Electric Field Levels Research Articles

Preparation of Novel ZnO/Cu2O Heterojunctions Composite Film by Codeposition Method and Their Enhanced Photocatalytic Performance Analysis

Refractory organic pollutants have caused widespread concern about their pollution of water environments. Photocatalytic oxidation technology is an effective way to remove organic pollutants. Photocatalyst is the components core of photocatalytic oxidation technology. The development of visible light responsive catalysts with high catalytic activity is of great significance for the removal of organic pollutants using sunlight as a light source. In this paper, a codeposition method is used to prepare ZnO/Cu2O composite film with a heterojunction structure in one step. The microstructure and photoelectric properties of the prepared ZnO/Cu2O composite film are characterized and analyzed, and its photocatalytic performance is evaluated. Compared with pure the Cu2O film, the composite film exposes more (111) crystal planes, and has a smaller impedance and a larger photocurrent and open circuit voltage value. These findings indicate that the ZnO/Cu2O composite film exhibits excellent photogenerated carrier separation and migration efficiencies. Among the prepared samples, M2 demonstrates the highest photocatalytic and recycling performance. The calculation of the band position shows that the Fermi level of the composite film exhibits a significant shift compared to that of the pure Cu2O film. The analysis shows that the decrease in the recombination probability of photogenerated carriers caused by the shift of the Fermi level and formation of an internal electric field is the main factor for the significant enhancement in the Cu2O photocatalytic performance. This article provides a novel method and idea to realize the efficient removal of organic dye pollutants in sewage.

Effects of high voltage electric field on storage life and antioxidant capacity of whole pomegranate fruit

The objective of this study was to investigate the effects of high voltage electric field (HVEF) on the antioxidant system in stored pomegranate fruit. The experiments were conducted at cold storage for two months under three selected electric field levels (0, 1.5 and 3 kV/cm). Results showed that non-enzymatic antioxidant contents including phenols and ascorbic acid were better preserved by 1.5 kV/cm treatment than control after 60 days of storage. While the activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) in pomegranate fruit were significantly enhanced with 1.5 kV/cm treatment compared to control, Guaiacol peroxidase (G-POX) levels in the control group increased steadily and were highest at the end of the storage. Although the results obtained from 3 kV/cm treatment were acceptable till the end of the first month, due to oxidative damage of reactive oxygen species (ROS) produced in response to HVEF stress, their results come close to the control group at the end of the second month. These data suggest that the optimum electric field intensity for enhancing antioxidant contents in stored pomegranate fruits was 1.5 kV/cm.

EMI radiation of power transmission lines in Malaysia.

Background: There has been rising concern amongst the public regarding their home's proximity to high tension power transmission lines. The primary cause of fear is the impact of the electromagnetic interference (EMI) radiation on the nearby occupants' health. Despite the presence of national permissible limits of EMI radiation, there is still lack of information with regards to the EMI radiation of the types of power lines configuration in Malaysia. Methods: The electric and magnetic fields of several selected power transmission lines were simulated using the EMFACDC software program from the recommendation ITU-T K.90. Five types of power transmission lines available in Malaysia are considered. Results: It was found that the simulated electric and magnetic field levels at all the power lines' right of way (ROW) boundary complies with the prescribed exposure limit. However, the electromagnetic fields (EMF) level increases significantly as the separation distance is reduced from 30m. For a more conservative approach, the ROW can be set at 30m across all transmission voltage level and corridor area condition. Conclusion: It can be concluded that Malaysia's power transmission lines are within the prescribed exposure limits. To further minimize the electric and magnetic field level, it is recommended that the residential building should be built at least 30 meters away from the power transmission lines, especially for the 275kV double circuit, 275/132kV quadruple circuit, and 500kV double circuit lines.

