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Journal ArticleDOI

Equivalent-circuit models for split-ring resonators and complementary split-ring resonators coupled to planar transmission lines

TL;DR: In this paper, a new approach for the development of planar metamaterial structures is developed, and analytical equivalent circuit models are proposed for isolated and coupled split-ring resonators/CSRRs coupled to planar transmission lines.
Abstract: In this paper, a new approach for the development of planar metamaterial structures is developed. For this purpose, split-ring resonators (SRRs) and complementary split-ring resonators (CSRRs) coupled to planar transmission lines are investigated. The electromagnetic behavior of these elements, as well as their coupling to the host transmission line, are studied, and analytical equivalent-circuit models are proposed for the isolated and coupled SRRs/CSRRs. From these models, the stopband/passband characteristics of the analyzed SRR/CSRR loaded transmission lines are derived. It is shown that, in the long wavelength limit, these stopbands/passbands can be interpreted as due to the presence of negative/positive values for the effective /spl epsiv/ and /spl mu/ of the line. The proposed analysis is of interest in the design of compact microwave devices based on the metamaterial concept.
Citations
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Journal ArticleDOI
27 Feb 2010-Science
TL;DR: In this paper, the authors demonstrate a form of memory capacitance which interfaces metamaterials with a class of devices known collectively as memory devices, and demonstrate electrically-controlled persistent frequency tuning of a metammaterial, allowing lasting modification of its response using a transient stimulus.
Abstract: The resonant elements that grant metamaterials their unique properties have the fundamental limitation of restricting their useable frequency bandwidth The development of frequency-agile metamaterials has helped to alleviate these bandwidth restrictions by allowing real-time tuning of the metamaterial frequency response We demonstrate electrically-controlled persistent frequency tuning of a metamaterial, allowing lasting modification of its response using a transient stimulus This work demonstrates a form of memory capacitance which interfaces metamaterials with a class of devices known collectively as memory devices

739 citations

Journal ArticleDOI
TL;DR: In this article, a metamaterial-inspired microwave microfluidic sensor is proposed, where the main part of the device is a microstrip coupled complementary split-ring resonator (CSRR), and the liquid sample flowing inside the channel modifies the resonance frequency and peak attenuation of the CSRR resonance.
Abstract: A new metamaterial-inspired microwave microfluidic sensor is proposed in this paper. The main part of the device is a microstrip coupled complementary split-ring resonator (CSRR). At resonance, a strong electric field will be established along the sides of CSRR producing a very sensitive area to a change in the nearby dielectric material. A micro-channel is positioned over this area for microfluidic sensing. The liquid sample flowing inside the channel modifies the resonance frequency and peak attenuation of the CSRR resonance. The dielectric properties of the liquid sample can be estimated by establishing an empirical relation between the resonance characteristics and the sample complex permittivity. The designed microfluidic sensor requires a very small amount of sample for testing since the cross-sectional area of the sensing channel is over five orders of magnitude smaller than the square of the wavelength. The proposed microfluidic sensing concept is compatible with lab-on-a-chip platforms owing to its compactness.

527 citations

Journal ArticleDOI
TL;DR: The limiting effects of varying the thickness of a dielectric overlayer on planar double split-ring resonator (SRR) arrays are studied by terahertz time-domain spectroscopy and the bounds of resonance shifting are discussed.
Abstract: The limiting effects of varying the thickness of a dielectric overlayer on planar double split-ring resonator (SRR) arrays are studied by terahertz time-domain spectroscopy. Uniform dielectric overlayers from 100 nm to 16 µm thick are deposited onto fixed SRR arrays in order to shift the resonance frequency of the electric response. We discuss the bounds of resonance shifting and emphasize the resulting limitations for SRR-based sensing. These results are presented in the context of typical biosensing situations and are compared to previous work and other existing sensing platforms.

487 citations

Journal ArticleDOI
18 Jan 2013-Science
TL;DR: By leveraging metamaterials and compressive imaging, a low-profile aperture capable of microwave imaging without lenses, moving parts, or phase shifters is demonstrated and allows image compression to be performed on the physical hardware layer rather than in the postprocessing stage, thus averting the detector, storage, and transmission costs associated with full diffraction-limited sampling of a scene.
Abstract: By leveraging metamaterials and compressive imaging, a low-profile aperture capable of microwave imaging without lenses, moving parts, or phase shifters is demonstrated. This designer aperture allows image compression to be performed on the physical hardware layer rather than in the postprocessing stage, thus averting the detector, storage, and transmission costs associated with full diffraction-limited sampling of a scene. A guided-wave metamaterial aperture is used to perform compressive image reconstruction at 10 frames per second of two-dimensional (range and angle) sparse still and video scenes at K-band (18 to 26 gigahertz) frequencies, using frequency diversity to avoid mechanical scanning. Image acquisition is accomplished with a 40:1 compression ratio.

478 citations

Journal ArticleDOI
TL;DR: In this paper, the design of miniaturized resonant inclusions to be employed in the practical realization of metamaterial samples with anomalous values of the real part of the permeability is presented.
Abstract: We present the design of miniaturized resonant inclusions to be employed in the practical realization of metamaterial samples with anomalous values of the real part of the permeability. Such inclusions, in fact, can be employed in the design of both mu-negative (MNG) materials and artificial magnetodielectrics (with negative and high-positive values of the real part of the permeability, respectively). The inclusions here considered are the multiple split-ring resonators (MSRRs), that represent a straightforward extension of the commonly used split-ring resonators (SRRs), and the spiral resonators (SRs), that enable a greater miniaturization rate. Some physical insights on the resonance mechanism and on the inherent saturation of the resonant frequency when increasing the number of the rings of the MSRRs and the number of the turns of the SRs are given in the paper. New and accurate analytical design formulas, based on a quasi-static model, for both MSRRs and SRs are derived and tested through a proper comparison with the existing formulas and full-wave numerical results. Both MSRRs and SRs are shown to be useful to reduce the electrical dimensions of the resonant inclusions when synthesizing artificial metamaterials.

