Journal ArticleDOI
Anisotropic metamaterials as antenna substrate to enhance directivity
Bae-Ian Wu,Weijen Wang,Joe Pacheco,Xudong Chen,Jie Lu,Tomasz M. Grzegorczyk,Jin Au Kong,Peter Kao,Paul A. Theophelakes,Michael J. Hogan +9 more
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TLDR
In this article, a waveguide simulation of a unit cell is used to retrieve the effective permittivity and permeability with which they compute the far-field radiation of a monopole embedded in a metamaterial substrate using an analytic method.Abstract:
Simulations have been carried out on metamaterials in the microwave regime. S-parameters obtained from waveguide simulations of a unit cell are used to retrieve the effective permittivity and permeability with which we compute the far-field radiation of a monopole embedded in a metamaterial substrate using an analytic method. We find that the analytic method is able to predict features of the experimental results, implying that within a certain frequency range, we can treat the metamaterial as being anisotropically homogeneous. Based on the methodology, a structure is optimized for the application of metamaterials as antenna substrate to enhance directivity by minimizing its refractive index. The experimental results are presented and compared with the analytic calculations. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 680–683, 2006; Pubished online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/mop.21441read more
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Oxides, Oxides, and More Oxides: High-κ Oxides, Ferroelectrics, Ferromagnetics, and Multiferroics
TL;DR: In this article, the authors review and critique the recent developments on multifunctional oxide materials, which are gaining a good deal of interest, focusing mainly on high-κ dielectric, ferroelectric, magnetic and multiferroic materials.
Journal ArticleDOI
A novel flat lens horn antenna designed based on zero refraction principle of metamaterials
TL;DR: In this article, a horn antenna filled with a metamaterial structure as lens inner the aperture is presented, which results in a great improvement for the directivity of the horn antenna based on the zero refraction characteristics of the metammaterial.
Journal ArticleDOI
Radiation properties of a split ring resonator and monopole composite
Kamil Boratay Alici,Ekmel Ozbay +1 more
TL;DR: In this paper, the far field radiation properties of a new resonator antenna composed of split ring resonators (SRRs) and a monopole were studied. And it was shown that the antenna size at the operation frequency (3.52 GHz) is approximately one tenth of the free space wavelength (λ/10).
Journal ArticleDOI
Directive Emission Obtained by Coordinate Transformation
TL;DR: In this paper, coordinate transformation theory is used to realize substrates that can modify the emission of an embedded source, and it is shown that with proper transformation functions the energy radiated by a source embedded in these space variant media will be concentrated in a narrow beam.
Journal ArticleDOI
Directive emission obtained by coordinate transformation
TL;DR: In this article, coordinate transformation theory is used to realize substrates that can modify the emission of an embedded source, and it is shown that with proper transformation functions the energy radiated by a source embedded in these space variant media will be concentrated in a narrow beam.
References
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BW media—media with negative parameters, capable of supporting backward waves
TL;DR: In this paper, it is shown that a lateral backward wave can arise when a plane wave is transmitted through an interface when one of the four parameters of the uniaxial medium is negative.
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Magnetic activity at infrared frequencies in structured metallic photonic crystals
Stephen O'Brien,John B. Pendry +1 more
TL;DR: In this paper, the authors derived the effective permeability and permittivity of a nanostructured metallic photonic crystal by analysing the complex reflection and transmission coefficients for slabs of various thicknesses.
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Guided modes with imaginary transverse wave number in a slab waveguide with negative permittivity and permeability
TL;DR: In this paper, the guidance conditions of modes with both real and imaginary transverse wave numbers inside a dielectric slab with negative permittivity and permeability are solved, and it is shown that for real transversal wave numbers, cutoffs exist for all modes, unlike in conventional media where the first even mode is always propagating.
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Electromagnetic wave interaction with stratified negative isotropic media
TL;DR: In this article, a general formulation for the electromagnetic wave interaction with stratified media and then specialize to slabs of negative isotropic media is presented. And the authors demonstrate and locate the positions of the perfect images of the antenna sources in the presence of the slabs.
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Čerenkov radiation in materials with negative permittivity and permeability
TL;DR: The mathematical solution for Cerenkov radiation in a novel medium, left-handed medium (LH medium), which has both negative permittivity and permeability, is introduced and it is shown that the particle motion in the LH medium generates power that propagates backward.