Experimental retrieval of the effective parameters of metamaterials based on a waveguide method.
TL;DR: A waveguide-based retrieval method for measuring complex permittivity and permeability tensors of metamaterials is presented and shows its effectiveness in the effective parameters extraction.
Abstract: A waveguide-based retrieval method for measuring complex permittivity and permeability tensors of metamaterials is presented. In the proposed scheme, multiple independent sets of scattering data for the material under test with different orientations are measured in the frequency range corresponding to the dominant TE(10) mode. The method is applied to various metamaterials and shows its effectiveness in the effective parameters extraction.
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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
Cites methods from "Experimental retrieval of the effec..."
...The effective electromagnetic parameters were also retrieved experimentally and numerically from the transmission and reflection data [15]–[19]....
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...It is due to the engineering convention for the time harmonic fields in contrast to the proposed retrieval procedures in [15]–[18], in which is selected....
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TL;DR: An alternative approach of invisibility cloaking is experimentally demonstrated that can combine technical advantages of all current major cloaking strategies in a unified manner and thus can solve bottlenecks of individual strategies.
Abstract: We experimentally demonstrated an alternative approach of invisibility cloaking that can combine technical advantages of all current major cloaking strategies in a unified manner and thus can solve bottlenecks of individual strategies. A broadband cylindrical invisibility cloak in free space is designed based on scattering cancellation (the approach of previous plasmonic cloaking), and implemented with anisotropic metamaterials (a fundamental property of singular-transformation cloaks). Particularly, nonsuperluminal propagation of electromagnetic waves, a superior advantage of non-Euclidian-transformation cloaks constructed with complex branch cuts, is inherited in this design, and thus is the reason of its relatively broad bandwidth. This demonstration provides the possibility for future practical implementation of cloaking devices at large scales in free space.
90 citations
TL;DR: In this paper, a triple-band antenna for the frequency bands 2.4, 3.5 and 5 GHz is proposed for the IEEE 802.11a/b/g and 802.16e standards.
Abstract: This paper presents a compact triple band antenna for the frequency bands 2.4, 3.5 and 5 GHz. These bands are assigned to the IEEE 802.11a/b/g and IEEE 802.16e standards. The resonant modes for WLAN, WiMAX bands are achieved by employing a rectangular slot and a metamaterial inspired split ring structure. The extraction procedure of negative permeability for the proposed split ring resonator is discussed in detail. Tunability between the WLAN and WiMAX standards is demonstrated by using a single PIN diode. The proposed antenna with a compact size of 27 mm × 25 mm is fabricated and tested. The triple band antenna yields a −10 dB impedance bandwidth of about 18.6%, 4.3% and 40.3% in 2.4, 3.5 and 5 GHz bands respectively. Stable radiation patterns with low cross polarization and high average antenna gain of 2.46 dBi are observed for the operating bands.
82 citations
TL;DR: In this paper, a compact metamaterial multiband antenna is proposed for wireless local area network (WLAN), worldwide interoperability for microwave access (WiMAX) and international telecommunication union (ITU) band applications using a modified Triangular Split Ring Resonator (TSRR).
Abstract: In this paper, a compact metamaterial multiband antenna is proposed for wireless local area network (WLAN), worldwide interoperability for microwave access (WiMAX) and international telecommunication union (ITU) band applications using a modified Triangular Split Ring Resonator (TSRR). In this work, we designed a modified TSRR with metamaterial property to obtain desirable negative permeability bands that help in accommodating all three frequency bands of interest in a single device. This approach leads to the considerable reduction of the device structure. The overall dimension of the proposed antenna structure has a compact size of 25.7 × 23.2 × 1.6 mm 3 and covers specific bands from the frequency spectra of 2.4/5.2/5.8, 3.5, and 8.2 GHz for WLAN, WiMAX, and ITU, respectively, with uniform radiation characteristics. The designed antenna structure is simulated using the High Frequency Structural Simulator (HFSS), and a prototype is developed and tested. The detailed analysis of the results obtained is presented. It is determined that the performance of the proposed antenna is superior to that of the existing antennas in the literature.
80 citations
TL;DR: In this paper, a miniaturized ultra wideband (UWB) antenna with metamaterial for WLAN and WiMAX applications is designed Ghz using fractalization of the radiating edge and slotted ground structure approach.
