You should use a waveport and look at Z0.
If you want more information use the "Port Only" solution mode, and you will get Alpha and Beta and some more info.
Later you can ofcourse renormalze the S matrix to your required impedance or use Optimetrics to optimize the MS to the correct Z0.
For calculating precise impedances change the port accuracy from 2% to 0.3% (or even 0.1%).
Thank you very much!
But I am still not clear now.
The Z0 is characteristic impedance of one port, right? The Z matric is not the input impedance??
I want to know if I should take account of the feed line, for the different length cause different Z matric. So, which is the input impedance of the antenna?
The ports setting in HFSS is treated in this way: outward of the port is connected with transmission line, the characteristic impedance of the transimission line is Z0(which you change this value and normalize it to any value you want). It is assumed that they are perfectly matched. If you are dealing with µ-strip antenna, you can read Z-matrix, it is the real input impedance.
The ports setting in HFSS is treated in this way: outward of the port is connected with transmission line, the characteristic impedance of the transimission line is Z0(which you change this value and normalize it to any value you want). It is assumed that they are perfectly matched. If you are dealing with µ-strip antenna, you can read Z-matrix, it is the real input impedance.