Measurement Of Electromagnetic Radiation Research Articles

Third order nonlinear correlation of the electromagnetic vacuum at near-infrared frequencies

In recent years, electro-optic sampling, which is based on Pockel’s effect between an electromagnetic mode and a copropagating, phase-matched ultrashort probe, has been largely used for the investigation of broadband quantum states of light, especially in the mid-infrared and terahertz frequency range. The use of two mutually delayed femtosecond pulses at near-infrared frequencies allows the measurement of quantum electromagnetic radiation in different space-time points. Their correlation allows therefore direct access to the spectral content of a broadband quantum state at terahertz frequencies after Fourier transformation. In this work, we will prove experimentally and theoretically that when using strongly focused coherent ultrashort probes, the electro-optic sampling technique can be affected by the presence of a third-order nonlinear mixing of the probes’ electric field at near-infrared frequencies. Moreover, we will show that these third-order nonlinear phenomena can also influence correlation measurements of the quantum electromagnetic radiation. We will prove that the four-wave mixing of the coherent probes’ electric field with their own electromagnetic vacuum at near-infrared frequencies results in the generation of a higher-order nonlinear correlation term. The latter will be characterized experimentally, proving its local nature requiring the physical overlap of the two probes. The parameters regime where higher order nonlinear correlation results predominant with respect to electro-optic correlation of terahertz radiation is provided.

Electric near-field scanning for electronic PCB electromagnetic radiation measurement

This paper introduces a design and test of an electric (E) near-field scanning (NFS) system by using innovative 4-layer miniature probe for electromagnetic compatibility (EMC) application. The probe works in the challenging frequency band up to 12 GHz with spatial resolution lower than 2 mm. The NFS is designed to operate by automation based on PC driven by LabVIEW® interface controlling a vector network analyzer (VNA). The PC communicates with the VNA through the local area network to read and save the measured data emitted by the device under test (DUT). The LabVIEW® interface is designed to control the E-NF positioning motion core by means of STM32® microcontroller. A stepper motor is used to move the E-NF probe along the scanning surface plan. Finally, the NFS is validated by visualizing the E-NF intensity maps generated in real time after calibration with a reference device under test represented by microstrip line and a microwave circuit.

Electromagnetic danger of electric and hybrid vehicles

Problem statement. In electric and hybrid transport, passengers sit very close to the electrical system of considerable power, usually for a considerable time. People are concerned about the level of frequency, intensity of electromagnetic radiation, and the time spent in transport. The relatively high currents achieved in these systems and the short distances between power devices and passengers mean that the latter can be exposed to the corresponding magnetic fields. This means that there is a need to assess the electromagnetic environment inside these vehicles before they are put on the market. When designing electric and hybrid vehicles and their components, it is necessary to take into account the hazards of magnetic field exposure to drivers, passengers and the environment. The aim is to study the effect of electromagnetic radiation on people and improve the efficiency of vehicle operation by assessing the electromagnetic safety of electric and hybrid vehicles at the stage of their operation, as well as to improve methods for assessing electromagnetic radiation depending on operating conditions. Methodology. Methods are a systematic approach to research, protection against electromagnetic radiation in transport, conducting measurements of electromagnetic radiation in electric and hybrid transport, finding out the spatially strong inhomogeneity of the magnetic field and building 3D topology using numerous uniformly distributed magnetic field sensors in the vehicle interior, i.e. by a differential phase-gradient method for the study of ultra-low frequency amplifiers from 0.001 - 100 Hz of geomagnetic variations, a method of testing magnetic fields. This method allows using three three-component magnetic sensors arranged in a triangle at a short distance from each other (magnetic gradiometer) to construct a vector of gradients and phase velocities of magnetic variations for any of the three components of magnetic fields. As a result, the phase-gradient method has found its application for measuring magnetic fields in electric and hybrid vehicles, as well as for detecting the topology of magnetic fields, taking into account their extreme spatial heterogeneity, the sensors in the cabin should be located quite densely, i.e., the number of sensors should be at least 10-20 (evenly at a distance of ten centimeters at floor level, at head level of drivers and passengers, etc.). Scientific novelty: the study of electrical equipment in electric and hybrid transport has shown that the source of electromagnetic fields, which have a strong temporal and spatial heterogeneity in the frequency range from 0 to hundreds of megahertz, that they are a superposition of fields from many sources (from electric motors, traction batteries, live elements, various electrical equipment (starting and braking resistance, group switches, rheostat units, electrical circuits for ventilation, lighting, heating, etc.). Practical relevance. The problems of determining the moment of occurrence of electromagnetic hazards in electric and hybrid vehicles are considered. It is established that electronic devices on board are usually higher in frequency than magnetic fields, which is associated with changes in traffic modes. Safety measures against electromagnetic radiation in electric and hybrid modes of transport are presented.