К вопросу моделирования высоковольтного изолятора в программном комплексе COMSOL Multiphysics 5.6

The article discusses the main aspects of modeling suspended polymer high-voltage insulation of overhead power lines (PTL) in the COMSOL Multiphysics 5.6 software package. Analytical expressions of the mathematical model of the electromagnetic field around the insulator are given, on the basis of which a numerical solution is formed within the software package that allows you to build a model of the electric field in two-dimensional and three-dimensional space. There are three main stages of working with the program interface. At the first stage, the task of the geometric dimensions of the model and the surrounding area is considered, attention is paid to the formation of the design features of polymer insulators. In the second stage, the physical properties of the structural materials of the insulator, as well as the surrounding space, are described. The third stage is reduced to the determination of boundary conditions for solving the Poisson differential equation. Recommendations for finite element mesh density are given. A gradient picture of the distribution of the electric potential near the surface of the insulator is presented. The graphs of the distribution of the normal component of the electric field strength along the surface of the insulator are also plotted. On the basis of the obtained results, the influence of external factors on the properties of the polymer insulator is studied. A possible variant of modeling influencing factors, such as pollution and moisture, by making changes in the description of the physical properties of the insulator surface, namely by including a uniform and continuous layer with a given conductivity, is described. The distribution of the normal component of the electric field strength along the surface of the insulator with contamination is obtained. The results of modeling the electric field distribution with the presence of contamination on the surface of the insulator and its absence are summarized in the table where the electric field strength is indicated depending on the distance to the traverse. Based on the analysis of the results obtained, an assumption is made about the overestimated level of the maximum electric field on the insulators recommended by the manufacturers. The convergence of the considered models with the experimental data obtained in the course of long-term observation of the dynamics of the degradation and aging processes of the surface of polymer suspended insulators of overhead transmission lines is discussed.

Observation of surface magnons and crystalline electric field shifts in superantiferromagneticNdCu2nanoparticles

An ensemble of superantiferromagnetic ${\mathrm{NdCu}}_{2}$ nanoparticles has been produced to perform a detailed analysis of magnetic excitations using inelastic neutron scattering. Neutron diffraction measurements indicate a mean nanoparticle size of $\ensuremath{\langle}D\ensuremath{\rangle}\ensuremath{\approx}13$ nm, where the bulk commensurate antiferromagnetic structure is retained at the nanoparticle core. Magnetic measurements evidence the interaction among the magnetic moments located at the nanoparticle surface to be strong enough to establish a spin glass behavior. Specific heat analyses show a broad Schottky contribution, revealing the existence of a crystalline electric field. Inelastic neutron scattering analyses disclose that the splitting of the crystalline electric field levels associated with the ${\mathrm{Nd}}^{3+}$ ions, as well as the spin-wave excitations that emerged below the N\'eel transition $({T}_{\mathit{\text{N}}}\ensuremath{\approx}6 \mathrm{K})$ in polycrystalline ${\mathrm{NdCu}}_{2}$ are maintained in the nanoparticle state. We have been able to isolate the scattering contribution arising from the nanoparticle surface where both crystalline electric field splitting and the collective magnetic excitations are well-defined despite the symmetry breaking. Quantitative analyses of this surface scattering reveal that finite-size effects and microstrain lead to a partial inhibition of the transitions from the ground state to the first excited level, as well as a positive shift $(\ensuremath{\sim}15%)$ of the energy associated to collective magnon excitations.

Magnetic properties and signatures of ordering in triangular lattice antiferromagnet KCeO2.

The magnetic ground state and the crystalline electric field level scheme of the triangular lattice antiferromagnet are investigated. Below mK, develops signatures of magnetic order in specific heat measurements and low energy inelastic neutron scattering data. Trivalent ions in the local environment of this compound exhibit large splittings among the lowest three Kramers doublets defining for the free ion the sextet and a ground state doublet with dipole character, consistent with recent theoretical predictions in M. S. Eldeeb et al. Phys. Rev. Materials 4, 124001 (2020). An unexplained, additional local mode appears, and potential origins of this anomalous mode are discussed.

Coupled spin waves and crystalline electric field levels in candidate multiferroic ErFeO3

We report an inelastic neutron scattering study of candidate multiferroic ErFeO3, a compound that has been previously reported to have three different magnetic states and undergoes signatures of Fe3+−Er3+ cooperative coupling. The spectrum at low energy transfer is dominated by excitations of the Er3+ character, even above the Er3+ antiferromagnetic ordering temperature of 4.5 K. In addition, a crystalline electric field excitation at 6 meV exhibits additional energy splitting upon cooling through 4.5 K with mode-dependent polarization. This indicates different moment directions for these modes, an interesting consequence of Cy ordering of the Er3+ moments.

