请教校长在matlab上的FDTD程序
请教校长有没有在matlab上的FDTD程序关于一维时域有限差分法(分层介质,反射,透过系数-FFT) ,先谢谢校长了[ 本帖最后由 cdwxg 于 2006-8-22 21:01 编辑 ]
回复:(young20123)请教校长在matlab上的FDTD程序
<P>%***********************************************************************<BR>% 1-D FDTD code with simple radiation boundary conditions<BR>%***********************************************************************<BR>%<BR>% Program author: Susan C. Hagness<BR>% Department of Electrical and Computer Engineering<BR>% University of Wisconsin-Madison<BR>% 1415 Engineering Drive<BR>% Madison, WI 53706-1691<BR>% 608-265-5739<BR>% <a href="mailthagness@engr.wisc.edu" target="_blank" >hagness@engr.wisc.edu</A><BR>%<BR>% Date of this version:February 2000<BR>%<BR>% This MATLAB M-file implements the finite-difference time-domain<BR>% solution of Maxwell's curl equations over a one-dimensional space<BR>% lattice comprised of uniform grid cells.<BR>%<BR>% To illustrate the algorithm, a sinusoidal wave (1GHz) propagating <BR>% in a nonpermeable lossy medium (epsr=1.0, sigma=5.0e-3 S/m) is <BR>% modeled.The simplified finite difference system for nonpermeable<BR>% media (discussed in Section 3.6.6 of the text) is implemented.<BR>%<BR>% The grid resolution (dx = 1.5 cm) is chosen to provide 20<BR>% samples per wavelength.The Courant factor S=c*dt/dx is set to<BR>% the stability limit: S=1.In 1-D, this is the "magic time step."<BR>%<BR>% The computational domain is truncated using the simplest radiation<BR>% boundary condition for wave propagation in free space: <BR>%<BR>% Ez(imax,n+1) = Ez(imax-1,n)<BR>%<BR>% To execute this M-file, type "fdtd1D" at the MATLAB prompt.<BR>% This M-file displays the FDTD-computed Ez and Hy fields at every <BR>% time step, and records those frames in a movie matrix, M, which is<BR>% played at the end of the simulation using the "movie" command.<BR>%<BR>%***********************************************************************</P><P>clear</P>
<P>%***********************************************************************<BR>% Fundamental constants<BR>%***********************************************************************</P>
<P>cc=2.99792458e8; %speed of light in free space<BR>muz=4.0*pi*1.0e-7; %permeability of free space<BR>epsz=1.0/(cc*cc*muz); %permittivity of free space</P>
<P>freq=1.0e+9; %frequency of source excitation<BR>lambda=cc/freq; %wavelength of source excitation<BR>omega=2.0*pi*freq;</P>
<P>%***********************************************************************<BR>% Grid parameters<BR>%***********************************************************************</P>
<P>ie=200; %number of grid cells in x-direction</P>
<P>ib=ie+1;</P>
<P>dx=lambda/20.0; %space increment of 1-D lattice<BR>dt=dx/cc; %time step<BR>omegadt=omega*dt;</P>
<P>nmax=round(12.0e-9/dt); %total number of time steps</P>
<P>%***********************************************************************<BR>% Material parameters<BR>%***********************************************************************</P>
<P>eps=1.0;<BR>sig=5.0e-3;</P>
<P>%***********************************************************************<BR>% Updating coefficients for space region with nonpermeable media<BR>%***********************************************************************</P>
<P>scfact=dt/muz/dx;</P>
<P>ca=(1.0-(dt*sig)/(2.0*epsz*eps))/(1.0+(dt*sig)/(2.0*epsz*eps));<BR>cb=scfact*(dt/epsz/eps/dx)/(1.0+(dt*sig)/(2.0*epsz*eps));</P>
<P>%***********************************************************************<BR>% Field arrays<BR>%***********************************************************************</P>
<P>ez(1:ib)=0.0;<BR>hy(1:ie)=0.0;</P>
<P>%***********************************************************************<BR>% Movie initialization<BR>%***********************************************************************</P>
<P>x=linspace(dx,ie*dx,ie);</P>
<P>subplot(2,1,1),plot(x,ez(1:ie)/scfact,'r'),axis();<BR>ylabel('EZ');</P>
<P>subplot(2,1,2),plot(x,hy,'b'),axis();<BR>xlabel('x (meters)');ylabel('HY');</P>
<P>rect=get(gcf,'Position');<BR>rect(1:2)=;</P>
<P>M=moviein(nmax/2,gcf,rect);</P>
