Direct-Detect 250/310 GHz Pseudo-Correlation Radiometer and Double-Sideband 380 GHz Sounder for Ice Cloud Sensing

We demonstrate an integrated mm-wave receiver system that is designed for ice cloud measurements via conical scans at 45° incidence angle for its 250 GHz/310 GHz radiometers and its 380GHz sounder. The direct-detect radiometers are the first-ever pseudo-correlation receivers designed around 250GHz and 310GHz with 11GHz and 6GHz instantaneous bandwidth, respectively. We measure 1600K and 2000K noise temperatures, as well as >6 dB and >8 dB switching isolation around 250GHz and 310GHz, respectively. A 380GHz receiver is used for upper-atmosphere humidity sounding across an 8GHz bandwidth, and we measure 1500K double-sideband noise temperature. This highly-integrated receiver is built in a single waveguide housing with monolithic mm-wave integrated circuits (MMICs) using Northrop Grumman's IACC25 25nm indium-phosphide (InP) High Electron Mobility Transistors (HEMTs).