All-Angle Nonlocal Metasurfaces on Demand: Universal Realization of Normal Susceptibilities via Multilayered Printed-Circuit-Board (PCB) Cascades

Abstract

Embedding normal susceptibilities in metasurfaces (MS), in tandem with their tangential counterparts, greatly enriches their spatial dispersion. Particularly, judicious siphoning of the microscopic nonlocality associated with such enhanced meta-atoms facilitates global control over the MS response across the entire angular range, specifically at challenging near-grazing scenarios. In this paper, we introduce a rigorous closed-form methodology to realize such intricate mixtures of tangential and normal components via a highly practical platform -- printed-circuit-board- (PCB) compatible cascaded admittance sheets. To this end, we derive a universal all-angular link between this MS-level composite, which leverages macroscopic nonlocality of multiple reflections, to its underlying meta-atom-level susceptibilities. We demonstrate this scheme by devising a PCB all-angle-transparent generalized Huygens' MS radome and an all-angle perfect-magnetic-conductor (PMC) PCB MS. Validated in simulation and experiment, our results pave the path toward a new insightful paradigm for studying and engineering nonlocal metadevices, e.g., optical analog computers and spaceplates.