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- 摘要
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Realization of a three-dimensional photonic topological insulator
摘要： Confining photons in a finite volume is highly desirable in modern photonic devices, such as waveguides, lasers and cavities. Decades ago, this motivated the study and application of photonic crystals, which have a photonic bandgap that forbids light propagation in all directions1–3. Recently, inspired by the discoveries of topological insulators4,5, the confinement of photons with topological protection has been demonstrated in two-dimensional (2D) photonic structures known as photonic topological insulators6–8, with promising applications in topological lasers9,10 and robust optical delay lines11. However, a fully three-dimensional (3D) topological photonic bandgap has not been achieved. Here we experimentally demonstrate a 3D photonic topological insulator with an extremely wide (more than 25 per cent bandwidth) 3D topological bandgap. The composite material (metallic patterns on printed circuit boards) consists of split-ring resonators (classical electromagnetic artificial atoms) with strong magneto-electric coupling and behaves like a ‘weak’ topological insulator (that is, with an even number of surface Dirac cones), or a stack of 2D quantum spin Hall insulators. Using direct field measurements, we map out both the gapped bulk band structure and the Dirac-like dispersion of the photonic surface states, and demonstrate robust photonic propagation along a non-planar surface. Our work extends the family of 3D topological insulators from fermions to bosons and paves the way for applications in topological photonic cavities, circuits and lasers in 3D geometries.
关键词： 3D photonic topological insulator,split-ring resonators,Dirac surface states,robust photonic propagation,topological bandgap
更新于2025-09-23 15:23:52
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Analytical model of the fundamental mode of 3D square split ring resonators
摘要： An analytical model is developed for the charge and potential distributions of the fundamental mode of three-dimensional (3D) singly split ring resonators (SRRs) with square cross section, which nowadays can be conveniently fabricated by additive manufacturing techniques. This model allows the derivation of approximate formulas for the equivalent capacitance and the analysis of the resonant properties of this type of SRRs at any frequency. The total capacitance is expressed as the sum of the usual gap capacitance and a surface capacitance associated with the charges on the SRR walls, which are determined from the solution for the irrotational part of the electric field of a square split cylinder obtained by conformal mapping. The applicability of the proposed model for a broad range of SRR parameters is demonstrated by comparing the resonance frequency of sample SRR configurations found theoretically with the corresponding values obtained by numerical simulations and experiments. Furthermore, the functions describing the charge and current mode profiles provided in this work can be instrumental in estimating the near-field interaction and the coupling constants of an ensemble of resonant 3D square split rings and thus for tailoring the response of metamaterials and other devices formed by these elements.
关键词： capacitance,resonance frequency,analytical model,split ring resonators,metamaterials
更新于2025-09-23 15:22:29
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PERFORMANCE IMPROVEMENT OF PATCH ANTENNA USING CIRCULAR SPLIT RING RESONATORS AND THIN WIRES EMPLOYING METAMATERIALS LENS
摘要： In this paper, the left-handed metamaterial which acts as a lens is employed to improve the performance of a microstrip patch antenna. The left-handed metamaterial used in this work is a three-dimensional periodic structure which consists of circular split ring resonators and thin wires. The three-dimensional periodic metamaterial structure shows angular independency characteristics in wide range angles, so it acts as a metamaterial lens. However, the MTM structure in?nite periodicity truncation has no impacts on the MTM lens scattering, e?ective parameters and homogeneity. The left-handed metamaterial is placed in front of the microstrip patch antenna and due to the negative refractive index property of the left-handed metamaterial; the radiated electromagnetic beam size decreases which results in a highly focused beam. The proposed antenna has been designed and simulated using CST microwave studio, and the metamaterial e?ective parameters are extracted from the S parameters by using Nicolson-Ross-Weir algorithm and by selecting the appropriate ambiguity branch parameter. Furthermore, the angular independency of the metamaterial lens has been veri?ed by rotating the metamaterial structure with respect to the excitation probe of the transverse electromagnetic waves and extracting the S-parameters and the e?ective parameters for each rotation angle. A parametric analysis has been performed to study the e?ects of the patch antenna and left-handed metamaterial lens separation and the size of the three-dimensional left-handed metamaterial structure on the radiating properties and the impedance matching of the proposed antenna. For the experimental veri?cation, the proposed antenna operating at 10 GHz is fabricated; the return loss, radiation pattern and gain for the proposed antenna with and without metamaterial are measured. Furthermore, the results show that the antenna gain is improved by 4.6 dB which validates the concept of beam focusing using negative refractive index metamaterial structure, while the return loss and bandwidth are slightly reduced. The simulation and experiment investigated the idea of the beam focusing using negative refractive index metamaterial lens in microwave regime.
