H-POLARIZED SCATTERING FROM SINGLE AND MULTIPLE ELONGATED CAVITIES

H-polarized scattering is investigated for perfectly conducting surfac es containing one, two, or many parallel grooves. Incidence is transve rse to the axes of the cavities, which are of rectangular cross sectio n and on the order of the incident wavelength in size. For cases with many regularly spaced cavities, a Floquet and waveguide, mode-matching scheme is used that incorporates the effects of a nonplanar, nonunifo rm incident beam, a corresponding receiving pattern, and a finite targ et size. Realistic simplification of the receiving pattern greatly red uces the computational requirements for the case of backscatter. For s ingle grooves, point matching is used between waveguide mode and integ ral expressions. Measured backscatter patterns show negligible couplin g effects for two nearby cavities; thus, pattern multiplication using single-cavity patterns is applied to obtain results for dual-cavity st ructures. Calculated patterns for single-cavity and multiple-cavity ta rgets agree well with Ka-band laboratory measurements. The results hig hlight the significance of the finite beam and lab setting in surface scattering studies, and show grating type behavior for two or more sca ttering cavities. Parametric studies and spectral analysis for multipl e-cavity structures suggest an ability to estimate individual cavity w idth and separation for sets of similar cavities, and to estimate cavi ty separation even for dissimilar cavities.