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We seem to be making some progress. I would at first use a regular grid and try out the subcell methods in chapter 10 of Taflove (3rd edition) for the cells containing the curved material interface. (A somewhat improved method is covered in Gedney lecture notes.)
These subcell methods can be...
Being an unpaid private consultant is not really what I want to spend my time on, but I don't mind answering questions on the forum.
Before going any further you would have to
1) state what you actually know about FDTD (what books/papers did you read)
2) describe the model (the physical...
You might want to put a bit more effort into your postings. If I understand you correctly you are interested in using various coordinate systems for FDTD. That is possible. Most textbooks contain some information on this point. But to get help here you must be a bit more generous with the amount...
When I asked for more details I meant details which can be used to figure out points 1-3 earlier. I know fdtd but I have not used it much for antennas. People here have very different backgrounds.
I don't know what you mean by w-band = wide-band? or t field equations = equations in the time...
I don't see why not. FDTD can model pretty much anything. The question is how effective it is.
You would need to consider
1) the ratio of the smallest geometrical details and the total size of the model
2) special properties of the material involved
3)ratio of wavelength and smallest geometric...
First some general hints:
perfect reflection =>
usually some nonzero constant may be mistakenly set to 0
reflection and increase in amplitude (nearly doubling) =>
usually a sign error
But let me repeat the earlier suggestions.
Record the field values when the excitation arrives for the first...
zmcddn,
I am still not sure where exactly your problem is (I do not have time to look at your code). Are the 'good' and 'bad' snapshots taken at identical moments?
Also try all four corners (same distance) and compare the output. If one corner has 'better' behaviour I would use a debugger or...
How do you got the 'correct' plot (analytically, different program perhaps different type of ABC?)
In any case ABCs like 2nd order Mur make a number of simplifying assumptions. The closer a source is to the boundary the greater the error these assumptions produce. PML is much better in this...
Do you mean generate? If so look at the definition of Gaussian pulses e.g.
Gaussian function - Wikipedia, the free encyclopedia
If you mean show (which I doubt) then how about plotting field values against time?
Basically anything you like, but to keep errors low you should take a pulse whose spectrum peaks in the frequency region you are interested in say 40-400THz.
You could start by actually stating "Yee’s FDTD method in a one-dimensional staggered grid". And then calculating the error term using appropriately truncated Taylor series.
I almost always use dt_max for doubles and 0.9999 * dt_max for floats.
The smaller dt/dt_max gets the larger the error
I was actually interested in concrete numbers.
This may be the reason for your problems. I occasionally used 2nd order Mur which does have
stability problems. I think I...
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