Transmission into staggered parallel-plate waveguides

The modal field transmitted into a staggered parallel-plate waveguide when illuminated by a line source is studied. To widen the limited applicability of existing ray methods, an aperture field integration (AFI) method is developed, in which the field in the waveguide aperture is first calculated by high-frequency techniques (uniform asymptotic theory (UAT) and spectral theory of diffraction (STD)) and then decomposed into modal fields via the Fourier analysis. For problems in which the exact Wiener-Hopf and/or the ray solutions are available, AFI gives excellent numerical results. New results are staggered waveguides which find application in the analysis of a waveguide lens.