| "Bill Miller" wrote in message
| ...
|
| wrote in message
| ...
|| From......: "Bill Miller"
|| Newsgroups: sci.physics.electromag
|| Sent......: Wednesday, August 18, 2010 10:44 PM
|| Subject...: vemsa3d 1.1 - a floss visual em simulator
|| for 3d antennas
||
|| wrote in message ...
|| -
|| ...
||
|| How does this work differ from NEC Numeric Electromagnetic
|| Code for antenna analysis?
||
|| Bill Miller
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|
| Dear Mr. Miller,
|
| VEMSA3D can not work differently, because it is based
| on the same theoretical method as NEC does, that is on
| the Method of Moments.
|
| However, since each of these numerical applications use
| a different basis of the current function space and since
| their corresponding computer programs use unavoidably
| finite linear combinations of them, in general, they
| produce different results.
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1
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|
| Can you quantify further or explain the nature of thes
| "different results?"
|
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Well, I can try. These numerically different results are due
to the different coupling -reaction, or impedance- between two
current distributions for which different function -expression,
type, formula, or equation- is used to describe them in each
one of the two applications, VEMSA3D and NEC.

2
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| Are there certain classes of antennas for which VEMSA3D
| might produce more accurate results than NEC?
|
| Thanks!
|
| Bill Miller
|
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You are welcome!

VEMSA3D is a thin-wire polygonal modeler in "free space".
Therefore, it has to "exactly" predict or justify the
characteristics of any thin-wire antenna. For this class of
antennas VEMSA3D can be certainly compared with NEC. Anyhow,
this comparison can only be indirect: you have to build and
measure the specific thin-wire antenna first and then to
overlay the results of both applications upon the
measurements. But since this kind of knowledge is definitely
a posteriori, you can try a comparison of both applications
for *any* class of antennas. Here, only the advertisement
builds knowledge a priori; but usually this is followed by
a deep disillusionment.

Regards,

Petros Zimourtopoulos