Characteristic mode analysis of a patch antenna with substrate

Dear all,

I am trying to learn the correct way to simulate Characteristic mode analysis. As many works in literature use FEKO, I am also using it to replicate the results of one of the papers (YANG AND ADAMS: COMPUTING AND VISUALIZING THE INPUT PARAMETERS OF ARBITRARY PLANAR ANTENNAS). Even though they have used their own computational codes, I was hoping that their first example, a simple rectangular patch with a substrate (12 cm × 7.6 cm, h = 5 mm, Air substrate), shown in Fig. 5(a), could be easily simulated.

But when I simulated with the settings suggested in this forum before, the modal results of the CMA solver were not at all close to the results in the paper Fig. 1. I have tried both with finite and infinite substrate/ground sizes (both the CADFEKO files are attached here), but still they are not matching. I am quite sure I am making some mistakes here, so please help me here. Thank you.