Re: transmission line z

On Thu, 19 Jun 2025 07:37:20 -0700, john larkin <jl@glen--canyon.com>
wrote:

On Thu, 19 Jun 2025 13:30:55 -0000 (UTC), "Don" <g@crcomp.net> wrote:
>

Leo Baumann wrote:

Leo Baumann:

schrieb john larkin:

ir
__________________ copper
.........................................fr4
__________________ copper
>
air

>
www.leobaumann.de/newsgroups/Stripline_without_Groundplane.pdf
>

>
It is necessary to determine the effective material permittivity of the
geometry.

>
OK. It's easy enough for me to mentally model the stripline as a
complexly constructed capacitor.

>
With inductance.
>

>
Open question: Is it possible to view the stripline as unterminated long
wire antenna with a length longer than one or two wavelengths? In this
case the radiation pattern's major lobe constricts to increasingly align
with the antenna axis.
>
Danke,

>
People don't usually include radiation in calculating transmission
line behavior, even though some geometries probably do radiate. I'd
expect that copper and dielectric losses are a lot worse than
radiation, and we usually ignore them too.
>
Stripline between ground planes shouldn't radiate, at least into free
space.
>
Some really fast txlines have serious losses, like later gen PCIe and
such. They need adaptive equalizing.
>
I was at the microwave show in San Francisco yesterday. A guy from R+S
was demonstrating an ADC chip that digitizes at 64 Gbps

I meant 64 G samples/sec. Just run a wideband antenna into the ADC.