Fft Technology Applications In Microwave Circuits And Electromagnetic Scattering Analysis

Applying numerical value algorithm to solve the problem of electromagnetic field by use of computer has gotten extensive application since the 1960's.Firstly, this paper introduces two kinds of accurate methods exacting the network parameters of microwave integrated circuit based on the Method-of-Moments (MoM) algorithm and fast Fourier transformation(FFT) algorithm: Four-points technique and Short-Open calibration(SOC) technique. The SOC technique is directly used in a full-wave MoM algorithm. It is applied to divide the entire structure into two distinct parts: the static feed lines and the dynamic discontinuity; the MoM-CG-FFT is formulated in such a way that the port voltages and currents are represented through relevant network matrices. This technique is used to remove or separate unwanted parasites brought by the approximation of the impressed voltage source and also the problem of resulting consistency between the two-dimensional and three-dimensional simulations.This paper also introduces the iterative algorithms combined with the Nonuniform fast Fourier transformation(NUFFT) algorithm developing recently to solve the electromagnetic field integral equation. Compared to the conventional methods with a uniform grid, nonuniform fast Fourier transformation algorithm provides an important flexibility in dividing grids. And it is combined with the Conjugate Gradient(CG), Generalized Minimum Residual Method(GMRES) to develop the CG-NUFFT , GMRES-NUFFT algorithm. Under the condition of the same computation complexity O(Nlog2 N), these methods require much smaller computer memory and CPU-time than MoM.