With the advent and fast-paced development of ultrahighspeed digital interconnects for next-generation computing systems, low-latency broadband wireless communications for fifth generation and beyond, high-resolution imaging techniques and emerging parametric sensing systems for medical/biomedical and security applications, material and structure analyses and evaluations, and deep-space radio astrophysics, and so on, the search for system solutions with larger bandwidth has sparked a growing research in expanding the electromagnetic spectrum into the terahertz (THz) regime. Generally, the THz frequency covers 300 GHz through 10 THz, which presents the most fundamental spect rum gap between elect ronics and photonics.

This paper describes the design and flight model measurements of a 874-GHz Schottky receiver for ice cloud characterization that uses high-efficiency amplifiers and varactor multipliers in the LO chain to achieve low DC power with uncompromised sensitivity in a compact configuration optimal for CubeSat platforms. The total required DC power for the LO, including the 24.278 GHz dielectric resonator oscillator (DRO), is less than 3.75W. For the best flight model, the measured mixer noise temperature is 4000K DSB with 11.5dB conversion loss. Performance as a function of ambient temperature from 0-40C is also presented.

The operation of GaAs Schottky barrier diodes, the critical mixer element used in heterodyne receivers for a variety of scientific applications in the terahertz frequency range, is reviewed. The constraints that the receiver system places on the diodes are considered, and the fundamental guidelines for device optimization are presented. The status of ongoing research, both experimental and theoretical, is examined. Emphasis is placed on investigations of the various effects that can limit diode performance at these high frequencies. Investigations of planar diode technology are summarized, and the potential replacement of whisker-contacted devices with planar structures is considered.>