2.5-THz GaAs monolithic membrane-diode mixer

A novel GaAs monolithic membrane-diode (MOMED) structure has been developed and implemented as a 2.5-THz Schottky diode mixer, The mixer blends conven tional machined metallic waveguide with micromachined monolithic GaAs circu itry to form, for the first time, a robust, easily fabricated, and assemble d room-temperature planar diode receiver at frequencies above 2 THz, Measur ements of receiver performance, in air, yield a T-receiver of 16 500-K doub le sideband (DSB) at 8.4-GHz intermediate frequency (IF) using a 150-K comm ercial Miteq amplifier. The receiver conversion loss (diplexer through IF a mplifier input) measures 16.9 dB in air, yielding a derived "front-end" noi se temperature below 9000-K DSB at 2514 GHz, Using a CO2-pumped methanol fa r-infrared laser as a local oscillator at 2522 GHz, injected via a Martin-P uplett diplexer, the required power is approximate to 5 mW for optimum pump ing and can be reduced to less than 3 mW with a 15% increase in receiver no ise, Although demonstrated as a simple submillimeter-wave mixer, the all-Ga As membrane structure that has been developed is suited to a wide variety o f low-loss high-frequency radio-frequency circuits.