ASSESSMENT OF THE IMPACT OF ELECTROMAGNETIC RADIATION IN LOW-FREQUENCY ENERGY FACILITIES ON THE RESIDENTIAL ECOLOGICAL ZONE

Nowadays, one of the key issues in the ecological field and environmental protection is the influence of the electromagnetic field distribution intensity generated by low-frequency energy objects on the urban system. The purpose of environmental monitoring is to establish sanitary protection zones, taking into account the necessary maximum permissible conditions, during the construction and commissioning of new energy facilities. The agglomeration environment of the Shymkent city in the Republic of Kazakhstan where there is an increased electromagnetic pollution propagation generated by 110 and 220 kV high-voltage lines has been taken as the object under study. At the initial stage, the geometric parameters of power transmission lines have been determined by ground-based laser scanning and were later used in the main calculations to determine the electric and magnetic field distribution intensity. The mirror image method has been used to determine the electric and magnetic field levels in high-voltage transmission lines. As a result of the calculations obtained a geoinformation map was constructed based on the gradient of electric and magnetic fields in the studied territories using the inversely weighted distance method with the use of the ESRI ARC Gis application program. A three-dimensional characteristic is constructed that visually shows the dependence of the time spent by people in the zone of electromagnetic radiation, which depends on the radiated object. This characteristic is a sanitary protection zone that restricts the routing of line workers.

Design and simulations of the HEBT spiral buncher cavities for the high current injector at IUAC

The high energy beam transport (HEBT) section of the high current injector (HCI) accelerator requires two spiral buncher (SB) cavities to match the input Twiss parameters at the entrance of the superconducting super buncher (SSB) cavity by providing the longitudinal phase matching between drift tube linac (DTL) and SSB. The spiral type open-ended quarter-wave (λ/4) resonators were chosen for their high shunt impedance, mechanical, and vibrational stability. The 48.5 MHz frequency of cavities was chosen for its broad acceptance of time width. TRACE 3D codes were simulated to determine the bunching voltage for the spiral buncher cavities. The locations of HEBT spiral bunchers have been fixed in such a way that the ion beam can be transported from DTL to SSB with negligible growth in longitudinal beam emittance within the framework of first-order linear beam optics. The cavity parameters were optimized to get the significantly high shunt impedance and quality factor to achieve the desired electric field level at the minimum input power. The inner and outer radii of the drift tubes were honed to get the uniform electric field profile along the beam direction while βλ/2 was kept constant during the refinement. The HEBT SB cavities require ~2 kW of input power to produce ~160 kV across two RF gaps. The simulated quality factor and shunt impedance for two identical HEBT SB cavities are ~8300 and ~13.5 MΩ, respectively. The cylindrical type chamber will be fabricated of copper-plated mild-steel (MS) while other components including end plates, spiral, stem, and flanges were fabricated of pure OFHC copper due to excellent electrical as well as thermal conductivity. The cavity frequency can be easily coarse tuned by varying the length of the spiral. The distinguishing feature of the design is to tailor the cavity frequency by ±250 kHz by varying the diameter of the drift tubes and stem, even after fabrication. A cylindrical type frequency tuner of diameter 90 mm and thickness 10 mm has been designed which is capable of providing the additional frequency correction of ± 250 kHz in the travel distance of ~200 mm. The details of longitudinal beam optics, ion-optical and electrical design, simulations, and mechanical design are discussed in this article.

Actuation mechanisms in mixed-phase K0.5Bi0.5TiO3-BiFeO3-PbTiO3 ceramics

We report an in-situ synchrotron X-ray diffraction study of K0.5Bi0.5TiO3-BiFeO3-PbTiO3 ceramics, which exhibit a Tc of around 450 °C. The electromechanical actuation mechanisms comprise contributions from coexisting tetragonal and rhombohedral phases. The tetragonal {200} grain family exhibited the highest effective lattice strain, up to 8.2 × 10−3 at 5 kV/mm. Strong strain anisotropy in the tetragonal phase and field-induced intergranular stresses facilitate a partial transformation from tetragonal (high strain anisotropy) to rhombohedral (low strain anisotropy) at high electric field levels, with an average linear transformation strain of -1.54 × 10-3. The domain switching behavior was effectively enhanced in both tetragonal and rhombohedral phases after the phase transformation, due to the release of intergranular stress. This observed self-adapting mechanism in tuning intergranular stress through partial phase switching in the morphotropic KBT-BF-PT composition with large lattice distortion could also be exploited in other perovskite systems in order to achieve high performance high temperature piezoelectric ceramics.

