Impedance to Frequency HFSS

[shellyondiet]

Hi im trying to get characteristic impedance to sweeping frequency for coplanar waveguide. When I do the plot (Z0 to frequency ) why do i get two lines (Z0(1) and Z0(2) ? what does the one and two mean ?

 

[vfone]

Is related to exitation modes.
Read page 64 of this guide:

 

[hoijin]

Is related to exitation modes.
Read page 64 of this guide:

could you very simple and clear way explain please?

 

[PlanarMetamaterials]

could you very simple and clear way explain please?

The wave ports will excite multiple modes. Those are the impedances of the first 2 modes the port solved.