抄録
The propagation of microwaves in a metal film is studied theoretically. For a p-polarized incident wave, the absorption coefficient of a thick film is proportional to sec θ, if the incidence angle θ is not close to π/2, and takes a maximum value 2/3 at an angle close to π/2. The transmission coefficient of a thin film is proportional to sec2 θ for θ not close to π/2 and takes a maximum value 1/4 at an angle close to π/2. Qualitatively, these results can also be explained in classical optics, if the dielectric constant of the metal is taken to be infinite. The reflection of a monochromatic spherical wave from a metal surface is discussed in passing. For frequencies greater than the metallic plasma frequency, and unusual reflection occurs; namely, besides the ordinary reflected wave, an additional one appears, whose wave fronts are cones with the axis normal to the surface and whose amplitude is inversely proportional to the square of the distance from the image source. This is the optical analogue of a lateral wave well-known in acoustics.