Characteristics and variation laws of electromagnetic radiation generated during explosion

AbstractThe characteristics and laws of explosive electromagnetic radiation must be clarified to investigate its interference with electronic equipment. Currently, studies pertaining to explosive electromagnetic radiation are performed via small equivalent explosive explosion tests, and conclusions regarding the regularity of electromagnetic radiation from warhead explosions are not confirmed. This study analyzes the power laws of explosion electromagnetic radiation via numerical simulations, literature comparisons, experimental testing, and other methods. The results show that the duration of the explosion electromagnetic radiation is proportional to the 1/3 power of the equivalent. The delay time is between 44 and 53 μs and is inversely proportional to the detonation velocity. The peak time is positively correlated with the 1/2 power of the equivalent. The electric field intensity of an explosive explosion is directly proportional to the 1/3 power of the equivalent, whereas the electric field intensity of a warhead explosion is positively correlated but not linearly related with the equivalent power. The spectral distribution of the electromagnetic radiation caused by different types of explosives differ significantly. The electromagnetic radiation measurement results for explosive explosions can be predicted via numerical simulation. However, the simulation results do not match the measurement data of warhead explosions, thus highlighting the necessity of warhead explosion electromagnetic measurements.

PRELIMINARY STUDY OF AMBIENT ELECTROMAGNETIC RADIATION AT BASE TOWER STATIONS IN RESIDENTIAL AREAS IN KUALA NERUS

Introduction: Mobile communications developed into an integral component of our daily life. The growing demand for mobile communication services in Kuala Nerus has seen an increase in the installation of base station towers (BST) in residential areas, as well as near schools, and hospitals. Kuala Nerus was selected as a study location because it is a newly developed district in Terengganu, hence, it is crucial to perform electromagnetic radiation (EMR) measurements in the early stages. Objective/aim: This study aimed to measure the RF EMR exposure level in residential areas in Kuala Nerus by measuring the strength of its electric field (EF) strength and power density (PD) value while comparing it with the ICNIRP’s standard guidelines. Materials and methods: Measurements were made using NARDA NBM 550, connected to a probe that could detect frequencies from 100kHz to 6GHz. The data collection period for each point was approximately 6 minutes during daytime. Results: Average radiation levels in terms of EF strength at all locations were found to vary between 0.26 (V/m) to 3.35 (V/m) (PD value about 0.02 µW/cm² to 2.97 µW/cm²). The highest level was measured at Surau Kg Pok Tuyu, which was 5.48% or 18 times lower than the MCMC exposure limit for public areas. Conclusion: The RF value obtained does not exceed the standard limit, which in turn contributes indirectly to health monitoring initiatives for public NIR exposure. This study found that exposure levels in selected BSTs in residential areas in Kuala Nerus were within the standard guideline limits.
 
 

