On the Exact and Asymptotic Expressions for Dyadic Green's function above Impedance Surface: Vertical Dipole Case

An exact and asymptotic expression for dyadic Green function of a vertical dipole above impedance surface is studied in this paper. Based on the single image expression for Sommerfeld integral, the vector field quantities caused by a vertical dipole placed above impedance surface are derived. In addition, the far-field asymptotic expression is presented in terms of series expansion, which provides new physical insights of the vertical dipole radiation above impedance surface.