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1.
电磁脉冲对目标腔体的孔缝耦合效应数值研究   总被引:17,自引:0,他引:17  
利用时域有限差分(FD-TD)方法研究了超宽带电磁脉冲(UWB),快上升前沿电磁脉冲(FREMP),核电磁脉冲(NEMP)对目标腔体的孔缝耦合效应。研究表明:对于较小尺寸的目标腔体,在孔缝尺寸也较小的情况下,FREMP和UWB相对于NEMP更容易通过腔体上的孔缝耦合进入目标腔体,而且更容易引起孔腔共振。  相似文献   

2.
本文利用时域有限差分(FD—TD)法研究快上升前沿电磁脉冲(FREMP)目标腔体的孔缝耦合效应。并将计算结果与核电磁脉冲(NEMP)的耦合结果进行比对。研究表明:对于较小尺寸的目标腔体,在孔缝尺寸也较小的情况下,FREMP相对于NEMP更容易耦合进入目标腔体,且更容易引起孔腔谐振。  相似文献   

3.
为提高电子设备及系统在复杂电磁环境下工作的稳定性,应用时域有限差分方法对不同脉宽电磁脉冲通过带有不同形状(方形环,圆环,矩形环)环形孔缝屏蔽腔体的耦合规律进行了分析.研究结果表明:电磁脉冲通过环形孔缝耦合现象明显,其通过圆环的耦合能量最小;对于矩形环,当入射波极化方向与环形孔缝的短边平行时,若矩形环孔缝纵横比越大,则耦合能量也越大,当极化方向与短边垂直时,则纵横比越大,耦合能量越小;入射电磁脉冲脉宽越短,电磁脉冲越容易耦合进入环形孔缝;腔体壁的反射及谐振会增强耦合效应.  相似文献   

4.
核电磁脉冲与开孔金属腔体耦合特性研究   总被引:1,自引:0,他引:1       下载免费PDF全文
利用基于时域有限差分法(FDTD)的电磁仿真软件XFDTD,研究了核电磁脉冲与开孔腔体的耦合规律。分析了不同极化方向的核电磁脉冲入射时,矩形孔洞长宽比对耦合特性的影响;讨论了核电磁脉冲照射下,腔体谐振和孔缝与腔体的耦合谐振现象;给出了腔体内部电场分布的截面图,讨论了核电磁脉冲入射时腔体内外电场的空间分布情况。研究结果表明:当核电磁脉冲的极化方向与开孔矩形短边平行时,耦合的电场强度比正方形开孔时的要大,且长宽比越大,耦合的电场强度越大;当核电磁脉冲的极化方向与开孔矩形长边平行时,耦合的电场强度比正方形开孔时的小,且长宽比越大,耦合的电场强度越小。极化方向与矩形开孔短边平行时,腔体内产生了腔体谐振和孔缝与腔体的耦合谐振,开孔尺寸的变化会引起谐振频率的偏移;极化方向平行于长边时无明显电磁谐振发生。核电磁脉冲对屏蔽体内的影响主要局限于开孔附近。  相似文献   

5.
导电平面上槽与缝的散射   总被引:1,自引:1,他引:0  
在雷达散射截面(RCS)和电磁脉冲(EMP)研究中,我们常常需要考虑目标上各个部分结合处存在的槽或缝的散射。在现代,随着RCS减缩技术的发展,这些槽和缝对目标双站散射行为的影响已经日益突出。对此,通过等效原理导出相应问题的全波公式,研究了具有不同几何形状和不同材料填充的槽或缝对目标散射图形的影响  相似文献   

6.
导电平面上槽与缝的散射   总被引:1,自引:0,他引:1  
在雷达散射截面(RCS)和电磁脉冲(EMP)研究中,我们常常需要考虑目标上各个部分结合处存在的槽或缝的散射。在现代,随着RCS减缩技术的发展,这些槽和缝对目标双站散射行为的影响已经日益突出。对此,通过等效原理导出相应问题的全波公式,研究了具有不同形状和不同材料填充的槽或缝对目标散射图形的影响。  相似文献   