High capacitive performance at moderate operating field in (Bi0.5Na0.5)TiO3-based dielectric ceramics via synergistic effect of site engineering strategy

Despite a great deal of research efforts on the search for high recoverable energy storage density (Wrec) at high breakdown strength, high voltage operating security and high cost of associated insulation technology are the major barriers to limiting the actual applications of advanced pulse power capacitors, and thus have increased the requirement on the electrostatic energy storage at finite electric field level. Herein, we propose an effective strategy on tailoring energy storage performance under moderate driving field via the synergistic effect of site engineering in (Bi0.5Na0.5)TiO3-based ceramics. Based on extensive experimental researches, a large Wrec (2.78–3.46 J/cm3) and a high efficiency (80–90%) under moderate electric field (<250 kV/cm) have been synchronously attainted in the optimized relaxor ferroelectric ceramics, generating a high energy storage coefficient that exceeds most previously reported dielectric bulk ceramics. Besides, the optimized ceramic possesses good thermal stability (25–200 °C), strong fatigue endurance (after 2 *105 cycles) and outstanding frequency stability (1–500 Hz). More importantly, high discharge density of 1.15 J/cm3, large power density of 65.6 MW/cm3, and ultra-short discharge time of 72 ns with excellent fatigue endurance are also simultaneously achieved. This contribution not only develops a practical lead-free candidate material for electrostatic energy storage, but also offers a feasible approach to design high-efficiency lead-free dielectrics for low electric field high-energy storage applications using synergistic effect of site engineering.

Effect of high-voltage power lines electromagnetic field on growth and development of green bean (Phaseolus vulgaris L.)

Relevance. High voltage electric power transmission lines (HVEPTL) cover a fairly large area of agricultural land all over the world. Investigations of electromagnetic field effect on growth and development of plants are held in various countries. The reaction of individual plant species and even varieties to the electromagnetic field manifests itself in different ways. The network of HVEPTL is growing steadily in our region as well. Nevertheless, information about the effect of the electromagnetic field on bean plants is rather scares. The aim of the present work was to evaluate HVEPTL effect on the growth and development of vegetable beans, depending on the intensity of the electromagnetic field.Material and Methods. The work was achieved on green beans Phaseolus vulgaris L. (Sakfit, Pagoda, MBZ 556, Arishka cvs) grown in conditions of different electromagnetic field values under HVEPTL. Biometrical parameters, plant productivity, yield, dry matter, photosynthetic pigments content, ascorbic acid, total antioxidant activity and total phenolics were determined.Results. In the ranges of electric field values from (5-10) to (400-440) B/m and magnetic field from 0 to 0.53 μT a beneficial effect of electromagnetic field on accumulation of leaves photosynthetic pigments (15-65% increase of chlorophyll а and 6-52% increase of chlorophyll b), polyphenol content (increase up to 17%), antioxidant activity (1-15% increase), and dry matter content (2,5-11% increase) and beans ascorbic acid levels (12-28% increase) were registered. Accordingy, increased plants growth, development and productivity were demonstrated. Peculiarities of beans plants grown under HVEPTL included decrease leaves carotene levels at electric field level of 60-100 B/m (70 m form HVEPTL), and lack of correlation between chlorophyll and carotene in leaves and total antioxidant activity and phenolics content at the stage of technical ripening.

Design and thermal-structural analysis of a high power ICRH travelling wave array antennas

Travelling wave array (TWA) antennas have been proposed for the ICRH (Ion Cyclotron Resonance Heating) antennas of fusion reactors in view to decreasing the antenna voltage and associated electric field. This paper reports the progress of the design and structural analysis of an actively cooled high power TWA antenna for WEST. First, the design of a non-cooled mock-up that will be tested in the TITAN facility is presented. The main objective is to assess the voltage stand-off of the antenna at power and electric field levels relevant for future nominal operation in a fusion device. The main characteristics of the mock-up are detailed and the results from thermal and structural analysis of the mock-up tested in TITAN are presented. In the second part, the compatibility with WEST environment for an actively-cooled TWA antenna is assessed. Mechanical, electromagnetic, thermal and hydraulics constrains (.i.e VDE, plasma radiation, toroidal magnetic field ripple…) are listed in a system loads specification. A Virtual Reality analysis using IRFM tools has been performed to check compliance of the design in term of assembly inside the WEST vacuum vessel.

