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A high gain miniaturised patch antenna with an epsilon near zero superstrate
摘要： In this paper, a miniaturized patch antenna (MPA) with Zero Index Metamaterial (ZIM) as Superstrate at 518MHz is designed and fabricated. The proposed method is utilized for retrieving the effective properties, i.e., impedance, refractive index, as well as the permittivity, and permeability of the unit cell. We have investigated the effect of distance between the antenna and the Superstrate on performance of the antenna. Moreover, the performance of the antenna is evaluated by both simulations and measurements. The results of our study have shown more directional and higher gain patch antennas. Also, a good agreement between the measured and the simulation values is found. It is demonstrated that the gain of antenna, having the ZIM Superstrate, is much higher compared to the one without the ZIM superstrate. Furthermore, the mean value of the gain for the proposed Metamaterial antenna (which is Superstrate-based) is considerably improved from -1.9 to 3.97 dBi comparing to the patch antenna alone. In fact, the directivity of the antenna is dramatically improved based on the zero refraction properties of the Metamaterial.
关键词： Low profile,Metamaterial,Epsilon near zero material,High gain antenna
更新于2025-09-23 15:23:52
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-shaped chiral metamaterials
摘要： A highly sensitive refractive index sensor based on the conjugated bilayer-shaped chiral metamaterial is proposed. It is composed of two-shaped structures and a microstrip connecting line. The strong conductive coupling between two-shaped structures can be realized by microstrip connecting line. The chiral metamaterial shows giant circular dichroism (CD) effect, and the CD effect can up to 93.8% and 96.2% at 1.767Thz and 3.008Thz, respectively. The physical origin of the observed CD effect is elucidated through distributions of magnetic and current at resonances. The designed conjugated bilayer-shaped chiral metamaterial as a refractive index sensor can achieve sensitivity of 1.065Thz/RIU and 1.777Thz/RIU, respectively. The effect of structural parameter on the sensitivity and CD spectra is investigated. Through this study we presented the giant CD metamaterial based on conductive coupling and its application potentials for low detection-limit physical and biochemical sensing applications.
关键词： chiral metamaterial,conductive coupling,circular dichroism,resonance,refractive index sensor,metamaterial
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Wide-Angle Frequent Scanning Metamaterial Leaky Wave Antenna Array for Automotive Radars
摘要： This paper designs a wide-angle frequency scanning metamaterial (MTM) leaky wave antenna (LWA) array for automotive radars. The gap capacitors and the vialess open stub-loaded resonators are used to construct the frequency scanning MTM LWA array. The propagation constant of the MTM LWA array is able to change from negative to positive values as the frequency is increased, resulting in backward to forward beam scanning. Compared to mechanical beam scanning arrays and phased arrays, the frequency scanning MTM LWA arrays have advantages of reducing the system complexity, light weight and low cost. The presented MTM LWA array has a maximum gain of 13 dB and wide scanning angle from -60° to +80° as the frequency varies from 23.5 to 25.6 GHz which is well suited for automotive radar applications.
关键词： frequency scanning antenna,composite right/left-handed transmission line,Antenna array,metamaterial,leaky wave antenna
更新于2025-09-23 15:22:29
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DESIGN OF DUAL- AND QUAD-BAND E-CRLH-TLS WITH ARBITRARY PHASE CHARACTERISTICS
摘要： In this paper, extended composite right/left-handed (E-CRLH) transmission line (TL) metamaterial structures, with two left-handed (backward) and two right-handed (forward) pass bands, are investigated. Also, design procedures in order to design dual- and quad-band E-CRLH-TLs are presented in detail and the parameters of these structures are extracted by clean formulas, while satisfying arbitrary phase shifts at the operating frequencies. Finally, the dispersion and characteristic impedances of these transmission lines are derived and plotted. The results of this paper can be applied to any type of TL-based dual- and quad-band microwave component.
关键词： microwave component,metamaterial,phase shift,dual-band,E-CRLH,quad-band,transmission line
更新于2025-09-23 15:22:29
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Design and Analysis of Complimentary Split Ring Resonator Backed Microstrip Transmission Line Using Equivalent Circuit Model
摘要： This article presents a compact, low-profile Band-Stop Filter (BSF) designed using Complimentary Split Ring Resonator (CSRR). An equivalent circuit model is also presented along with the simplified mathematical approach to extract the parameters of the circuit model. This paper also presents the effect of variation in the dimensions of split rings on characteristics of BSF. The proposed BSF has a compact size of 27 × 20 mm2 designed an FR-4 substrate with dielectric constant (εr) 4.3. The filter provides complete suppression of the band at 2.4 GHz. The design and circuit analysis of this metamaterial based filter is presented in terms of reflection coefficient, transmission coefficient and impedance curve.
