Development of MMIC receivers for cosmic microwave background interferometry

We report on the development of some of the key technologies that will be needed for a large-format Cosmic Microwave Background (CMB) interferometer with many hundreds of wideband W-band (75-110 GHz) receivers. A scalable threebaseline prototype interferometer is being assembled as a technology demonstration for a future ground- or space-based instrument. Each of the prototype heterodyne receivers integrates two InPMonolithic Microwave Integrated Circuit (MMIC) low-noise amplifiers, a coupled-line bandpass filter, a subharmonic balanced diode mixer, and a 90° local oscillator phase switch into a single compact module that is suitable for mass production. Room temperature measurements indicate bandaveraged receiver noise temperatures of 500 K from 85-100 GHz. Cryogenic receiver noise temperatures are expected to be around 50 K.