a problem about impedance matching

I am designing a TE10 cavity filter. And 50 ou microstrip is used as the input and output.I have two questions about impedance matching:

(1)The impedance of the input microstrip must match the impedance of the first cavity by impedance transform?

(2)The impedance of the filter network(including the input and output microstrip) must be 50 ou? How to get the impedance of the filter network
by simulation,such as HFSS,CST?

Thanks in advance!

same question.

Hello Burton,

If you look at the 2D results in CST there is a folder called port modes, check the line impedance on either e or h folder and this line impedance is the network impedance.

Now, for microstrip line the impedance changes with strip width, substrate and height of the substrate. Try to change the width of the stripline and look for the line impedance. If you decrease the stripwidth, impedance will increase and vice-versa. So make the strip width when line impedance is 50 ohms and that should be the n/w impedance too.

Hope it helps.

Praful