FDTD算法的Matlab源程序

%*********************************************************************** 
%    3-D FDTD code with PEC boundaries 
%*********************************************************************** 
% 
%    Program author: Susan C. Hagness 
%                    Department of Electrical and Computer Engineering 
%                    University of Wisconsin-Madison 
%                    1415 Engineering Drive 
%                    Madison, WI 53706-1691 
%                    608-265-5739 
%                    hagness@engr.wisc.edu 
% 
%    Date of this version:  February 2000 
% 
%    This MATLAB M-file implements the finite-difference time-domain 
%    solution of Maxwell's curl equations over a three-dimensional 
%    Cartesian space lattice comprised of uniform cubic grid cells. 
% 
%    To illustrate the algorithm, an air-filled rectangular cavity 
%    resonator is modeled.  The length, width, and height of the 
%    cavity are 10.0 cm (x-direction), 4.8 cm (y-direction), and 
%    2.0 cm (z-direction), respectively. 
% 
%    The computational domain is truncated using PEC boundary 
%    conditions: 
%          ex(i,j,k)=0 on the j=1, j=jb, k=1, and k=kb planes 
%          ey(i,j,k)=0 on the i=1, i=ib, k=1, and k=kb planes 
%          ez(i,j,k)=0 on the i=1, i=ib, j=1, and j=jb planes 
%    These PEC boundaries form the outer lossless walls of the cavity. 
% 

%    The cavity is excited by an additive current source oriented 
%    along the z-direction.  The source waveform is a differentiated 
%    Gaussian pulse given by 
%          J(t)=-J0*(t-t0)*exp(-(t-t0)^2/tau^2), 
%    where tau=50 ps.  The FWHM spectral bandwidth of this zero-dc- 
%    content pulse is approximately 7 GHz. The grid resolution 
%    (dx = 2 mm) was chosen to provide at least 10 samples per 
%    wavelength up through 15 GHz. 
% 
%    To execute this M-file, type "fdtd3D" at the MATLAB prompt. 
%    This M-file displays the FDTD-computed Ez fields at every other 
%    time step, and records those frames in a movie matrix, M, which 
%    is played at the end of the simulation using the "movie" command. 
% 
%*********************************************************************** 

clear 

%*********************************************************************** 
%    Fundamental constants 
%*********************************************************************** 

cc=2.99792458e8;            %speed of light in free space 
muz=4.0*pi*1.0e-7;          %permeability of free space 
epsz=1.0/(cc*cc*muz);      %permittivity of free space 

%*********************************************************************** 
%    Grid parameters 
%***********************************************************************