Stripline to Microstrip transition using Ansoft HFSS 11

Hello everyone,

I am trying to simulate a stripline to microstrip transition, The impedance is matched to 50 ohms, but the return loss is very low in the order of -1 db.
I need to acheive a return loss of more than -20 db.
For this, I have constructed a simple stripline and a via which feeds to a microstrip line.

How do you acheive S11 to be > -20db
S21 and S31 to be >-3db.

The solution frequency is 18Ghz.

Secondly, If i want to acheive a broadband operation over the entire frequency range( i.e., having a uniform S11, S21, S31 over the frequency range from 15Ghz to 18Ghz.)

Added after 2 minutes:

Hello everyone,

I am trying to simulate a stripline to microstrip transition, The impedance is matched to 50 ohms, but the return loss is very low in the order of -1 db.
I need to acheive a return loss of more than -20 db.
For this, I have constructed a simple stripline and a via which feeds to a microstrip line.

How do you acheive S11 to be > -20db
S21 and S31 to be >-3db.

The solution frequency is 18Ghz.

Secondly, If i want to acheive a broadband operation over the entire frequency range( i.e., having a uniform S11, S21, S31 over the frequency range from 15Ghz to 18Ghz.)

Regards,
Avin

Hello everyone,

Help needed Please look into the project.

Regards,
Avi