2021 Vol. 33, No. 12

Recommend Articles
Progress and prospect of high-confidence measurement technology for high-intensity electromagnetic pulse
Qin Feng, Gao Yuan, Ma Hongge
2021, 33: 123001. doi: 10.11884/HPLPB202133.210482
Design and performance evaluation of boundary deformation reverberation chamber
Cheng Erwei, Wang Pingping, Zhao Min, Meng Cui
2021, 33: 123002. doi: 10.11884/HPLPB202133.210472
Cover and Contents
Cover and Contents, High Power Laser and Particle Beams, No 12, Vol 33, 2021
Editorial Office
2021, 33: 1-3.
Invited Articles
Progress and prospect of high-confidence measurement technology for high-intensity electromagnetic pulse
Qin Feng, Gao Yuan, Ma Hongge
2021, 33: 123001. doi: 10.11884/HPLPB202133.210482
Abstract:
High-confidence high-intensity electromagnetic pulse testing technology, as an important and basic technology in the field of high-intensity electromagnetic pulse research, has been attracting great attention from domestic and foreign scientific researchers in recent years. In this article, we mainly review the current research progress of high-confidence high-intensity electromagnetic pulse testing technology from the aspects of antenna (sensor) and signal transmission distortion compensation. Moreover, considering the development trend of high-intensity electromagnetic pulse generation technology, high-intensity electromagnetic pulse effect and protection, we try to expound the challenges of high-intensity electromagnetic pulse testing, and make a preliminary prospect on the development of high-confidence high-intensity electromagnetic pulse testing, providing a reference for researchers in the field of high-intensity electromagnetic pulse technology.
Design and performance evaluation of boundary deformation reverberation chamber
Cheng Erwei, Wang Pingping, Zhao Min, Meng Cui
2021, 33: 123002. doi: 10.11884/HPLPB202133.210472
Abstract:
The perturbation theory was used to analyze the influence of cavity deformation on the resonance frequency drift, and the feasibility of the boundary deformation reverberation chamber was demonstrated theoretically. The influence of the boundary deformation parameters on the uniformity of the electric field in the space of the reverberation chamber was obtained by calculation. A design method of boundary deformation reverberation chamber with flexible shielding cloth as the cavity material and stepping motor controlling the surface deformation of the cavity was proposed. The statistical characteristics of the electric field were tested experimentally. And the results show that the electric field inside the reverberation chamber obeys the Rician distribution, and the consistency with the theoretical model becomes better as the frequency increases; when the deformation amplitude reaches 400 mm, the internal electric field perturbation ratio of the cavity was greater than 20 dB. The standard deviation of the electric field was less than 3 dB, which meets the limit requirements of electromagnetic compatibility on the uniformity of the platform.
Basic Theory of Complex Electromagnetic Environment
Statistical analysis on electromagnetic emission characteristics of phased array antenna
Zhao Yunru, Wang Quanfeng, Wu Qi
2021, 33: 123003. doi: 10.11884/HPLPB202133.210389
Abstract:
The beam direction of the phased array antenna changes dynamically. Its electromagnetic emission characteristics show significant statistical laws, and the resources required for analysis and testing are numerous. In this paper, polynomial chaos expansion (PCE) is used to explore the statistical characteristics of the two-dimensional planar phased array antenna’s emission. The objective function of the phased array antenna is determined according to the pattern product theorem, and PCE is used to establish an equivalent surrogate model of the array’s emission characteristics. The paper starts from the phased array antenna composed of ideal point sources, and considers two typical cases that the main beam direction obeys the uniform distribution and the normal distribution. The statistical characteristics of the equivalent surrogate model are obtained by computer simulation. The results of the traditional Monte Carlo (MC) method are used as a reference to evaluate the effectiveness and reliability of the PCE method. At the end of the paper, the situation that the beam direction of the dipole phased array antenna obeys two typical distributions is briefly discussed. The comparison of simulation results shows that the PCE method can greatly reduce the sampling numbers of calculation while ensuring the accuracy of the results, and significantly improve the efficiency of analysis and testing.
