Semianalytically Designed Dual-Polarized Printed-Circuit-Board (PCB)-Compatible Metagratings

Metagratings (MGs), sparse (periodic) composites of subwavelength-polarizable particle meta-atoms (MAs), have demonstrated highly efficient diffraction engineering capabilities via meticulous tailoring of the interaction between individual scatterers. To date, MGs at microwave frequencies have mostly been devised for either transverse electric (TE)- or transverse magnetic (TM)-polarized scenarios, which limits their use in many practical applications. Herein, we bridge this gap and present a comprehensive semianalytical design method for dual-polarized MGs with a separable response for TE and TM waves. First, by relating a printed circuit board (PCB)-compatible array of dog-bone elements with the canonical dipole line analytical model, we establish an MA for TM-polarized MGs, featuring negligible interaction with TE waves. Subsequently, we integrate the proposed configuration with a systematic synthesis scheme to implement a TM beam splitter MG, harnessing the equivalent dipole line model to resolve analytically the optimal MA coordinates and dog-bone polarizability, without resorting to full-wave optimization. Finally, we show that a dual-polarized MG beam splitter can be conveniently synthesized correspondingly, combining the TM-polarized structure as is with previously reported TE-polarized MG designs. This work paves a clear path toward the integration of sparse, semianlaytically synthesized, efficient MGs in practical dual-polarized communication and imaging applications.