Hi,
Have you get your problem solved?
I have try floquet port and wave port. To plot the reflection phase in HFSS, just go to "HFSS" -> "Results" -> "Create Modal Solution Data Report" -> "Rectangular Plot" after click on "Rectangular Plot" a new trace window will appear here you can configure the setting of your results, set "Category:" to "S Parameter" and set "Function:" to "cang_deg", by default the reflection phase is plot against frequency, to plot reflection phase vs phase shifting parameter, just change the "Primary Sweep:" to your phase shifting parameter name then you get the curve for reflection phase versus parameter.
Hope this help.