Broad-bandwidth and low-loss metamaterials: Theory, design and realization
01 Jan 2006-Journal of Zhejiang University Science (Zhejiang University Press)-Vol. 7, Iss: 1, pp 5-23
TL;DR: In this paper, the authors summarize some recent activities in the field of metamaterial research at the National University of Singapore (NUS) and summarize some special characteristics of the metammaterials.
Abstract: In this paper, we summarize some recent activities in the field of metamaterial research at the National University of Singapore (NUS). Integral equations are applied for electromagnetic modelling of supernatural materials. Some special characteristics of the metamaterials are shown. Moreover, quasi-static Lorentz theory and numerical method (i.e., the method of moments for solving the electric field integral equation) and the transmission line theory are both presented to obtain the effective constitutive relations of metamaterials, respectively. Finally, feasibility of fabricating metamaterials based on analysis of equivalent transmission line model in the microwave spectrum and even higher is also shown and correspondingly some broad-bandwidth and low-loss metamaterial structures are designed and synthesized.
Citations
More filters
Patent•
16 Feb 2007
TL;DR: In this paper, the properties of metamaterials are adjustable according to active feedback of interaction with electromagnetic waves, and the properties are adjusted according to an active feedback model of the interaction with the electromagnetic waves.
Abstract: Artificial materials, such as metamaterials, include adjustable properties. In some approaches the properties are adjustable according to active feedback of interaction with electromagnetic waves.
210 citations
TL;DR: In this paper, a novel type of microstrip antenna is proposed for compact wideband wireless applications, which is composed of six unit cells of left-handed metamaterial (LHM) and a dipole element.
Abstract: A novel type of microstrip antenna is proposed for compact wideband wireless applications. The antenna is composed of six unit cells of left-handed metamaterial (LHM) and a dipole element. The dipole is directly connected to three of six LHM unit cells, which are arranged in a 2 times 3 antenna array form. In this aspect, the proposed antenna is regarded as LHM loaded dipole antenna. The antenna is matched with a stepped impedance transformer and rectangular slot in the truncated ground plane. The coupled LH resonances and simultaneous excitation of different sections of unit cells and dipole result into broad bandwidth. The proposed antenna has a maximum gain of -1 dBi at 2.5 GHz. The measured return loss indicates 63% bandwidth for |S11| < -10 dB over the band of 1.3-2.5 GHz. The overall size of LHM loaded antenna is lambda0/2.87 times lambda0/11.27 times lambda0/315.80 at the center frequency. The radiation of the electrically small LHM unit cells is also demonstrated by the simulated radiation pattern, which is an important concept for the antenna miniaturization.
149 citations
TL;DR: The stable surface current distribution, negative refractive index characteristic, considerable gain and radiation properties make this proposed negative index metamaterial antenna optimal for UWB microwave imaging applications.
Abstract: A miniaturized antenna employing a negative index metamaterial with modified split-ring resonator (SRR) and capacitance-loaded strip (CLS) unit cells is presented for Ultra wideband (UWB) microwave imaging applications. Four left-handed (LH) metamaterial (MTM) unit cells are located along one axis of the antenna as the radiating element. Each left-handed metamaterial unit cell combines a modified split-ring resonator (SRR) with a capacitance-loaded strip (CLS) to obtain a design architecture that simultaneously exhibits both negative permittivity and negative permeability, which ensures a stable negative refractive index to improve the antenna performance for microwave imaging. The antenna structure, with dimension of 16 × 21 × 1.6 mm³, is printed on a low dielectric FR4 material with a slotted ground plane and a microstrip feed. The measured reflection coefficient demonstrates that this antenna attains 114.5% bandwidth covering the frequency band of 3.4-12.5 GHz for a voltage standing wave ratio of less than 2 with a maximum gain of 5.16 dBi at 10.15 GHz. There is a stable harmony between the simulated and measured results that indicate improved nearly omni-directional radiation characteristics within the operational frequency band. The stable surface current distribution, negative refractive index characteristic, considerable gain and radiation properties make this proposed negative index metamaterial antenna optimal for UWB microwave imaging applications.
91 citations
TL;DR: High fidelity factor and gain, smooth surface-current distribution and nearly omni-directional radiation patterns with low cross-polarization confirm that the proposed negative index UWB antenna is a promising entrant in the field of microwave imaging sensors.
