NEC-LIST: NEC-WIN PRO & Buildings

Dear George & other CEMists,

The best technique for your problem depends on the type of antenna,
the frequency of operation and whether the buildings are in the near
field of the antenna or not.

If the buildings are NOT in the near field, integral methods such as
NEC are likely to be too computationally demanding and you would be
better off with a high frequency asymptotic method such as GTD or UTD
(Geometric/Uniform Theory of Diffraction). This technique is employed
in antenna analysis, in programs such as NEC-BSC (Basic Scattering
Code - no connections with the Method of Moments NEC) from the Ohio
State University as well as in propagation software, e.g. for mobile
'phone predictions in built up areas or inside buildings.

If the buildings are in the near field, then NEC could be used but
FDTD (Finite Difference Time Domain) or a related method might be
better, albeit computationally demanding.

Hope this is of use. There is some background (but fairly basic)
information on these techniques on www.fanfield.co.uk. The OSU
website has details of NEC-BSC. (Try http://hertz.eng.ohio-state.edu
- but that might be out of date by now).

Regards,

Paul Carlier
FanField Ltd.
Braxted Park
Witham
Essex CM8 3XB England
(Tel. +44 (0) 1621 893500)
www.fanfield.co.uk
Received on Mon Apr 02 2001 - 06:49:16 EDT