You can use a schematic block to put in a transmission line with its length determined by a parameter. This is a phase shifter.

I think a phase shifter can be created by using the built-in "Phase Shifter" component. This component can be found in the "EM Components" library and can be added to your simulation by dragging and dropping it into the "Schematic" window. Once added, you can adjust the phase shift of the component by setting the "Phase" parameter. Additionally, you can also adjust the frequency of operation of the phase shifter by setting the "Frequency" parameter.

Mostly, creating separate kinds of sub-arrays within the antenna with each of the sub-arrays controlled by the phase-shifter should work.

I hope this will help.