Transient response analysis method of shielded cable based on minimum phase method
Xu Qinglin, Zhang Jie, Liu Pingan, Yuan Jun
2021, 33: 123004. doi: 10.11884/HPLPB202133.210177
Abstract:
To analyze the transient electromagnetic response of shielded cables in time domain when they are subjected to electromagnetic pulse, a frequency domain equivalent method based on minimum phase method is studied in this paper. First, by establishing the circuit model of the transfer impedance testing system, the transfer function of the system in frequency domain is derived, and it is verified as the cascade of a minimum phase system and an all-pass system. Secondly, the minimum phase of the measured amplitude-frequency curve is reconstructed by using the minimum phase method, then the phase of the reconstructed transfer function is compensated according to the distribution of zeros and poles. Finally, the time domain response of the shielded cable is obtained after multiplying the compensated transfer function with the transient interference signal in frequency domain and transforming into time domain. The effectiveness of the proposed method is verified by simulation and experiment.
Thinned array optimization based on genetic model improved artificial bee colony algorithm
Sun Jianbang, Li Jianbing, Wang Ding, Sun Yuqi, Luo Zhihao
2021, 33: 123005. doi: 10.11884/HPLPB202133.210233
Abstract:
To solve the problem that artificial bee colony algorithm is good at exploration and neglect exploitation, this paper proposes an improved artificial bee colony algorithm based on genetic model, which has been successfully applied to array synthesis. Firstly, the global optimal solution is introduced into the neighborhood search process to guide the bees to find the best nectar source thus to accelerate the convergence of the algorithm. Secondly, to avoid the local optimization of the algorithm, the exploitation ability of artificial bee colony algorithm must be improved. The evolutionary mechanism of genetic algorithm is used for reference, and a genetic model is established to carry out genetic operation on the honey source after adopting the optimal retention, to enrich the diversity of honey source. The improved artificial bee colony algorithm is tested on a set of widely used numerical functions, and the experimental data show that the proposed algorithm has strong competitiveness compared with other algorithms. Then, the algorithm is applied to the sparse optimization of the linear array to reduce the peak sidelobe level of the array. The optimization is compared with other algorithms under the same array constraints. The simulation results further prove the effectiveness of the algorithm.
Time reversal cavity path and its influence on signal to noise ratio
Lu Xicheng, Qiu Yang, Jiang Ling, Wang Haibo, Tian Jin, Guo Xinwei
2021, 33: 123006. doi: 10.11884/HPLPB202133.210171
Abstract:
Time reversal has the characteristics of spatiotemporal focusing and has potential applications in many field. The reversal system based on time reversal cavity (TRC) is an important reversal system. It can be used for pulse compression, beam forming, perturbation detection and so on. The TRC is usually an electrically large microwave chaotic cavity, and the propagation of electromagnetic wave in it has obvious multipath characteristics. That is, time dispersion characteristics. Therefore, in the process of time reversal, the TRC can compensate the phase of the reversal signal and reconstruct the initial signal, which can give time compression and spatial focusing at the initial position. To enhance the application of TRC, this paper studies the influence of cavity parameters on the reversal signal to noise ratio (SNR) based on the multipath channel model, focusing on the analysis of the influence of path attenuation, crosstalk and superposition. Moreover, it summarizes the main parameters and basic laws affecting the SNR.
Effects and Mechanism of Complex Electromagnetic Environment
Interference mechanism analysis of new tpye of fuze
Dong Erwa, Hao Xinhong, Li Ping, Zhou Wen
2021, 33: 123007. doi: 10.11884/HPLPB202133.210370
Abstract:
To deal with the threaten of new type radio fuze, we focus research on the interference mechanism of ultra wideband (UWB) radio fuze which is a new type radio fuze. In this paper, the response mechanism of the UWB fuze sensitive waveform is revealed, the response characteristic of fuze under periodic modulation jamming signal is deduced theoretically, and the correlator response characteristic of fuze under the interference of noise, sinusoidal amplitude modulation, and sinusoidal frequency modulation signal, is calculated and simulated. Based on the signal-interference-ratio gain, through theoretical calculation, simulation analysis and experimental verification, it is concluded that the AM sweep jamming is the more effective than the FM sweep jamming in the periodic modulation interference.
