Electromagnetic Environmental Effects Research Articles

A broadband multi-frequency microwave combined biological exposure setup.

With the rapid popularization of wireless electronic devices, there has been an increasing concern about the impacts of the electromagnetic environment on health. However, most research reports on the biological effects of microwaves have focused on a single frequency point. In reality, people are exposed to complex electromagnetic environments that consist of multiple frequency microwave signals in their daily lives. It is important to investigate whether multi-frequency combined microwave energies have different biological effects compared with single frequency microwave energy. Unfortunately, there are limited reports on this topic due to the lack of suitable platforms for research on multi-frequency microwave energy combined with biological exposure. To address this issue, this study presents a setup that has a very wide working frequency bandwidth and can be compatible with single frequency and multi-frequency microwave combined exposure. Moreover, it can achieve relatively equal exposure to multiple biological samples at any frequency point in the working frequency range, which is crucial for electromagnetic biology research. The experimental results are in good agreement with the simulation results, confirming its capability to facilitate the study of complex electromagnetic environment effects on organisms.

Simulation Analysis of Electromagnetic Environment Effect and Shielding Effectiveness for VPX Chassis under Plane Wave Radiation

The chassis based on the VPX bus standard structure has been widely applied to the fields of vehicle, missile, radar, etc. In this paper, we analyze the electromagnetic environment effect on VPX chassis via the CST software, and investigate the electromagnetic coupling characteristics of VPX chassis under 20 v/m plane wave radiation according to the RS103 test defined in the MIL-STD-461G standard. By simulation, we analyze the electromagnetic coupling paths of the VPX chassis, find the key positions of the electromagnetic protection such as the air intake, air outlet, trapdoor, and panel gaps, and we propose the electromagnetic protective measures for the weak parts of the VPX chassis. The electromagnetic shielding effectiveness before and after protection design is evaluated. Finally, the simulation results are verified by the experiments. It has guiding significance for the electromagnetic protection design of VPX chassis.

Dynamic Strain Measurement of Rotor Blades in Helicopter Flight Using Fiber Bragg Grating Sensor.

Fiber Bragg grating (FBG) sensor has a lot of advantages over the resistance strain gauge and has been used in many applications. However, there are few applications of rotor blade dynamic measurement in helicopter flight. In this paper, a method for blade dynamic strain measurement using an FBG sensor in a helicopter's real flight is presented. The corresponding measurement system is established and can eliminate the effects of the helicopter's electromagnetic environment on the electrical sensing components in the measurement system with the orthogonal frequency-division multiplexing modulation. The measured dynamic strains on the rotor blades of the helicopter in real flight contain six harmonic frequencies with the vibration characteristics of rotor blades, indicating that the established FBG measurement method and system have practical engineering applications.

A Review of Quantitative Evaluation of Electromagnetic Environmental Effects: Research Progress and Trend Analysis.

With the increasing complexity of the electromagnetic environment, existing electronic systems and various equipment are greatly threatened. The study of the assessment of the effects of the electromagnetic environment has attracted more and more attention in the academic field and industry. In this review, the definition of the electromagnetic environmental effects assessment could be classified into two categories: objective and subjective equipment electromagnetic environmental effect assessments. Studies on both are comprehensively reviewed. The electromagnetic environmental effect assessment models are described and analyzed. The effects evaluation models mainly calculate the electromagnetic environmental effect index by various weighting, probability, and normalized interference level methods. However, each proposed model has certain limitations, so it cannot deal with all the electromagnetic interference effects. Therefore, a comprehensive evaluation model for complex electromagnetic environmental effects has not yet been established. Recent studies have shown that neural networks can be used to improve the adaptability of evaluation models in electromagnetic environments. The evaluation result of the normalized interference level method is more consistent with the actual work efficiency. The combination of the two can unify the objective and subjective assessments, which is of great significance to the improvement of the consistency and accuracy of the results of the effects evaluation of the electromagnetic environment. Accordingly, challenges for future research are revealed, which plays a vital role in the development of electromagnetic environmental effects research and provides a reference for researchers.

Novel Electromagnetic Characterization Methods for New Materials and Structures in Aerospace Platforms.

