Re: NEC-LIST: Gridding up vehicles

From: John Ross <johnross_at_email.domain.hidden>
Date: Wed, 20 Oct 1999 19:29:53 -0600

Matt Taylor wrote:
>
> Assume that one desires to model an antenna on a vehicle of some type,
> whether that vehicle is a land, sea or air vehicle. Assume that one
> has some computer model of the vehicle, like an Autocad drawing file.
> What is the easiest way to mesh up the vehicle for NEC modeling? ...

Matt,

If you find such an item please let me know. I work on vehicular
antennas for the auto industry and this is the single biggest problem
we face. I currently use some proprietary CAD tools that can mesh very
complicated surfaces. Unfortunately, even with these sophisticated
tools we still have to do lots of manual fixing before we have a mesh
suitable for NEC. In the event that you already have a mesh in DXF or
IGES you can convert it to NEC format using a program called CAD2NEC
available on my website. As for ignoring details, yes, that is
essential, but you must be careful. The usual situation is that there
is far more detail in pracitcal vehicle surfaces than can be used in
any EM model. Sound judgement must be used to intelligently smooth out
the surfaces and reduce complexity. If your model is large enough as
compared to a wavelength, you may be able to use the asymptotic
methods such as GTD/UTD to avoid huge matrices. Good luck.

John

-- 
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Received on Wed Oct 20 1999 - 23:07:46 EDT

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