An octave-bandwidth negligible-loss radiofrequency metamaterial

Abstract

Metamaterials provide an unprecedented ability to manipulate electromagnetic waves and are an enabling technology for new devices ranging from flat lenses that focus light beyond the diffraction limit to coatings capable of cloaking an object. Nevertheless, narrow bandwidths and high intrinsic losses arising from the resonant properties of metamaterials have raised doubts about their usefulness. New design approaches seek to turn the perceived disadvantages of dispersion into assets that enhance a device's performance. Here we employ dispersion engineering of metamaterial properties to enable specific device performance over usable bandwidths. In particular, we design metamaterials that considerably improve conventional horn antennas over greater than an octave bandwidth with negligible loss and advance the state of the art in the process. Fabrication and measurement of a metahorn confirm its broadband, low-loss performance. This example illustrates the power of clever implementation combined with dispersion engineering to bring metamaterials into their full potential for revolutionizing practical devices.

State-of-the-art of Metamaterials: Characterization, Realization and Applications

“…2). More recent designs include metamaterial-coated electrically small antennas investigated by Ziolkowski (Ziolkowski & Erentok, 2006), transmission line (TL) metamaterial-enabled leaky-wave antennas designed by Liu et al (Liu, Caloz & Itoh, 2002), broadband negligible-loss metaliners for horn antennas that support low sidelobes and low cross polarization introduced by Lier et al (Lier, Werner, Scarborough, Wu & Bossard, 2011), metamaterial lenses for broadband highly directive multibeam antennas proposed by Zhou et al (Zhou, Zhang & Xin, 2010), high-gain conformal antennas prototyped by Jiang et al , and many others. Several metamaterial-based low-profile antennas have been successfully proposed by Qureshi, Erentok, Antoniades and Kokkinos that adopt metamaterial-like resonator structures placed close to the radiating structure (Qureshi, Antoniades & Eleftheriades, 2005;Erentok & Ziolkowski, 2008;Kokkinos & Feresidis, 2009).…”

Design of a Pyramidal Horn Antenna With Low E-Plane Sidelobes Using Transformation Optics

“…Some efforts have been made to reduce the sidelobe levels of horn antennas [2][3][4][5][6][7][8][9]. State-of-theart techniques for implementing horn antennas having low sidelobe levels are corrugating the interior surfaces [2][3][4], which yields a structure more bulky and difficult to fabricate, applying longitudinal metallic vanes or trifurcations inside the horn to step the electric field in the E plane [5], using optical ray technique [6], employing dispersion engineering of metamaterial properties [7], and design of metasurfaces [8] to taper the aperture distribution.…”

“…State-of-theart techniques for implementing horn antennas having low sidelobe levels are corrugating the interior surfaces [2][3][4], which yields a structure more bulky and difficult to fabricate, applying longitudinal metallic vanes or trifurcations inside the horn to step the electric field in the E plane [5], using optical ray technique [6], employing dispersion engineering of metamaterial properties [7], and design of metasurfaces [8] to taper the aperture distribution. A new technique was recently proposed, which uses transformation optics [9] in order to design a horn antenna with low H-plane sidelobes.…”

“…This design, which results in low loss and wide frequency band, is based on air holes drilled on a homogeneous dielectric material. Compared to the previous horn antennas with low sidelobes [2][3][4][5][6][7][8][9], our designs are less demanding, which are thus easier to realize. Therefore, our approach provides a more advantageous recipe for the practical realization of pyramidal horn antennas with low E-plane sidelobes based on coordinate transformation.…”

Study and analysis of an electric Z-shaped meta-atom

“…Metamaterials offer remarkable properties that go beyond conventional natural materials and are actually used in novel class electromagnetic devices such as invisibility cloaks [1][2][3][4][5], rotators [6], retroreflectors [7], Luneburg lenses [8], waveguide tapers [9] and directive antennas [10][11][12][13][14][15][16][17]. A typical metamaterial is an artificially engineered structure made of a periodic array of sub wavelength metallic or dielectric inclusions called meta-atoms.…”