<P>%***********************************************************************<BR>% BEGIN TIME-STEPPING LOOP<BR>%***********************************************************************</P>
<P>for n=1:nmax</P>
<P>%***********************************************************************<BR>% Update electric fields<BR>%***********************************************************************</P>
<P>ez(1)=scfact*sin(omegadt*n);</P>
<P>rbc=ez(ie);<BR>ez(2:ie)=ca*ez(2:ie)+cb*(hy(2:ie)-hy(1:ie-1));<BR>ez(ib)=rbc;</P>
<P>%***********************************************************************<BR>% Update magnetic fields<BR>%***********************************************************************</P>
<P>hy(1:ie)=hy(1:ie)+ez(2:ib)-ez(1:ie);</P>
<P>%***********************************************************************<BR>% Visualize fields<BR>%***********************************************************************</P>
<P>if mod(n,2)==0;</P>
<P>rtime=num2str(round(n*dt/1.0e-9));</P>
<P>subplot(2,1,1),plot(x,ez(1:ie)/scfact,'r'),axis();<BR>title(['time = ',rtime,' ns']);<BR>ylabel('EZ');</P>
<P>subplot(2,1,2),plot(x,hy,'b'),axis();<BR>title(['time = ',rtime,' ns']);<BR>xlabel('x (meters)');ylabel('HY');</P>
<P>M(:,n/2)=getframe(gcf,rect);</P>
<P>end</P>
<P>%***********************************************************************<BR>% END TIME-STEPPING LOOP<BR>%***********************************************************************</P>
<P>end</P>
<P>movie(gcf,M,0,10,rect);<BR></P>
三维FDTD的Matlab编程
请问校长有没有关于三维FDTDMatlab的程序,谢谢校长了 慢慢看 3维的FDTD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
%***********************************************************************
ie=50; %number of grid cells in x-direction
je=24; %number of grid cells in y-direction
ke=10; %number of grid cells in z-direction
ib=ie+1;
jb=je+1;
kb=ke+1;
is=26; %location of z-directed current source
js=13; %location of z-directed current source
kobs=5;
dx=0.002; %space increment of cubic lattice
dt=dx/(2.0*cc); %time step
nmax=500; %total number of time steps
%***********************************************************************
% Differentiated Gaussian pulse excitation
%***********************************************************************
rtau=50.0e-12;
tau=rtau/dt;
ndelay=3*tau;
srcconst=-dt*3.0e+11;
%***********************************************************************
% Material parameters
%***********************************************************************
eps=1.0;
sig=0.0;
%***********************************************************************
% Updating coefficients
%***********************************************************************
ca=(1.0-(dt*sig)/(2.0*epsz*eps))/(1.0+(dt*sig)/(2.0*epsz*eps));
cb=(dt/epsz/eps/dx)/(1.0+(dt*sig)/(2.0*epsz*eps));
da=1.0;
db=dt/muz/dx;
%***********************************************************************
% Field arrays
%***********************************************************************
ex=zeros(ie,jb,kb);
ey=zeros(ib,je,kb);
ez=zeros(ib,jb,ke);
hx=zeros(ib,je,ke);
hy=zeros(ie,jb,ke);
hz=zeros(ie,je,kb);
%***********************************************************************
% Movie initialization
%***********************************************************************
tview(:,:)=ez(:,:,kobs);
sview(:,:)=ez(:,js,:);
subplot('position',),pcolor(tview');
shading flat;
caxis([-1.0 1.0]);
colorbar;
axis image;
title(['Ez(i,j,k=5), time step = 0']);
xlabel('i coordinate');
ylabel('j coordinate');
subplot('position',),pcolor(sview');
shading flat;
caxis([-1.0 1.0]);
colorbar;
axis image;
title(['Ez(i,j=13,k), time step = 0']);
xlabel('i coordinate');
ylabel('k coordinate');
rect=get(gcf,'Position');
rect(1:2)=;
M=moviein(nmax/2,gcf,rect);
%***********************************************************************
% BEGIN TIME-STEPPING LOOP
%***********************************************************************
for n=1:nmax
%***********************************************************************
% Update electric fields
%***********************************************************************
ex(1:ie,2:je,2:ke)=ca*ex(1:ie,2:je,2:ke)+...
