A 220-GHz InP HEMT Direct Detection Polarimeter

In this article, a 220-GHz direct detection polarimetric receiver is reported. This polarimetric receiver is intended for sensing of the microphysical properties of cloud ice in the earth's upper atmosphere. In the article, we report the measured RF performance, including RF gain of approximately 35 dB per channel and integrated noise figure of the receiver. The noise figure is measured to be 5.1 dB for the horizontally polarized channel and 5.4 dB for the vertically polarized channel. The receiver measures only 1.8 cm × 3.0 cm × 6.4 cm and has a total regulated dc power consumption of 520 mW. This article represents the first 220-GHz polarimetric direct detection receiver and is enabled by an advanced 25-nm indium phosphide (InP) HEMT monolithic microwave integrated circuit (MMIC) technology.