hfss coax feed diameters - how to calculate ?

[mtu]

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

 

[mauloftin]

hfss coax feed diameters

Hi,

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

it's the answer to your question?

 

[Mustafa_Engineer]

Re: hfss coax feed diameters

Hi Irfan,


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

https://web.awrcorp.com/Usa/Products/Optional-Products/TX-Line/


for more help please upload your file.

 

[mtu]

Re: hfss coax feed diameters

ASA, Mustafa

Thanks you really helped me
Irfan

 

[Mustafa_Engineer]

Re: hfss coax feed diameters

Hi Irfan,

You are welcome.

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


regards

 

[mtu]

Re: hfss coax feed diameters

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

 

[EdmundZheng]

hfss coax feed diameters

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

Edmund

 

[Abhishekabs]

hfss coax feed diameters

Ratio is coming 3.5 in mtu's case not 2.3

 

[Mustafa_Engineer]

Re: hfss coax feed diameters

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)