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From: simich@elm.eecs.ucdavis.edu (Myron Simich)
Newsgroups: sci.electronics
Subject: Re: R.A.M. (was Re: Police Radar Frequency Info)
Message-ID: <9220@ucdavis.ucdavis.edu>
Date: 25 Jun 91 20:15:39 GMT
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As I understand it, and I have not made any real effort to explore the 
nitty gritty as to how it is done, the material acts as an attenuator
at microwave frequencies.  As a microwave signal impacts upon this
type of material and penetrates into it, the signal is dramatically
attenuated.  This means that real part of the propagation coefficient
gamma is real.  For any real part of gamma greater than zero there is
an expnential decay of a wave in the material.

Of course the material should have an impedance such that the majority
of the wave is absorbed into the material and not reflected.  I assume
that this has been taken into account (the material works quite well in
the research that I have been doing so it would seem that this is the 
case).

As far as I know, this is not the same material user in stealth aircraft.
I believe that they use some sort of carbon fiber material but I am not
sure.

Again, let me state that this is *my* understanding of how the material
works.  I don't claim that this is *exactly* the way it works, just my
understanding of how it works.

Myron Simich
Simich@iris.eecs.ucdavis.edu