RE: Loss through concrete

Hello everyone!

I would suppose that the report mentioned in the message reproduced below
refers to the attenuation of a plane wave propagating *entirely* through the
material, and that reflections at the interfaces are neglected. Wouldn't a
complex permittivity measurement be more useful? I don't think that it could
be derived from these attenuation figures, as they really only express the
phase angle of epsilon_r, and not it's magnitude.

Am I correct?

Is that kind of complex permittivity data tabulated somewhere? I am thinking
of attempting one day the simulation of a small wire antenna placed near a
concrete wall, and might use for that the Somerfeld lossy ground auxiliary
program of NEC.

JUST WAIT A SECOND! I just remembered that I had seen this exact same
question asked on a USENET forum last year, and that I had saved the answer.
Here it is:

> 10 Mar 1995 18:15:29 -0600
>
> Try:
>
> The Chemistry of Cements, Vol. 2, ch. 23, H. F. W. Taylor ed., Academic
Press, 1964.
>
> J. Materials Science, 26, p. 2984, 1991.
>
> Mag. Concrete Res., 36, #126, p. 42, 1984.
>
> Alan

This apperently initially came from : kridnix_at_master.ceat.okstate.edu
(Richard Cheville)

I have never been to check the references at the library, so I don't know
what they're worth. I'll have to see. I had also seen in an other thread a
while back the following answer to a similar question, but on liquids:

> You can find a lot of dielectric data on liquids and solids on:
> A.R.Von Hippel, DIELECTRIC MATERIALS AND APPLICATIONS, M.I.T. Press

Comments anyone?

Alexandre Kampouris

G&A Télécom S.A.R.F.
Montréal
e-mail: ak_at_bethune.com

At 16:39 01.07.96 -0500, you wrote:
>
>All,
>
>There is a report out of Rome Air Development Center RADC-TR-67-446, Feb.
>1968 by C.M. Brennan et al titled EM shielding of building materials. It
>is referenced in a more recent Sept. 1984 report by J.C. Wyss titled
>Building Penetration Project that is available through NTIS, number
>PB85-126001. The loss through Portland cement concrete, aggregate to
>cement ratio = 3:1, that was saturated with moisture is reported from the
>former in the latter, with a 10% "assigned uncertainty", to be:
>
>Freq, Hz Attn., dB/cm
> 1.0 E4 2.98 E-7
> 1.0 E5 4.41 E-7
> 1.0 E6 1.50 E-6
> 1.0 E7 2.58 E-6
> 1.0 E8 4.84 E-5
> 1.0 E9 7.6 E-4
> 1.0 E10 7.6 E-3*
>
>* denotes extrapolation.
>
>Plywood, dry wall, Doglas Fir, etc. are also listed in the NTIS report.
>
>
>Allen Davidson
>Motorola Rm 2240
>1301 E. Algonquin Rd.
>Schaumburg, IL 60196
>
>E-Mail: CASR04_at_email.mot.com
Received on Tue Jul 02 1996 - 17:54:00 EDT