Hertzian Dipoles Supporting Directional Currents

The concept of directional currents flowing on vertical electric and horizontal magnetic dipoles are introduced for synthesizing far fields of aperture antennas. Explicit expressions for directional currents that simulate far fields of rectangular horn antennas in simple media are derived. This is followed with the derivation of the analytical far field expressions of rectangular horn antenna radiating over a simple lossy dielectric half-space incorporating the Green functions derived by Norton under high contrast approximation. Numerical results are presented for the radiation fields of pyramidal horns in E- and H-planes.