Abstract:
Boundary value problems for two-layer cylindrical waveguides (namely, for a circular two-layer closed waveguide and a dielectric waveguide in an unbounded medium) are considered. It is shown that the same eigenvalues determining the wave numbers of waves in the waveguides can correspond to different solutions of the boundary value problem.
Key words:adjoint solutions, complex waves, dispersion equation, eigenvalues, wave numbers, boundary value problems for Helmholtz’s equation.