RE: NEC-LIST: dielectric/ferrite-clad antennas

Good day,

        "Inexpensive" is the key word in your query. There are FDTD
codes availbable for pc platforms, but they are very costly. I am
writing a code to model wires wrapped around a dielectric, based on
ideas from a bargain Artech House book.

   Catedra et al. "The CG-FFT Method", 1995.

The material, dielectric or magnetic, is treated as free space with an
equivalent current to account for the difference between the actual
internal fields and the applied fields. Their book goes into a
Moment-Method formulation, which they then solve with the CG-FFT
methods. I am using the equivalent current approach, and some of
their MM formulation techniques, but I think my problem size will be
small enough that I can solve the matrix equation directly. Other,
less detailed, papers on the topic are in the collection,

   Miller et al. "Computational Electromagnetics", IEEE Press, 1992.

I am writing my code in APL, which is probably of no use to you, but I
eventually plan to convert it to C or C++. Also, I am using a
coordinate system for the dielectric that is conformal to the body I
want to model. However, now that I've been through the
equation-writing drill, it should not be hard to redo it for another
geometry.

        I would be interested to model some of the antennas you have
built, if you can give me good geometry and performance data,
particularly input impedance vs. frequency. Perhaps we can do some
useful collaboration, if you are not in too big a hurry.

Douglas B. Miron
phone: 605-692-7977
FAX: 605-692-2960
e-mail: dbmiron_at_brookings.net
Received on Thu Oct 30 1997 - 10:02:24 EST