I currently teach Antennas and Wave Propagation to third year BE students.
If anyone has animations which may help students for better understanding, that would be great.
You can start from Youtube. There is a plenty of nice films and animations related to electromagnetic wave behaviour.
I would suggest if you have access to a Commercial or an open source EM simulator to create your own examples.
The below MATLAB 2013b script generates an animation of the time-harmonic electric field in a parallel-plate waveguide. The fields are excited by a line current, which is also in the presence of a perfectly conducting wire in order to reflect the fields to realize unidirectional wave propagation. We are about to submit it to IEEE Magazine, including the analytical derivations, exactly to address these types of questions and to supply the academic community with more illustrative examples.
%%%%%%%%% MAIN SCRIPT %%%%%%%%%
f = 1e9; % Frequency
Omega = 2*pi*f; % Radial frequency
k = Omega/3e8 - 1j*1e-20; % Wavenumber in free space Im(k)=0^-
Lambda = 2*pi/real(k); % Wavelength in the medium
a = 0.54*Lambda; % Parallel-plate separation distance
kxn_Lambda = real(2*pi/sqrt(k^2-(pi/a)^2)); % Guide wavelength mode n=0
d = 0.25*kxn_Lambda; % Reflecting wire at Lambda_g/4
z = -a/2 : a/100 : a/2; % z-Coordinates
x = -6*a : a/100 : 6*a; % x-Coordinates
[X,Z] = ndgrid (x,z); % Generate x,z grid of points
Ei = E_Field (X,Z,a,k); % Compute incident field
G = Gamma (d,k,a); % Compute reflection coeffcient Gamma
Es = G * E_Field (X+d,Z,a,k); % Compute the scattered field
E = Ei + Es; % Compute the total field
vidObj = VideoWriter('FileName.avi'); % Prepare video file
open(vidObj); % Open the video file
M=125; % Take M frames
for m = 1 : M
close all
Phase = 2*pi / M*(m-1); % Compute the phase for that frame
if m==1 % Enter for first iteration only
[~,h] = contourf(X,Z,abs(real(E*exp(1j*Phase)))); % Plot the field
c = get(h,'LevelList'); % Store contour levels
v = caxis; % Store axis settings
else
contourf(X,Z,abs(real(E*exp(1j*Phase))),c); % Plot the field
caxis = v; % Use the initial axis settings
end
axis equal
axis tight
axis off
xlabel('x [\lambda]')
ylabel('z [\lambda]')
set(gca,'nextplot','replacechildren');
drawnow; % Needed to improve stability when
pause(0.2); % capturing frames
currFrame = getframe; % Capture the frame
writeVideo(vidObj,currFrame); % Write to file
end
close(vidObj); % Close the file
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%% HELPER FUNCTION %%%%%%%%%
function E = E_Field (X,Z,a,k)
E = zeros(size(X));
for n = 0 : 99 % Number of modes
kzn = (pi/a) * (1 + 2*n);
kxn = sqrt(k^2 - kzn^2);
E = E + ((-1)^n)*sin(kzn*(abs(Z)-a/2))./kxn.*exp(-1j*kxn*abs(X));
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%% HELPER FUNCTION %%%%%%%%%
function G = Gamma (d,k,a)
NUM=0;
DEN=0;
for n = 0:99 % Number of modes
kzn = (pi/a) * (1 + 2*n);
kxn = sqrt(k^2 - kzn^2);
NUM = NUM + exp(-1j*kxn*d)/kxn;
DEN = DEN + kxn^(-1);
end
G = - (NUM / DEN);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
You can find some example as online applets at http://www.tet.ovgu.de/Forschung/Tools+.html. The examples are described in German, but some online translator should be helpful.
http://www.tet.ovgu.de/Forschung/Tools+.html
Thanks Mr.Mathias. Could you please send me the same in English format as it is in portugesh.....
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