Study on outgassing effect of electromagnetic radiation on aluminum film
Li Yao, Fan Jieqing, Zhang Fang, Tan Qun, Hao Jianhong, Dong Zhiwei, Zhao Qiang
2021, 33: 123008. doi: 10.11884/HPLPB202133.210191
Abstract:
To study the electromagnetic radiation effect of the thermal control layer covering the surface of general spacecraft in the space environment, a model of electromagnetic wave irradiated metal aluminum film material was established. The PIC (Particle-in-Cell)-MCC (Monte Carlo collisions) method was adopted to numerically simulate the changes of positive ions and collision ionization electrons under different outgassing densities. The simulation results show that when the gas density on the surface of the aluminum film is small, avalanche ionization will not occur due to the low probability of outgassing collision ionization on the surface of the material. Only when the outgassing density exceeds the threshold, the outgassing collision ionization process on the material surface is strengthened, and avalanche ionization occurs on the surface of the material to generate plasma, which absorbs electromagnetic wave energy, and the total energy of its ions and electrons increases, which may cause damage to the metal aluminum film material.
Coupling effect of high altitude nuclear electromagnetic pulse of electrical wiring interconnection system cable
Wang Tao, Cong Peixi, Shi Rongrong, Zhou Shu, Liang Peng
2021, 33: 123009. doi: 10.11884/HPLPB202133.210379
Abstract:
There are two main ways to couple high altitude nuclear electromagnetic pulse (HEMP) impact on electronic equipment. On the one hand, it is the “front door coupling” mode that the electromagnetic interference enters the electronic system through the antenna coupling channel on the equipment (product); and on the other hand, it is the “back door coupling”, that is, the coupling is carried out through the gaps and holes of the shell, power cord, cable and chassis on the equipment (product). In this paper, the coupling effect of electrical wiring interconnection system (EWIS) harnessing assembly against high altitude nuclear electromagnetic impact is mainly studied. By studying the characteristics and energy distribution of HEMP interference, the mathematical model of HEMP is established, the coupling effect is simulated by CST software, and tests is carried out at the same time, then the general conclusions and laws of HEMP coupling effect are obtained by synthesizing the simulation results.
Test and Evaluation of Complex Electromagnetic Environment
Quantification characterization technology of electromagnetic compatibility based on test results
Chen Xin, Qiu Yang, Tian Jin, Zuo Jiangjiang, Lu Xicheng, Yang Chun, Xu Liang, Zhao Renzhong
2021, 33: 123010. doi: 10.11884/HPLPB202133.210138
Abstract:
Based on the quantitative requirements of equipment electromagnetic compatibility (EMC), the test results can be divided into EMI type and EMS type according to the characteristics of EMC test data. Thus the quantitative representation methods of EMI and EMS test results are put forward and the mathematical model is established in this paper. By analyzing the characteristics of EMI test data, the corresponding quantization representation model is constructed through the two dimensions of standard data share and excessive features. According to the characteristics that EMS test results are only qualitative description and combined with the sensitive phenomena in the measurement process, a quantitative characterization model is constructed from two dimensions of interference source and sensitive frequency band. Besides, the relevant quantitative model is realized by software and verified by experimental measurement. In this paper, the quantitative research of the test results is carried out and the mathematical quantification model of the corresponding test items is obtained, and the quantitative characterization of the EMC qualitative test results based on the national military standard is achieved. The relevant research results of this paper have certain reference significance in system-level EMC performance quantitative evaluation, big data analysis of test results and optimization design of equipment EMC.