Electron Heating in Shocks: Statistics and Comparison

AbstractSupernova remnant (SNR) shocks are the highest Mach number non‐relativistic shocks in electron‐ion plasmas. These shocks are the most efficient particle accelerators in space. SNR shock parameters are inferred from measurements of electromagnetic radiation from heated and accelerated particles. Temperature of the shock heated electrons is one of the most important parameters in supernova remnant shocks. Knowledge of the downstream electron‐to‐ion temperature ratio or of the ratio of the downstream electron temperature to the incident ion energy is crucial for understanding physics of the very high‐Mach number SNR shocks. Heliospheric shocks have substantially lower Mach numbers than SNR shocks but can be extensively studied in in situ observations with further extrapolation of the findings to higher Mach numbers. Magnetospheric Multiscale mission observations of the Earth bow shock are used to analyze dependence of the electron heating on the shock Mach number. It is found that the ratio of the downstream electron temperature to the incident ion energy decreases with the increase of the Mach number. At high Mach numbers this ratio and stabilizes at about 2.5%. The electron‐to‐ion temperature ratio stabilizes at about 10%. The peak electron temperature occurs at the overshoot maximum, further downstream electrons cool down. The mean ratio of the 4.5 s averages of the downstream and maximum electron temperatures is 0.85. Electron heating does not follow the thermodynamic adiabatic law. The heating and cooling behavior implies that the energy is provided by the overall cross‐shock potential while small‐scale electric fields rapidly isotropize the electron distribution.

Measurement method for electromagnetic radiation generated during a high-capacity warhead explosion

To study the impact of explosion electromagnetic radiation on electronic equipment and to improve the anti-interference ability of electronic equipment in an explosion electromagnetic environment, it is necessary to understand the characteristics and laws of explosion electromagnetic radiation. An explosive electromagnetic measurement test is necessary to study this problem. In view of the measurement conditions of the explosive field and the interference factors in the process of a warhead explosion, protection and improvement measures have been proposed. It designs a repeater to compensate for excessive transmission loss of explosive electromagnetic signal. It enhances the anti-interference ability of the measurement system by adopting electromagnetic shielding methods for signal transmission cables. The closed aperture method was used to solve the field line coupling problem in the measurement system. By analyzing the law of seismic wave propagation, equivalent simulation test of instrument vibration and optimization of test point layout, which are conducted to deal with adverse effects such as explosive seismic wave and fragment strike. Finally, an electromagnetic radiation measurement method suitable for the environment of a high-capacity warhead explosive field has been formed.

Research on the Method of Near-Field Measurement and Modeling of Powerful Electromagnetic Equipment Radiation Based on Field Distribution Characteristics

With the wide application of power equipment consisting of high switching frequencies and large current switching devices in the integrated power system on ships, the low-frequency radiation interference caused by the powerful electromagnetic equipment becomes more and more serious. Establishing an equivalent model of radiation interference based on the near-field measurement data is the key to subsequent electromagnetic compatibility design. Due to the large size of the equipment, there will be many measurement points in the near-field measurement area, which leads to long testing times and low modeling efficiency. To solve the above problems, this article first proposes a method of near-field measurement and a modeling method of powerful electromagnetic equipment radiation based on field distribution characteristics. Firstly, the near-field measurement data are obtained by the sparse and uniform sampling of the near-field measurement plane at large sampling intervals. Then, the near-field measuring plane is separated into several regions by the magnetic field’s distribution characteristics. The near-field measurement data required for modeling are obtained by further sampling in the region with a large magnetic field amplitude. Finally, the equivalent radiation model is obtained by the equivalent dipole method. Simulations and experiments show that the method can significantly reduce the amount of measurement data and testing time while improving the efficiency of equivalent radiation modeling and maintaining the accuracy of the modeling.

Research on vector characteristics and applications of electromagnetic radiation induced by rock failure

Coal and rock electromagnetic radiation (EMR) measurement plays an essential role in the monitoring and early warning of underground engineering dynamic hazards as a real-time, dynamic, non-contact geophysical monitoring method of coal and rock fissure. The electromagnetic field has obvious directionality; however, the EMR measurement instruments used in underground engineering are scalar rather than vector instruments. Therefore, this paper uses a self-developed three-axis antenna to measure the vector EMR for rock Brazil splitting failure. Study the influence of crack size (D), the distance of measuring point (r) and crack azimuth angles (θ 0) on the vector characteristics of EMR induced by rock splitting failure. Analyze the vector response mechanism of EMR induced by rock splitting failure, and conduct on-site vector EMR measurements in the Lilou Coal Mine. The study achievements are concluded as follows: the amplitude of vector EMR ( A s) increases linearly with the increase of crack size (D), decreases with the distance square (r 2) from the measurement point to the crack increases, and increases and then decrease with the increase of angles (θ 0) between the sample direction and the initial fixed position, showing arching changes; The direction of vector EMR ( A s) is mainly affected by θ 0 impact. The results of experiments are consistent with that of theoretical analysis. The field measurement results show that the stress concentration area and its orientation of the roadway could be measured using the three-axis vector EMR instrument we researched and developed.

