Coupled Microstrip HFSS Simulation and Results

Hi everyone,

I've been trying to simulate and analyze a Coupled Microstrip in HFSS.
I got to the point where I might need some help because I'm having too many questions now and I can't really figure out my problem.

The structure (please see attached HFSS file) comprises a ground plane, a dielectric, two copper stripes, 2 waveports and a radiation boundary.
I want to fabricate this structure on PCB board and then solder a microantenna on it so that I can analyze it with a VNA, but right know I'm only concerned with the coupled microstrip without an antenna on it.

HFSS file: View attachment Coupled Microstrip Edu.rar

So I'm concerned about the results I'm getting with HFSS. Think I need some help to interpretate both S-parameter and Z-parameter plots. Are they correct? What can I do? I think I know what to expect from the Z-parameter plot but I'm not sure about the S-parameter plot.
Also I'd like to know if my Waveports HFSS specifications are correct (modes and integration lines) and also want to know if a radiation boundary is really necessary (There's is a second file, "Without radiation boundary" that's giving me a weird Z-parameter plot, any comments on that?)
I want to have a 50 ohm impedance matched structure at 5GHz (for instance).


Thank you.

Hi everyone,

can someone please help me to understand what's happening with the Z-parameter plot?

Thank you.