Research is continuing on the NRL Ku-band ubitron amplifier after several major component modifications. Specifically, the input coupler has been modified for broader bandwidth and lower transmission loss, and the wiggler has been redesigned to generate a much more uniform field in the interaction region and lengthened. Steps have also been taken to remove discontinuities that excited oscillations at high wiggler fields. With a 250 kV, 100 A, 4 mm radius beam and these modifications, we expect to see saturated gain of 25 - 30 dB, efficiency greater than 15%, and bandwidth exceeding 20% in the 12.4 - 18 GHz band. Measurements will be compared with the 3-D nonlinear code ARACHNE[1].
|