Direct Optimisation of a Five-State Reconfigurable Reflectarray for 5G Applications

This paper presents the preliminary design of re-configurable reflectarrays using a direct optimisation approach, which has not been done before. The reflectarray employs a five-state configuration based on an aperture-coupled stacked patch element, offering phase quantisation within a 320
^○
dynamic range. It operates in the 24.5-27.5 GHz band and is tailored for 5G applications. Several reflectarrays have been optimised to achieve beam scanning over ±70° with strict side lobe suppression. Furthermore, reflectarrays that radiate a fan-shaped beam have been optimised. The study confirms the suitability of this array element for beam-steering and shaped beam reflectarrays and highlights the simplicity of using the direct optimisation approach in antenna design.