Dispersion analysis of open periodic structures using reflection pole method

A technique to analyze open structures based on reflection pole method (RPM) is introduced. These structures are treated as a general kind of grounded slab waveguides which can be 1D or 2D. The slab is illuminated by a plane wave and poles of the reflection coefficient are leaky or bound modes of the open waveguide. Using the phase and amplitude variation at the poles, the dispersion diagram can be determined. The frequency is scanned for every incident angle, where in the slow wave region the incident angle is an imaginary value to realize the wavenumbers greater than the free space wavenumber and generate an evanescent incident plane wave. Results are in good agreement with other methods.