how can i make 'cylindrical wave incidence' in wave optics module?

Hi all, i'm in elemetary level using comsol, and deppressed by successive failure in computing... please give me a hand..

i want to simulate a cylindrical wave impinging on periodic metasurfaces placed on a curved surface(cylinder). so the patterns have angular periodicities.

for this situation, i placed a periodic curved port above the cylinder's surface, but comsol says like 'periodic port should be on flat surface'.

so, is there any way to make angularly periodic port with cylindrical incident wave? or should i make a flat port and then induce an 'incidence angle variation' for each position?

thanks.