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- 摘要
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- 实验方案
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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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Microstrip Line Impedance Matching Using ENZ Metamaterials, Design and Application
摘要： The idea of this paper is to extend the tunneling effect of epsilon-near-zero (ENZ) narrow channel for matching two microstrip lines with different impedance characteristics. The main advantage of this method is the possibility to design a channel with subwavelength electrical size and obtain similar matching condition when compared with a conventional λ/4-transformer. The bandwidth of the structure is directly related to the bandwidth of the ENZ-metamaterials (MTM). The suggested matching circuit is comprised of a metallic wall and an ENZ narrow channel. To realize the ENZ channel, a rectangular waveguide which operates in TE10 mode is designed and implemented using a substrate integrated waveguide (SIW) technology. A set of vias are also needed for emulating the metallic wall to reduce the ENZ channel cross section. The proposed structure for different impedance values of 50?, 100?, and 150? was designed, simulated, fabricated, and tested. Moreover, as an important application of a matching network, a microstrip patch antenna has been matched over the desired frequency band. Simulation results based on CST microwave studio have good agreement with measurements. It is shown that the bandwidth of the circuit is 8%–15%.
关键词： impedance matching,metamaterials (MTM),Epsilon-near-zero (ENZ),microstrip line,tunneling
更新于2025-09-23 15:22:29
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Electromagnetic wave cloaking and scattering around an antiresonance-resonance symmetrical pair in the frequency domain
摘要： Cloaking and scattering cancellation of electromagnetic waves have attracted much attention since they allow control of rf and light waves and are of scientific interest. The analytical results demonstrated in this paper reveal that plasmonic cloaking, which is one of the schemes for scattering cancellation, occurs in the vicinity of Tonks-Dattner resonances in the frequency domain, where resonances enhance wave scattering. This antiresonance-resonance pair for cloaking and scattering is cross-correlated by the symmetrical locations above and below the electron plasma frequency, respectively. However, the cloaking effect is almost independent of electron collisions with neutral particles, whereas scattering at resonance is fairly sensitive to them, leading to unclear resonance. An experimental verification of this analytical prediction is performed for the cloaking effect on working points passing through the cloaking condition and approaching resonance, which is dynamically controlled by changing the electron density. Numerical calculations based on a model configuration similar to the experimental setup confirm scattering cancellation and an increase in scattering as the points get close to the resonance condition. These results are direct evidence of scattering cancellation with a uniform epsilon-near-zero material and demonstrate the effectiveness of plasma as a cloaking material.
关键词： plasma,electromagnetic cloaking,scattering cancellation,Tonks-Dattner resonances,epsilon-near-zero material
更新于2025-09-23 15:22:29
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Coupling between plasmonic nanohole array and nanorod arrays: the emerging of a new extraordinary optical transmission mode and epsilon-near-zero property
摘要： The compound Ag nanohole structures with an Ag nanorod in the middle of an Ag nanohole are investigated by finite-difference-time-domain calculations. The structure shows strong polarization-dependent optical properties. A new extraordinary optical transmission (EOT) mode is observed when the polarization direction is aligned with the long axis of the nanorods, and its resonance wavelength red-shifts exponentially with the nanorod length. Around this resonance wavelength, the real part of the effective permittivity also becomes zero, demonstrating the epsilon-near-zero (ENZ) property. The new EOT mode is found to be the result of the enhanced local radiation of the nanorods as well as the electromagnetic coupling to the nanoholes to produce the enhanced transmission. The tunable resonance wavelength, EOT, strong near-field enhancement, and ENZ properties make the structure ideal for many potential applications, such as ultrathin optical filter, polarizers, surface-enhanced spectroscopies, etc.
关键词： tunable transmission,epsilon-near-zero,nanohole array,extraordinary optical transmission,nanorod array
更新于2025-09-23 15:21:01
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Epsilon-near-zero medium for optical switches in Ho solid-state laser at 2.06????m
摘要： Indium tin oxide (ITO), an epsilon-near-zero material in the low-dimensional family, was successfully fabricated and first used as an optical switcher in 2.06 μm. In the Tm:fiber pumped passively Q-switched laser, a maximum average output power of 312 mW was obtained with a shortest pulse width of 2.42 μs and a repetition rate of 20.53 kHz, corresponding to a single pulse energy and a peak power of 15.20 μJ and 6.28 W, respectively. Results suggest that ITO is looking forward to develop into a kind of suitable saturable absorber for generation of nanosecond pulse in solid state lasers.
关键词： Passively Q-switched,Optical switch,Indium tin oxide,Epsilon-near-zero,2.06 μm
更新于2025-09-23 15:19:57
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Tailoring absorption spectrum by inserting an epsilon-near-zero film into metal-dielectric-metal assembly
摘要： A method of tailoring the absorption band generated by metal-dielectric-metal (MDM) resonator is analytically proposed and numerically investigated in this paper. By inserting an epsilon-near-zero (ENZ) ?lm into the MDM layers, the absorption bandwidth can be su?ciently widened due to the coupling from ENZ mode to localized edge plasmon mode. Theoretical instructions of how to design respective layer thickness to obtain optimized absorption rate are investigated with the guidance of vast simulations and the hybrid resonance characteristics by the coupling from ENZ mode are further inspected by monitoring the resonant electric and magnetic ?eld. The meta-absorber can achieve high absorption with a large bandwidth under oblique incidence. The method and the structure proposed in this paper have potential views in highly integrated nanostructures in solar cells, photovoltaic and sensing application ?elds.
