Impulsive Radiation From a Horizontal Electric Dipole Above an Imperfectly Conducting Surface

Solutions for the impulsive wave fields generated by a horizontal electric dipole situated above an imperfectly conducting surface are derived. The space-time expressions for the reflected wave fields open the door to analysis of their properties in the far-, intermediate-, and near-field regions, and can serve as benchmark for numerical methods employed to wave simulation with applications in antenna design and radio communication. The EM properties of the conductive material are represented by a surface impedance and translated to the wave motion via employing the local plane wave relation as the boundary condition. At the core of tackling the impedance boundary value problem is the derivation of three space-time reflected-wave Green´s functions. In contrast to the vertical electric dipole problem, a coupling term is present in the transform-domain wave solutions, and hinders direct application of the extended Cagniard-De Hoop method. A partial-fraction decomposition of this coupling term is the key to furnishing the transformation back to the time domain. Numerical results illustrate time traces and spectra of the measurable reflected electric field strength.