ОСОБЕННОСТИ ИССЛЕДОВАНИЯ ОБНАРУЖЕНИЯ И ИЗМЕРЕНИЯ ПОБОЧНЫХ ЭЛЕКТРОМАГНИТНЫХ ИЗЛУЧЕНИЙ ШИРОКОПОЛОСНЫХ СИГНАЛОВ НА ПРИМЕРЕ ИНТЕРФЕЙСА DISPLAYPORT

The article deals with the technical channel of information leakage due to the side electromagnetic radiation of broadband signals on the example of DisplayPort interface. The peculiarities of detection and measurement of side electromagnetic radiation of broadband signals of modern digital interface - DisplayPort are briefly outlined. The architecture of DisplayPort interface is considered and its peculiarities are revealed. The laboratory stand with the help of which practical research on detection and measurement of side electromagnetic radiation of broadband signals on the example of DisplayPort interface is described in detail. According to the results of measurements the conclusion is made about the correctness of the DisplayPort interface research assumptions.

Research on Electromagnetic Radiation Characteristics of Energetic Materials

During the explosion of energetic materials, electromagnetic interference is generated, which can affect the normal operation of surrounding electronic equipment. Therefore, an electromagnetic radiation measurement device based on a short-wave omnidirectional antenna and ultra-wideband omnidirectional antenna was designed to measure the electromagnetic radiation generated by the explosion of energetic materials of different masses, and the electromagnetic radiation characteristics were obtained through data processing. The results showed that the electromagnetic signal can still be collected hundreds of milliseconds after the explosive is detonated, and the electromagnetic radiation generated by the explosion is continuous and intermittent, which is a phenomenon that has not been found in this field at present. The mass of the energetic material had a significant effect on the time-domain characteristics of the electromagnetic radiation generated by the explosion: the higher the mass of the energetic material was, the shorter the delay response of the electromagnetic signal was, the longer the duration was, and the earlier the peak appeared. The frequency of electromagnetic radiation signals generated by the explosion of energetic materials was mainly concentrated below 100 MHz, and the energy was most concentrated in the frequency band of 0~50 MHz. The composition of energetic materials had the greatest influence on the spectral distribution, and the spectral distribution of electromagnetic radiation produced by the explosion of explosives with different compositions had obvious specificity. The electromagnetic radiation intensity generated by the explosion of energetic materials had a strong correlation with the distance from the explosion center, and it significantly decreased as the distance increased. The structure and detonation method of energetic materials changed the geometrical motion pattern during the explosion, resulting in the non-uniformity of electromagnetic radiation propagation.

Study on Electromagnetic Radiation Interference Caused by Rocket Fuel

During the launch and return of a spacecraft, the intense combustion of propellants generates strong electromagnetic radiation, which interferes with the operation of electronic equipment in the spacecraft. To improve the electromagnetic compatibility of electronic equipment in spacecraft, it is necessary to study the electromagnetic radiation characteristics of rocket fuel. An electromagnetic radiation measurement system based on antennas is designed to measure the electromagnetic radiation generated by rocket fuel, and the electromagnetic radiation characteristics are obtained through data analysis. The mechanism of the electromagnetic radiation generated by rocket fuel is comprehensively analysed through the spatial, time-domain, frequency-domain, and energy-domain characteristics. A characterization model is established to provide a reliable scheme for evaluating the influence of rocket fuel electromagnetic radiation on electronic equipment in spacecraft.

Electromagnetic radiation detection using cantilever-based photoacoustic effect: A method for realizing power detectors with broad spectral sensitivity and large dynamic range

A sensitive photoacoustic detection approach employing a silicon cantilever is investigated for power measurement of electromagnetic radiation. The technique which is actuated by pressure waves generated through radiation-induced heat depicts high sensitivity for a considerably large spectral range from 325 nm to 1523 nm. The implemented method shows linear response in the measurement of radiation power from 15 nW to 6 mW demonstrating a dynamic range of almost six orders of magnitude. A numerical model has been developed to analyze and optimize the measurement sensitivity. The model allows studying different dimensions of the cantilever which is one of the key components of the radiation detection process. The numerical results are in good agreement with experimental results. The electromagnetic power detection technique shows future potential for industrial applications and scientific studies.

