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## How to model a coaxial cable in AC/DC electrical circuit interface?

Hi everyone,

I' am modeling a configuration of two devices which are connected by a coaxial cable. My model includes both Electrical Currents and Electrical Circuits interfaces: The only problem is the connection between them, I cannot find a "coaxial cable" tool in Electrical circuit interface.

Has anyone been faced with such a task? Many thanks in advance!

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Sh.Arakelyan

5 Replies Last Post 26/12/2018, 21:04 GMT-5

Posted: 2 years ago

Hi,

in the context of AC/DC the coaxial cable can be replaced by the equivalent circuit. This is a series inductor, series resistor and parallel capacitors. The coaxial cable must be much shorter than any wavelength in the model.

Cheers Edgar

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Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com

Posted: 2 years ago

Hi,

in the context of AC/DC the coaxial cable can be replaced by the equivalent circuit. This is a series inductor, series resistor and parallel capacitors. The coaxial cable must be much shorter than any wavelength in the model.

Cheers Edgar

Thanks for your comment Mr. J. Kaiser,

the approach proposed by you is very rough approximation for my task, since I investigate the effect of coaxial cable length. Regards Shant

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Sh.Arakelyan

Posted: 2 years ago

I would say, it depends. The equivalent parameters depend on the length, e.g. the capacitance for a typical 50 Ohm cable is 90 pF/m. The equivalent circuit can be good enough as long as the wavelength of the signal is much larger than the cable length. If the cable length gets longer than lambda/10 (this limit depends on the accuracy requirements) and you have to take transmission line effects into account you need a different approach.

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Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com

Posted: 2 years ago

Modeling the coaxial cable with several lumps per wavelength will provide a good approximation. For "several"- four is enough, eight better, more probably not necessary. Most accurate will be to use T or pi sections.

D.W. Greve DWGreve Consulting