Bifunctional Microwave Metagrating Used as Reflectarray for Diffraction Pattern Manipulation

The concept of metagratings is a powerful means to control diffracted electromagnetic fields by accurately engineering the near-field. In this letter, a bifunctional metagrating that can differently allocate energy of distinct diffraction orders at the same frequency is designed. In one mode, the metagrating anomalously reflects total diffracted power in -1st order, and in the other mode, the diffracted power is equally redirected between the -1st order and +1st order. To manipulate the diffraction pattern, a meta-atom is designed to be switchable via the incorporation of a pin diode, which is compatible with low-complexity external control circuits. A prototype is fabricated and measured in an anechoic chamber. The measured results, consistent with full-wave numerical simulations, demonstrate an excellent qualitative manipulation of the diffracted energy. The proposed switchable metagrating paves the way for the implementation of metagratings in efficient real-time programmable functionalities for wireless power transmission, beam manipulation, and imaging holography.