الفهرس 
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Abstract
The basic problem o~ antennas above the ground was ~ormulated and solved by Arnold Sommer~eld in 1909 h the result given in terms o~ Sommer~eld integrals. o~ the slow convergence o~ these integrals, many have studied other ~ormulations, which usually have n approximate in one way or another and thus, with app licabi I i ty. Other authors approach is based on an image principle, amounts to replacing the ground by a suitable image ,:source. One o~ the ~irst papers to express the image method jforthe Sommer~eld problem was written by Booker and Clemmow in 1950. Their image, however, was exponentially diverging, which posed certain di~~iculties to the actual calculation. Two authors gave recently a series o~ papers introducing an exact image principle with image location in complex space. In chapters IV and V o~ this thesis the application o~ the exa~t image principle ~or the calculation o~ ~ields o~ antennas above the ground is considered squares or by using an existing approximating ystem consisting oT a linear and an in~inite thin vertical antenna OT horizontal wire is. in air above a lossy ground with complex dielectric • The current induced on the horizontal wire due to Teeding on the antenna is obtained using a inverse Fourier TransTorm. Both the antenna and the assumed to be thin and perTectly conducting. chapter a suitable polynomial approximation Tor is used to evaluate the image current in the determination oT the exact image Tor the problem OT a vertical electric dipole (VEO) plan’ ar inter~ace permittivity. This approximation is obtained by either the method oT using any o~ these polynomials it is possible to image current Tucntion by per~orming simple • Also, the asymptotic representation o~ the 1 Tunction is Tound suitable Tor obtaining the image nt Tunction ~or large values o~ complex permittivities. er~ this ~orm needs the evaluation oT gamma Tunctions mplex arguments which has been carried out using a