Progress on a 94 GHz omniguide traveling-wave tube gain experiment

Compact, efficient, high-bandwidth and high-power mm-wave sources are essential for many applications in secure communications, environmental monitoring, imaging, spectroscopy for remote sensing in nonproliferation, and basic research such as radio astronomy. Commercial microwave tube amplifiers are available at frequencies up to only 100 GHz (W-band) and have to trade off maximum output power against bandwidth. A wide-band mm-wave traveling-wave tube (TWT) amplifier based on a slow-wave cylindrically-symmetric photonic band gap (PBG) structure, or an “omniguide” is being developed at Los Alamos National Laboratory. The omniguide represents a periodic system of concentric dielectric tubes. PBG TWT structures have great potential for very large bandwidth and linear dispersion.