A Novel Millimeter-Wave Structure for Longitudinal Interaction With a Sheet Electron Beam

We offer and describe a novel slow-wave structure (SWS) formed by a periodic array of rectangular rings (RRs) interconnected by parallel diagonal conductors forming two zigzag lines. The zigzags form the inductive part of the SWS, whereas the broad sides of the RRs are largely capacitive. The sheet electron beam topology has the potential to significantly increase the output power of traveling-wave amplifiers at millimeter-wave frequencies. The small period of the offered circuit enables operation at relatively high voltages, far from the conditions for backward-wave oscillation. We present measurements and simulations of the cold characteristics of the circuit and analyses of mode competition and bandwidth optimization.