rf dc block

Hello guys,

I a circuit used in gps application. Its an LNA connected to a RF switch. My problem is how to solved the correct capacitor to couple between the LNA and RF switch. Please see attached picture for you reference.

Thanks in advance...

smith chart is the most applicable to solve your problem. you need the output impedance of upc8236t6n and the input impedance of the upg2021tb or vice versa. then plot on the smith chart and solve for the right match

Hope you can show me an example on how solve this problem. I have long gone forgotten how to solve using smith chart..

A collection of Smith Chart tutorials are here:

http://sss-mag.com/smith.html

You don't need to use the Smith chart if its just a coupling cap.

Just use a 10pF.

use 1pF or 10pF or 100pF.
Your job of blocking DC will be done.
It will not change output much.