关键词： Epsilon-near-zero (ENZ),Absorber,Metamaterial
更新于2025-09-23 15:19:57
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A Designed Broadband Absorber Based on ENZ Mode Incorporating Plasmonic Metasurfaces
摘要： In this paper, we present a numerical study of a metamaterial absorber that provides polarization-insensitive absorption over a broad bandwidth of operation over the mid-infrared region. The absorber consists of a periodically patterned metal-dielectric-metal structure integrated with an epsilon-near-zero (ENZ) nanolayer into the insulating dielectric gap region. Such an anomalous broadband absorber is achieved thanks to a couple of resonant modes including plasmon and ENZ modes that are excited under mid-IR light illumination. By adding a 0.06-μm-thick ENZ layer between the patterned gold rectangular grating and the SiO2 dielectric layer, the absorber captures >95% light over a 1.5 μm bandwidth centered at a near-8-μm wavelength over a wide range of oblique incidence under transverse-magnetic and -electric polarizations. The designed ENZ-based wideband absorber has potential for many practical applications, including sensing, imaging and solar energy harvesting over a wide frequency regime.
关键词： wideband absorber,plasmon mode,Brewster mode,epsilon-near-zero
更新于2025-09-19 17:13:59
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Epsilon-near-zero response in indium tin oxide thin films: Octave span tuning and IR plasmonics
摘要： Epsilon near zero (ENZ) materials exhibit strongly confined optical modes and plasmonic response around and beyond the ENZ wavelength (λENZ). In order to exploit the novel properties of ENZ materials for real-world applications, it is important to develop material platforms that offer continuous tuning of λENZ from 1280 nm to 2900 nm in commercially available thin films of indium tin oxide (ITO), employing a low temperature annealing protocol. Electrical, spectroscopic, and optical measurements establish the physical basis of the observed tunability in free electron density by over an order of magnitude and quantify the real and imaginary components of the refractive index for ITO thin films. Excitation of surface plasmon polaritons (SPPs) in the metallic regime of ITO probes its infrared plasmonic response demonstrating continuous tunability of SPP frequency and crossover to the tunable ENZ plasmon mode in ultrathin films. Finally, dispersion tuning of optical fiber modes by optical coupling with a tunable λENZ platform is demonstrated by investigating modal interference in a tapered silica fiber in contact with various custom tuned ITO films.
关键词： plasmonics,tuning,optical properties,Epsilon near zero,indium tin oxide
更新于2025-09-19 17:13:59
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Negative Refraction in Time-Varying Strongly Coupled Plasmonic-Antennaa??Epsilon-Near-Zero Systems
摘要： Time-varying metasurfaces are emerging as a powerful instrument for the dynamical control of the electromagnetic properties of a propagating wave. Here we demonstrate an efficient time-varying metasurface based on plasmonic nano-antennas strongly coupled to an epsilon-near-zero (ENZ) deeply subwavelength film. The plasmonic resonance of the metal resonators strongly interacts with the optical ENZ modes, providing a Rabi level spitting of ～30%. Optical pumping at frequency ω induces a nonlinear polarization oscillating at 2ω responsible for an efficient generation of a phase conjugate and a negative refracted beam with a conversion efficiency that is more than 4 orders of magnitude greater compared to the bare ENZ film. The introduction of a strongly coupled plasmonic system therefore provides a simple and effective route towards the implementation of ENZ physics at the nanoscale.
关键词： time-varying metasurfaces,epsilon-near-zero,plasmonic nano-antennas,negative refraction,phase conjugation
更新于2025-09-19 17:13:59
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Monolithic Plasmonic Waveguide Architecture for Passive and Active Optical Circuits
摘要： Guided-wave plasmonic circuits are promising platforms sensing, interconnection, and quantum applications in the subdiffraction regime. Nonetheless, the loss-confinement trade-off remains a collective bottleneck for plasmonic-enhanced optical processes. Here, we report a unique plasmonic waveguide architecture that can alleviate such trade-off and improve the efficiencies of plasmonic-based emission, light-matter-interaction, and detection simultaneously. Specifically, record experimental attributes such as normalized Purcell factor approaching 104, 10 dB amplitude modulation with <1 dB insertion loss and fJ-level switching energy, and photodetection sensitivity and internal quantum efficiency of ?54 dBm and 6.4% respectively have been realized within our amorphous-based, coupled-mode plasmonic structure. The ability to support multiple optoelectronic phenomena while providing performance gains over existing plasmonic and dielectric counterparts offers a clear path toward reconfigurable, monolithic plasmonic circuits.
关键词： plasmonics,epsilon-near-zero,field-effect modulator,Purcell factor,Schottky photodetector
更新于2025-09-19 17:13:59