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

We study the propagation of creeping waves on a convex object satisfyi ng an anisotropic impedance boundary condition. We obtain, as in the c ase of an isotropic impedance, two independant creeping wave modes. Ho wever, the presence of a non zero extra-diagonal term in the impedance matrice is responsible for new physical phenomena : both modes have n on 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 exponent ial. These effects only appear when the extradiagonal term is differen t from zero. When this term is equal to zero, the results are similar to the isotropic impedance case.