Threat assessment method based on quantification of margins and uncertainties for electrical electronic equipment under high-altitude electromagnetic pulse
Dong Ning, Sun Yingli, Wang Zongyang, Xie Yanzhao, Chen Yuhao
2021, 33: 123011. doi: 10.11884/HPLPB202133.210386
Abstract:
High altitude electromagnetic pulse (HEMP) may cause failure or damage to wide-area infrastructure. For economic reasons, it is necessary to evaluate the vulnerability of key electrical and electronic equipment under HEMP This study combines uncertainty quantification with equipment effect assessment. Based on the idea of margins and uncertainties quantification (QMU), this paper summarizes the procedures of vulnerability assessment method for electrical and electronic equipment based on QMU. First, select the key parameters of the equipment, usually the norm of coupling channel current and voltage; Second, obtain the probability distribution of key parameters under HEMP as the stress of equipment by numerical simulation and uncertainty quantification; Then, carry out the HEMP effect test and estimate the probability distribution of equipment effect threshold as the strength of the equipment; Finally, by calculating the Euclidean distance between stress and strength of the equipment, calculate the QMU metric and evaluate the equipment vulnerability by the QMU method. This study uses an example to illustrate the feasibility and procedure of the vulnerability assessment method based on QMU.
Continuous-wave electromagnetic environment effects on laser radar
Ma Liyun, Wang Yuming, Chen Yazhou
2021, 33: 123012. doi: 10.11884/HPLPB202133.210385
Abstract:
To test the safety and reliability of laser radar in the continuous-wave electromagnetic environment, the electromagnetic interference effect test of laser radar under continuous-wave was operation carried out. The single line off-axis laser radar was taken as the experimental object. Through the experiment, the relationship between the sensitive frequency, sensitive frequency band, and jamming effect of laser radar in different polarization directions and the field strength of jamming signal is obtained. When the polarization direction of jamming antenna is different, the sensitive frequency and frequency band of the same laser radar are also different. And the jamming signal field strength corresponding to the jamming effect of different sensitive frequency and frequency band is also different. The greater the field strength at the same sensitive frequency, the worse the laser radar gets. Finally, the reasons for the jamming of laser radar are analyzed, which provides a basis for improving the adaptability of laser radar to the electromagnetic environment.
Statistical characteristics of S-band microwave pulse breakdown time in free space
Yang Hao, Yan Eryan, Nie Yong, Yu Chuan, Bao Xiangyang, Zheng Qianglin, Hu Haiying
2021, 33: 123013. doi: 10.11884/HPLPB202133.210365
Abstract:
In the vicinity of atmospheric breakdown threshold, microwave pulse breakdown discharge becomes a probabilistic problem, which is closely related to breakdown time. When atmospheric breakdown occurs, the transmission pulse width and peak power will be shortened. The development of high power microwave technology is severely restricted by the hazards. To study the breakdown problem in high power microwave atmospheric transmission, the probability distribution curves of breakdown time in different processes are compared, and the effects of ionization rate and seed electron generation rate on breakdown time are discussed. The breakdown process of free space microwave was experimentally studied using S-band high power microwave pulse source. The breakdown time of plasma was monitored by photomultiplier tube, and a series of experiments were carried out in the presence or absence of cesium 137 seed electron source. The results show that increasing the seed electron generation rate is a more effective method to increase the pulse breakdown probability. In the process of repetition frequency, if there is cumulative effect, the breakdown delay time probability distribution curve will move to the left and tend to be stable. And the gas after breakdown will be easy to breakdown again in a short time.
Simulation of Complex Electromagnetic Environment
3D parallel full electromagnetic particle-in-cell method for simulating responses of cavity internal electromagnetic pulse
Meng Xuesong, Li Guangrong, Zhao Zhenguo, Yan Chaoxu, Zhang Linyu
2021, 33: 123014. doi: 10.11884/HPLPB202133.210351
Abstract:
Cavity internal electromagnetic pulse (IEMP) is generated by the irradiation of X-rays on cavities, such as spacecrafts. It would disturb the normal operation of electrical systems inside spacecrafts and further affect their survival. In this paper, we present a 3D parallel full electromagnetic particle-in-cell (PIC) method for simulating cavity IEMP responses. In the proposed method, the finite difference time domain (FDTD) method and the PIC method are used to solve the coupling between the formation of transient electromagnetic fields and the movement of particles; the effective current distribution method is adopted to compute the source of electromagnetic fields, which is the current density. The proposed method is coded based on JASMIN, so it supports massively parallel computing and could be used to simulate cavity IEMP responses with hundreds of millions mesh cells and hundreds of millions particles. In the end, the proposed method is applied to compute the IEMP responses of a cylinder irradiated by pulsed X-rays. The results agree well with those from literature, verifying the accuracy of the proposed method.