The tendency over the last decades in the aerospace industry is to substitute classic metallic materials with new composite materials such as carbon fiber composites (CFC), fiber glass, etc., as well as adding electronic devices to ensure the safety and proper platform operation. Due to this, to protect the aircraft against the Electromagnetic Environmental Effects (E3), it is mandatory to develop accurate electromagnetic (EM) characterization measurement systems to analyze the behavior of new materials and electronic components. In this article, several measurement methods are described to assess the EM behavior of the samples under test: microstrip transmission line for a surface current analysis, free space to obtain intrinsic features of the materials and shielding effectiveness (SE) approaches to figure out how well they isolate from EM fields. The results presented in this work show how the different facilities from the National Institute of Aerospace Technology (INTA) are suitable for such purposes, being capable of measuring a wide variety of materials, depending on the type of test to be carried out.

A Prediction Method of Electromagnetic Environment Effects for UAV LiDAR Detection System

With the rapid development of science and technology, UAVs (Unmanned Aerial Vehicles) have become a new type of weapon in the informatization battlefield by their advantages of low loss and zero casualty rate. In recent years, UAV navigation electromagnetic decoy and electromagnetic interference crashes have activated widespread international attention. The UAV LiDAR detection system is susceptible to electromagnetic interference in a complex electromagnetic environment, which results in inaccurate detection and causes the mission to fail. Therefore, it is very necessary to predict the effects of the electromagnetic environment. Traditional electromagnetic environment effect prediction methods mostly use a single model of mathematical model and machine learning, but the traditional prediction method has poor processing nonlinear ability and weak generalization ability. Therefore, this paper uses the Stacking fusion model algorithm in machine learning to study the electromagnetic environment effect prediction. This paper proposes a Stacking fusion model based on machine learning to predict electromagnetic environment effects. The method consists of Extreme Gradient Boosting algorithm (XGB), Gradient Boosting Decision Tree algorithm (GBDT), K Nearest Neighbor algorithm (KNN), and Decision Tree algorithm (DT). Experimental results show that, comprising with the other seven machine learning algorithms, the Stacking fusion model has a better classification prediction accuracy of 0.9762, a lower Hamming code distance of 0.0336, and a higher Kappa coefficient of 0.955. The fusion model proposed in this paper has a better predictive effect on electromagnetic environment effects and is of great significance for improving the accuracy and safety of UAV LiDAR detection systems under the complex electromagnetic environment on the battlefield.

Normative and methodological support of control of electromagnetic fields at the ships

The seafarers carried out the professional activity in a complex electromagnetic environment (EME), with technical means, structural materials, depending on the purpose of the watercraft, architectural features, and vessel classification. There are static electric fields, permanent magnetic and low-frequency electric and magnetic fields on ships. Marine radio-electronic means (REM) creates Electromagnetic fields (EMF) of the radio frequency range that provide communication, the safety of navigation and operation, and solving navigation problems. According to the documents of the sanitary legislation, specialists carry out control of the maximum permissible EMF levels for watercraft and marine structures at the design stage of the vessel by calculating the intensity of electromagnetic fields during commissioning, instrumental control of EMF levels. There are new technical means in modern automated vessels of various types and purposes that create electromagnetic fields in the crew's stay zones, which makes it urgent to improve regulatory and methodological documents in the area of ensuring the electromagnetic safety of the team and passengers. The study aims to develop proposals for regulatory, methodological, and hardware control over compliance with the maximum permissible levels of electromagnetic fields on ships to ensure the electromagnetic safety of the crew. Generalization of materials of own research of EME on ships, systematization of sources of electromagnetic fields. Analysis of regulations in occupational safety and health for the protection of the crew from the effects of EME, methodological documents on the calculation forecasting, and instrumental determination of the levels of electromagnetic fields. Experts have revealed that there are electromagnetic fields of a wide frequency range in the premises of ships and on open decks. The study showed that electromagnetic fields of a wide frequency range are created in the premises of ships and on open decks. Indoors, the most significant is the impact on the crew of electric and magnetic fields with a frequency of 50 Hz created by the ship's electric power systems. In addition, on open decks (at workplaces and in crew recreation areas), the protection of the crew from EMF antennas of the radio frequency range is relevant. Therefore, it is necessary to develop methods for calculating the prediction of EMF levels and improve the means of measuring electromagnetic fields on ships. The most common sources of EMF in the crew's stay areas are radio communication and radar facilities, ship's electric power systems. The task of developing a methodological document on the calculated prediction of EMF levels in rooms and on open decks at the design stage of ships is urgent. In addition, it is necessary to develop devices-meters of electromagnetic fields for instrumental monitoring of EMF levels in actual operating conditions of the vessel.

