Scattering from Narrow Grooves and Slits

Analytical expressions are derived for the equivalent magnetic current distributions over the apertures of filled grooves and slits in a thick ground plane. These are obtained via a low frequency solution of the exact integral equations and exhibit the expected edge behavior at the groove or slit terminations. They are used to derive closed-form expressions for the associated characteristic parameters such as aperture potentials, aperture admittances, transfer admittances, radar echo widths, and transmitted powers. Both principal polarizations are treated and the results are potentially useful in constructing suitable models for long and narrow three-dimensional structures.