Design and Characterization of 1.8-3.2 THz Schottky-based Harmonic Mixers

A room-temperature Schottky diode-based WM-86 (WR-0.34) harmonic mixer was developed to build high-resolution spectrometers, and multi-pixel receivers in the THz region for applications such as radio astronomy, plasma diagnostics, and remote sensing. The mixer consists of a quartz-based Local Oscillator (LO), Intermediate-Frequency (IF) circuits, and a GaAs-based beam-lead THz circuit with an integrated diode. Measurements of the harmonic mixer were performed using a 2 THz solid-state source and 2.6906 THz QCL. A conversion loss of 27 dB for the 3rd harmonic mixing and a conversion loss of 30 dB for the 4th harmonic mixing was achieved. This is the first development of a wideband WM-86 (WR-0.34) harmonic mixer with planar Schottky diode integrated on a beam-lead THz circuit that uses a lower LO harmonic factor for 1.8-3.2 THz RF frequency. Furthermore, this result represents the best Schottky-based mixer in this frequency range

Phase Locking Of A 2.5 THz Quantum Cascade Laser To A Microwave Reference Using THz Schottky Mixer

The frequency of a 2.5 THz QCL are stabilized to sub-hertz accuracy by phase-locking to a stable 100 MHz microwave reference, using a 2.3–3.2 THz room temperature Schottky diode based harmonic mixer. The down-converted phase locked beat note is stable over a long term test