Multi-scale system-by-design synthesis of printed WAIMs for waveguide array enhancement

A task-oriented multiscale material synthesis problem is addressed through an instance of the system-by-design (SbD) paradigm. More specifically, wide-angle impedance matching (WAIM) layers based on printed metasurfaces are designed to enhance the radiation efficiency of planar phased arrays. Toward this end, a task-oriented formulation is adopted where the layer geometrical features are the microscale solution descriptors, while the minimization of the array power reflection is the synthesis macroscale objective. The WAIM synthesis (i.e., the definition of the microscale structure of the WAIM and not the dielectric properties of the WAIM layer, unlike previous approaches) is yielded through an iterative process in which the direct optimization of its unit cells is made possible by the SbD mapping between the WAIM microscale features and the associated macroscopic properties. Selected numerical examples are presented and discussed to illustrate the current potentialities in terms of performance, feasibility, and computational efficiency of the proposed design strategy also in comparison with recent and competitive state-of-the-art WAIM design methodologies.