A multifrontal block ILU preconditioner for the 3D finite-element eigenvalue analysis of lossy slow-wave structures of traveling-wave tubes

A novel multifrontal block incomplete LU preconditioner (MFBILU) for large-scale complex unsymmetric linear generalized eigenvalue problems (GEPs), which are formed by the 3D finite-element (FE) eigenvalue analysis of lossy slow-wave structures (SWSs) of traveling-wave tubes (TWTs). We organized it with the p-type multigrid preconditioner (PMP) and obtained a novel mixed high efficient preconditioner. By simulating many practical SWSs with the new preconditioner, it was shown that the high-frequency parameters of SWSs can be obtained rapidly and accurately and with low memory requirement. This would make the modeling of SWSs cheaper and more efficient.