Three-Dimensional Broadband and Isotropic Double-Mesh Twin-Wire Media for Meta-Lenses

Abstract

Lenses are used for multiple applications, including communications, surveillance and security, and medical instruments. In homogeneous lenses, the contour is used to control the electromagnetic propagation. Differently, graded-index lenses make use of inhomogeneous materials, which is an extra degree of freedom. This extra degree of freedom enables the design of devices with a high performance. For instance, rotationally symmetric lenses without spherical aberrations, e.g., the Luneburg lens, can be designed. However, the manufacturing of such lenses is more complex. One possible approach to implement these lenses is using metamaterials, which are able to produce equivalent refractive indices. Here, we propose a new type of three-dimensional metamaterial formed with two independent sets of wires. The double-mesh twin-wire structure permits the propagation of a first mode without cut-off frequency and with low dispersion and high isotropy. These properties are similar to periodic structures with higher symmetries, such as glide symmetry. The variations of the equivalent refractive index are achieved with the dimension of the meandered wires. The potential of this new metamaterial is demonstrated with simulated results of a Luneburg meta-lens.

Compact and Lightweight Additive Manufactured Parallel-Plate Waveguide Half-Luneburg Geodesic Lens Multiple-Beam Antenna in the K$_{\mathrm{a}}$-Band

“…It also relaxes interfaces and flanges design, leading to more compact designs with less or even no screws. Most of the developments that have been proposed to date are based on the use of polymers as a support material on which a metallic coating is subsequently applied to provide the component with conductivity [22] or on the use the polymer itself as a dielectric material [23]. Although this process is qualified for space applications, metal-only parts generally provide better mechanical properties and are preferred for on-board microwave systems.…”

Simulation Conditions to Compute the Dispersion Diagram of 3D Periodic Structures

“…In most cases, engineered periodic structures are arranged in a rectangular two-dimensional (2D) configuration [18], [19] or a simple cubic (sc) three-dimensional (3D) configuration [20], [21]. For 3D periodic structures, studies have explored configurations with symmetries.…”

V-Band Fully Metallic Geodesic Luneburg Lens Antenna

“…The inset shows the electric field distribution in this geodesic Luneburg lens excited with a point source at the border of the lens. was proposed in [9], however, its matching to free-space is challenging, making this configuration difficult to be used as an antenna.…”