Interpretation of scattering phenomenology in slotted waveguide structures via time-frequency processing

The scattering phenomenology in slotted waveguide structures is investigated using time-frequency processing of numerically simulated data. Two geometries are studied, a finite waveguide with one slot on each end and a linear slotted waveguide array comprised of 16 equally spaced slots. The numerical simulation is accomplished via a three-dimensional moment-method procedure in conjunction with a connection scheme which makes possible the simulation of a long waveguide structure spanning over 32 wavelengths at 10 GHz. The resulting numerical data are then processed using the short-time Fourier transform to identify the dominant scattering mechanisms. In the joint time-frequency plane, the unique scattering physics associated with slotted waveguide structures are more clearly revealed. In particular, the Floquet harmonics due to the exterior slot structure, the dispersion due to the interior waveguide modes, and the “interior Floquet” phenomenon can be readily identified and fully interpreted