A cryogenic focal plane array for 85-115 GHz using MMIC preamplifiers

A new focal plane array for 85-115 GHz is described in this paper. This array has 16 pixels, and uses InP monolithic-microwave integrated-circuit preamplifiers with 40-dB gain, followed by a wide-band subharmonic mixer to convert to a 5-20-GHz intermediate-frequency band. A low-loss isolator is used to achieve an excellent input match. Square corrugated feed horns are used for efficient filling of the focal plane. Critical components are operated at a temperature of 20 K. Noise temperature varies from 50 to 130 K, including all pixels across the full band.