Design and Validation of a Metagrating for Dual Operation

Metagratings are promising devices in various applications for their characteristics of simple structure, large steering angle, high efficiency, and multiband functionality. In this letter, we propose a new method for the design of dual-operation metagratings (DMGs) based on the principle of period-conversion for wide-angle reflection. The DMG is realized by designing a unit cell with dual-band capacitive response. As such, the symmetrical unit cell can perform as one period at low frequencies and as two periods at high frequencies, thus realizing independent beam manipulation at two different frequencies by periodic conversion. Combined with analytical design and local periodic approximation, the design procedure is fast and accurate avoiding time-consuming numerical optimizations. A dual-operation printed metagrating that performs perfect anomalous reflections at 6.16 and 20 GHz is designed and experimentally validated. The results reveal an efficiency above 93% at the two frequencies and suggest potential applications to multifunctional antenna platforms.