Abstract: This paper presents a negative index metamaterial incorporated UWB antenna with an integration of complementary SRR (split-ring resonator) and CLS (capacitive loaded strip) unit cells for microwave imaging sensor applications This metamaterial UWB antenna sensor consists of four unit cells along one axis, where each unit cell incorporates a complementary SRR and CLS pair This integration enables a design layout that allows both a negative value of permittivity and a negative value of permeability simultaneous, resulting in a durable negative index to enhance the antenna sensor performance for microwave imaging sensor applications The proposed MTM antenna sensor was designed and fabricated on an FR4 substrate having a thickness of 16 mm and a dielectric constant of 46 The electrical dimensions of this antenna sensor are 020 λ × 029 λ at a lower frequency of 31 GHz This antenna sensor achieves a 1315% bandwidth (VSWR < 2) covering the frequency bands from 31 GHz to more than 15 GHz with a maximum gain of 657 dBi High fidelity factor and gain, smooth surface-current distribution and nearly omni-directional radiation patterns with low cross-polarization confirm that the proposed negative index UWB antenna is a promising entrant in the field of microwave imaging sensors
78 citations
TL;DR: In this paper, a compact ultrawideband (UWB) patch antenna based on the resonance mechanism of a composite right/left-handed (CRLH) transmission line (TL) is proposed.
Abstract: A new compact ultrawideband (UWB) patch antenna based on the resonance mechanism of a composite right/left-handed (CRLH) transmission line (TL) is proposed. The radiating element of the antenna is made from three left-handed (LH) metamaterial (MTM) unit cells placed along one axis, where each unit cell combines a modifled split-ring resonator (SRR) structure with capacitively loaded strips (CLS). An analysis of the eigenfrequencies of these unit cells yields one- and two-dimensional dispersion diagrams, which correspond to a one-unit cell antenna and the three unit cell antenna, respectively. A trident feed and a slotted-partial ground plane are used to match the right- and left-handed (RH and LH) modes of the antenna, respectively. In addition, an analysis of the surface current distribution of the antenna shows that slots on the metallic area reduce the Q-factor. This reduction in the Q-factor results in a wide bandwidth of 189% at 3.7GHz, which spans the UWB frequency range between 2.9{ 9.9GHz. The total footprint of the antenna at the lowest frequency is 0:2‚0£0:2‚0£0:015‚0, where ‚0 is the free space wavelength. The gain of the antenna ranges between i1 to 5dB throughout the frequency band.
53 citations
Cites background from "Broad-bandwidth and low-loss metama..."
...The two resonance mechanism enables a lower resonance for the entire structure through the combined induced current [26]....
[...]
References
More filters
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
"Broad-bandwidth and low-loss metama..." refers background in this paper
...However, research work in this area did not draw much attention in the engineering and physics communities until Pendry et al.(1996; 1999) and Pendry (2000) theoretically formulated the LHM, in particular, a concept of perfect lens was brought forward although only superlens is accepted by the community later on. Smith et al.(2000) further studied the LHM, and experimentally realized this material with periodically-arranged conducting ......
[...]
10,495 citations
"Broad-bandwidth and low-loss metama..." refers background in this paper
...Veselago (1968) initially assumed a material with negative permittivity and permeability simultaneously and theoretically demonstrated the abnormal electromagnetic properties....
[...]
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
"Broad-bandwidth and low-loss metama..." refers background in this paper
...However, research work in this area did not draw much attention in the engineering and physics communities until Pendry et al.(1996; 1999) and Pendry (2000) theoretically formulated the LHM, in particular, a concept of perfect lens was brought forward although only superlens is accepted by the community later on. Smith et al.(2000) further studied the LHM, and experimentally realized this material with periodically-arranged conducting ......
[...]
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
"Broad-bandwidth and low-loss metama..." refers background in this paper
...However, research work in this area did not draw much attention in the engineering and physics communities until Pendry et al.(1996; 1999) and Pendry (2000) theoretically formulated the LHM, in particular, a concept of perfect lens was brought forward although only superlens is accepted by the community later on. Smith et al.(2000) further studied the LHM, and experimentally realized this material with periodically-arranged conducting ......
[...]
Book•
01 Jan 1960
TL;DR: In this paper, the authors present a model for waveguide decomposition in terms of waveguide discontinuities and waveguides and cavities, and apply it to artificial dielectrics.
Abstract: Preface. Basic Electromagnetic Theory. Green's Functions. Transverse Electromagnetic Waves. Transmission Lines. Waveguides and Cavities. Inhomogeneously Filled Waveguides and Dielectric Resonators. Excitation of Waveguides and Cavities. Variational Methods for Waveguide Discontinuities. Periodic Structures. Integral Transform and Function-Theoretic Techniques. Surface Waveguides. Artificial Dielectrics. Mathematical Appendix. Name Index. Subject Index. About the Author.
4,393 citations
"Broad-bandwidth and low-loss metama..." refers methods in this paper
...After taking into account electrically small inclusions, our deductions begin with the electric and magnetic dipole moments (pe, pm) based on the quasi-static Lorentz theory ( Collin, 1991 )....
[...]