scholarly journals Wideband Absorption at Low Microwave Frequencies Assisted by Magnetic Squeezing in Metamaterials

2020 ◽  
Vol 8 ◽  
Author(s):  
Zhenxu Wang ◽  
Jiafu Wang ◽  
Yajuan Han ◽  
Ya Fan ◽  
Xinmin Fu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Compatibility ◽  
High Efficiency ◽  
Field Enhancement ◽  
Normal Incidence ◽  
Resonance Region ◽  
Square Lattice ◽  
Absorption Enhancement ◽  
Squeezing Effect ◽  
Low Frequencies

In this paper, the magnetic squeezing effect in metamaterials is explored and applied to achieve wideband absorption in low-frequency microwave bands. To this end, a metamaterial absorber (MA) is proposed, which consists of a square lattice of a split ring resonator (SRR) placed on top of a magnetic absorbing material (MAM) layer backed by a conducting ground. In the positive resonance region of SRRs, a strong magnetic squeezing effect occurs and more concentrated magnetic field lines are confined within SRRs. This results in significant magnetic field enhancement within the MAM layer, which provides a prerequisite for high-efficiency absorption enhancement at low frequencies. To verify this method, we fabricated a prototype using a 3.0 mm thick silicone MAM sheet. Both the simulation and experiment results show that with the assistance of magnetic squeezing in the SRR array, the absorption at lower frequencies is significantly enhanced and is above 90% in 1.25–2.31 GHz under normal incidence. Furthermore, the MA exhibits satisfactory stability for different polarization states and incident angles due to the square lattice of the SRR array. This design method may find potential applications in fields such as electromagnetic compatibility, wireless communication, and others.

scholarly journals Lattice Rayleigh Anomaly Associated Enhancement of NH and CH Stretching Modes on Gold Metasurfaces for Overtone Detection

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1265 ◽  
Author(s):  
Daler R. Dadadzhanov ◽  
Tigran A. Vartanyan ◽  
Alina Karabchevsky
Keyword(s):  
Near Infrared ◽  
Field Enhancement ◽  
Dielectric Substrate ◽  
Square Lattice ◽  
Localized Surface Plasmon ◽  
Absorption Enhancement ◽  
Absorption Bands ◽  
Transparent Dielectric ◽  
Infrared Spectral ◽  
Rayleigh Anomaly

Molecular overtones stretching modes that occupy the near-infrared (NIR) are weak compared to the fundamental vibrations. Here we report on the enhancement of absorption by molecular vibrations overtones via electromagnetic field enhancement of plasmonic nanoparallelepipeds comprising a square lattice. We explore numerically, using finite element method (FEM), gold metasurfaces on a transparent dielectric substrate covered by weakly absorbing analyte supporting N-H and C-H overtone absorption bands around 1.5 μ m and around 1.67 μ m, respectively. We found that the absorption enhancement in N-H overtone transition can be increased up to the factor of 22.5 due to the combination of localized surface plasmon resonance in prolonged nanoparticles and lattice Rayleigh anomaly. Our approach may be extended for sensitive identification of other functional group overtone transitions in the near-infrared spectral range.

scholarly journals Wideband RCS reduction of thin metallic edges mediated by spoof surface plasmon polaritons

2021 ◽  
Vol 8 ◽  
pp. 8
Author(s):  
Xinghua Li ◽  
Mingde Feng ◽  
Jiafu Wang ◽  
Xinmin Fu ◽  
Yajuan Han ◽  
...  
Keyword(s):  
Cross Section ◽  
Surface Plasmon ◽  
Electromagnetic Waves ◽  
Electromagnetic Compatibility ◽  
High Efficiency ◽  
Specular Reflection ◽  
Field Enhancement ◽  
Radar Cross Section ◽  
Edge Diffraction ◽  
Back Scattering

The back-scattering from front edge diffraction contributes significantly to mono-static radar cross section under TE-polarization when the specular reflection of an object is eliminated by elaborate shaping. With the aim to suppress the back-scattering of thin metallic edge, we propose to achieve wideband radar cross section (RCS) reduction by integrating an absorbing structure (AS) in front of the edge. The unit cell of AS is composed of a longitudinal array of metallic strips with linearly decreasing lengths. Under TE-polarized illumination, spoof surface plasmon polariton (SSPP) can be excited with high efficiency. Due to the deep-subwavelength property of SSPP, electromagnetic waves are highly confined around the AS, leading to strong local field enhancement and hence to wideband absorption. In this way, back-scattering of the edge is suppressed and the mono-static RCS can be reduced significantly over wide band. To verify this method, we designed, fabricated and measured a prototype. The results of both simulation and measurement indicate that our proposal can significantly suppress edge scattering, whose RCS reduction more than 10 dB achieves at range of 8.8–17.8 GHz under TE polarization. This work provides a new alternative of suppressing edge diffraction and may find applications in electromagnetic compatibility, radar stealth, etc.

