Research multi-frequency mode of the three-gap cavity with resonant elements on printed circuit boards

We have studied the multigap resonance system, which is a rectangular cavity resonator with two suspended ceramic substrates, on which the two sides is applied by lithography strip line. During modeling process the resonator structure was calculated on three main modes with a maximum characteristic impedance, antiphase oscillation mode (π), π / 2 oscillation mode and in-phase mode (2π) oscillation mode. It is found that the π and π / 2 modes have significant dependence on the length of adjustment element, while in-phase oscillation mode (2π) weakly depends on the length of adjustment element and the dielectric constant of the substrate. The results can be used in the development of new types of vacuum microdevices multibeam klystron type with matrix field emission cathodes working in the S, C, X range.