352 citations


Cites background or methods from "Equivalent-circuit models for split..."

  • ...Particularly, the model proposed in [15], [28] is limited to the cases , 3, whilst the models pre-...

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  • ...Extending the formulation reported in [15] and [28] for the case of the regular SRR, it easy to verify that in the...

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  • ...This kind of inclusion has been already analyzed in [24], while a slightly different geometry has been proposed in [15], [28]....

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  • ...A helpful circuit model of SRRs has been presented in [14] for the concentric and the broadside-coupled geometries, while in [15] the same formulation has been extended to the synthesis of the complementary SRRs (CSRRs)....

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  • ...(or squared) loop having an equivalent radius (or side) given by the average between the inner and the outer radii (or sides) of the rings [13]–[15]....

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References
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Journal ArticleDOI
TL;DR: The authors' simulations show that a version of the lens operating at the frequency of visible light can be realized in the form of a thin slab of silver, which resolves objects only a few nanometers across.
Abstract: Optical lenses have for centuries been one of scientists’ prime tools. Their operation is well understood on the basis of classical optics: curved surfaces focus light by virtue of the refractive index contrast. Equally their limitations are dictated by wave optics: no lens can focus light onto an area smaller than a square wavelength. What is there new to say other than to polish the lens more perfectly and to invent slightly better dielectrics? In this Letter I want to challenge the traditional limitation on lens performance and propose a class of “superlenses,” and to suggest a practical scheme for implementing such a lens. Let us look more closely at the reasons for limitation in performance. Consider an infinitesimal dipole of frequency v in front of a lens. The electric component of the field will be given by some 2D Fourier expansion,

10,974 citations


"Equivalent-circuit models for split..." refers background in this paper

  • ...It is also worth mentioning the controversy originated four years ago from the paper published by Pendry [2], where amplification of evanescent waves in LHMs is pointed out [3]–[6]....

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Journal ArticleDOI

10,495 citations


"Equivalent-circuit models for split..." refers background in this paper

  • ...These are artificial periodic structures composed of sub-wavelength constituent elements that make the structure behave as an effective medium with negative values of permittivity ( ) and permeability ( ) at the frequencies of interest....

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Journal ArticleDOI
06 Apr 2001-Science
TL;DR: These experiments directly confirm the predictions of Maxwell's equations that n is given by the negative square root ofɛ·μ for the frequencies where both the permittivity and the permeability are negative.
Abstract: We present experimental scattering data at microwave frequencies on a structured metamaterial that exhibits a frequency band where the effective index of refraction (n) is negative. The material consists of a two-dimensional array of repeated unit cells of copper strips and split ring resonators on interlocking strips of standard circuit board material. By measuring the scattering angle of the transmitted beam through a prism fabricated from this material, we determine the effective n, appropriate to Snell's law. These experiments directly confirm the predictions of Maxwell's equations that n is given by the negative square root of epsilon.mu for the frequencies where both the permittivity (epsilon) and the permeability (mu) are negative. Configurations of geometrical optical designs are now possible that could not be realized by positive index materials.

8,477 citations


"Equivalent-circuit models for split..." refers background in this paper

  • ...Following this seminal paper, other artificially fabricated structures exhibiting a left-handed behavior were reported [8]–[11] including the experimental demonstration of negative refraction [12]–[14] and backward wave radiation [15]....

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Journal ArticleDOI
TL;DR: In this paper, it was shown that microstructures built from nonmagnetic conducting sheets exhibit an effective magnetic permeability /spl mu/sub eff/, which can be tuned to values not accessible in naturally occurring materials.
Abstract: We show that microstructures built from nonmagnetic conducting sheets exhibit an effective magnetic permeability /spl mu//sub eff/, which can be tuned to values not accessible in naturally occurring materials, including large imaginary components of /spl mu//sub eff/. The microstructure is on a scale much less than the wavelength of radiation, is not resolved by incident microwaves, and uses a very low density of metal so that structures can be extremely lightweight. Most of the structures are resonant due to internal capacitance and inductance, and resonant enhancement combined with compression of electrical energy into a very small volume greatly enhances the energy density at critical locations in the structure, easily by factors of a million and possibly by much more. Weakly nonlinear materials placed at these critical locations will show greatly enhanced effects raising the possibility of manufacturing active structures whose properties can be switched at will between many states.

8,135 citations


"Equivalent-circuit models for split..." refers background in this paper

  • ...The original medium proposed in [7] consists of a bulky combination of metal wires and split-ring resonators (SRRs) [16] disposed in alternating arrows....

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Journal ArticleDOI
TL;DR: A composite medium, based on a periodic array of interspaced conducting nonmagnetic split ring resonators and continuous wires, that exhibits a frequency region in the microwave regime with simultaneously negative values of effective permeability and permittivity varepsilon(eff)(omega).
Abstract: We demonstrate a composite medium, based on a periodic array of interspaced conducting nonmagnetic split ring resonators and continuous wires, that exhibits a frequency region in the microwave regime with

8,057 citations


"Equivalent-circuit models for split..." refers background in this paper

  • ...In spite of these interesting properties, it was not until 2000 that the first experimental evidence of left-handedness was demonstrated [7]....

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  • ...ELECTROMAGNETIC BEHAVIOR OF SRRs AND CSRRs...

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