field distribution using 3D FDTD

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ravi8331

Joined: 04 Jul 2008
Posts: 337
Helped: 95
Location: India

22 Sep 2009 10:56 field distribution using 3D FDTD

Hii
i want to calculate electric field distribution within a dielectric slab due to direct contact with an antenna using 3D FDTD .
plz tell me how can i calculate the electric field distribution using 3D FDTD.
i want to see the varriation of electric field with x, y and z direction within the dielectric slab.
plz help me.
i want to do this using MATLAB.
plz help me .....................
if anyone have any example or any document related to this problem then plz mail me at ravi8331(at)gmail.com

skysearcher

Joined: 20 Jul 2009
Posts: 10

22 Sep 2009 17:01 field distribution using 3D FDTD

Two good books - "The Finite-Difference Time-Domain Method for Electromagnetics with Matlab Simulations" by Elsherbeni and Demir and "Electromagnetic Simulation Using the FDTD Method" by Sullivan. I don't think that either have complete code, but they can get you there. You could also try looking through the archives, here, because I think people occasionally post FDTD sample code.

ravi8331

Joined: 04 Jul 2008
Posts: 337
Helped: 95
Location: India

23 Sep 2009 4:39 Re: field distribution using 3D FDTD

thanks for replying...........
i have both books and i hv gone through these books and in first book author provide information about field distribution in 2D but not in 3D and similarly in second book will not provide any thing for 3D object.
i want to do in 3D objects..if anybody having anything which can help me then plz send me......................or upload here.............
thanks ................

iyami

Joined: 12 Apr 2008
Posts: 120
Helped: 16

23 Sep 2009 10:24 Re: field distribution using 3D FDTD

Quote:

i have both books and i hv gone through these books and in first book author provide information about field distribution in 2D but not in 3D and similarly in second book will not provide any thing for 3D object.

That is because there is no conceptual difference.

As far as code is concerned:
2d => double loop
3d => triple loop

ravi8331

Joined: 04 Jul 2008
Posts: 337
Helped: 95
Location: India

23 Sep 2009 10:29 Re: field distribution using 3D FDTD

ok here i will provide the code in 2D then plz do the modiofication and convert it in to 3D..
% display sampled electric fields on a plane
for ind=1:number_of_sampled_transient_E_planes
figure(sampled_transient_E_planes(ind).figure);
Es = zeros(nxp1, nyp1);
component = sampled_transient_E_planes(ind).component;
switch (component)
case 'x'
Es(2:nx,: ) = 0.5 * (Ex(1:nx-1,: ) + Ex(2:nx,: ));
case 'y'
Es(:,2:ny) = 0.5 * (Ey(:,1:ny-1) + Ey(:,2:ny));
case 'z'
Es = Ez;
case 'm'
Exs(2:nx,: ) = 0.5 * (Ex(1:nx-1,: ) + Ex(2:nx,: ));
Eys(:,2:ny) = 0.5 * (Ey(:,1:ny-1) + Ey(:,2:ny));
Ezs = Ez;
Es = sqrt(Exs.^2 + Eys.^2 + Ezs.^2);
end
imagesc(xcoor,ycoor,Es.');
axis equal; axis xy; colorbar;
title(['Electric field <' component '>[' num2str(ind) ']']);
drawnow;
end

% capture sampled time harmonic electric fields on a plane
for ind=1:number_of_sampled_frequency_E_planes
w = 2 * pi * sampled_frequency_E_planes(ind).frequency;
Es = zeros(nxp1, nyp1);
component = sampled_frequency_E_planes(ind).component;
switch (component)
case 'x'
Es(2:nx,: ) = 0.5 * (Ex(1:nx-1,: ) + Ex(2:nx,: ));
case 'y'
Es( :,2:ny) = 0.5 * (Ey( :,1:ny-1) + Ey( :,2:ny));
case 'z'
Es = Ez;
case 'm'
Exs(2:nx,: ) = 0.5 * (Ex(1:nx-1,: ) + Ex(2:nx,: ));
Eys( :,2:ny) = 0.5 * (Ey ( :,1:ny-1) + Ey( :,2:ny));
Ezs = Ez;
Es = sqrt(Exs.^2 + Eys.^2 + Ezs.^2);
end
sampled_frequency_E_planes(ind).sampled_field = ...
sampled_frequency_E_planes(ind).sampled_field ...
+ dt * Es * exp(-j*w*dt*time_step);
end

plz tell me the correction to covert it into 3D electric field distribution..............

iyami

Joined: 12 Apr 2008
Posts: 120
Helped: 16

23 Sep 2009 11:38 Re: field distribution using 3D FDTD

Quote:

ok here i will provide the code in 2D then plz do the modiofication and convert it in to 3D..

Sorry, I do not touch matlab (or whatever that is).
There also are a number of unexplained function calls.

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ravi8331

Joined: 04 Jul 2008
Posts: 337
Helped: 95
Location: India

26 Sep 2009 13:35 Re: field distribution using 3D FDTD

plz help me i m still waiting for ur response................................

nmliuhai

Joined: 05 Nov 2007
Posts: 5

17 Oct 2009 10:51 field distribution using 3D FDTD

Dear ravi8331

Do you have the ebook of 'The Finite-Difference Time-Domain Method for Electromagnetics with Matlab Simulations'. If you have, will you please send it to me. My Email is nmliuhai(at)163.com