Re: transmission line z

JM wrote:

john larkin wrote:
>

Suppose you have a slab of FR4 with copper on both sides, standard
ebay stuff. Now shear off a long thin slice. That's a balanced
transmission line.
>
air
__________________ copper
.........................................fr4
__________________ copper
>
air
>
>
>
What's that called?
>
Does anyone know of a calculator that handles this case?

>
It's just a parallel plate waveguide.
>
For the TEM mode Z0 = 377*sqrt(ur/er)*(d/w).
>
ur/er - substrate permeability/permittivity (relative)
d - dist between copper
w - width copper strip
>
Formulas for the higher modes also exist.
>
But I'd have to look them up.

Your free space impedance is easier for me to comprehend than the one
contained in Chemandy's calculator:

<https://chemandy.com/calculators/microstrip-transmission-line-calculator.htm>

Danke,

--
Don, KB7RPU, https://www.qsl.net/kb7rpu
There was a young lady named Bright Whose speed was far faster than light;
She set out one day In a relative way And returned on the previous night.