High-Performance Transmissive Meta-Surface for $C$ -/ $X$ -Band Lens Antenna Application

Conventional multiband transmissive devices suffer from strong interaction among different working frequencies, complex configurations, and low efficiencies. We propose a novel strategy to design high-performance dual-band transmissive meta-surfaces by using anisotropic ABBA systems (a four-layer system with identical structures in layers 1 and 4, and another group of identical structures in layers 2 and 3). The ABBA element provides a new freedom to enhance the transmission and suppress the fluctuations by tuning the coupling among cascaded layers. Dual-band operating property is performed by employing the polarization-related electromagnetic response. A well-designed transmissive meta-surface, operating at <inline-formula> <tex-math notation="LaTeX">$f_{1} = 6.5$ </tex-math></inline-formula> GHz and <inline-formula> <tex-math notation="LaTeX">$f_{2} = 10.5$ </tex-math></inline-formula> GHz, consists of <inline-formula> <tex-math notation="LaTeX">$13 \times 17$ </tex-math></inline-formula> ABBA elements with parabolic phase distributions. Good focusing effects with the same focal length and small reflection are observed at both frequencies under different polarizations. For practical applications, a dual-band lens antenna (LA) is implemented by launching the meta-lens with a self-made Vivaldi antenna. Numerical and experimental results coincide well, indicating that the proposed LA is better in many aspects such as high radiation gain, comparable aperture efficiencies to other designs in literature, and having a simple fabrication process. The finding opens up a new avenue to design high-performance meta-surfaces operating in multiband or achieving integrated functionalities.