High-performance full-wave computational electromagnetic analysis for chip-system under electromagnetic pulse
Wang Weijie, Zhao Zhenguo, Hu Shaoliang, Li Hanyu, Zhou Haijing
2021, 33: 123015. doi: 10.11884/HPLPB202133.210359
Abstract:
The objective of this work is to investigate high-performance electromagnetic field finite element solver towards high resolution and high fidelity electromagnetic simulations of product-level ICs and electronics. The emphasis of this work is to overcome the parallel bottleneck of multiscale problems and fulfill full-wave electromagnetic simulation of complex problems. Numerical simulation software can be developed quickly based on our software-platform. Finally, the capability and benefits of the algorithms are validated and illustrated through practical simulation of chip in computer case.
Electromagnetic pulse effect simulation and rating of RF front-end of super-heterodyne receiver
Liu Chang, Li Hanyu, Bao Xianfeng, Zhou Haijing
2021, 33: 123016. doi: 10.11884/HPLPB202133.210380
Abstract:
A co-simulation method using Verilog-a and circuit netlist is adopted for modeling and simulating the electromagnetic pulse (EMP) effects of RF front-end. The low-noise amplifier (LNA) within the RF front-end is modeled via Verilog-a, which is then extended to include the damage effect due to EMP. A standard yet simplified RF front-end of super-heterodyne receiver is constructed using the extended LNA model. The results of S-parameter simulation and transient simulation show that the front-end itself and the extended LNA model can be used to simulate the normal operational functionalities of the receiver. For verifying the extended LNA model’s capability that it can be used to simulate the normal, disturbance and damage effects due to EMP environment, an EMP-dipole antenna coupling channel is modeled via equivalent circuit, the output voltage signals of the circuit are simulated with different EMP-dipole antenna coupling voltage signals as the inputs. In the paper, the EMP effects are categorized into three different levels: non-effect, disturbance, and damage. The corresponding peak voltage thresholds are identified for the RF front-end of super-heterodyne receiver.
FDTD-based time domain hybrid method and its application in numerical simulation of platform-antenna integrated coupling
Bao Xianfeng, Chen Xiaojie, Li Hanyu, Liu Chang, Zhou Haijing
2021, 33: 123017. doi: 10.11884/HPLPB202133.210193
Abstract:
Intense electromagnetic pulse has posed a direct threat to dense electronic platforms such as aircraft. Antenna structure is an important coupling channel for intense electromagnetic pulse (EMP) entering the aircraft platform to produce electromagnetic environmental effects. It is of great significance to analyze the electromagnetic coupling response of platform airborne antenna through numerical simulation. The platform-antenna integrated coupling simulation is a typical method to solve multi-scale time-domain electromagnetic calculation problem. The tens meter platform contains hundreds of micro meter microstrip lines, circuit elements and other local fine structures. When the traditional FDTD method is used to simulate this kind of problems, the computational efficiency is very low due to the need of grid division. This paper introduces a time-domain hybrid method, which combines the non-uniform FDTD method with the thin wire FDTD method and the multi grid lumped element FDTD method, thus can effectively reduce the computational overheads. Combined with parallel computing technology, the transient voltage and current response of the antenna port can be calculated quickly. The method is successfully applied to the numerical simulation of UAV platform antenna integrated coupling.
