Abstract: The unknown current distributions (UCDs) and input impedances admittances of H.F. Yagi antennas placed horizontally above real earth, are determined in this paper. The UCDs are determined by numerical solving of the system of integral equations of Hallen's type (SIE-H) using polynomial approximation for the currents. The simplified expressions for potentials (the Hertz's vector potential and electric scalar potential), obtained with the assumption that the module of refractive index ground/air is much greater than one, n_10>>1, are used for establishing the SIE-H. Thus, the problem of numerical evaluation of so-called Sommerfeld's integrals is partially avoided. The paper shows that very accurate results for the current distributions and input impedances of the antennas are obtained even if n_10>3. Fortunately, the last one is satisfied in most of the practical cases.
Key words: Yagi antenna, conducting half-space, current distribution, input impedance.