Transient plane wave coupling to transmission lines above a lossy earth

An exact solution to the coupling of a plane wave to an infinite multiple conductor transmission line over a lossy earth is developed, which is valid for all incident angles and polarizations of the incident plane wave and arbitrary earth electrical properties. The exact solution is formulated in the frequency domain, with time-domain results obtained using the Fourier transform. The transient currents induced on various transmission structures for typical earth properties and EMP excitations is presented. Of specific interest is the comparison to the quasi-TEM theory for grazing angles of incidence, and for cases of small earth conductivity. These situations are where maximum induction to transmission systems occurs, and unfortunately are the cases where the quasi-TEM approximations is the poorest. The application of an equivalent single-conductor model, which is simpler to use, is examined.<>