Note on the Brewster Angle in Lossy Dielectric Media

摘要

In electromagnetism, the Brewster angle is the angle of incidence at which there is no reflection of the parallel (i.e. vertical) polarized wave from a planar interface between materials with differing permittivity. That is, the reflection coefficient goes to zero at this angle and all of the incident power is transmitted into the dielectric medium. The reflection coefficient is a function of the constitutive parameters permittivity and permeability of the two media forming the interface as well as the angle of incidence. For media with the Brewster angle is commonly expressed where the r subscript denotes the relative constitutive parameter, the i subscript denotes the parameter of the medium in which the incident wave is propagating, and the t subscript denotes parameter of the medium into which the wave is transmitted. We assume the incident medium is free space and the transmitted medium is soil for the purposes of ground penetrating radar (GPR). For perpendicularly polarized waves, no real incident angle exists that will reduce the reflection coefficient to zero.