CREEPING WAVES ON A CONVEX OBJECT SATISFYING AN ANISOTROPIC IMPEDANCE BOUNDARY-CONDITION

We study the propagation of creeping waves on a convex object satisfying an anisotropic impedance boundary condition. We obtain, as in the case of an isotropic impedance, two independant creeping wave modes. However, the presence of a non zero extra-diagonal term in the impedance matrice is responsible for new physical phenomena : both modes have non zero components of electric and magnetic fields along the creeping ray binormal; moreover, the propagation constants are modified by this extradiagonal term; finally, the equation giving the amplitude of the creeping wave is modified by new terms, one algebric and one exponential. These effects only appear when the extradiagonal term is different from zero. When this term is equal to zero, the results are similar to the isotropic impedance case.