Impedance in microstrips

[pareshatlnmiit]

I have calculated line capacitance through variational method using equations,please tell me how to calculate impedance ?Any equation realting line capacitace and impedance?

 

[nhomuathu_hanoi]

I think you may have your answers from:

how to calculate impedance ?

at the book:
Microstrip antenna Design Hand book - (appendix B).
related link:
**broken link removed**

and your second one:

Any equation realting line capacitace and impedance?

It's can be found at chapter II - Microwave Engineering, David M. Pozar.

Have fun!

 

[vfone]

https://chemandy.com/calculators/microstrip_transmission_line_calculator.htm

 

[pareshatlnmiit]

Thanks vfone but in that calculator they are not calculating impedance though line capacitance,I want equatioon which can relate line capacitance to impedance.

 

[vfone]

Zo = √(L/C)

 

[livemath]

Hi,

Take note that equation above is valid for uncoated trace or copper, PCB manufacturer normally cover the trace or copper with mask with a thickness of 8-10 mills and that will turn the equation to;


er' = er{ 1 - pow(e, ((-1.55*(H+T+M))/H) ) }
where
e =euler's constant
H =Trace distance from a ref plane
T =Trace thickness
M =Mask thickness

and it will effect if you're implementing controlled impedance where;
Zo = (79/sqrt(er'+1.41))*ln(5.98*H/(0.8*(W+T)))Ω valid for 5<W<15 mills
or
Zo = (87/sqrt(er'+1.41))*ln(5.98*H/(0.8*(W+T)))Ω valid for 15<W<25 mills

And also take note that this 2 equation is accurate to ±5% when W to H ratio is less than 0.6, when the ratio rise from 0.6 or more, accuracy typically drop to ±20%.

and the intrinsic capacitance is;
Co = (1.41*er')/ln(5.98H/0.8(W+T)

You may refer to IPC-D-317A for more literature.


Goodluck...

 

[imodelit_moderator]

Hi,

Check this http://imodelit.com/ViewDetails.aspx?AID=142

Best Regards,
imodelit Moderator

 

[jallem]

I have calculated line capacitance through variational method using equations,please tell me how to calculate impedance ?Any equation realting line capacitace and impedance?

You should also calculate by variational method the line inductance.

 

[pareshatlnmiit]

Thank you all of you but i have found the answer in one of the papers of great Yamashita,if any wants that can tell to me

 

[7rots51]

pareshatlnmiit:

Thank you all of you but i have found the answer in one of the papers of great Yamashita,if any wants that can tell to me

Please send link or upload that article.

 

[pareshatlnmiit]

"This paper has already been attached",message comes when i am attaching this paper so i m sending u link you can see from there and if you have any query regarding this topic ,ask me i have already finishes with the equations of this paper
Here is the link

 

[akedar]

i am not able to download from megaupload..can u upload on rapidshare

 

[pareshatlnmiit]

Akedar tell me the way,i will upload on rapidshare.