Excitation of the Zenneck surface wave by a vertical aperture

Excitation of the Zenneck wave is examined for both finite and infinit vertical apertures over a homogeneous conducting flat ground. The infinit vertical aperture with a Zenneck wave variation is found to excite only the Zenneck wave with no radiation field. The finite vertical aperture excites a field which is similar to the Zenneck wave near the aperture but resembles the usual ground wave at large distances. Numerical results for various aperture heights are given for frequencies of 1 and 10 MHz. Both homogeneous ground and sea water paths are considered.