Double-layer geodesic and gradient-index lenses

• Published in: Nature communications Vol. 13; no. 1; p. 2354
• Main Authors: Chen, Qiao, Horsley, Simon A. R., Fonseca, Nelson J. G., Tyc, Tomáš, Quevedo–Teruel, Oscar
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 29.04.2022; Nature Publishing Group; Nature Portfolio
• Subjects: 639/624/1075/1081; 639/624/400/1105; Antennas; Communications systems; Equivalence; Geometrical optics; Humanities and Social Sciences; Inverse problems; Lenses; Millimeter waves; multidisciplinary; Optics; Science; Science (multidisciplinary); Waveguides; Wireless communication systems
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-022-29587-9

A double-layer lens consists of a first gradient-index/geodesic profile in an upper waveguide, partially surrounded by a mirror that reflects the wave into a lower guide where there is a second profile. Here, we derive a new family of rotational-symmetric inhomogeneous index profiles and equivalent geodesic lens shapes by solving an inverse problem of pre-specified focal points. We find an equivalence where single-layer lenses have a different functionality as double-layer lenses with the same profiles. As an example, we propose, manufacture, and experimentally validate a practical implementation of a geodesic double-layer lens that is engineered for a low-profile antenna with a compact footprint in the millimeter wave band. Its unique double-layer configuration allows for two-dimensional beam scanning using the same footprint as an extension of the presented design. These lenses may find applications in future wireless communication systems and sensing instruments in microwave, sub-terahertz, and optical domains. A double-layer lens consists of a first gradient-index/geodesic profile in an upper waveguide, partially surrounded by a mirror that reflects the wave into a lower guide where there is a second profile. A family of such lens profiles are derived.