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 14:17:50 GMT, Fred Bloggs <nospam@nospam.com> Gave
us:

>
>
>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.


 Semi-rigid is the term, and if it is in coax, it doesn't need to be
IN the PCB from point to point.

  I wish you guys would stop cross posting all over the place.  Many
ISPs have group inclusion limits.

  It is also not considered proper Usenet practice.

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