... Thank you very much gentlemen for your recommendations and answers. I will implement what you suggested, especially the idea of using impedance boundary on the dielectric layer.As for modifying my 3D model to be suitable for an eigenmode simulation, I think all I need to do is remove the port (shown in the figure) and connect the two wires directly with a piece of Cu (close/short the loop).As soon as I have some results, I will attach the results here and any further questions to make this post more useful for other HFSS users (hopefully).nnThanks!!nMAn