Coupling mechanism of two dipoles within a conductor-backed thin dielectric slab above the earth

A coupling mechanism between two dipoles within a conductor-backed thin dielectric layer above the earth, suggested as subsurface interface CW radar transmitting and receiving antennas, is calculated by a saddle-point method. When the dielectric layer is thin enough to support a cutoff mode, the electric field at the point of receiving dipole due to a transmitting point dipole may be approximated by sum of contributions of branch points of TE mode and poles of TM mode. The branch points and poles contributions are interpreted as evanescent lateral-waves and leaky-waves, respectively. Comparison of numerical results and asymptotic results shows excellent agreement.