Building Coaxial transmission line on PCB?

I think transmitting high-speed signals is very easy when you have a 
360-degree ground reference, round conductors,
and no other nearby signals like in coaxial cables. My aim is to design PCB 
tracks as much like a coaxial cable as
possible. Anyone tried this before? Is it possible with regular FR4, anyway? 
Thanks for your help.

Gero 

On Mon, 12 Feb 2007 12:10:43 +0100, "Geronimo Stempovski"
<geronimo.stempovski@arcor.de> wrote:

>I think transmitting high-speed signals is very easy when you have a 
>360-degree ground reference, round conductors,
>and no other nearby signals like in coaxial cables. My aim is to design PCB 
>tracks as much like a coaxial cable as
>possible. Anyone tried this before? Is it possible with regular FR4, anyway? 
>Thanks for your help.

---
http://en.wikipedia.org/wiki/Microstrip


-- 
JF

"John Fields" <jfields@austininstruments.com> schrieb im Newsbeitrag 
news:urq0t2533bdm5e2t2ui82b7fo8ppvsbqs8@4ax.com...
>
> http://en.wikipedia.org/wiki/Microstrip
>

Microstrip has absolutely nothing to do with the coaxial structure I had in 
mind. 

"Geronimo Stempovski" <geronimo.stempovski@arcor.de> wrote in message
news:45d06e12$0$30327$9b4e6d93@newsspool1.arcor-online.net...
>
> "John Fields" <jfields@austininstruments.com> schrieb im Newsbeitrag
> news:urq0t2533bdm5e2t2ui82b7fo8ppvsbqs8@4ax.com...
> >
> > http://en.wikipedia.org/wiki/Microstrip
> >
>
> Microstrip has absolutely nothing to do with the coaxial structure I had
in
> mind.

But a microstrip will achieve the same results without the technical
difficulty of a real coaxial line. It is even easier to use
balanced/differential connections.

Meindert

Geronimo Stempovski wrote:

> 
> "John Fields" <jfields@austininstruments.com> schrieb im Newsbeitrag
> news:urq0t2533bdm5e2t2ui82b7fo8ppvsbqs8@4ax.com...
>>
>> http://en.wikipedia.org/wiki/Microstrip
>>
> 
> Microstrip has absolutely nothing to do with the coaxial structure I
> had in mind.

http://en.wikipedia.org/wiki/Stripline

You won't get any more TEM-like on a PCB.

regards
Henning

F'up2 d.s.e. (Da darfst Du dann auch wieder deutsch sprechen.)

> I think transmitting high-speed signals is very easy when you have a 
> 360-degree ground reference, round conductors,
> and no other nearby signals like in coaxial cables. My aim is to design PCB 
> tracks as much like a coaxial cable as
> possible. Anyone tried this before? 

Nope- in all the decades of high speed PC circuit design, you are the 
first to think of it!

>Is it possible with regular FR4, anyway? 

Not even close, the "phase velocity," or speed to you, will be less than 
that of free space by a factor of 1/sqrt(epsilon-sub-r), so go figure.

On Feb 12, 6:10 am, "Geronimo Stempovski"
<geronimo.stempov...@arcor.de> wrote:
> I think transmitting high-speed signals is very easy when you have a
> 360-degree ground reference, round conductors,
> and no other nearby signals like in coaxial cables. My aim is to design PCB
> tracks as much like a coaxial cable as
> possible. Anyone tried this before? Is it possible with regular FR4, anyway?
> Thanks for your help.
>
> Gero

You can build a wave guide out of a multi-layer board with lots of
micro vias. The performance gain was non-existent vs traditional micro/
strip/line, and cost a lot of money. These days you can satisfy
yourself of this reality with a 3D field solver. Back when we tried
this, workstations were as slow as building it "for real", and more
expensive.
Just break out to a connector, use a coax assembly, and connect back
in. Easy peasy.

a7yvm109gf5d1@netzero.com wrote:
> On Feb 12, 6:10 am, "Geronimo Stempovski"
> <geronimo.stempov...@arcor.de> wrote:
> 
>>I think transmitting high-speed signals is very easy when you have a
>>360-degree ground reference, round conductors,
>>and no other nearby signals like in coaxial cables. My aim is to design PCB
>>tracks as much like a coaxial cable as
>>possible. Anyone tried this before? Is it possible with regular FR4, anyway?
>>Thanks for your help.
>>
>>Gero
> 
> 
> You can build a wave guide out of a multi-layer board with lots of
> micro vias. The performance gain was non-existent vs traditional micro/
> strip/line, and cost a lot of money. These days you can satisfy
> yourself of this reality with a 3D field solver. Back when we tried
> this, workstations were as slow as building it "for real", and more
> expensive.
> Just break out to a connector, use a coax assembly, and connect back
> in. Easy peasy.
> 

There is such a thing as microcoax, so he can chisel out a little groove 
in a thick pc and stuff that in there.

On Mon, 12 Feb 2007 12:10:43 +0100, "Geronimo Stempovski"
<geronimo.stempovski@arcor.de> wrote:

>I think transmitting high-speed signals is very easy when you have a 
>360-degree ground reference, round conductors,
>and no other nearby signals like in coaxial cables. My aim is to design PCB 
>tracks as much like a coaxial cable as
>possible. Anyone tried this before? Is it possible with regular FR4, anyway? 
>Thanks for your help.
>
>Gero 
>

Sure. Microstrip, stripline, coplanar waveguide, or even the very
strange slotline.

John

On Mon, 12 Feb 2007 14:39:30 +0100, "Geronimo Stempovski"
<geronimo.stempovski@arcor.de> wrote:

>
>"John Fields" <jfields@austininstruments.com> schrieb im Newsbeitrag 
>news:urq0t2533bdm5e2t2ui82b7fo8ppvsbqs8@4ax.com...
>>
>> http://en.wikipedia.org/wiki/Microstrip
>>
>
>Microstrip has absolutely nothing to do with the coaxial structure I had in 
>mind. 

---
Well, Mister Nasty-Ass, what exactly did you have in mind, then?


-- 
JF