RE: NEC-LIST: Modelling the RF absorber

Daryl van Vorst asked: "Is there a way to approximate an RF absorber in an NEC2
simulation?"

Daryl,

I have modelled planer lossy surfaces with NEC before using a wire grid with each of
the grid wires resistively loaded. We modelled "teledeltos paper" or "space paper"
which has a few 100 Ohm per square resistance (not actually 377/sq like I thought).
Was very successful. I believe if you extend it to a 3D sort of wire mesh representing
the absorber it should be possible to do using wire MoM. Some of the FEM and TLM
methods are certainly more suitable, but if you are used to NEC models and have it
availabel it may work fine and be good fun. Please let me know if you try it and it
works (or does not). We are still considering the same technique to model dielectrics
(using capacitors in the wire grid or mesh) - have not really tried this but should be
quite useful for modelling small dielectric components (radomes?) if it works.

The reference below describes the study and measurements we have done if
anybody is interested:

A R Clark, A P C Fourie, and J Dresel. Modelling lossy surfaces using a wire
Method-of-Moments code. IEE Proceedings-Microwaves, Antennas and
Propagation, 147(3):247-248, June 2000.
Regards
Andre Fourie

Tel: Intl + 27 11 262 5155
Fax: Intl + 27 11 262 5156
Website: http://www.poynting.co.za
email: andre.fourie_at_poynting.co.za
Papermail: Prof. APC Fourie, PO Box 76579, Wendywood, 2144, South Africa

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