The Definition of the Paramethers of Superconducting Film for Production of Protection Equipment Against Electromagnetic Environmental Effects

The paper presents the results of evaluating the propagation of a plane electromagnetic wave (EMW) over the surface of a film made of a high-temperature superconductor (HTS) in both superconducting S and normal N states, as well as an analysis of the parameters of a thin HTS film necessary for implementing a device for protection against electromagnetic radiation. Evaluation of the propagation of EMW over the surface of a thin HTS film was performed on the basis of a two-fluid model. As a result of the research, relations were obtained for determining the value of the surface impedance and the depth of penetration of EMW into a superconducting film in S and N states. It is shown that the expression for determining the penetration depth of EMW into a superconducting film in the normal N state is applicable provided that the frequency of the signal field does not exceed the critical value, which is determined by the binding energy of charge carriers at a temperature not exceeding the transition temperature to the superconducting state. Based on the relations for determining the surface impedance of a thin HTS film, relations are obtained for the active surface resistance, which is the real part of the surface impedance, and the surface reactance, which is its imaginary part, in the superconducting and normal states. Using these ratios, the quality parameter of the HTS thin film is introduced. The dependence of the quality factor of the HTS film on its thickness is found. It is shown that the highest value of the quality factor is realized when the film thickness is less than or of the order of the penetration depth. It is noted that this dependence is valid only if the film thickness does not depend on its quality. Keywords — superconducting film, electromagnetic wave, two-fluid model, surface impedance, penetration depth.

Characterization of Joints between Carbon Fiber Composite Parts Using a Microstrip Transmission Line Method.

The electromagnetic performance of aerial platforms, which are composed mostly of nonmetallic materials, is a subject of great interest at present time. The behavior of this type of composite structure against electromagnetic environmental effects (E3), such as lightning, is not well-studied as in the case of metalic structures. The purpose of this article is to characterize the joints present in aerial platforms constructed mainly of nonmetallic composite materials. The study of these joints is fundamental because electrical discontinuities or preferential routes can produce changes in the electromagnetic behavior of an aircraft. The proposed measurement system for the characterization of these joints is a microstrip line. The flexibility of the test setup allows for evaluation of different joints in carbon fiber composite (CFC) samples with a different number of plies. Additionally, approximated models of the behavior of the joints as well as the detection of possible defects in the joining process are reported.

Evaluation Model and Method of Margin in Electromagnetic Environmental Effects for Complex Systems

Margin is an important index in the control of Electromagnetic environmental effects (E3) and Electromagnetic compatibility (EMC) design for systems. How to define and verify the E3 margins of complex systems such as ships and airplanes is a difficult problem. A new method of system-level E3 margin evaluation is proposed. Based on the theory of fault tree, the evaluation model of system-level margin is constructed. The complex system function is transformed into the equipment and subsystem that affect the function, and the relationship between margin of system-level and equipment is established. The change from margin of equipment to system-level margin is realized. According to the action process of Electromagnetic environment (EME), the verification and evaluation methods of EME domain, response domain and effect domain are put forward. The margin calculation formula of EME domain and typical electromagnetic energy coupling response are deduced. The problem of margin evaluation for equipment under different input parameters is solved. A typical application example is given. The verification test scheme is designed. The methods of electromagnetic energy radiation and injection are adopted. The system-level margin is analyzed by the data obtained from the effective test verification. The results show that the model and method are reasonable and feasible.

