Electric Field Vector Distributions Research Articles

Triple-broadband asymmetric transmission via cross-polarization conversion based on composite chiral metasurface structure

In this paper, a novel composite chiral metasurface (CCMS) was proposed and investigated, which is composed of a rectangle-patch-ring resonator (RPRR) structure sandwiched between two twisted sub-wavelength metal gratings separated by a dielectric substrate. Both simulation and experimental results demonstrate that the proposed CCMS achieves a significant asymmetric transmission (AT) effect and efficient cross-polarization conversion for the incident linear polarization wave in a triple-broadband range. Simulation results are in good agreement with the experiments. Specifically, the CCMS converts normal impinging y-/x-polarization wave along the forward/backward (-z/+z) direction into transmitted x-/y-polarization wave with the cross-polarization transmission coefficient over 0.7 at 4.15–5.5 GHz, 7.29–10.77 GHz and 12.49–16.59 GHz, respectively. In addition, the AT coefficient (Δlin) and the total transmittance (Tx) of the x-polarization wave propagation along the –z axis direction are both over 0.5 in the triple-broadband frequency range. The simulated polarization azimuth rotation and ellipticity angles, induced surface current, and electric field vector distributions further confirm the characteristics of the triple-broadband high-efficiency AT effect and cross-polarization conversion of the designed CCMS. The proposed CCMS design serves as an important reference for practical applications of microwave devices.

Ultraweakly low-dispersion epsilon-negative response of GR-CNT/PVDF ternary metacomposites

The epsilon-negative (ε’ < 0) response displayed by metacomposites offers notable potential for diverse applications in the design of dielectric and electromagnetic (EM) devices, underpinned by novel principles. However, achieving a weakly low-dispersion ε′-negative performance within the radio frequency (RF) band remains challenging. In this study, we bypassed this issue by constructing three-dimensional (3D) conductive networks through the integration of graphene (GR) and carbon nanotubes (CNT) with polyvinylidene fluoride (PVDF) serving as the matrix material. Leveraging the modifiable GR-CNT network, a ε′-negative response at approximately −20 was attained spanning the 100 MHz-1 GHz range. This ultraweak ε′-negative response was attributed to the formation of a moderate plasmonic state of free carriers within the metacomposites. Further, simulations were conducted, assessing the electric field vector distribution of the ε′-negative materials, revealing promising EM shielding performance. Concurrently, this investigation elucidates the RF ε′-negative response mechanism, paving the way for the practical application of metacomposites.

Tightly focused optical skyrmions and merons formed by electric-field vectors with prescribed characteristics

Abstract Optical skyrmions, which are topological quasi-particles with nontrivial electromagnetic textures, have garnered escalating research interest recently for their potential in diverse applications. In this paper, we present a method for generating tightly focused optical skyrmion and meron topologies formed by electric-field vectors under 4π-focusing system, where both the topology types (including Néel-, Bloch-, intermediate- and anti-skyrmion/meron) and the normal direction of the two-dimensional topology projection plane can be tailored at will. By utilizing time-reversal techniques, we analytically derive the radiation pattern of a multiple concentric-ring array of dipoles (MCAD) to obtain the required illumination fields on the pupil planes of the two high numerical aperture lenses. The Deby vector diffraction integral theory is employed to calculate the corresponding tightly focused field, and their topology characteristics are quantitatively evaluated by the electric-field vector distribution. The results demonstrate that arbitrary electric-field based skyrmion and meron can be conveniently generated by adjusting the oscillation direction of each dipole in the MCAD and the normal direction of the dipole array. The generated optical topologies with fully controllable degrees of freedom provide potential applications in optical information processing, transmission, and storage.

Quaternary nanoparticle array antenna for graphene/silicon near-infrared detector

