Thread: RF Filter PCBs
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Old November 8th 07, 02:45 AM posted to rec.radio.shortwave
Telamon Telamon is offline
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Default RF Filter PCBs

In article ,
msg wrote:

Telamon wrote:

In article ,
David wrote:


snip

A transmission line is a bunch of capacitors and resistors.



A transmission line can be visualized as a series of LC not RC circuits.


Depending on physical scale, R or L may dominate in the models, please
see: http://sigcon.com/Pubs/news/7_01.htm "chip-scale transmission lines"


Classic transmission line theory is loss-less LC, which is a description
of constrained path propagation. R is a parasitic in real life models
not a part of the description of how the path theoretically functions.

Transmission lines in semiconductors and the packages they go into have
an extreme constraint placed upon them that does not occur any place
else.

As I stated earlier in the thread that was sniped out "You always have
two major ways to lose signal, which are conductor and dielectric in PCB
and coax. Either type of loss can dominate depending on materials and
construction."

The conductor losses are due to the resistance heating of the conductor
and the dielectric losses come from the electric field heating the
dielectric. Both loss types are dissipative and increase with frequency.

--
Telamon
Ventura, California