Reflectarrays and Metasurface Reflectors as Diffraction Gratings: A tutorial

Reconfigurable reflectors have significant potential in future telecommunication systems, and approaches to the design and realization of full and tunable reflection control are now actively studied. Reflectarrays, being the classical approach to realize scanning reflectors, are based on the phased-array theory (the so-called generalized reflection law) and physical optics approximation of the reflection response. To overcome the limitations of the reflectarray technology, researchers actively study inhomogeneous metasurfaces, using the theory of diffraction gratings. To make these devices tunable and fully realize their potential, it is necessary to unify the two approaches and study reconfigurable reflectors from a unified point of view. Here, we offer a tutorial on reflectarrays and metasurface reflectors, explaining their common fundamental properties that stem from the diffraction theory. This tutorial is suitable for graduate and postgraduate students and hopefully will help to develop deeper understanding of both phased arrays and diffraction gratings.