Simulation study of internal system generated electromagnetic pulse of cylinder cavity
Sun Huifang, Dong Zhiwei, Zhou Haijing
2021, 33: 123018. doi: 10.11884/HPLPB202133.210354
Abstract:
The internal system generated electromagnetic pulse (SGEMP) effects induced by photoelectrons emitted from cylinder top surface is simulated by the 3D PIC code. First for validation, the results are compared to that from literature. Subsequently, the internal 3D SGEMP effects of the cylinder is studied by this code, the simulated results show the emitting current is 20 A, intense of electric field could get 150 kV/m and magnetic field is 3.0×10−5 T when the blackbody X-ray of temperature 2 keV and fluence 100 J/m2 perpendicularly irradiates the side of cylinder cavity with height of 4.5 cm and radius of 7.5 cm. The space distributions of electrons and electric field are studied elementarily for different X-ray fluences.
Electromagnetic Protection and Application
Vehicle cable electromagnetic pulse coupling simulation and suppression
Wang Zhen, Cai Jinliang, Qin Feng, Hu Zezheng
2021, 33: 123019. doi: 10.11884/HPLPB202133.210227
Abstract:
Transient electromagnetic pulses can be coupled to vehicle electronic system through cables, causing electronic equipment disturbance, even damage. Research on the suppression characteristics of transient protection devices on electromagnetic pulse can provide strong support for vehicle electromagnetic hardening. In this paper, we build the electromagnetic simulation model of vehicle engine by considering the key metal structure, cables and electronic equipment. Cables coupling characteristics were calculated under transient electromagnetic pulse; A test platform for transient protection devices was built, and the response characteristics of transient voltage suppress (TVS) and metal oxide varistor (MOV) were obtained, such as response time, clamping voltage, and peak voltage leakage. Based on the simulation and test results, a type of TVS was selected. This TVS is used to the signal line electromagnetic protection of camshaft position sensor. The result shows that this type of TVS has an ability of cable interference suppression close to 20 dB, and placing it in the front of filter can effectively suppress cable coupling interference and protect terminal equipment.
An anti-jamming hybrid beamforming system designed based on support vector machine algorithm
Xu Lei, Zang Yuejin, Zhou Xinyao, Liu Guanfa, Zhou Lisha
2021, 33: 123020. doi: 10.11884/HPLPB202133.210235
Abstract:
A low-cost adaptive beamforming system is designed to solve the space radiation interference problem of millimeter wave communication in complex electromagnetic environment. Firstly, the communication system model in complex electromagnetic environment and the objective function are established. Then, the support vector machine algorithm in machine learning is used to simplify the objective function to obtain the ideal coding vector. Finally, the gradient pursuit algorithm is used to build sparse reconstruction of the ideal beam vector to achieve low-cost anti-jamming beam. Simulation results show that the proposed beamforming system can effectively suppress the interference and improve the communication quality.
Effect of antireflection film on performance of monocrystalline silicon solar cell
Sun Hongwei, Hao Jianhong, Zhao Qiang, Fan Jieqing, Zhang Fang, Dong Zhiwei
2021, 33: 123021. doi: 10.11884/HPLPB202133.210240
Abstract:
In the evaluation of solar cell efficiency, the cell material, doping concentration, diffusion length and so on are important parameters. Reasonable change of relevant parameters can optimize the performance of solar cells and improve their efficiency. In addition, there is an important means to improve the efficiency of solar cells by coating a layer of antireflection optical film on the surface of solar cells. To improve the cell efficiency, the micro parameters such as doping concentration and diffusion length of monocrystalline silicon solar cells were calculated and optimized, and the changes of cell efficiency with doping concentration and diffusion length were analyzed. On this basis, the influence of different antireflection films on the efficiency of the battery is analyzed, and the influence of antireflection film thickness on the efficiency of the battery is given. The results show that after optimizing the doping concentration and diffusion length of the cell, and selecting suitable antireflection films, the cell efficiency can reach 20.35%, which is 8.25% higher than that without optimization.
