"Comb-Quad" millimeter-wave coupled-cavity TWT interaction structure

摘要: The "Comb-Quad" interaction structure has been under study for millimeter-wave space-harmonic TWTs as an electrically comparable, but mechanically very different, substitute coupled-cavity stacks with "staggered" coupling apertures. Based on four one-piece copper combs, Comb-Quad construction relies few piece parts, establishes the periodicity prior to assembly, and leads a low-loss thermally robust circuit. "Ferrules" are absent, interaction-gap capacitance typically is significantly less than that of ferrule-less conventional cavity stack same period, gap length frequency band. dispersion found readily controllable such generous "hot" bandwidths may be obtained even at low beam perveances associated TWTs. Topological electrical equivalents determinants "cold" bandwidth have identified, parameters dispersion, capacitance, impedance, attenuation examined. Secondary passbands possible extraneous modes were characterized impact dimensional variations defects charted. Broadband waveguide couplers easily implemented. Data from X-band exploratory test vehicle operated variable perveance validated means assembled predicting small-signal gain matters stability.