Coupling between a dipole antenna and an infinite cable over an ideal ground plane

A formulation is given for the fields radiated by an electric or magnetic dipole of arbitrary orientation in the presence of a cable suspended above a flat and perfectly conducting ground. The cable can be a solid conductor, a leaky coaxial cable, a CATV cable, or a surface-wave transmission line. Illustrative numerical results for both the far-field radiation pattern and excitation of the modal currents on the cable are given for the case of a vertical electric dipole source. Among other things, we find that the resultant radiation or far fields are not markedly influenced by the presence of the cable unless the dipole source is very near the cable. However, there is a significant cross-polarized component produced by the presence of cable that could have important consequences in producing bearing errors in low frequency beacon navigation systems.