Scattering from an annular slot on a radial waveguide

The boundary‐value problem of scattering from an annular slot on a radial waveguide is solved. The scattered fields are expanded in terms of eigenfunctions based on the Fourier series and Hankel transform. Boundary conditions are enforced to constitute a set of simultaneous equations. A fast convergent series solution is obtained using residue calculus. Computations are performed to investigate radiation and coupling by an annular slot on a radial waveguide. Favorable agreement is observed between our theory and other existing results.