Re: NEC-LIST: Boundary Element/Moment Method interaction matrix

Alexandre, you asked
>
> Do the Eigenvalues and Eigenvectors of the moment method interaction
> matrix have any physical meaning?
>
 
Yes, roughly speaking, the values represent the relative significance
of each mode (most significant closest to zero). The vectors
correspond to the current distribution associated with each mode.

Very useful and much better overview in paper by Austin and Murray,
IEEE-AP Magazine, Feb 1998, p7-21 "The Application of
Characteristic-Mode Techniques to Vehicle-Mounted NVIS antennas"

We currently have a M.Sc. student, Thomas Abbott, who will investigate
the same method to try to obtain a "multi-mode" HF antenna (NVIS and
long distance patterns) for base stations. We hope to extend this to
aircraft once all the tools are in place. We are modifying the
SuperNEC program to compute the eigen values and vectors and hence
plot currents/patterns corresponding to the modes.

Still have to figure out how to handle the slightly asymmetric
impedance matrix - would be nice if anybody got any ideas.

Regards
Andre Fourie
Tel: Intl + 27 11 4030380
Fax: Intl + 27 11 4030381
Website: http://www.poynting.co.za
email: fourie_at_poynting.co.za
Papermail: Dr APC Fourie, PO Box 318, Wits, 2050, South Africa
Received on Tue Feb 23 1999 - 04:01:25 EST