Metamaterial Lenses and Their Applications at Microwave Frequencies

Abstract

Metamaterials (MTMs) are artificial structures characterized by flexible and designable electromagnetic (EM) properties, including permittivity, permeability, and refractive index. Because of their subwavelength-scale composing units, MTMs are able to manipulate the propagation of EM waves at extremely fine resolutions and offer solutions for new-concept devices and components with novel functionalities and challenge-breaking properties. From among the attractive applications of MTMs, this review article focuses on MTM lenses (also termed metalenses) developed in recent years for the purpose of microwave engineering, including beam forming, beam steering, and imaging. Bulk lenses made of 3D MTMs and planar lenses made of 2D transmission-type metasurfaces are both involved and investigated. Different categories of metalenses, together with the theory, principles, methods, and advantages of their designs, are introduced and discussed. Potential and future applications of metalenses at microwave frequencies are also presented.

Broadband near unity absorption meta-structure for solar thermophotovoltaic systems and optical window applications

“…R eq and L eq are induced by the circular and cross-shaped nickel resonator layer 2, whereas C eq is caused by the spaces between the patterns. Hence, the effective impedance Z eff of the proposed meta-structure is estimated using eqn (12).…”

“…Artificially constructed materials, namely meta-structures, meta-materials or meta-surfaces, are widely used for a variety of applications, such as absorbers, [1][2][3] filters, 4 polarization converters, 5 radar systems, 6 microwave imaging, 7 invisible cloaks, 8 sensors, 9,10 polarization converters, 11 telescopes, 12 refractive index sensing, [13][14][15][16][17] and temperature sensing. 18 Notably, meta structures operate in the visible and near-infrared ranges and are also utilized in several applications, including solar energy absorption, 19 blue and ultraviolet light absorbers, 20 photodetector sensors, 21 and optical meta structure-based color transformer systems for fiber optics.…”

Double Negative Metamaterial Based on Moebius Strip

“…However, the specifics of how the properties of the metacells combine in the metasurface will depend on the specific design and arrangement of the metacells. On the other hand, the proposed design of metamaterial cells based on double Moebius strip can be used for the improvement of metamaterial lens [21,22]. This approach also needs to be explored.…”

Wide-Oblique-Incident-Angle Stable Polarization-Insensitive Ultra-Wideband Metamaterial Perfect Absorber for Visible Optical Wavelength Applications

“…Veselago first demonstrated the unusual electromagnetic properties such as negative permittivity or permeability of complex materials [ 1 ], which is known as metamaterials (MMs) [ 2 ]. The characteristics of MMs depend on its physical structure, not its chemical composition, which makes it suitable for use in various applications such as absorbers [ 3 ], filters [ 4 ], antennae [ 5 ], imaging [ 6 ], invisible clocks [ 7 ], sensors [ 8 ], polarization converters [ 9 ], and lenses [ 10 ]. Landy first introduced the metamaterial perfect absorber (MPA) [ 11 ], which has opened a new research area due to its extensive use in different applications such as energy harvesting [ 12 ], solar cells [ 13 ], photodetectors [ 14 ], and thermal emitters.…”