Evaluation of Electromagnetic Environmental Effects for Ship System Based on Impact Degree

The ship system should be compatible with the electromagnetic environment (EME) in which it works. The evaluation of electromagnetic environmental effects (E3) is the premise and means to realize this goal. A method for E3 evaluation of ship system based on impact degree is proposed. The normalized index is used to synthesize the E3 impact degree of different types of E3 elements and different types of susceptible receptors with this method. The mathematical model and calculation method are presented. Through the comparison of the two groups of ship system design schemes before and after the improvement, taking the effects of electromagnetic interference, external radio frequency, radiation field hazards and antenna coverage performance as examples, the numerical results of various effects and the total E3 impact degree are calculated respectively. The results show that the method can support the balance and optimization of ship system E3 multi-index design, and the actual effect is obvious.

A quantification control method of electromagnetic environmental effects for complex systems

ABSTRACT Modern aircraft, ship, and other systems have different consequences when faced with the own and external radio frequency, lightning and other electromagnetic environments (EME) radiation, that is called electromagnetic environmental effects (E3). In this paper, a new method of system-level E3 quantitative control is proposed. A two factor E3 impact degree model composed of susceptible receptor importance and consequence severity is established. The selection and calculation method of relevant parameters is given. The application process of this method is illustrated with examples of high intensity radiated fields (HIRF), lightning, electromagnetic interference (EMI) and radiation hazard elements for aircraft. It is proved that this method can quantitatively, clearly and accurately express the impact degree of E3, balance the conflict of multi-index and multi-objective design, and achieve the engineering optimization when solving the whole system, whole element and whole process E3 control problems.

Second-order Intermodulation Low Frequency Blocking Effect and Mechanism for Communication Radio under Electromagnetic Radiation

In order to reveal the complex electromagnetic environment effects mechanism of communication radio, the blocking effect of single-frequency and out-of-band dual-frequency electromagnetic radiation for the ultra-short wave digital communication radio is experimentally studied by irradiation method. The rule of single-frequency electromagnetic radiation effect and the susceptible bandwidth are determined. The experimental data show that the tested radio is 9～23 dB more susceptible to out-of-band dual-frequency third-order intermodulation blocking than single-frequency electromagnetic radiation blocking. A sensitive phenomenon of dual-frequency electromagnetic radiation which can neither be explained by the dual-frequency non-intermodulation superposition mechanism nor by the third-order intermodulation mechanism has been found in the experiment.

Simulation analysis of complex electromagnetic environment effect of helicopter engine

With the improvement of equipment informatization, the adaptability of complex electromagnetic environment of airborne engine equipment is becoming increasingly important. The mechanism and degree of influence of complex electromagnetic environment on engine are quite different, which has seriously threatened flight safety. In order to predict and analyze part of electromagnetic environment faced by airborne engine, FEKO electromagnetic simulation software is used for simulation research. According to the relevant test methods of SAE-ARP5416, SAE-ARP5412, GJB-1389A and other standards of American Society of engineers, the field strength and cable coupling of airborne engine under lightning effect and high field intensity irradiation are predicted by simulation. The conclusion has certain guiding significance for further research on complex electromagnetic field protection of engine.

Evaluation method for impact of jamming on radar based on expert knowledge and data mining

The effects of complex electromagnetic environment on a radar system involve many factors and their interrelationships are also complicated, so it is difficult to quantitatively describe the impact of jamming on the radar. In this study, the authors start from the signal models of several jamming types and the basic signal processing flow of pulse-Doppler radar and propose a unified evaluation framework based on expert knowledge and data mining. On the one hand, the evaluation index from expert knowledge is calculated by the two-dimensional image entropy of the time–frequency distributions of echoes. On the other hand, the evaluation index from data mining is constructed from the principle patterns extracted from samples by robust principal component analysis. In addition, the fused evaluation index is achieved by taking a weighted average of the indices from expert knowledge and data mining, where the weights are designed from the samples. Finally, the proposed evaluation approach is validated by analysing its feasibility, consistency and robustness in experiments and the results show that it can stably and quantitatively measure the impact of jamming on the radar.