cb*(hz(1:ie,2:je,2:ke)-hz(1:ie,1:je-1,2:ke)+...
hy(1:ie,2:je,1:ke-1)-hy(1:ie,2:je,2:ke));
ey(2:ie,1:je,2:ke)=ca*ey(2:ie,1:je,2:ke)+...
cb*(hx(2:ie,1:je,2:ke)-hx(2:ie,1:je,1:ke-1)+...
hz(1:ie-1,1:je,2:ke)-hz(2:ie,1:je,2:ke));
ez(2:ie,2:je,1:ke)=ca*ez(2:ie,2:je,1:ke)+...
cb*(hx(2:ie,1:je-1,1:ke)-hx(2:ie,2:je,1:ke)+...
hy(2:ie,2:je,1:ke)-hy(1:ie-1,2:je,1:ke));
ez(is,js,1:ke)=ez(is,js,1:ke)+...
srcconst*(n-ndelay)*exp(-((n-ndelay)^2/tau^2));
%***********************************************************************
% Update magnetic fields
%***********************************************************************
hx(2:ie,1:je,1:ke)=hx(2:ie,1:je,1:ke)+...
db*(ey(2:ie,1:je,2:kb)-ey(2:ie,1:je,1:ke)+...
ez(2:ie,1:je,1:ke)-ez(2:ie,2:jb,1:ke));
hy(1:ie,2:je,1:ke)=hy(1:ie,2:je,1:ke)+...
db*(ex(1:ie,2:je,1:ke)-ex(1:ie,2:je,2:kb)+...
ez(2:ib,2:je,1:ke)-ez(1:ie,2:je,1:ke));
hz(1:ie,1:je,2:ke)=hz(1:ie,1:je,2:ke)+...
db*(ex(1:ie,2:jb,2:ke)-ex(1:ie,1:je,2:ke)+...
ey(1:ie,1:je,2:ke)-ey(2:ib,1:je,2:ke));
%***********************************************************************
% Visualize fields
%***********************************************************************
if mod(n,2)==0;
timestep=int2str(n);
tview(:,:)=ez(:,:,kobs);
sview(:,:)=ez(:,js,:);
subplot('position',),pcolor(tview');
shading flat;
caxis([-1.0 1.0]);
colorbar;
axis image;
title(['Ez(i,j,k=5), time step = ',timestep]);
xlabel('i coordinate');
ylabel('j coordinate');
subplot('position',),pcolor(sview');
shading flat;
caxis([-1.0 1.0]);
colorbar;
axis image;
title(['Ez(i,j=13,k), time step = ',timestep]);
xlabel('i coordinate');
ylabel('k coordinate');
nn=n/2;
M(:,nn)=getframe(gcf,rect);
end;
%***********************************************************************
% END TIME-STEPPING LOOP
%***********************************************************************
end
movie(gcf,M,0,10,rect); 请问校长一个关于仿真天线的问题,: 怎样才能在fdtd程序中加入要仿真的器件呢? 有相关的仿真程序校长能给新手法一份么?非常感谢!!!我的邮箱:bingbing1341@163.com 请问校长有没有二维的光子晶体电磁场传输特性的FTDT的matlab程序,非常非常感谢! 正好需要可惜还是看不懂! 相当的复杂,存下来慢慢消化 请问;一维光子晶体传输矩阵模拟禁带Matlab编程原代码?
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