| Abstract: | The University of New Mexico has had a vigorous program in high power microwave (HPM) sources. We have made significant advances recently in both Cerenkov and crossed-field devices. In Cerenkov devices we have demonstrated a relativistic backward wave oscillator (BWO) that utilizes a novel Bragg reflector instead of a cavity reflector to reflect the backward-propagating wave into a forward wave. In addition to reflecting the backward TM01 wave, the Bragg reflector self-consistently converts it to a forward propagating TE11 wave. Furthermore, this design can lead to either single frequency or dual frequency operation. We have designed a metamaterial slow wave structure (MSWS) that has a dispersion curve that cannot be reproduced using conventional periodic structures. This MSWS generates radiation in S-band in a structure whose dimensions would be cutoff in smooth-walled waveguide. We recently demonstrated in experiment a relativistic magnetron with diffraction output (MDO) operating at over 60% efficiency when driven by a transparent cathode; we have designed an MDO with no physical cathode in the electromagnetic interaction region; we have designed an MDO using a permanent magnet assembly to provide the axial magnetic field; finally, we have a simple compact design of an MDO that, although operates less efficiently than the full size MDO, is significantly smaller and lighter weight. |