Аддитивное воздействие электрических и магнитных полей на электротехнический персонал

The article is devoted to the formation of a safe working environment at the industrial enterprises. Conducted experimental studies allowed to reveal not only the presence of electric and magnetic fields of 50 Hz, but also the spectrum of higher harmonic components at the workplaces of electrical personnel. Similar situation is observed in the electric (freight) alternating current locomotives of the railway transport. This is due to the specific features of electrical installations of two-pole and single-phase traction power supply. The important problem was solved related to the assessment of the additive effects of electric and magnetic fields with their simultaneous effect on the personnel. The new method is proposed for calculating and standardizing electric and magnetic fields of 50 Hz based on consideration of their dose energy characteristics at their simultaneous harmful effects on the personnel. The standardization is proposed to be carried out on the basis of the current maximum permissible levels of the parameters of 50 Hz electric and magnetic fields but in the form of the field energy characteristics based on the definition of the Poynting vector. The additivity of the effect of electric and magnetic fields on the personnel is proposed to be assessed by the additivity coefficient in the form of a quantitative measure of the combined harmful effect of the field strengths components. At the additive standardization of simultaneously two harmful factors of the electric and magnetic field strengths, the standardized indicators of magnetic and electric strengths required for assessing the total energy maximum safe level are reduced by 2 times. Based on the maximum permissible levels of electric and magnetic fields, a graph was built for the changes in the energy load of these fields versus the length of exposure. Technical device was developed that measures the level of energy load of the electric and magnetic fields. Using this device, it is possible to minimize the total effect of harmful factors on the electrical personnel with the help of protective means.

Effective strategy to optimize energy storage properties in lead-free (Ba0.3Sr0.7)TiO3 ceramics by the suppression of leakage current

Ceramic capacitors require promising energy storage properties to meet the demands of electronic industry which can be tailored by ferroelectric polarization and electrical breakdown strength. Electrical breakdown exhibits close relation to leakage current in advanced dielectric materials when stimulated by high levels of electric field. The suppression of leakage can be an effective strategy to elevate dielectric breakdown. In this work, Zr ions were employed to replace Ti ions in Ba0.3Sr0.7TiO3 ceramics to achieve the improvement of dielectric breakdown and then increase energy storage ability. Zr doping can obviously reduce the leakage current more than an order of magnitude by blocking the path between two adjacent Ti ions and increasing the distance of electron hopping. A promising energy storage density can be obtained with good fatigue endurance upto cycles of 105. This indicates that the strategy of suppressing leakage by trace amount of Zr doping is an effective approach to tailor energy storage behavior of dielectric ceramics.

Numerical analysis and simulation of micro-EDM plasma in de-ionised water

Micro-EDM is extensively used for the manufacture of miniature components in the field of biomedical, aerospace and automobile applications, where the surface integrity of the manufactured component is a crucial factor. But it has still not replaced other manufacturing methods like Laser Beam Machining because of its low energy efficiency. In order to improve the process efficiency and make it a commercially viable, so many parametric studies have been conducted, considering the various input and output parameters involved. Very little effort is taken in the direction of studying about the plasma, which is the actual source of energy in micro-EDM. This is due to difficulty in analysing it as the plasma lasts only for a few micro seconds in micro-EDM. The existing studies about plasma formation and its role in material removal in a micro EDM process is lacking in many respects, considering the underlying mechanism of plasma formation. This simulation is an attempt to bridge that gap. A one-dimensional model, based on fluid dynamic approach, considering the chemistry involved in plasma formation is simulated. The evolution of plasma characteristics was studied for one level of electric field and gap width. The results obtained for electron density is compared with experimentally obtained results and is found to be in close agreement. The value of temperature obtained is much lower compared to that found in literature. This shows that the data imported as chemical reactions is not complete in all respects. The simulation requires further improvement.

