Metagratings on Low-Cost Substrates for Efficient Anomalous Reflection: Addressing Dielectric Loss

We present a theoretical framework and practical methodology for designing high-efficiency metagratings (MGs), sparse periodic arrangements of sub-wavelength polarizable particles (meta-atoms), on low-cost dielectric substrates with non-negligible losses. The formulation incorporates these losses and exploits multiple degrees of freedom to optimize beam manipulation efficiency within a simple realistic printed-circuit-board (PCB) configuration. Importantly, the various loss mecha-nisms are analyzed using a judiciously devised equivalent circuit model, providing insights on their respective contributions. We validate our theory by designing, fabricating, and experimen-tally characterizing an efficient FR4-based anomalous reflection PCB MG, demonstrating good agreement between analytical predictions, full-wave simulations, and laboratory measurements. This work opens avenues for realizing efficient, low-profile beam manipulation devices at reduced cost, offering practical solutions to mitigate loss limitations in diverse material sets across the electromagnetic spectrum.

M.Sc. student under the supervision of Prof. Ariel Epstein.