Design, Simulation, and Cold Test of a W-Band Double Nonparallel Staggered Grating Backward Wave Oscillator

A novel double nonparallel staggered grating (DNPSG) slow wave structure (SWS) is proposed to enhance the coupling impedance in a ${W}$ -band backward oscillator (BWO) driven by pseudospark-sourced sheet electron beam. The DNPSG SWS has been shown broadband of 72–125 GHz and higher compared with traditional (DSG) simulation. BWO consisting ten units output designed fabricated. In cold test BWO, measured notation="LaTeX">${S}_{11}$ (double losses BWO) above −10 dB most band, which satisfactory pseudospark-driven high-power device. hot-test performance analyzed particle-in-cell (PIC) simulation beam voltage range 14–90 kV current density 1.5– notation="LaTeX">$5\times10$ 7 A/m2, obtaining high power (max. 190 kW) over an ultrawide tuning band 38 (75–113 GHz) due enhanced impedance.