dielectric feeds+coaxial feed

I need to to drive a patch with coax probe. I want to know how to calculate coax outer diameter and inner conductor diameter.?
Is there any relation with frequency?

Irfan

Hi,

try this: http://en.wikipedia.org/wiki/Coaxial_cable. The most important is "Characteristic impedance"

it's the answer to your question?

Hi Irfan,


to get the exact dimensions of the coaxial probe use this free calculator:

http://web.awrcorp.com/Usa/Products/...ducts/TX-Line/


for more help please upload your file.

ASA, Mustafa

Thanks you really helped me
Irfan

Hi Irfan,

You are welcome.

If you you want to make the simulation easier, use the dielectric as free space with epsilon=1.


regards

I used calculator, with 2.4 GHz and 50 ohm line with air and copper.
The inner and outer dia seems to be quite immpractical like d inner=0.146777mm and d outer=0.49999mm. is it ok?

irfan

depend on dielectric of feed substrate, if you choose air, the ratio of outer and inner diameter is 2.3.

Edmund

Ratio is coming 3.5 in mtu's case not 2.3

Hello,

The correct equation used to calculate the dimensions is below:

Z=60/√(epsilon)×ln (b/a)

and when epsilon equals one then:

Z=60×ln(b/a)