Dynamics of autonomous rock electromagnetic radiation measurement instrumentation

Dynamics of autonomous rock electromagnetic radiation measurement instrumentation

On Measurement of Electromagnetic Radiation by Computer System in Indoor Electromagnetic Environment

The source of electromagnetic radiation in the computer system will not only cause biological effects of electromagnetic radiation on the human body, but also cause pollution to the ecosystem, so the measurement of the amount of electromagnetic radiation in the computer system is particularly important. In this paper, the current situation and types of electromagnetic radiation pollution and indoor electromagnetic environment in the computer system electromagnetic radiation measurement instruction, and electromagnetic radiation occupational protection measures are analyzed, for the reference of readers.

Analysis effect of winding on radiation-electromagnetic field on the tesla coil

Utilization of modern technology has been widely felt by the public as well as utilizing wireless charging technology on android phones. The charging, of course, uses the concept of Tesla coil, namely the transfer of electricity without wires. The Tesla coil can emit electromagnetic radiation which depends on its input. This study aims to design a miniature tesla coil as a magnetic inductor. In this design, measuring electromagnetic radiation with a coil diameter of 0.3 mm, 0.4 mm and 0.5 mm with the same number of turns is 500 turns. The method used is an experimental method using determinants such as the diameter of the coil, the height of the measurement of electromagnetic radiation, and the distance measurement of electromagnetic radiation. Experiments carried out varying independent variables including diameter of the coil, measurement distance, height and number of turns as a constant quantity. The measurement uses the electromagnetic radiation detector DT-1130 to measure the electromagnetic radiation at several heights of the Tesla coil. The results showed that electromagnetic radiation which has the highest value is at the top or at the end of the coil for the position near the primary coil obtained the lowest electromagnetic radiation results among the three measurements, whereas for distance researchers get the result that the further measurement between the electromagnetic sensor and the Tesla coil electromagnetic radiation is getting weaker. At a winding diameter of 0.3 mm which produces the smallest radiation but when brought closer to the Neon lamp the light intensity of the Neon lamp is brighter compared to the diameter of the winding 0.5 mm which has the most radiation.

What is the radiation before 5G? A correlation study between measurements in situ and in real time and epidemiological indicators in Vallecas, Madrid

BackgroundExposure of the general population to electromagnetic radiation emitted by mobile phone base stations is one of the greater concerns of residents affected by the proximity of these structures due to the possible relationship between radiated levels and health indicators. ObjectivesThis study aimed to find a possible relationship between some health indicators and electromagnetic radiation measurements. MethodsA total of 268 surveys, own design, were completed by residents of a Madrid neighborhood surrounded by nine telephone antennas, and 105 measurements of electromagnetic radiation were taken with a spectrum analyzer and an isotropic antenna, in situ and in real – time, both outside and inside the houses. ResultsIt was shown statistically significant p - values in headaches presence (p = 0.010), nightmares (p = 0.001), headache intensity (p < 0.001), dizziness frequency (p = 0.011), instability episodes frequency (p = 0.026), number of hours that one person sleeps per day (p < 0.001) and three of nine parameters studied from tiredness. Concerning cancer, there are 5.6% of cancer cases in the study population, a percentage 10 times higher than that of the total Spanish population. Discussion: People who are exposed to higher radiation values present more severe headaches, dizziness and nightmares. Moreover, they sleep fewer hours.

