Need Help in trace separation

[monolothics]

Hi

i want to design a interdigital capacitor in microstrip and also need to use the microstrip gap discontinuity

what i want to ask about how to calculate the trace separation in microstrip??

i got confuse, and i've had searched everywhere but i can't get the calculation of the trace separation..


thx

 

[per_lube]

if you have access to ADS software, you can use it to design inter-digital capacitors without knowing the formuars,
use Microstrip Circuits Design guides of ADS if you have access to ADS...

cheers,
per_lube

 

[monolothics]

hi per_lube
thx for the reply

yes, i have access ADS software, but we need to input the trace separation (s), so how to calculate the trace separation between two microstril lines because i still don't know how to calculate it.
from all book that i've read like inder bahl, jia-sheng and pozar, i still can't understand how to calculate the trace separation (s)

 

[tony_lth]

you can set the separation as a variable, then optimize it.

 

[per_lube]

you can set the separation as a variable, then optimize it.

hi monolothics,

As tony_lth has mentioned, optimization will work perfectly.
and if you know how to use the design guide feature of ADS, it will generate the schematic model component and layout once you enter the values into the parameters.

The important thing is, when you select the line separation, it should be a realizable value without much error. For normal milling, etching operations available in labs, 0.15-0.2 mm line separation would be the practical limitation of minimum line separation.

However if you badly need the calculations, these papers will help you (I just googled a little bit). Try to look at their references as well. They will also might help you.

https://arxiv.org/ftp/arxiv/papers/1006/1006.0856.pdf
https://www.just.edu.jo/~nihad/files/pap/CPW-IDC.pdf
https://www.just.edu.jo/~nihad/files/pap/36.pdf

cheers,
per_lube