title: Soret fishnet metalens antenna.
abstract: At the expense of frequency narrowing, binary amplitude-only diffractive optical elements emulate refractive lenses without the need of large profiles. Unfortunately, they also present larger Fresnel reflection loss than conventional lenses. This is usually tackled by implementing unattractive cumbersome designs. Here we demonstrate that simplicity is not at odds with performance and we show how the fishnet metamaterial can improve the radiation pattern of a Soret lens. The building block of this advanced Soret lens is the fishnet metamaterial operating in the near-zero refractive index regime with one of the edge layers designed with alternating opaque and transparent concentric rings made of subwavelength holes. The hybrid Soret fishnet metalens retains all the merits of classical Soret lenses such as low profile, low cost and ease of manufacturing. It is designed for the W-band of the millimeter-waves range with a subwavelength focal length FL = 1.58 mm (0.5λ0) aiming at a compact antenna or radar systems. The focal properties of the lens along with its radiation characteristics in a lens antenna configuration have been studied numerically and confirmed experimentally, showing a gain improvement of ~2 dB with respect to a fishnet Soret lens without the fishnet metamaterial.
authors.affiliation: Antennas Group-TERALAB, Universidad Pública de Navarra, Pamplona 31006, Spain.
authors.forename: Bakhtiyar
authors.initials: B
authors.lastname: Orazbayev
authors.affiliation: Antennas Group-TERALAB, Universidad Pública de Navarra, Pamplona 31006, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Beruete
authors.affiliation: Antennas Group-TERALAB, Universidad Pública de Navarra, Pamplona 31006, Spain.
authors.forename: Víctor
authors.initials: V
authors.lastname: Pacheco-Peña
authors.affiliation: Antennas Group-TERALAB, Universidad Pública de Navarra, Pamplona 31006, Spain.
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Crespo
authors.affiliation: Antennas Group-TERALAB, Universidad Pública de Navarra, Pamplona 31006, Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Teniente
authors.affiliation: 1] Optical and Semiconductor Devices Group, Department of Electrical and Electronic Engineering, Imperial College London, London, SW7 2BT, UK [2] Centre for Plasmonics and Metamaterials, Imperial College London, London, SW7 2AZ, UK [3] Centre for Terahertz Science and Engineering, Imperial College London, London, SW7 2AZ, UK.
authors.forename: Miguel
authors.initials: M
authors.lastname: Navarro-Cía