TM diffraction by a partly leaky halfplane

The paper presents a hybrid method for the computation of scattered fields from a leaky halfplane illuminated by an electric line source. The structure consists of a large array of nonuniformly spaced, thin, perfectly conducting coplanar strips near the edge of a perfectly conducting halfplane. The analysis is carried out by a combination of the integral equation and physical optics methods. The solution for the current distribution on the strips is obtained by the use of the conjugate contrast source truncation iterative algorithm. Thus, matrix inversion is circumvented and the method is particularly well suited for large arrays of strips. An approximate procedure based on a physical optics derived resistive taper is given for the synthesis of strip spacings. Numerical results indicate that a moderate increase in diffraction loss in the halfplane shadow region is feasible by a judicious choice of strip spacing. Advantages and limitations of the method are also discussed