共查询到20条相似文献,搜索用时 15 毫秒
1.
《Electromagnetic Compatibility, IEEE Transactions on》2009,51(2):284-292
2.
Hao-Ming Shen King R.W.P. Wu T.T. 《Electromagnetic Compatibility, IEEE Transactions on》1984,(1):4-13
The input properties of the parallel-plate Harvard EMP simulator (HES) and the means for matching the simulator to the pulse generator have been studied in detail. Due to mismatching, multiple reflections occur between connections, and the originally generated single pulse becomes a complicated pulse sequence which includes not only the main impulse, but also many parasitic pulses. The parasitic pulses can be eliminated by meeting the conditions for match, or they can be separated from the main pulse by increasing the electrical distance between the simulator and the generator. The input properties of the simulator can be represented in terms of an "apparent impedance" which depends on the part of the pulse sequence under consideration. For the main incident pulse, the apparent impedance is a resistance close to the characteristic impedance of the simulator for CW operation at low frequencies. 相似文献
3.
This paper investigates the possibility of using the impulse-radiating antenna (IRA) as both a transmitter and receiver of electromagnetic energy for the purpose of target identification. Of specific interest is estimating the induced open-circuit voltage at the IRA's source terminals, when it is illuminated by the scattered EM field from simple conducting bodies excited by an incident field from the same IRA acting as a transmitter. In this study, several different canonical scatters are considered, including thin wires, spheres, conducting boxes, and an infinite conducting plate. For a 7 kV pulse excitation of the IRA, received peak transient voltages at the antenna ranged from a few volts to about 400 volts, depending on the scatterer. 相似文献
4.
Transient Currents Induced on a Metallic Body of Revolution by an Electromagnetic Pulse 总被引:2,自引:0,他引:2
A numerical technique is presented that may be used to predict the current induced on a thin metallic body of revolution excited by an electromagnetic pulse. Examples are given. Introduced here is the use of the radiation condition in a finite difference solution. This development alleviates the requirement that finite difference techniques be applied to a bounded region of space. 相似文献
5.
Design of Low-Pass Elliptic Filters by Means of Cascaded Microstrip Rectangular Elements 总被引:1,自引:0,他引:1
《Microwave Theory and Techniques》1982,30(9):1348-1353
A new method for synthesizing nonredundant low-pass elliptic filters in a microstrip configuration is presented. The realization consists of the cascade connection of proper rectangular elements, each one corresponding to four reactive elements of the lumped-constant prototype. This allows an effective control of parasitic and unwanted reactance which results in the possibility of realizing higher order filters with cutoff frequencies up to X-band. Fifth- and seventh-order filters were fabricated on alumina substrates showing very good performance, particularly in the passband. 相似文献
6.
《Microwave Theory and Techniques》1977,25(11):904-907
A dieletric loaded rectangular guide (Fig. 1) is analyzed taking into account the losses of the line, the substrate, and the metallic shield. For this study, Schelkunoff's method is used in considering the propagation modes as a convenient combination of coupled modes of the empty waveguide. Computations and experimental measurements are made for two different lines. 相似文献
7.
用于超宽带穿墙雷达的窄脉冲产生技术 总被引:1,自引:0,他引:1
用于超宽带穿墙雷达的脉冲产生技术是一种无载波极窄脉冲产生技术,在无线电通信领域有着广阔的应用前景。提出了使用延时芯片和ECL门产生极窄脉冲的方法,并对其产生原理做了理论分析。设计了原理框图和电路图,最后给出并分析了试验结果。 相似文献
8.
9.
Kumar Gaurav Singh Mahender Ahlawat Sarita Yaduvanshi Rajveer S. 《Wireless Personal Communications》2019,109(3):1661-1672
Wireless Personal Communications - In this article, we present the study to improve the bandwidth of the dielectric resonator antenna (DRA) excited by aperture coupled feed by using a stacked DRA... 相似文献
10.
《Electromagnetic Compatibility, IEEE Transactions on》2009,51(2):293-300
11.
Novel Parameter Estimation of Double Exponential Pulse (EMP, UWB) by Statistical Means 总被引:1,自引:0,他引:1
High-power electromagnetic environments, such as the high-altitude electromagnetic pulse (HEMP) and the ultrawide-band (UWB) pulses, pose dangerous threats to electronic systems. Such pulse shapes are often described physically by the characteristic parameters: the rise time tr, pulse width tfwhm and maximum electric field strength Emax, and mathematically by the double exponential function with characteristic parameters alpha, beta ,kappa . and E0. In practice, it is very necessary to transform the two groups of parameters into each other. In this paper, a novel relationship between the two groups of parameters is established by statistical means. This method utilizes only four assistant variables to realize the transform, and the overall estimation error is less than 2.0%. 相似文献
12.