Abstract: This paper presents a miniaturized ultra wideband (UWB) antenna with metamaterial for WLAN and WiMax applications. For miniaturization of UWB antenna resonating 3.1–10.6 is designed Ghz using fractalization of the radiating edge and slotted ground structure approach. A miniaturization of active patch area and antenna volume is achieved up to 63.48% and 42.24% respectively, with respect to the conventional monopole UWB antenna. This antenna achieves a 143% impedance bandwidth covering the frequency band from 2.54GHz to 15.36GHz under simulation and 132% (2.95–14.28 GHz) in measurement. The electrical dimension of this antenna is 0.32λ × 0.32λ (38mm×38mm) at lower frequency of 2.54GHz. As per IEEE 802.11a/b/g and IEEE 802.16e standards, WLAN (2.4–2.5 GHz, 5.150–5.250 GHz, 5.725–5.825 GHz), WiMAX (3.3–3.8 GHz) bands are achieved by using slotted ground structure and metamaterial rectangular split ring resonator. The proposed antenna is fabricated on FR4 substrate of thickness 1.6mm and a dielectric constant 4.3 and tested. The proposed antenna yields a −10 dB impedance bandwidth of about 11.1% (2.39–2.67 GHz), 59.1% (2.87–5.28 GHz) and 7.4% (5.58–6.01 GHz) under simulation and 4.5% (2.41–2.52 GHz), 51.1% (3.12–5.26 GHz) and 3.8% (5.69– 5.91GHz) in measurement for 2.4, 3.5 & 5 and 5.8GHz bands respectively. Stable radiation patterns with low cross polarization, high average antenna gain of 3.02 dBi under simulation and 2.14 dBi in measurement and measured peak average radiation efficiency of 76.6% are observed for the operating bands. Experimental results seem in good agreement with the simulated ones of the proposed antenna.
70 citations
References
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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
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
TL;DR: In this article, the authors analyzed the reflection and transmission coefficients calculated from transfer matrix simulations on finite lengths of electromagnetic metamaterials, to determine the effective permittivity and permeability.
Abstract: We analyze the reflection and transmission coefficients calculated from transfer matrix simulations on finite lengths of electromagnetic metamaterials, to determine the effective permittivity ~«! and permeability ~m! .W e perform this analysis on structures composed of periodic arrangements of wires, split ring resonators ~SRRs!, and both wires and SRRs. We find the recovered frequency-dependent« and m are entirely consistent with analytic expressions predicted by effective medium arguments. Of particular relevance are that a wire medium exhibits a frequency region in which the real part of « is negative, and SRRs produce a frequency region in which the real part of m is negative. In the combination structure, at frequencies where both the recovered real parts of « and m are simultaneously negative, the real part of the index of refraction is also found to be unambiguously negative.
2,689 citations
TL;DR: In this article, an improved method to retrieve the effective constitutive parameters (permittivity and permeability) of a slab of metamaterial from the measurement of S parameters is proposed.
Abstract: We propose an improved method to retrieve the effective constitutive parameters (permittivity and permeability) of a slab of metamaterial from the measurement of S parameters. Improvements over existing methods include the determination of the first boundary and the thickness of the effective slab, the selection of the correct sign of effective impedance, and a mathematical method to choose the correct branch of the real part of the refractive index. The sensitivity of the effective constitutive parameters to the accuracy of the S parameters is also discussed. The method has been applied to various metamaterials and the successful retrieval results prove its effectiveness and robustness.
1,941 citations
TL;DR: A bilayer of materials for which not all of the principal elements of the permeability and permittivity tensors have the same sign can transfer a field distribution from one side to the other, including near fields, without requiring internal exponentially growing waves.
Abstract: The range of available electromagnetic material properties has been broadened by recent developments in structured media, notably photonic band gap materials and metamaterials. These media have allowed the realization of solutions to Maxwell’s equations not available in naturally occurring materials, fueling the discovery of new physical phenomena and the development of devices. Photonic crystal effects typically occur when the wavelength is on the same order or smaller than the lattice constant of the crystal. Metamaterials, on the other hand, have unit cell dimensions much smaller than the wavelength of interest. A homogenization process, not unlike
987 citations