On the Spurious Solutions in Boundary Integral Formulation for Waveguide Eigenvalue Problems

In this paper the properties of the spurious solutions occuring in the boundary integral equation formulation for a waveguide eigenvalue problem are investigated. The conditions under which no spurious solutions appear are established. A criterion which can be used to distinguish the spurious solutions in the computed eigenvalues are proposed. Numerical results are also presented for demonstrating the theory developed.