In the article the algorithm of eigenmodes calculation of three-gap axially symmetrical resonator of klystron is under consideration. The “nearly R-functions” approach is applied to describe the resonator structure. The finite-elements method with application of atomic functions as basic functions is used for calculations. It provides the high speed of convergence and significant efficiency of the algorithm.
Department of mathematics, Faculty of Physics, Lomonosov Moscow State University. Moscow 119991, Russia.