High Power Multibeam Klystrons Using Resonators with Metamaterial

Physical principles of output power limitation in low-voltage multibeam klystrons are considered. It is demonstrated that metamaterial consisting of array of metal inductive inserts and located in the cavity's interaction region makes possible significant increasing of phase velocity of transversal wave in the gap. This reveals the opportunity to enhance uniformity of the rf field interacting with the beams in the gap, interaction region diameter, beams current and power of the klystron without cathode voltage increase. Resonators in
$\mathbf{S}$
and Ka bands are analyzed.