Estimation of electric and magnetic fields in a 230 kV electrical substation using spatial interpolation techniques

This study presents the estimation of the electric and magnetic fields level inside a 400 MVA electrical substation. Located in the northeast region of Brazil, the power plant operates with 230 and 69 kV at 60 Hz frequency. The on-site measurements were performed at previously selected locations covering the whole courtyard and followed the international and national regulatory standards. The electrical and magnetic fields 2-D contour maps over the entire courtyard are presented, which allow better visualisation and analysis of the exposure levels around all equipment. By using the GoldenSurfer V.13 tool, eight interpolation methods were applied to predict unsampled locations. The plots were made using the method that best fit the sampled dataset after the cross-validation technique is used. The measurements were taken during six days during a period of 16 h on 741 locations. For this electrical substation, the maps validate the high electric field level close to breakers and switches at 230 kV and high magnetic field close to equipment operating at 69 kV. The comparison between the exposure levels and those established in current guidelines indicate that the electromagnetic environment on this substation is safe for the occupational population as well as for the general public.

Tunable intraband optical conductivity and polarization-dependent epsilon-near-zero behavior in black phosphorus.

Black phosphorus (BP) offers considerable promise for infrared and visible photonics. Efficient tuning of the bandgap and higher subbands in BP by modulation of the Fermi level or application of vertical electric fields has been previously demonstrated, allowing electrical control of its above-bandgap optical properties. Here, we report modulation of the optical conductivity below the bandgap (5 to 15 μm) by tuning the charge density in a two-dimensional electron gas induced in BP, thereby modifying its free carrier-dominated intraband response. With a moderate doping density of 7 × 1012 cm-2, we were able to observe a polarization-dependent epsilon-near-zero behavior in the dielectric permittivity of BP. The intraband polarization sensitivity is intimately linked to the difference in effective fermionic masses along the two crystallographic directions, as confirmed by our measurements. Our results suggest the potential of multilayer BP to allow new optical functions for emerging photonics applications.

Метод измерения напряженности неоднородных электрических полей по среднему значению

Measurement and control of the intensity levels of inhomogeneous electric fields with high accuracy is quite a difficult task. The solution to this problem is connected both with the development of new sensors and methods for measuring the electric field strength. The creation of new high-precision electrical induction sensors has exhausted its capabilities at the current level of technology and technology. Therefore, new ideas are needed for solving the problems of high-precision measurement of the electric field strength. One of these ways is the development of new measurement methods. Existing measurement methods characterized by the complexity of the measurement processes, suitability in some cases, and unsuitability in others, do not provide the desired metrological characteristics. Therefore, the work related to the development of methods for measuring the intensity of inhomogeneous electric fields does not stand still, and is relevant. The aim of the study is to create a new method for measuring the strength of electric fields using known sensors, which makes it possible to significantly reduce the error in measuring inhomogeneous electric fields. The idea of constructing a new measurement method is formed. The idea of the method is that in the presence of two physical quantities measured with different sign values of the error, the average value of the physical quantity will always be closer to the true value. Based on this, a new method for measuring the intensity of inhomogeneous electric fields is proposed, associated only with the original measurement process. The measurement method id named «Average value method» (MSZ). The estimation of the error of this method shows a decrease in the measurement error to +5 % with the full spatial measurement range 0a1. Using the «Average value method» it is possible to achieve a significant increase in the accuracy of measuring the strength of inhomogeneous electric fields in a wide spatial range of measurements in comparison with known methods

Сдвоенные сферические датчики напряженности низкочастотных электрических полей нового поколения

These electric fields adversely affect the environment, technical and biological objects. In this regard, it is necessary to control the levels of electric fields, an important characteristic of which is the strength of the electric field. Sensors of the electric field strength are required to sense the electric field. The existing sensors are inconvenient in operation and have a high error in the perception of the electric field strength, reaching  20 %. In the work under consideration, the idea of creating a universal sensor of a new type, related to the type of dual sensors, is put forward. Its versatility lies in the fact that it embodies all types of known sensors — single, double, and now twin. The error in the perception of the intensity of the inhomogeneous electric field of the dual sensors does not exceed + 5 % in the entire spatial measurement range 0a1. In this case, the distance d to the field source is limited only by the radius of the spherical base of the sensor, i.e. d  R. At the same time, for sensors that are part of a dual sensor in the same spatial measurement range, the error is  35 %. Using a dual sensor, it is possible to achieve a significant increase in the accuracy of measuring the strength of inhomogeneous electric fields in a wide spatial measurement range in comparison with known sensors.