# RE: [SI-LIST] : Proposal: Rs correlation/collaboration for W-Elem

Mellitz, Richard ([email protected])
Mon, 2 Aug 1999 15:16:42 -0700

Ok here's what I did. I ignored your 1MHz. I converted your numbers back to
Re(rs) and subtracted the DC component, 4.449 ohms/meter. Then I curve fit
these results back to a sqrt(f) function. The value I then come up with is
1.289E-3 Ohms/(sqrt(Hz)*meter). If I multiply by sqrt(2) I get
Mag(Rs)=1.823E-3 Ohms/(sqrt(Hz)*meter). It looks pretty close to the closed
from equation to me.

... Rich

-----Original Message-----
From: Ray Anderson [mailto:[email protected]]
Sent: Monday, August 02, 1999 1:44 PM
To: [email protected]
Subject: Re: [SI-LIST] : Proposal: Rs
correlation/collaboration for W-Elements

I ran Richard's microstrip example under Apsim RLGC 1.500.0
(a spectral
domain solver) and came up with the following results:

Evaluated @ Re(Rs)
----------- --------------------------------
@1MHz 1.4874E-3 Ohms/(sqrt(Hz)*meter)
@100MHz 1.0933E-3 Ohms/(sqrt(Hz)*meter)
@1GHz 1.2272E-3 Ohms/(sqrt(Hz)*meter)
@5GHz 1.3207E-3 Ohms/(sqrt(Hz)*meter)

The value at 1 MHz is curious in that it is larger than the
values at higher frequencies which seem to fall on a
frequency
dependent monotonic line.

Ray Anderson
Sun Microsystems Inc.

> I would like to make a proposal. I would like to know what
various field
> solvers report in regards to the above propagation
function. Let's start
> with a microstrip first (and only look at skin effect).
The geometry
> follows.
>
> Height over ground: 0.004"
> Width of conductor: 0.006"
> Thickness of conductor: 0.001"
>
> Conductivity: 0.58E8 mho/meter
>
> Let's all use the same units for Rs. Say:
> Ohms/(sqrt(Hz)*meter)
>
> Now, A colleague of mine has supplied a formula that is
used in microwave
> design. I have attached a PDF file with details. (Too
tough for text, TTFT
> :-)), I remember foobar)
>
> The answer, using the closed form formula for Rs is:
> 1.806E-03 ohms/(sqrt(Hz)*meter)
>
> If this is the magnitude of complex Rs, then Re(Rs) would
be
> 1.277E-03 ohms/(sqrt(Hz)*meter)
>

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