Re: [SI-LIST] : Proposal: Rs correlation/collaboration for W-Elements

Ray Anderson (
Mon, 2 Aug 1999 10:43:40 -0700 (PDT)

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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