Transformation optics

About: Transformation optics is a research topic. Over the lifetime, 2687 publications have been published within this topic receiving 102378 citations.

Coordinate-transformation-based ultra-directive emission

Abstract: The modelling, practical implementation and characterisation of an ultra-directive antenna around 10 GHz are presented. The design of the antenna is based on the transformation optics concept by transforming a radiating cylindrical space into a rectangular one. Metamaterials presenting electric and magnetic resonances are used to achieve the transformation. Field intensity mappings and direct far-field measurements are performed to experimentally demonstrate the narrow beam profile.

Surface Wave Transformation Lens Antennas

Abstract: A new class of dielectric sheet antennas is presented based on transformation optics. Specifically, we successfully implement the transformation with a consideration of surface wave eigenmode properties, and carry out a practical perforated design by drilling holes to synthesize the required dielectric constants for their potential realization. The full wave simulation shows that our surface wave transformation lens antenna is capable of obtaining a greatly improved directivity, while maintaining the original low profile.

Elastic Metamaterials Making Use of Chirality: A Review

Abstract: Metamaterials are artificially designed composite materials exhibiting unusual physical properties not easily found in nature. In most cases, these properties appear in a wave environment where local resonance comes into play. Therefore the design principle of these metamaterials relies intimately on creation of appropriate local resonances and their interplay with background waves. In this review, we show that the coupling between rotation and bulk deformations of two-dimensional chiral solids is able to provide a unique resonant mechanism in designing elastic metamaterials, and the recent advances in this area will be reviewed. We begin with a metamaterial with a single-negative parameter by integrating a chiral lattice with resonating inclusions, and demonstrate that this metamaterial not only is suitable for broadband vibration isolation but also provides a mixed-type resonance due to microstructure chirality. This mixed-type resonance is further explored to realize elastic metamaterial with double-negative parameters, which can refract elastic wave with a negative refraction angle. Finally, we present also recent development on micropolar constitutive models, which are potentially suitable for modeling chiral elastic metamaterials.

Strategy for designing broadband epsilon-near-zero metamaterials

Abstract: A strategy is proposed to design a certain kind of metamaterial with near-zero electric permittivity over a broad frequency band, i.e., the broadband epsilon-near-zero (ENZ) metamaterials. Based on the Bergman–Milton spectral representation of the effective permittivity, the design is first carried out in the dimensionless spectral space, where the effective permittivity of the ENZ metamaterials is mathematically determined by a series of zeros and poles (singularities), which can be easily arranged as required by the operating band. Then, through a fast inverse algorithm, the mathematical structures of the ENZ metamaterials can be transformed back to their physical structures, which can be put into practical applications. The effective permittivity of the designed ENZ metamaterials is examined, and the distribution of the electric field inside the designed ENZ metamaterials is also explored, in order to reveal the physical reason behind the broadband ENZ phenomenon.

Anisotropic metamaterial gain-enhancing lens for antenna applications

Abstract: Examples of the present invention include metamaterials, including metamaterial lenses, having material properties that approximate the behavior of a material with low (0