Dual-band multiple quasi-non-diffracting beams with orthogonal linear polarization by a holographic artificial admittance superposition surface

Non-diffracting beams, due to their highly localized energy concentration, have attracted widespread attention in the past decades. However, no matter what method is used to generate non-diffracting beams, they usually have one function in terms of controlling polarization, number of beams, and selection of the working band. As application scenarios become more complex and the degree of integration increases, it is of great significance to design a simple device to generate non-diffracting beams with multiple functions. In this paper, a single-layer holographic artificial admittance surface (HAAS) is demonstrated for producing multiple quasi-non-diffracting beams operating in dual bands with orthogonal linear polarization. The HAAS consists of varying sub-wavelength cross-shaped metal patches on a grounded dielectric substrate, and the two arm lengths of the cross-shaped meta-atom control the incident waves of the orthogonal polarized state of two bands. Through the method of input admittance modulation superposition, HAASs are designed, one HAAS is fabricated, and it is experimentally demonstrated that pre-designed quasi-non-diffracting beams can be realized. These HAASs have potential applications in smart communication, remote power transmission, and near field imaging.