关键词： microstrip patch antenna,CST microwave studio,beam focusing,Nicolson-Ross-Weir algorithm,parametric analysis,left-handed metamaterial,circular split ring resonators,negative refractive index,angular independency,experimental verification,thin wires
更新于2025-09-23 15:21:01
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SRR LOADED COMPACT UHF RFID TAG FOR BROADBAND OPERATION
摘要： An SRR loaded compact RFID tag for broadband operation over the UHF RFID band is presented. The tag antenna structure is composed of a dipole whose arms are symmetrically loaded with square split ring resonators (SRRs) along a short circuited strip between the SRRs. The antenna is made inductive and reduced in overall size by the SRR sections. The measured read range characteristics of the proposed RFID tag with an RFID chip Alien Higgs-3 are presented. The proposed tag operates over the entire UHF RFID band about a maximum read range of 7 meters in the entire elevation angular ranges and over wide azimuthal angular ranges.
关键词： square split ring resonators,read range,compact RFID tag,dipole antenna,broadband operation,UHF RFID band,SRR
更新于2025-09-23 15:21:01
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Free-Standing Complementary Asymmetric Metasurface for Terahertz Sensing Applications
摘要： We designed and tested a highly sensitive metasurface device based on free-standing complementary asymmetric split-ring resonators at terahertz frequencies. It is utilized for sensing a galactose film. We characterized the device using the induced red shift of a Fano resonance observed in the THz transmission. The sensor has a high sensitivity of 91.7 GHz/RIU due to a significant interaction between the galactose overlayer and the metasurface.
关键词： terahertz,asymmetric split-ring resonators,sensing,free-standing
更新于2025-09-23 15:19:57
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[IEEE 2018 18th Mediterranean Microwave Symposium (MMS) - Istanbul, Turkey (2018.10.31-2018.11.2)] 2018 18th Mediterranean Microwave Symposium (MMS) - Chiral SRR Metasurfaces for Circular Polarisation Conversion
摘要： A circular polarization dual band metamaterial polarization rotator composed of two double split ring resonators rotated 90o with respect to each other is presented. Asymmetric transmission between Txx and Tyy and symmetric transmission between Txy and Tyx has been achieved. The circular polarization is caused by the symmetric transmission between Txy and Tyx. The design has been demonstrated numerically at microwaves frequency. The structure holds promise for ultra-compact polarizing devices for any frequency range given the scalability of the approach.
关键词： Metasurfaces,Circular polarization,Chiral metamaterial,Split Ring Resonators
更新于2025-09-19 17:15:36
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Numerical and Theoretical Study of Tunable Plasmonically Induced Transparency Effect Based on Brighta??Dark Mode Coupling in Graphene Metasurface
摘要： In this paper, we numerically and theoretically study the tunable plasmonically induced transparency (PIT) effect based on the graphene metasurface structure consisting of a graphene cut wire (CW) resonator and double split-ring resonators (SRRs) in the middle infrared region (MIR). Both the theoretical calculations according to the coupled harmonic oscillator model and simulation results indicate that the realization of the PIT effect significantly depends on the coupling distance and the coupling strength between the CW resonator and SRRs. In addition, the geometrical parameters of the CW resonator and the number of the graphene layers can alter the optical response of the graphene structure. Particularly, compared with the metal-based metamaterial, the PIT effect realized in the proposed metasurface can be flexibly modulated without adding other actively controlled materials and reconstructing the structure by taking advantage of the tunable complex surface conductivity of the graphene. These results could find significant applications in ultrafast variable optical attenuators, sensors and slow light devices.
