Analysis of multilayer infinite periodic array structures with different periodicities and axes orientations

This paper presents a general procedure to analyze a multilayer array struc ture, where each layer may have different periodicities, different lattice structures, and/or the array axes between the layers may he nonparallel. Th e procedure involves determination of global cell with a global coordinate system, then computations of local generalized scattering matrices (GSM's) of individual lavers followed by modal mapping from local to global GSM's. The global GSM's for individual layers are then combined to characterize th e entire structure. The mapping relations are derived for two layers with d ifferent lattice structures, different periodicities, and array-axes orient ations, Three examples of practical importance are considered to demonstrat e the methodology, The first example is a two-layered patch array with diff erent periodicities. The second example is an array of subarrays with sever al patch elements within a subarray, It is shown that a subarray can be cha racterized rigorously by characterizing only one element of a subarray inst ead of analyzing all the elements of the subarray simultaneously, Consequen tly, analytical and computational complexities reduce considerably. The las t example is a patch array loaded with multilayer meander-line polarizer. T he patch array and the meander-line array have two different periodicities and the axes are nonparallel. Detailed radiation characteristics of the str ucture are presented and compared with that of a strip-grid polarizer. Comp utational advantages of this method are discussed.