Research on several test issues of electromagnetic radiation susceptibility for electronic equipment

According to the practical problem that some electronic equipments still exist electromagnetic incompatibility phenomenon in training and fighting stage after passing the normal electromagnetic compatibility test required by National Military Standard of China, on the basis of systematically analyzing the technical requirements and test methods in the current military standard, considering the technology accumulation of our research team on the electronic information equipment electromagnetic environment effects in recent years, the influence the several conditions on the electronic information equipment electromagnetic radiation susceptibility test results were discussed. These conditions contain not searching the sensitive receiving direction of the equipment under test(EUT), lacking of electromagnetic radiation susceptibility test in in-band frequency, multi-source radiation causing remarkable reduction of the susceptibility threshold of the EUT and so on. On the basis of the discussion, the measures and suggestions which can solve the above related problems were given. The development tendency of the high intensity electromagnetic radiation effect test technology and the complex electromagnetic environment adaptability evaluation technology for electronic equipment were discussed.

Sample-based calibration for cryogenic broadband microwave reflectometry measurements

The characteristic frequencies of a system provide important information on the phenomena that govern its physical properties. In this framework, there has recently been renewed interest in cryogenic microwave characterization for condensed matter systems since it allows to probe energy scales of the order of a few μeV. However, broadband measurements of the absolute value of a sample response in this frequency range are extremely sensitive to its environment and require a careful calibration. In this paper, we present an in situ calibration method for cryogenic broadband microwave reflectometry experiments that is both simple to implement and through which the effect of the sample electromagnetic environment can be minimized. The calibration references are provided here by the sample itself, at three reference temperatures where its impedance is assumed or measured, and not by external standards as is usual. We compare the frequency-dependent complex impedance (0.1–2 GHz) of an a-Nb15Si85 superconducting thin film obtained through this Sample-Based Calibration (SBC) and through an Open-Short-Load Standard Calibration (SC) when working at a very low temperature (0.02–4 K) and show that the SBC allows us to obtain the absolute response of the sample. This method brings the calibration planes as close as possible to the sample, so that the environment electrodynamic response does not affect the measurement, provided it is temperature independent. This results in a heightened sensitivity, for a given experimental set–up.

Accurate Simulation of Shielding Effectiveness of Metallic Cabins Using an Improved Calderón Preconditioner-Based Time-Domain Integral Equation Method

An efficient simulation of shielding effectiveness of some metallic cabins or enclosures is performed using an improved Calderon preconditioner-based time-domain integral equation method. During its implementation, Rao–Wilton–Glisson and Buffa–Christiansen functions are used as the spatial basis functions for solving the Calderon preconditioned time-domain electric field integral equation, which generate a set of well-conditioned system matrices irrespective of the mesh density. Moreover, a set of approximate prolate spheroidal wave functions is chosen as the temporal basis functions; therefore, both late-time stability and accuracy are improved significantly for simulating electromagnetic pulse responses in some typical cabins. Numerical results are validated in comparison with those obtained by some commercial software. These results are useful for further evaluating electromagnetic environment effects in some complex systems.

A Study on Electromagnetic Environmental Effects(E3) Test and Evaluation of a Commercial Derivative Military Aircraft

A Study on Electromagnetic Environmental Effects(E3) Test and Evaluation of a Commercial Derivative Military Aircraft

Massively Parallel Simulation of Large-Scale Electromagnetic Problems Using One High-Performance Computing Scheme and Domain Decomposition Method

Massively parallel simulation of large-scale electromagnetic problems is performed on a supercomputer using an in-house developed high-performance computing scheme together with a domain decomposition method, where parallel adaptive unstructured mesh generation is at first performed for modeling an arbitrary multiscale structure. The accuracy, speedup, as well as scalability of such parallel scheme are numerically tested and validated during its implementation for simulating electromagnetic environmental effects (E3) on a ship platform using the TianHe-II supercomputer. It is demonstrated that this method can overcome the convergence deficiency of conventional iterative solver. In addition, numerical experiments are also carried out to show its adaptability to the number of subdomains and object electrical size. It is believed that our developed solver can be further used for solving various E3 or electromagnetic compatibility problems for the design of many large-scale platforms.