Infrared imaging chips are crucial for a broad range of military, medicine and biology applications. Although silicon detectors’ on-chip integration technology is matured, their low absorption in near-infrared light results in poor infrared photocurrent response. To increase the photodetector absorption efficiency, antenna-like metal nanoparticles have been widely adopted due to their plasmon resonance effects. Oligomer nanoparticles, including quaternary nanoparticles, exhibit plasmon resonance effects that localize and enhance the light field in a sub-wavelength range. Furthermore, they can interfere with each other to achieve Fano resonance and bound state in continuity, resulting in a stronger localization and enhancement of the electromagnetic field. In this study an array of gold quaternary nanoparticle oligomers is used as the antenna for a graphene/SOI (with 1 μm silicon) heterojunction near-infrared detector. Each oligomer consists of four gold squares, each with a size of 250 nm, forming two pairs of dipoles similar to the orbital hybridization of hydrogen atoms. This thus results in a multi-body coupling structure with bonding state and anti-bonding state. The antenna array parameters, such as the periodic constant, gap between nanoparticles, and angle (&lt;i&gt;θ&lt;/i&gt;) between the oligomers, are meticulously adjusted. The optimized device is characterized by using photocurrent and photocurrent mapping, achieving a 2-fold enhancement in photoresponsivity with the maximum value at &lt;i&gt;θ&lt;/i&gt; ~ 40°. Notably, a consistent dip in photocurrents is observed for different periods or gap arrays when the angle theta is 20°. The simulation is conducted by using finite-difference time-domain (FDTD), revealing the emergence of Fano-like resonance in the transmittance spectra of the array at approximately 850 nm. The interference caused by the strongly coupling system to the plane coupled leakage field and the nanoparticle plasmon mode results in the formation of a new discrete leakage mode, i.e. the Fano-like resonance. The antenna helps to concentrate and emit the light field energy directionally to the detector, while there is a trade-off between the loss caused by nanoparticles absorption and the leakage energy. The photocurrent reaches a minimal point at a theta angle of 20° angle. At this point, the energy is localized in the oligomers, and the metal absorption loss weakens the plasmon enhancement effect. These findings are further supported by the simulation results of electric field and Poynting vector distribution. These findings indicate an important and promising way to enhance the photo detection efficiency via nanostructured plasmonic antenna.

FEM Analysis of Piezoelectric Resonator Polarization Process

The polarization of the piezoelectric resonator depends on the direction of the applied electric field. The direction of the applied electric field is determined by the shape of the resonator and the position of the electrodes. In case of resonators with electrodes incompletely covering their bases, an inhomogeneous electric field is generated, which results in an inhomogeneous polarization of the resonator. The resonator will be polarized in some places either in a direction other than the desired one or not polarized at all. The aim of this work is to analyze the polarization process on resonators with electrodes incompletely covering their bases. The physical description is given by the linear piezoelectric equations, the Gaussian equation for the description of the electric field and by Newton’s law of force. On this basis, a FEM model is developed and used to analyze the polarization process. The results of the calculation of the electric field vector distribution are presented. Finally, the areas are identified in which polarization in the desired direction is achieved in the resonator as well as the ones where no polarization occurs.

Ultra-narrow-band terahertz perfect metamaterial absorber for refractive index sensing application

We numerically propose and demonstrate an ultra-narrow perfect metamaterial absorber (PMA) for refractive index sensing applications in the terahertz region. The designed PMA is only composed of a gallium arsenide (GaAs) cross-shaped resonator array on an opaque copper/silicon substrate. Simulated results show that the proposed PMA can achieve a near-perfect absorption peak with an absorptivity of 99.49% and a high quality factor value of 637 at 2.44THz. The physical mechanism of the narrow absorption is explained by the electric field, magnetic field and Poynting vector distributions. As a refractive index sensor, its sensitivity and figure of merit reach up to 1.94THz/refractive index unit (RIU) and 506RIU−1, respectively. These results make the proposed PMA to have great potential in detecting, imaging and sensing applications.

Lightning return stroke electromagnetic field and energy at close distance by using 3D FDTD simulation

In this paper, the lightning return stroke electromagnetic field at close distance is calculated by the way of transmission line (TL) model and full-wave three-dimensional electromagnetic field simulation software XFDTD, which is based on finite-difference time-domain (FDTD) method. The evolution of distributions of electric field and magnetic field are summarized in the study. Furthermore, the total electromagnetic field and major components are analyzed to clarify the electromagnetic hazard from lightning electromagnetic pulse (LEMP). Then the temporal and spatial distribution characteristic of Poynting vector of the electromagnetic environment is shown to expound the energy distribution of LEMP at close distance. The results based on the analyses of field strength and Poynting vector show that the distribution of electric field, magnetic field and Poynting vector at close distance is akin to multilayered cylinder, and LEMP in the region characterized by large amplitude, transient behavior and high electromagnetic energy is a potential threat to adjacent electronic equipments. Moreover, engineering basis concerning LEMP protection and electromagnetic compatibility (EMC) design in the region closed to the return stroke point can be provided by the synthetical analysis of LEMP.

Space Charge Distribution in a Dielectric Liquid Using an Optical Method

In order to diagnose the effectiveness of electrical insulation, it is necessary to obtain information regarding the electric field distribution in insulating materials. We have investigated the measurement of electric field vector distributions in liquid dielectrics using an original method. Electric field distributions could be measured in time intervals of milli-seconds by an optical system. In this study, the electric field in a liquid containing space charges was measured, and the change in the electric field caused by the charges in the liquid was examined. Moreover, the space charge distribution in the liquid was also studied. We believe that our study can aid a better understanding of the movement of charges in liquid dielectrics.

