A hybrid moment method solution for TEz scattering from large planar slot arrays

This paper develops a hybrid moment method (M-M) based numerical model for the electromagnetic scattering from large finite-by-infinite planar slot arrays. The model incorporates the novel concept of a physical basis function (PBF) to dramatically reduce the number of required unknowns. The model can represent a finite number of slot columns with slots oriented along the infinite axis, surrounded by an arbitrary number of coplanar dielectric slabs. Each slot column can be loaded with a complex impedance, allowing one to tailor the array's edge currents. In developing the model, the authors represent an individual slot column with equivalent magnetic scattering currents on an unbroken perfectly conducting plane. Floquet theory reduces the currents to a single reference element. In the array's central portion, where the edge perturbations have become negligible, the slot column reference elements are combined into a single basis function. Thus, one can represent an arbitrarily large number of slot columns with one PBF. A newly developed one-sided Poisson sum formula provides a convenient means to calculate the mutual coupling between the PBF and the slot columns in the presence of a stratified dielectric media. The array scanning method (ASM) gives the mutual coupling between the individual slot columns. The authors validate the hybrid method using both numerical and experimental reference data. The results clearly demonstrate the method's accuracy as well as its ability to handle array problems too large for traditional MM solutions.