An all-solid-state replacement for high-frequency Gunn diode oscillators (GDOs) has been proposed for use in NASA’s millimeter- and submillimeter-wave sensing instruments. Highly developed microwave oscillators are used to achieve a low-noise and highly stable reference signal in the 10–40-GHz band. Compact amplifiers and high-power frequency multipliers extend the signal to the 100–500-GHz band with minimal added phase noise and output power sufficient for NASA missions.
This technology can achieve improved output power and frequency agility, while maintaining phase noise and stability comparable to other GDOs. Additional developments of the technology include: a frequency quadrupler to 145 GHz with 18 percent efficiency and 15 percent fixed tuned bandwidth; frequency doublers featuring 124, 240, and 480 GHz; an integrated 874-GHz subharmonic mixer with a mixer noise temperature of 3,000 K DSB (double sideband) and mixer conversion loss of 11.8 dB DSB; a high-efficiency frequency tripler design with peak output power of 23 mW and 14 mW, and efficiency of 16 and 13 percent, respectively; millimeter-wave integrated circuit (MMIC) power amplifiers to the 30–40 GHz band with high DC power efficiency; and an 874-GHz radiometer suitable for airborne observation with state-of-the-art sensitivity at room temperature and less than 5 W of total power consumption.
This work was done by Thomas W. Crowe and David Porterfield of Virginia Diodes Inc. for Goddard Space Flight Center. GSC-15630-1