Numerical analysis of birefringence and coupling length on dual-core photonics crystal fiber with complex air holes

A type of high birefringence dual-core photonic crystal fibers (DC-PCFs) with a central row of elliptical air holes have been proposed. The transverse electric field vector distributions of the two modes are evaluated, the birefringence or coupling length with the different parameters is numerically analyzed based on finite-element method. The numerical results show values for the birefringence of 8.247×10−3 (for wavelength, λ=1.5μm and lattice length, Λ=1.3μm), and for the coupling lengths about 3.1mm and 2.6mm (λ=1.5μm and Λ=1.5μm) to modes of x and y polarized, respectively. With the increasing of the air-filling fraction in proposed DC-PCF, the coupling length becomes longer and the birefringence becomes higher.

Time Series Measurement of Electric Field and Electrical Space Charge Distributions in a Dielectric Liquid

It is important to obtain information about electric field and space charge distributions. We have investigated the measurement of electric field vector distributions in liquid dielectrics using an original method. We developed an optical system to measure electric field distributions on the order of milliseconds. Therefore, time series measurement of electric field distributions in a parallel plane electrode system was carried out. From the obtained field distributions, the time variation of a space charge density distribution was obtained. This is the first example in which the space charge distribution was measured at time intervals of 1 ms.

Improvement of accuracy of the measurement of electric field distributions using the Kerr electrooptic effect and computed tomography

AbstractComputed tomography (CT) has been used for industrial application as well as its principal development in the medical field. We have investigated the measurement of nonuniform electric field vector distributions in liquid dielectrics using an original method based on the electrooptic Kerr effect and the CT method. In applying the CT method to the reconstruction of the electric field, a principle of the CT method has been faithfully observed, which has been one cause of error. Specifically, the region passed through by the light in the measurements was not equal to the reconstructed region and the electric field was reconstructed without consideration of the value of cells outside the region for reconstruction. To solve these problems, we suggest an improved algorithm for reconstruction using the concepts which we called “actual region projection data” and “extension of region for reconstruction.” Simulations and experiments were used to investigate the usefulness of the improved method. © 2012 Wiley Periodicals, Inc. Electron Comm Jpn, 95(2): 8–15, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.10404

Highly Birefringent Two-Mode Photonic Crystal Fibers With Near-Zero Flattened Dispersion

Through introducing three sizes of holes in cladding, highly birefringent two-mode photonic crystal fibers (PCFs) are proposed. The full-vector finite-element method (FEM) is applied in the calculation of the transverse electric field vector distributions of the two modes, their effective indices, modal birefringence, chromatic dispersion, and confinement losses. The defect holes near the core region are deliberately designed to obtain high birefringence. Furthermore, the structural parameters are carefully selected to flatten chromatic dispersion curve and reduce confinement losses.

Optical measurement of electric field distributions with time in propylene carbonate

AbstractElectrical insulation diagnosis requires that we obtain information about the electric field distribution and the space charge distribution in insulating materials. We have measured nonuniform electric field vector distributions in liquid dielectrics by our original method based on the electrooptic Kerr effect and the CT method. We carried out time sequence measurement of the electric field vector distribution in propylene carbonate, which is a dielectric liquid. When a DC voltage pulse of 200‐ms width was applied to a parallel plane electrode system, the electric field vector distributions, which had the shape of a circle 12 mm in diameter, were measured at time intervals of 3 ms. The measurements were carried out while varying the conductivity of the liquid. The distribution a certain time after applying the voltage pulse seemed to be disturbed. Observation of the time at which the disturbance started would make it possible to determine the behavior and electrical characteristics of the liquid. We also studied the evaluation of remnant charges. © 2011 Wiley Periodicals, Inc. Electron Comm Jpn, 94(9): 45–51, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.10351

電気光学効果とCT法を利用した電界分布測定法の精度向上手法

Computed tomography (CT) method has been used for industrial application as well as it has been mainly developed in a medical field. We have investigated the measurement of nonuniform electric field vector distributions in liquid dielectrics using an original method based on electrooptic Kerr effect and CT method. In applying CT method to the reconstruction of the electric field, a principle of CT method has been faithfully observed, which has been one of cause of the error. Specifically, region passing through of the light for measurements was not equal to the reconstructed region and the electric field was reconstructed without consideration of the value of cells outside of the region for reconstruction. So, to solve these problems, we suggested the improved algorithm for reconstruction using the concepts which we called “actual region projection data” and “extension of region for reconstruction”. By a simulation and an experiment, the usefulness of the improved method was studied.