Evaluation and Substantiation of the Necessity to Revise Guidelines for Measuring Electromagnetic Radiation of Cellular Base Stations

Introduction: Measurements of electromagnetic radiation of the radio frequency range are of great relevance due to the increasing number of transmitting radio facilities in the densely populated territories, constant cell site upgrades, and emerging communication standards. The paper presents a brief description of the biological effects of radio frequency electromagnetic radiation and shows basic mechanisms of the negative effect on the most vulnerable organs and systems. Our objective was to evaluate valid guidelines for measuring electromagnetic radiations of the radio frequency range in residential areas, in houses and public buildings. Materials and methods: We reviewed specific characteristics of cellular base and radio relay stations, compared and described electromagnetic radiation measuring devices. The provided recommendations for their selection were based on frequencies at which the communication equipment operates. We also analyzed the current guidelines with account for characteristics of transmitting radio equipment of cellular base stations and the applied measuring instruments. Results: The results of assessing established significant differences are discussed. The analysis of the requirements for measurements demonstrated significant discrepancies and contradictions between the valid documents. The evaluation results demonstrated impossibility of simultaneous measurements of electromagnetic radiation from cellular BS and RRS due to violations of requirements for measurement procedures. We concluded that, according to the current method documents, measurements of electromagnetic radiation from the fourth (4G) and fifth (5G) generation mobile communications systems were not possible. Conclusions: We revealed the necessity to revise the compared guidelines МUК 4.3.1167–02 and МUК 4.3.1677–03, to harmonize regulatory requirements for measurements, and to develop a single document guiding measurements of radio frequency electromagnetic radiation. Recommendations for taking measurements are provided.

BLDC motorok elektromágneses sugárzásának mérésére alkalmas labor kialakítása

A tanulmány egy BLDC motorok elektromágneses sugárzásának mérésére alkalmas laboratórium és mérőkör kialakításának gyakorlati tapasztalatit mutatja be. Az Elektrotechnikai és Elektronikai Intézeti Tanszék EMC laboratóriuma az 1980-as években került kialakításra, amely a mai igényeknek nem felel meg, ezért szükségessé vált kismértékű átalakítása. A laborban új földelés lett kialakítva, amely kevésbé vonzza be a külső zajokat. A próbamérések eredményeire alapozva a háttérzajok kiszűrése érdekében a klasszikus botantenna helyett irányított antenna használata mellet döntöttünk. Az irányított antenna irányfüggő elektromágneses sugárzások pontos mérését teszi lehetővé, így alkalmas gömbi koordinátarendszerben sugárzási karakterisztika felvételére.

Photophysiology and Spectroscopy of Sun and Shade Leaves of Phragmites australis and the Effect on Patches of Different Densities

Remote sensing of vegetation has largely been revolving around the measurement of passive or active electromagnetic radiation of the top of the canopy. Nevertheless, plants hold a vertical structure and different processes and intensities take place within a plant organism depending on the environmental conditions. One of the main inputs for photosynthesis is photosynthetic active radiation (PAR) and a few studies have taken into account the effect of the qualitative and quantitative changes of the available PAR within the plants canopies. Mostly large plants (trees, shrubs) are affected by this phenomena, while signs of it could be observed in dense monocultures, too. Lake Balaton is a large lake with 12 km2 dense reed stands, some of which have been suffering from reed die-back; consequently, the reed density and stress condition exhibit a vertical PAR variability within the canopy due to the structure and condition of the plants but also a horizontal variability attributed to the reedbed’s heterogeneous density. In this study we investigate the expression of photosynthetic and spectroscopic parameters in different PAR conditions. We concentrate on chlorophyll fluorescence as this is an early-stage indicator of stress manifestation in plants. We first investigate how these parameters differ across leaf samples which are exposed to a higher degree of PAR variability due to their vertical position in the reed culm (sun and shade leaves). In the second part, we concentrate on how the same parameters exhibit in reed patches of different densities. We then look into hyperspectral regions through graphs of coefficient of determination and associate the former with the physiological parameters. We report on the large variability found from measurements taken at different parts of the canopy and the association with spectral regions in the visible and near-infrared domain. We find that at low irradiance plants increase their acclimation to low light conditions. Plant density at Phragmites stands affects the vertical light attenuation and consequently the photophysiological response of basal leaves. Moreover, the hyperspectral response from the sun and shade leaves has been found to differ; charts of the coefficient of determination indicate that the spectral region around the red-edge inflection point for each case of sun and shade leaves correlate strongly with ETRmax and α. When analysing the data cumulatively, independent of their vertical position within the stand, we found correlations of R2 = 0.65 (band combination 696 and 651) and R2 = 0.61 (band combination 636 and 642) for the ETRmax and α, respectively.