Development of Efficient Backward Wave Oscillators for Submillimeter Applications

Calabazas Creek Research, Inc. is funded by the National Aeronautics and Space Administration to develop efficient, light-weight, backward wave oscillators (BWOs) for applications from 300 GHz to 1 THz. These devices are needed as local oscillator (LO) sources in heterodyne receivers. Very low noise heterodyne receivers are needed at submillimeter wavelengths for low-background radioastronomy observations and remote sensing of comets, Earth and other planetary atmospheres. Above 100 GHz, only BWOs have broad tunability (over 100 GHz) and high output power (~1 mW); however, they are heavy (over 20 kg), consume a lot of power (270 W), required water cooling, and have poor output mode purity. Figure 1 shows a BWO of this design inside its magnet at the Jet Propulsion Laboratory in Pasadena, CA.