Radiation pattern synthesis techniques as applied to the study of perfectly conducting periodic structures of arbitrary profile: TE-polarization

Previous works [1]-[5] on planar perfectly conducting periodic structures had their mathematical formulation developed primarily with basis on the boundary conditions imposed on the conducting surface of the structure thus requiring near-field computation to be somehow performed. In the present work it is shown that the induced currents, and from that the resulting scattering properties of periodic structures, can also be determined exclusively from its scattered farfield characteristics. Firstly, the structure is regarded as an uniform infinite periodic array excited with a progressive phase-shift resulting from illumination by a plane-wave. From boundary conditions on the "shadow" side of the structure one can easily obtain the directions of the nulls of the array pattern which in fact are the nulls of the far-field array element-pattern. Synthesis techniques are then used to obtain the current on the structure from which the scattered field can be computed. Numerical results obtained with the present method compare quite favourably with previously published numerical results and also with experimental data.