converting lumped capacitor into distributed capacitor

[kazim]

dear friends

i simulated a 12 pF lumped capacitor in ADS at 900 MHz connected in series and now i want to convert this capacitor to distributed one, i mean to implement this using microstrip line. does anyone know how to do it...i read some literature regarding interdigital capaictor but still i had to confirm if someone among u have tried to implement it......

 

[sv1437]

Though I haven't implemented, even I have seen some papers where distributed capacitors are implemented by interdigital capacitors. I think that's the way to go.

 

[BigBoss]

12 pF is huge value for a interdigital capacitor because it will use fringe capacitor between metal fingers...But if you have space you may realize but it will have very low Q factor because of ESR.

 

[biff44]

I agree, 12 pf is a lot. You will need multiple fingers, with a very small gap, and have significant finger length. Also, you will incur significant shunt capacitance that needs to be analyzed too.

 

[kazim]

thanks gys for u help but i was wondering if there is some other way i could implement a distributed capacitor. i have space of 7 mm in total to put in the capacitor but as i said lumped capacitors have very low bandwith

 

[BigBoss]

thanks gys for u help but i was wondering if there is some other way i could implement a distributed capacitor. i have space of 7 mm in total to put in the capacitor but as i said lumped capacitors have very low bandwith

Using very thin substrate and high dielectric coefficient may help you to build up a stacked (2 or more layers) capacitor if you don''t have any thickness constraint..

\[\displaystyle C= \frac{{\varepsilon}_{0}{\varepsilon}_{r}A}{h}\]