Questions about FDFD

I've written a FDFD simulation in python following the procedure written by Dr. Rumpf here: http://emlab.utep.edu/ee5390cem/Lect...ementation.pdf

I think I'm having some issues with the source.


Slide 36 defines k0 as 2*pi / wavelength

If I let wavelength be 1000e-9 meters or 1000 nm k0 = 6283185.30718

nref = 1
kinc = k0 * nref * [0,1]

kinc then should be a source from the y direction

slide 40 defines the source field to be

fsrc (x,y) = exp(j *(kxinc X + kyinc Y) )

fsrc (x,y) = exp(j *( 0 + 6283185.30718 * Y) )

or f = exp(j * 6283185.30718 * n) ) n = 0..M

which just becomes a decaying function (because we aren't resolving a wavelength) unless I multiply my n term by some deltaX (1000e-10). Am i missing something somewhere?

The 'j' in your exponential term makes it oscillate and not decay. Also, when you multiple your very large k by a very small Y, you will get a reasonable number in your exponential. I recommend normalizing everything. Normalize your dimensions by multiplying by k0. Normalize your k vector components by dividing by k0.

BTW, try asking questions through the "CEM Lectures" channel on YouTube. I do not check EDABoard that often, but YouTube notifies me right away when a question is asked.

https://www.youtube.com/channel/UCPC...SK71MnPPcp8AGA


Happy to help you!