Gang Xu Sridhar Rajagopal Joseph R. Cavallaro Behnaam Aazhang 《The Journal of VLSI Signal Processing》2002,30(1-3):21-33
The multistage detection algorithm has been proposed as an effective interference cancellation scheme for next generation Wideband Code Division Multiple Access (W-CDMA) base stations. In this paper, we propose a real-time VLSI implementation of this detection algorithm in the uplink system, where we have achieved both high performance in interference cancellation and computational efficiency. When interference cancellation converges, the difference of the detection vectors between two consecutive stages is mostly zero. Under the assumption of BPSK modulation, the differences between the bit estimates from consecutive stages are 0 and ±2. Bypassing the zero terms saves computations. Multiplication by ±2 can be easily implemented in hardware as arithmetic shifts. However, the convergence of the algorithm is dependent on the number of users, the interference and the signal to noise ratio and hence, the detection has a variable execution time. By using just two stages of the differencing detector, we achieve predictable execution time with performance equivalent to at least eight stages of the regular multistage detector. A VLSI implementation of the differencing multistage detector is built to demonstrate the computational savings and the real-time performance potential. The detector, handling up to eight users with 12-bit fixed point precision, was fabricated using a 1.2 m CMOS technology and can process 190 Kbps/user for 8 users. 相似文献
13.
Hao-Ming Shen King R.W.P. Wu T.T. 《Electromagnetic Compatibility, IEEE Transactions on》1983,(1):40-46
The rhombic simulator excited by a pulse generator is investigated experimentally. The voltage pulse at the driving point of the simulator and the associated current pulses that travel along the conducting tubes that form the rhombus have been measured with different loads. The complex sequence of electromagnetic pulses (including the incident pulse, the reflected pulses from the load, and other reflection points) have been measured on the metal ground plane. The origin (localization) of each pulse has been carried out. From the Fourier transformation of the waveforms in the time domain, the spectrum of the electromagnetic pulse in the frequency domain is obtained. It is shown that the characteristics of the simulator with the two types of excitation (continuous wave and pulse) are consistent. 相似文献
14.
Modeling of an EMP conducted environment 总被引:7,自引:0,他引:7
Ianoz M. Nicoara B.I.C. Radasky W.A. 《Electromagnetic Compatibility, IEEE Transactions on》1996,38(3):400-413
The International Electrotechnical Commission (IEC) decided in 1988 to produce a civil standard on the electromagnetic effects of a high altitude EMP (HEMP). Different documents pertaining to the radiated environment and to specifications and test methods have been elaborated and are circulated. A standard conducted environment dependent on many parameters is, however, more difficult to define. The authors present a probabilistic approach which has been adopted to define a typical current shape for the conducted environment. The distribution functions of the peak current value for horizontal and vertical polarizations based on 1710 calculated cases reflecting a variation of the elevation and azimuthal angles from 0 to 90° are presented and discussed 相似文献
15.
A well-known result [1], [2] for the response of a two-wire transmission line illuminated by a nonuniform electromagnetic field is extended to multiconductor lines. A simple matrix equation for the currents induced in arbitrary termination networks is obtained. Air Development Center. 相似文献
16.
《Microwave and Wireless Components Letters, IEEE》2009,19(12):795-797
17.
提出并实验验证一种级联啁啾光纤光栅反馈半导体激光器产生宽带、无时延混沌激光的方法.在该方法中,级联啁啾光纤光栅的高色散引入不规则的外腔模式,破坏了外腔模式谐振,进而消除混沌信号的时延特征.此外,不规则的外腔模式与激光器内部模式拍频,引入了新的高频振荡,进而增强混沌信号的带宽.对比研究了单个与级联啁啾光纤光栅反馈系统中色... 相似文献
18.
由于群速度失配的影响,飞秒光脉冲在感应到FONPS(级联五阶非线性相移)的同时,将不可避免地发生脉冲畸变.通过理论分析及数值模拟,提出了使级联五阶非线性过程运行在较大相位失配条件下的解决方案,成功地消除了脉冲畸变.并且借助于该过程中倍频效率的提高,有效地补偿由于相位失配量的增大所造成的FONPS的下降,实现飞秒基频光脉冲在感应到大的FONPS的同时无脉冲畸变发生. 相似文献
19.
压缩感知技术可以用来实现对非合作宽带信号的欠采样快速处理。宽带脉冲压缩雷达能够有效解决雷达探测距离和距离分辨力的矛盾,在探测领域得到了广泛应用,为实现对非合作宽带脉冲压缩雷达信号的快速欠采样接收处理,本文首先开展了信号稀疏分解与重构算法研究,通过对贪婪算法、凸松弛类算法、组合类算法三大算法进行对比分析,选用了运行速度快且重构精度高的正交匹配追踪(OMP)算法针对非合作宽带脉冲压缩雷达信号进行压缩感知仿真分析。仿真结果表明:在一定信噪比条件下,OMP算法完全能够实现对非合作宽带脉冲压缩雷达信号的欠采样和信号重构,从而实现了对非合作宽带雷达信号的欠采样处理,为处理非合作超宽带雷达信号提供了很好的理论指导。 相似文献
20.
A. P. Trifonov O. V. Chernoyarov A. A. Milogorodskii A. N. Faul’gaber 《Journal of Communications Technology and Electronics》2018,63(5):454-463
The quasi-likelihood, maximum-likelihood, and quasi-optimal algorithms for estimating the instants of appearance and disappearance of an optical pulse with the rectangular intensity profile of an unknown height are synthesized and analyzed. The losses in estimation accuracy due to the a priori unknown intensity of the optical pulse are found. 相似文献