High-Directivity Ultra-Sparse Antenna Arrays Using Multielement Metagratings

We present a rigorous analytical model utilized to design highly-sparse antenna arrays, taking advantage of the recent concept of metagratings (MGs). The proposed semian-alytical methodology, avoiding full-wave optimization, enables replacement of the generally-large number of active radiating elements with passive capacitively-loaded wires (meta-atoms), without sacrificing array directivity. Contrary to common techniques to dilute arrays, relying mostly on optimization of active element distribution and excitation, our modular solution utilizes a standard array configuration with linearly-phased elements; grating-lobe suppression is achieved by proper engineering of the passive MG, harnessing Floquet-Bloch formalism to control power partition into diffraction orders. To facilitate dramatic dilution and comply with printed-circuit-board (PCB) design requirements, we extend our previous work, enabling inclusion of multiple meta-atoms per period within a multilayered dielectric substrate. This concept, verified via full-wave simulations, is expected to facilitate the development of low-cost, planar, low-loss, and highly-directive antenna systems for future cellular and satellite communication.