Theoretical and experimental study of the evolution of fields in an overdimensioned waveguide with a corrugated surface

To obtain answers to problems arising in many microwave applications, some labs use overdimensioned corrugated waveguides. The authors propose a theoretical approach with eigenmodes that enables one to determine the values of the limiting frequencies (frequencies of π modes in the periodic structure) of an overdimensioned parallelepiped cavity loaded with a thin corrugation as a function of the height of the aperture. In this approach, the electric field is represented by different analytical functions. The authors compare the theoretical results with the experimental values obtained for different apertures and periodicities, according to the value of the wavelength in comparison with the aperture and the period. Each function is in good agreement in a certain frequency range