Re: Surface wave questions
now you ask about the patch antenna (not the yagi in the first or third post), and the guiding surface here is the interface between the dielectric and air. I think the "wave guided by surface" definition above shouldn't cause confusion. "This" surface wave and that "earth" surface wave are the same concept. But the surface wave in the patch antenna is harmful, the earth surface wave is helpful.
Theoretically for the patch antenna with (transversally) infinite substrate, there is at least one surface wave (no cutoff frequency). There are papers on 1) calculating the leakage due to surface wave; 2)proposing methods to suppress them. It is too long to cite the results here.