Composite metamaterial enabled excellent performance of microstrip antenna array

This paper reports that the split ring resonators and complementary split ring resonators are compounded to construct a novel compact composite metamaterial. The composite metamaterial exhibits a unique property of blocking electromagnetic wave propagating in two directions near the resonant frequency. An example of two-element microstrip antenna array demonstrates that the developed metamaterial enables array performance that is an improvement in comparison with the traditional one, including mutual coupling suppression of 9.07 dB, remarkable side lobe suppression and gain improvement of 2.14 dB. The mechanism of performance enhancement is analysed based on the electric field and Poynting vector distributions in array. The present work not only is a meaningful exploration of new type composite metamaterial design, but also opens up possibilities for extensive metamaterial applications to antenna engineer.

Optical measurement of electric field distributions with time in a liquid at DC pulse voltage

AbstractFor electrical insulation diagnosis, it is necessary to obtain information about the electric field distribution and the space charge distribution in insulation materials. We have investigated the measurement of nonuniform electric field vector distributions in liquid dielectrics using an original method based on the electrooptic Kerr effect and the CT method. We developed an optical system that could measure electric field distributions in about 1 ms. In this study, when a DC voltage pulse of 50 ms width was applied to a sphere‐to‐plane electrode system, electric field distributions on some measurement planes were measured at intervals of 1 ms. The distribution a short time after application of the voltage pulse seemed to be disturbed. It is inferred that the “disturbance” was caused by changes in the density of the liquid due to movement of certain carriers in the liquid. Observation of the time of onset of the disturbance would make it possible to determine the behavior and electric characteristics of the liquid. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 172(1): 1–9, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20940

Modal characteristics of antiresonant reflecting pipe waveguides for terahertz waveguiding

Modal characteristics of the THz pipe waveguide, which is a thin pipe consisting of a large air core and a thin dielectric layer with uniform but low index, are investigated. Modal indices and attenuation constants are calculated for various core diameters, cladding thicknesses, and cladding refractive indices. Numerical results reveal that the guiding mechanism of the leaky core modes, which transmit most of the power in the air-core region, is that of the antiresonant reflecting guiding. Moreover, modal patterns including modal intensity distributions and electric field vector distributions are shown for the fundamental and higher order modes. Experiments using time-domain spectroscopy with PMMA pipes also confirm the antiresonant reflecting guiding mechanism.

An Endlessly Single-Mode Photonic Crystal Fiber With Low Chromatic Dispersion, and Bend and Rotational Insensitivity

A single-mode photonic crystal fiber (PCF) with low chromatic dispersion, low bend, and rotational sensitivity is presented. The transverse electric field vector distributions of the fundamental, higher order and fundamental space filling modes, their effective indices, chromatic dispersion, confinement, bending and rotational losses are reported using full-vector finite-element method (FEM). In addition, the endlessly single mode behavior is demonstrated by employing the V parameter of the proposed PCF. It has also been shown that the proposed PCF design is insensitive to bends and rotations.

プロピレンカーボネート中の電界分布の光学的時系列測定

Electrical insulation diagnosis requires that we obtain information about the electric field distribution and the space charge distribution in insulating materials. We have measured nonuniform electric field vector distributions in liquid dielectrics by our original method based on the electrooptic Kerr effect and the CT method. We carried out time sequence measurement of the electric field vector distribution in propylene carbonate, which is a dielectric liquid. When a DC voltage pulse of 200-ms width was applied to a parallel plane electrode system, the electric field vector distributions, which had the shape of a circle 12 mm in diameter, were measured at time intervals of 3 ms. The measurements were carried out while varying the conductivity of the liquid. The distribution a certain time after applying the voltage pulse seemed to be disturbed. Observation of the time at which the disturbance started would make it possible to determine the behavior and electrical characteristics of the liquid. We also studied the evaluation of remnant charges. © 2011 Wiley Periodicals, Inc. Electron Comm Jpn, 94(9): 45–51, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.10351

直流パルス印加場における液体誘電体中の電界分布の時系列測定

For electrical insulation diagnosis, it is necessary to obtain information about the electric field distribution and the space charge distribution in insulation materials. We have investigated the measurement of nonuniform electric field vector distributions in liquid dielectrics using an original method based on the electrooptic Kerr effect and the CT method. We developed an optical system that could measure electric field distributions in about 1 ms. In this study, when a DC voltage pulse of 50 ms width was applied to a sphere-to-plane electrode system, electric field distributions on some measurement planes were measured at intervals of 1 ms. The distribution a short time after application of the voltage pulse seemed to be disturbed. It is inferred that the “disturbance” was caused by changes in the density of the liquid due to movement of certain carriers in the liquid. Observation of the time of onset of the disturbance would make it possible to determine the behavior and electric characteristics of the liquid. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 172(1): 1–9, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20940