Surface impedance boundary conditions near corners and edges: Rigorous consideration

The two-dimensional problem of the magnetic field distribution inside and o utside an imperfectly conducting, 90-degree edge is solved using the pertur bation technique. The well-known solution of the problem for a perfectly co nducting edge is used as an initial approximation. The surface impedance ne ar the edge is represented in the form of asymptotic expansions in the smal l parameter proportional to the ratio of the skin depth and characteristic size of the conductor surface. An analytical solution for the electric fiel d in the conductor near the edge is obtained. The solution behavior is inve stigated and the approximate boundary conditions relating the tangential co mponents of the electric and magnetic fields on the conductor surface near the edge are proposed in a form suitable for numerical implementation.