Polarization dependence of transient signals in evaporation ducts

The vertical polarization dependence of transient signals in evaporation ducts is assessed. The evaporation duct model includes a discontinuous drop of the otherwise constant relative permittivity at the upper boundary of the duct. For a specified polarization of the primary source, electrical field strengths are determined exactly for fixed points within the duct layer. Numerical examples illustrate the importance of modal cut-off frequencies in explaining transient behavior in the evaporation ducts.