Design, Fabrication, and Low-Power Tests of a W-band Omniguide Traveling-Wave Tube Structure

We have designed, fabricated, and tested with low power a novel W-band traveling-wave tube (TWT) structure based on a slow-wave cylindrically symmetric photonic band gap (PBG) structure, or an ldquoomniguide.rdquo The development of wideband millimeter-wave power amplifiers is underway at Los Alamos National Laboratory. PBG TWT structures have great potential for very large bandwidth and linear dispersion. In addition, being cheap to fabricate, the PBG structures enhance commercial transferability of W-band TWT technology. The omniguide structure was designed and fabricated with silica dielectric with a copper harness. Cold-test results were found to be in excellent agreement with the design. A bandwidth of more than 10% was demonstrated. This structure is designed to generate millimeter-wave RF when driven by a 2-A 120-keV electron beam.