关键词： Bandstop filter (BSF),resonator,metamaterial,microstrip line,complementary split ring resonator (CSRR)
更新于2025-09-23 15:22:29
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Terahertz Active Metamaterials Based on Stacked Closed-Ring Resonator Arrays
摘要： Metamaterials, which can show novel optical functionalities beyond conventional optics, has been actively studied in recent years. As one of approaches to add tunability on resonant characteristics of metamaterials, slightly shifting relative position of stacked metamaterials or metasurfaces has been reported. In this study, based on numerical simulation we have designed stacked closed-ring resonator (CRR) arrays that show relatively large spectral shift with a small lateral shift of the stacked layers in terahertz (THz) range. We also show that changing dielectric constant of the dielectric media between CRR arrays is also effective to obtain large spectral shift of the resonant responses. Our findings may be utilized to develop novel type of THz active devices and also sensing devices.
关键词： terahertz,metamaterial,closed-ring resonator
更新于2025-09-23 15:22:29
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Four-Wave Mixing in Metamaterials
摘要： Interaction of four counterpropagating waves in a cubic medium being “left” for the signal wave is considered in the constant-intensity approximation. Analytical expression for the signal wave intensity is derived for the general case of four-wave interaction in a metamaterial. The influence of different parameters on the signal wave amplification coefficient, efficiency of conversion into the signal wave, and the reflection coefficient of the mirror whose role is played by the metamaterial is analyzed. It has been obtained for the first time that the determining role in the backward signal wave amplification is played by the total length of the metamaterial and the intensities of all three forward waves. An analysis has shown that the optimal thickness of the metamaterial depends not only on the phase mismatch and the strong coherent pump field intensity, as in the constant-field approximation, but also on the intensity of the weak wave at the frequency ω2. It has been demonstrated for the first time that the efficiency of frequency conversion in metamaterials depends on the total metamaterial length, input intensities of all four interacting waves, phase mismatch, and losses in the medium. It is established that the maxima of the reflection coefficient of the metamaterial depend on the total metamaterial length and the intensities of all three forward waves.
关键词： metamaterial,negative refraction,four-wave interaction,constant-intensity approximation
更新于2025-09-23 15:22:29
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Equivalent-Circuit Model with Retarded Electromagnetic Coupling for Meta-Atoms of Wired Metallic Spheres
摘要： This paper describes the equivalent-circuit model of a metamaterial composed of conducting spheres and wires. This model involves electromagnetic coupling between the conductors, with retardation. The lumped-parameter equivalent circuit, which imports retardation to the electromagnetic coupling, is developed in this paper from Maxwell’s equation. Using the equivalent-circuit model, we clarify the relationship between the retardation and radiation loss; we theoretically demonstrate that the electromagnetic retardation in the near-field represents the radiation loss of the meta-atom in the far-field. Furthermore, this paper focuses on the retarded electromagnetic coupling between two meta-atoms; we estimate the changes in the resonant frequencies and the losses due to the distance between the two coupled meta-atoms. It is established that the dependence characteristics are significantly affected by electromagnetic retardation.
关键词： meta-atom,equivalent-circuit model,metamaterial,electromagnetic coupling,radiation,retardation
更新于2025-09-23 15:22:29
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Generation of High-Power, Reversed-Cherenkov Wakefield Radiation in a Metamaterial Structure
摘要： We present the first demonstration of high-power, reversed-Cherenkov wakefield radiation by electron bunches passing through a metamaterial structure. The structure supports a fundamental transverse magnetic mode with a negative group velocity leading to reversed-Cherenkov radiation, which was clearly verified in the experiments. Single 45 nC electron bunches of 65 MeV traversing the structure generated up to 25 MW in 2 ns pulses at 11.4 GHz, in excellent agreement with theory. Two bunches of 85 nC with appropriate temporal spacing generated up to 80 MW by coherent wakefield superposition, the highest rf power that metamaterial structures ever experienced without damage. These results demonstrate the unique features of metamaterial structures that are very attractive for future high-gradient wakefield accelerators, including two-beam and collinear accelerators. Advantages include the high shunt impedance for high-power generation and high-gradient acceleration, the simple and rugged structure, and a large parameter space for optimization.
关键词： high-power microwaves,reversed-Cherenkov radiation,wakefield acceleration,electron bunches,metamaterial structure
更新于2025-09-23 15:22:29
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Left-Handed Metamaterial-Inspired Unit Cell for S-Band Glucose Sensing Application
摘要： This paper presents an oval-shaped sensor design for the measurement of glucose concentration in aqueous solution. This unit cell sensing device is inspired by metamaterial properties and is analytically described for better parametric study. The mechanism of the sensor is a sensing layer with varying permittivity placed between two nozzle-shaped microstrip lines. Glucose aqueous solutions were characterized considering the water dielectric constant, from 55 to 87, and were identified with a transmission coefficient at 3.914 GHz optimal frequency with double negative (DNG) metamaterial properties. Consequently, the sensitivity of the sensor was estimated at 0.037 GHz/(30 mg/dL) glucose solution. The design and analysis of this sensor was performed using the finite integration technique (FIT)-based Computer Simulation Technology (CST) microwave studio simulation software. Additionally, parametric analysis of the sensing characteristics was conducted using experimental verification for the justification. The performance of the proposed sensor demonstrates the potential application scope for glucose level identification in aqueous solutions regarding qualitative analysis.
关键词： sensors,metamaterial,glucose,diabetes
更新于2025-09-23 15:22:29