Fully Analytical Design of Dual-Wire PCB Metagratings for Beam Steering and Splitting

The printed circuit board (PCB)-type metagrating (MG), a periodic microstrip planar structure with discrete distribution of polarization currents, can realize high-angle wavefront shaping with near-unity efficiency for potential application in high beam-steering antennas or reflectors. For large-angle deflection, only a small number of meta-atoms are required in the MG's period. As such, here, we focus on a reflective PCB MG in the presence of only two meta-atoms, whose complex load impedance densities are explicitly derived from fully analytical expressions. The passive and lossless conditional equations as well as the equations for the power ratio control of the diffraction modes are given, which allows avoiding numerical optimization procedure. Three practical prototypes, including anomalous reflector and beam splitters, are designed, simulated, and measured. The measurement results agree well with the simulation results and are consistent with the theoretical predictions.

Automated summary

The study introduces a printed circuit board (PCB)-type metagrating (MG) that can achieve high-angle wavefront shaping with near-unity efficiency for potential use in high beam-steering antennas or reflectors. By using only a small number of meta-atoms in the MG's period, it enables large-angle deflection. The research focuses on a reflective PCB MG with only two meta-atoms, and their complex load impedance densities are derived analytically. The study provides passive and lossless conditional equations and equations for power ratio control of diffraction modes, eliminating the need for numerical optimization. Three practical prototypes, including anomalous reflectors and beam splitters, are designed, simulated, and measured, with the measurement results matching the simulation results and theoretical predictions.