High-Frequency Circuit Simulator: An Advanced Three-Dimensional Finite-Element Electromagnetic-Simulation Tool for Microwave Tubes

A 3-D advanced specialized simulator for designing a microwave-tube slow-wave structure (SWS), called the high-frequency circuit simulator (HFCS), has been developed. It is one module of our recently developed microwave-tube simulator suite. The four major features of the HFCS are as follows: 1) Both the lower and higher order tetrahedral basis functions are applied in the finite-element analysis; 2) two kinds of periodic boundary-condition techniques are proposed, one of which dramatically reduces memory requirements and solution times; 3) the Arnoldi algorithm is modified to more efficiently solve the required generalized eigenmatrix equation; and 4) the postprocessing parameters of the SWS can precisely be computed with the tangential-vector finite-element method. Various numerical examples are solved using HFCS. The accuracy and the performance of the HFCS are compared with commercial software HFSS and CST MWS. It is found that the results from the HFCS agree well with the experimental values as well as the simulated values from the commercial software packages. Moreover, the HFCS takes far lesser solution time and requires lesser memory than the commercial software in the simulation of two examples of SWSs, enabling faster prototyping and more elaborate design optimizations.