UAV intelligent electromagnetic attack and defense technology
Wang Yuming, Ma Liyun, Chen Yazhou
2021, 33: 123022. doi: 10.11884/HPLPB202133.210387
Abstract:
Unmanned aerial vehicle (UAV) plays a great role in missions that are boring,in harsh environment and/or dangerous. Because of its characteristics of low cost, zero casualties and low cost-effectiveness ratio, it has made great achievements in modern wars. While artificial intelligence brings great changes to UAV, the reliability and security of system operation increasingly depend on the stable transmission and control of information in complex electromagnetic environment. The survivability, adaptability and even electromagnetic check and balance ability of UAV in harsh electromagnetic environment lead the development trend of electromagnetic attack and defense of information equipment to a certain extent. Therefore, this paper summarizes the electromagnetic environmental effect and electromagnetic protection technology of UAV, expounds the methods of UAV electromagnetic countermeasures and electromagnetic protection at the information level and energy level, expecting to realize electromagnetic attack and defense of UAV from the intelligent point of view.
Complex Electromagnetic Environment Test
Evaluation of measurement uncertainty about power density for high power microwave effects test
Zhong Longquan, Miao Yu, Zhao Gang, Lin Jiangchuan, Sun Jian, Wu Hao, Qin Feng, Yan Zhiyang, Liu Zhong, Ge Yi, Zhang Ying
2021, 33: 123023. doi: 10.11884/HPLPB202133.210224
Abstract:
For the requirement of accurate measurement of radiation field in narrow band high power microwave (HPM) effects test, the quantities of measurement uncertainty about power density were analyzed and supplemented. A multiplicative and comprehensive model of measurement uncertainty was derived. On the basis of set values according to relating standards and information, the evaluation of quantity standard uncertainty in relative form was realized by using type B method. Besides, measurement evaluation method was given for quantities of influence of test environment and location deviation. This work provides a reference for reasonable evaluation of measurement uncertainty of power density parameters of HPM effect and an operation method for objective evaluation of measurement uncertainty of all components based on measured data.
Improvement of temperature stability of E-field sensor with LiNbO3 crystal
Yang Yan, Xie Shuguo, Tian Yumo, Wang Tiening, Yang Meiling
2021, 33: 123024. doi: 10.11884/HPLPB202133.210384
Abstract:
LiNbO3 crystal has been widely used in various electric field sensors due to its high electro-optic coefficient and stable physical and chemical properties. However, the refractive index of LiNbO3 crystal is sensitive to temperature. When using the direction of maximum electro-optic effect, the natural birefringence causes the crystal working point to drift with temperature. On the one hand, this makes the sensor work unstably, on the other hand, it also affects the sensitivity and dynamic range of the sensor. To eliminate this effect, two LiNbO3 crystals with equal optical path and orthogonal principal axes will be used in the probe. One is sensing crystal and the other is compensation crystal. Due to the compensation crystal, the natural birefringence of the sensor is greatly suppressed, and the temperature stability is also improved. The experimental results show that the working state stability of the compensated sensor is much better than that of the uncompensated sensor.
Signal compensation of coaxial cable based on Wiener filtering method
Chen Guangsen, Qin Feng, Gao Yuan
2021, 33: 123025. doi: 10.11884/HPLPB202133.210310
Abstract:
With the increase of signal frequency, bandwidth and transmission distance, the signal distortion problem brought by the low pass transmission characteristics of coaxial cable becomes serious and cannot be ignored. In this article, Wiener filtering method, an image reconstruction method that is usually employed in the field of image processing, is innovatively applied to the signal distortion compensation of coaxial cable. The input signal can be reconstructed only by using the S parameters of coaxial cable and output signal. Three different kinds of pulse signals, i.e., double exponential pulse signal, Gaussian modulated pulse signal and modulated square wave signal, transmitted in a 10 m coaxial cable were compensated. The results indicate that this method has excellent compensation performance for different kinds of signals. Moreover, compared with the commonly used attenuation compensation method, this method not only possesses high compensation accuracy, but also has outstanding computation efficiency, which is beneficial for practical application in the signal distortion compensation.