Progress on fabrication and testing of the omniguide traveling-wave tube structures

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 "omniguide". PBG TWT structures have great potential for very large bandwidth and linear dispersion. 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 band-width of more than 10 per cent was demonstrated. This structure is designed to generate millimeter-wave rf when driven by a 2-A, 120-kV electron beam.