Mode conversion in horn with oscillating perturbation of wall surface impedance

Bragg reflection and mode conversion of waves of both polarizations in horns with irregular walls are considered. A thin magnetized ferrite film on frequent corrugation is approximately described by impedance boundary conditions. Anisotropy and gyrotropy of the surface impedance tensor are caused by tilt of the corrugation and by magnetization in the normal direction. Longitudinal quasi-periodic inhomogeneity supplies resonance coupling of waves with different angular numbers or/and directions of propagation. The solution of a boundary-value problem is found by the asymptotic method of Krylov, Bogaliubov and Mitropolsky. Phenomenon of nonreciprocal Bragg conversion of waves with different polarizations is discovered for the case of a special combination of inhomogeneous corrugation tilt and ferrite gyrotropy.