Circuit analysis of an extended interaction klystron

The demand for high-power BF sources in the millimeter-wave region is motivating the development of a Ka-band extended interaction klystron (EIK). The EIK circuit consists of several reentrant multi-gap cavities. The stability of the optimized cavity structure is evaluated to avoid oscillations in the unloaded intermediate cavities. In order to accurately analyze the performance of an asymmetric three-dimensional circuit model, we applied a Wessel-Berg's analysis (WBA) in a computer simulation. The computed results are compared with results from a one-dimensional disk-model code, JPNDISK, and a two-dimensional PIC (particle-in-cell) code, MAGIC2D. These comparisons verify the validity of the circuit design.