Two-dimensional analysis of bandwidth of open hard surface

The study concerns the fundamental properties of an open hard surface when it is realised as an grounded dielectric slab and is illuminated by a spectrum of plane waves polarised tangentially to the surface, i.e. TE to the propagation direction along the surface. The plane-wave spectrum is excited by an infinite constant filament current. Previously, the open hard surface has only been studied for a single-plane wave incidence. It is shown that the grounded slab works as an ideal hard surface at the cutoff frequency of the first TE surface wave. The bandwidth of the hard surface is defined and determined by investigating the near field at frequencies in the vicinity of the hard frequency. Finally, an approximate expression is derived for the bandwidth by using the asymptotic closed-form solution for the electric field, and the influence on the bandwidth of the permittivity and permeability of the material and the source position is discussed. The results show that the bandwidth is proportional to /spl radic/(/spl mu//sub r///spl epsi//sub r/) and inversely proportional to the square root of the distance along which the wave propagates at the surface.