Admittance; Bessel functions; ground plane; half-space; loop Antennas.

This study deals with derivation of an exact expressions for the current distribution and the input impedance of a circular loop antenna over a lossy half-space. the analysis is based on the image method, the direct integration of the vector potential, and the spherical function expansion. the results for the current distribution of this study are in very good agreement with those corresponding results available in the literature, which checks the correctness of formulations of the study.