 Guilin Sun
Ansys Employee

"How is the phase calculated ?" I guess you know how the phase is calcualted right? it uses "angle" script, similar to atan(Imag/real).

"Why is there this discrepancy for the phase calculation between the two simulations ?" THere are two main reasons:

1: Phase is a relative quantity. so its beginning reference point is important. When you got your first plot, it uses the phase at the lowest frequency as reference point. In the 2nd case, it uses the zero T as reference.

This is a frequenctly asked question. We have to understand the unique property of the phase: relative. anything larger than abs(pi) will be discarded.

2: accuracy change. when you change the wavelength from broadband to single, the mesh and the material will change. So you should use the same mesh and the material fitting for the single wavelength case, by ticking this You may try to extract the the phase at the same exact wavelength as the single wavelength from the broadband simulation, and compare the case when both the mesh and the material fitting use the same settings from the broadband for the single wavelength simulation. 