Multipactor suppression via asymmetric grooves in S-band waveguide

To investigate multipactor, we designed a testbed for S-band frequencies with geometries akin to the standard WR-284 waveguide geometry. Narrowing height from dimensions 5.5 mm suitable frequency-gap product left cutoff frequency unaffected and RF signal propagating in dominant TE10 mode. A coaxial magnetron provides test input power at 2.85 GHz peak output of 4 MW 3.5 μs pulse width, an solid-state source using gallium nitride high-electron-mobility transistors delivers width 100 2 kW comparison threshold power. Local (electron multiplier tube) global (phase/power) diagnostic methods are implemented detect multipactor within setup. At levels tested (MW) gap, low orders (N = 1) observed. Prior numerical studies demonstrated that structures grooves broadside wall reduced susceptibility. Such run along direction propagation avoid continuous impedance mismatching. The efficacy this mitigation technique was experimentally evaluated. Differences over smooth noticeable, however limited.