Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Questions about FDFD

Status
Not open for further replies.

strspeed

Newbie level 3
Joined
Jul 20, 2016
Messages
3
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
36
I've written a FDFD simulation in python following the procedure written by Dr. Rumpf here: https://emlab.utep.edu/ee5390cem/Lecture 14 -- FDFD Implementation.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?
 

rrumpf

Full Member level 5
Joined
Jul 6, 2007
Messages
289
Helped
66
Reputation
132
Reaction score
43
Trophy points
1,308
Location
El Paso, TX
Activity points
3,559
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/UCPC6uCfBVSK71MnPPcp8AGA


Happy to help you!!!
 
Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top