关键词： plasmonically induced transparency effect,metasurface,mid-infrared region,graphene split-ring resonators,graphene cut wire resonator
更新于2025-09-19 17:13:59
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A novel wideband bandpass filter based on CSRRa??loaded substrate integrated folded waveguide
摘要： A novel wideband bandpass filter based on folded substrate integrated waveguide (FSIW) is presented in the article. Five square complementary split-ring resonators (CSRRs) are etched in the middle layer of the FSIW. By adjusting the physical size of the CSRR structure, the resonant frequency of the CSRRs can be tuned at the same time and the stopband performance can be changed. As transverse electromagnetic (TEM) mode can be transmitted in the stripline, FSIW excited by stripline shows wider passband than that excited by microstrip line directly. To achieve perfect impedance matching, two microstrip lines to stripline transitions are added in two ports of the filter. The proposed bandpass filter exhibits compact size, high selectivity, good stopband rejection, lower radiation loss, and wideband performances. The measured results show that the fractional bandwidth of the filter is about 35.5%. The measured return loss is better than 15 dB from 4.84 GHz to 6.90 GHz, and the insertion loss is less than 1.2 dB. The comparison between the simulated results and the measured ones validate the possibility of the technology that combines the FSIW and CSRR.
关键词： radiation loss,compact size,folded substrate integrated waveguide,bandpass filter,complementary split-ring resonators (CSRRs)
更新于2025-09-19 17:13:59
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[IEEE 2019 International Conference on Electromagnetics in Advanced Applications (ICEAA) - Granada, Spain (2019.9.9-2019.9.13)] 2019 International Conference on Electromagnetics in Advanced Applications (ICEAA) - Design of fully-planar CSRR-based substrate integrated waveguide circuits
摘要： We present here a fully planar, low-cost and easy to fabricate power divider and a slot array antenna operating at 5G communication bands, based on a new version of the substrate integrated waveguide (SIW). The proposed SIW is synthesized by replacing each via row, with two rows of broadside-coupled complementary split ring resonators (BC-CSRRs), etched on the top and bottom metal ground surfaces of the dielectric substrate. Such resonators provide a negative effective permittivity and are capable of perfectly confining the wave within the propagating channel. The proposed waveguide exhibits excellent propagation characteristics, with losses close to those of the conventional SIW, providing a highly promising platform to implement low-cost planar components for 5G applications.
关键词： 5G,power dividers,complementary broadside-coupled split ring resonators,substrate integrated waveguide,slot antennas
更新于2025-09-12 10:27:22
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Dual-Band High <i>Q</i> -Factor Complementary Split-Ring Resonators Using Substrate Integrated Waveguide Method and Their Applications
摘要： In modern microwave telecommunication systems, especially in low phase noise oscillators, there is a need for resonators with low insertion losses and high Q-factor. More specifically, it is of high interest to design resonators with high group delay. In this paper, three novel dual-band complementary split-ring resonators (CSRRs) featuring high group delay etched on the waveguide surface by using substrate integrated waveguides are investigated and proposed. They are designed for a frequency range of 4.5–5.5 GHz. Group delay rates for the first, second, and third resonators were approximated as much as 23 ns, 293 ns, and 90 ns, respectively. We also proposed a new practical method to develop a wide tuning range SIW CSRR cavity resonator with a small tuning voltage in the second resonator, which leads to about 19% and 1% of tuning frequency band in the first and second bands, respectively. Finally, some of their applications in the design of filter, diplexer, and low phase noise oscillator will be investigated.
关键词： complementary split-ring resonators,low phase noise oscillator,group delay,substrate integrated waveguide,high Q-factor
更新于2025-09-11 14:15:04