fdtd_1d_3[1].m

fdtd一维到三维算法

% Excercise 3
% 1D FDTD free space propagation
% modified programme (using Absorbing boundary condition ABC)
% Note: ABC works only in 1D - need Perfectly Matched Layer (PML)
%       for 2D and 3D problems.
% Coded by Pradip Mukhopadhyay
% 7 March 2005
%
% For EEE355F AJW
%
%
%
%


KE = 201;                %number of grid in z direction

kc = fix(KE/2) ;           % centre of the grid

ex = zeros(1,KE);         % initilize the Ex field

hy = zeros(1,KE);         % initilize the Hy field


cb = zeros(1,KE);

cb(1,:) = 0.5;


% Constant for ABC

ex_left_m1 = 0.0;

ex_left_m2 = 0.0;

ex_right_m1 = 0.0;

ex_right_m2 = 0.0;


% A Gaussian pulse

t0 = 36.0 ;

spread = 12 ;


NSTEPS = 300 ;          % number of time steps


for n=1:NSTEPS


    for k=2:KE

        ex(1,k) = ex(1,k) + cb(1,k).*(hy(1,k-1) -hy(1,k));

    end


    pulse = exp(-0.5*((t0-n)/spread)^2.0);    %The Gaussian pulse


    ex(1,kc) = pulse;                      % adding the pulse at the centre of the grid


    ex(1,1) = ex_left_m2;                       % left boundary

    ex_left_m2= ex_left_m1;

    ex_left_m1 = ex(1,2);


    ex(1,KE) = ex_right_m2;                  % right boundary

    ex_right_m2= ex_right_m1;

    ex_right_m1 = ex(1,KE-1);


    for k=1:KE-1

        hy(1,k) = hy(1,k) + 0.5*(ex(1,k) -ex(1,k+1));

    end


    plot(ex);


    axis([1 KE -1 1]);
    title('1D EM Propagation - ABC boundary condition')

    pause(0.01);

end