Design of Wideband Beamforming Metasurface With Alternate Absorption

In this paper, we propose a periodic structure that is capable of alternating between absorption and radiation mode. The designed periodic structure consists of an array of 6×6 square shaped unit cell. Each unit cell consists of a multi-layered structure, with dimensions of 0.5λ×0.5λ. The resonators are placed on the top layer and the feeding network is designed and implemented on the bottom layer. The ground layer is sandwiched between the two dielectric substrates. All resonators are connected to a 50Ω feed-line using the corporate feeding technique. To achieve broadband absorption, lumped resistors are inserted into the resonators. The proposed metasurface structure achieves broadband radiation, with low RCS and high gain, in the propagation direction whereas broadband absorption is achieved, when it is exposed to a free space plane wave. Moreover, the metamaterial absorber has stable absorptivity for an incident angle of (00-300). To verify the in-band absorption and radiation of the proposed design, a 6×6 periodic array of resonators has been fabricated and experimentally verified in an anechoic chamber. The measured results validate the performed simulations.