been shown that for icingcondition detection the required integration time can be as long as several tens of seconds. Most radiometers are built as heterodyne receivers. They suffer from relatively narrow bandwidth (typically 0.5 GHz). Direct detection receivers can operate ina much wider spectrum (10 GHz and wider) and thus have better sensitivity. In recent years, with advances in HEMT MMIC technology, implementation of MMIC radiometers for MMW spectrum became a reality. A new design of a dual-frequency polarimetricradiometer is proposed. The use of direct detection MMIC receivers will make it possible to improve sensitivity and achieve compactness and cost effectiveness. The area of application of the new radiometer is detection of icing conditions in-flight forsmall aircraft.