Microwave experimentation about electromagnetic diffraction from a metallic bigrating of prolate spheroidal cavities

The general theory of the diffraction of an electromagnetic plane wave from a bigrating of prolate spheroidal cavities hollowed in a perfectly conduct ing metallic plate has been carried out and numerical results were recently published. To valide these numerical results, an experimentation in microw ave range with two deep bigrating has been realized. Numerical and experime ntal results, which concern the efficiency in the (0,0)-order versus the wa velength and for quasi-normal incidence are in a good agreement and allow I ts to extend the possibilities of our codes. (C) 1999 Academie des sciences /Editions scientifiques et medicales Elsevier SAS.