scholarly journals Development of a Transient Magnetic Field Sensor Based on Digital Integration and Frequency Equalization

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4268
Author(s):  
Hongzhi Ouyang ◽  
Xueling Yao ◽  
Jingliang Chen
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Compatibility ◽  
Dynamic Range ◽  
Finite Impulse Response ◽  
Low Noise ◽  
Magnetic Field Sensor ◽  
Fiber System ◽  
Digital Integrator ◽  
Transient Magnetic Field ◽  
Field Sensor

Transient magnetic field sensors are used in various electromagnetic environment measurement scenarios. In this paper, a novel magnetic field sensor based on a digital integrator was developed. The antenna was a small B-DOT loop. It was designed optimally for the simulation. The magnetic field signal was digitally integrated with the improved Al-Alaoui algorithm, resulting in less integration error. To compensate for the bandwidth loss of the optical fiber system, we specially designed an FIR (finite impulse response) filter for frequency compensation. The circuit was described, and the transimpedance amplifier was specially designed to ensure the low noise characteristic of the receiver. The sensitivity of the sensor was calibrated at 68.2 A·m−1/mV, the dynamic range was 50 dB (1–300 kA/m), the linear correlation coefficient was 0.96, and the bandwidth was greater than 100 MHz. It was tested and verified under the action of an A-type lightning current. The sensor exhibited high-precision performance and flat amplitude-frequency characteristics. Therefore, it is suitable for lightning positioning, partial discharge testing, electromagnetic compatibility management, and other applications.

Abrikosov vortex corrections to effective magnetic field enhancement in epitaxial graphene

2021 ◽  
Vol 104 (8) ◽  
Author(s):  
Luke R. St. Marie ◽  
Chieh-I Liu ◽  
I-Fan Hu ◽  
Heather M. Hill ◽  
Dipanjan Saha ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Enhancement ◽  
Epitaxial Graphene ◽  
Effective Magnetic Field ◽  
Abrikosov Vortex ◽  
Magnetic Field Enhancement

scholarly journals Effects of Ag Nanocubes with Different Corner Shape on the Absorption Enhancement in Organic Solar Cells

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Feng Shan ◽  
Tong Zhang ◽  
Sheng-Qing Zhu
Keyword(s):  
Solar Cells ◽  
Active Layer ◽  
Organic Solar Cells ◽  
Field Enhancement ◽  
Localized Surface Plasmon ◽  
Absorption Enhancement ◽  
Absorption Performance ◽  
Different Shapes ◽  
Ag Ncs ◽  
Metallic Region

The effects of corner shape of silver (Ag) nanocubes (NCs) on optical absorptions of organic solar cells (OSCs) are theoretically investigated by finite element method (FEM) calculations. The absorption of sun light in the active layer is calculated. Significant absorption enhancements have been demonstrated in metallic region with different shapes of Ag NCs, among them corner radius (R) is zero result in the best light absorption performance of up to 55% enhancement with respect to bare OSCs. The origins of increased absorption are believed to be the effects of the huge electric field enhancement and increased scattering upon the excitation of localized surface plasmon resonance (LSPR). Apart from usingR=0, we show thatR=3, 6, and 11.29 of Ag NCs in metallic region of active layer may also result in the maximum comparable absorption enhancement of 49%, 41%, and 28%, respectively. In addition, a significant effect of the period of NCs is observed.

Magnetic field enhancement of the Hall effect anomalies in quantum critical point CeCu5.9Au0.1

2008 ◽  
Vol 403 (5-9) ◽  
pp. 1268-1269 ◽  
Author(s):  
D.N. Sluchanko ◽  
V.V. Glushkov ◽  
S.V. Demishev ◽  
O.D. Chistyakov ◽  
N.E. Sluchanko
Keyword(s):  
Magnetic Field ◽  
Hall Effect ◽  
Critical Point ◽  
Quantum Critical Point ◽  
Field Enhancement ◽  
Quantum Critical ◽  
Magnetic Field Enhancement
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