7.
军用电子装备的电磁防护新技术   总被引:1,自引:0,他引:1  
肖虹  彭渤 《电子质量》2000,(11):21-25
对现代军用电子装备的电磁防护的最新技术--抗核电磁脉冲(NEMP)与雷电电磁脉冲(LEMP)对对策技术以及防信息电磁泄露(TEMPEST)技术等进行了综述。  相似文献   

8.
高空核爆电磁脉冲(HEMP)对电子/电气设备构成严重威胁,是电磁兼容与电子/电气 设备安全领域的重要研究内容。基于时域有限差分法(FDTD)的总场-散射场体系建立仿真 空间,推导了连接边界的一维平面波引入方法,选择双层金属腔体为研究对象,仿真分析了 腔体在HEMP平面波作用下透过孔缝在各采样点的响应过程。仿真结果显示,各采样点都出现 了明显的振荡波形,其中外金属腔体孔缝中心比内金属腔体内部中心点耦合电场的峰值大; 相同面积下,正方形孔、矩形孔的耦合电场比圆孔的耦合电场小;内部腔体与外部腔体 在孔缝一侧距离的大小也会对耦合结果产生影响,间距越大,内部耦合电场的衰减越多。所 得结论 有利于指导双层金属腔体的电磁防护设计。  相似文献   

9.
INFORMATION FOR AUTHORS   总被引:1,自引:0,他引:1  
INFORMATIONFORAUTHORS¥//SEMICONDUCTORPHOTONICSANDTECHNOLOGY(SPAT)ispublishedquarterlywiththepurposeofprovidingthepublicationo...  相似文献   

10.
美国NetFRAME公司发布其NF8500系列中的两款新品NF8570和NF8590。它们是基于IntelPentium150MHz多CPU技术(4路SMP),标准内存、硬盘均为Pentium100MHz产品的1.5倍。NF8590服务器中的称为“Notes信息集群服务器”的配置为:NetFRAMEPentium150MHzClusterServer8590;MicrosoftNTServer3.5.1;LotusNotes4.0。目前,单台NetFRAMENotesMessageCluster…  相似文献   

11.
The electromagnetic fields produced by both direct lightning strikes and nearby lightning are compared with the nuclear electromagnetic pulse (NEMP) from an exoatmospheric burst. Model calculations indicate that, in the frequency range from 104 to near 107 Hz, the Fourier amplitude spectra of the return stroke magnetic fields near ground 1 m from an average lightning strike will exceed that of the NEMP. Nearby first return strokes at a range of about 50 m, if they are severe, produce electric-field spectra near ground which exceed that of the NEMP below about 106 Hz, while the spectra of average nearby first return strokes exceed that of the NEMP below about 3 x 105 Hz. Implications of these results for aircraft in flight are discussed.  相似文献   

12.
A technique for reducing the dimensions of the cavity of a cavity-backed slot antenna (CBSA) is presented, which facilitates proper fabrication and integration of miniaturized slot antennas on multilayer substrates. This is accomplished by replacing the solid metal around the traditional slot antennas with a specific metallic pattern that can be viewed as a series of parallel strip lines placed around the slot antenna. This metallic pattern is then modified by designing the parallel strips in a compact fashion to reduce the overall antenna dimensions and obtain a reduced-size CBSA. It is shown that, for a simple straight slot antenna, the overall occupied volume of the modified cavity backing the slot antenna can be reduced by more than 65% without affecting the high radiation efficiency of the antenna. A number of traditional cavity backed slot antennas and the proposed modified CBSAs are designed, fabricated, and measured. The reduced-size CBSAs show a very low input VSWR, low cross-polarized radiation levels, and high radiation efficiency. Despite their small ground plane size, the proposed cavity backed slot antennas have front-to-back ratio (FTBR) values in the range of 6-7 dB.  相似文献   

13.
A rectangular slot antenna on a spherical cavity with a conducting backing shell is investigated rigorously. The Green's function approach is used to formulate an integral equation for the magnetic slot current, which is solved using the moment method. Two previously developed methods to evaluate the admittance integrals are used and compared with each other. Both methods use recurrence formulas and analytical integration to speed the computation. The slot and cavity resonances of the structure are studied. In particular, two simple formulas for the first two natural resonances of the cavity structure are given. The effects of the shell size, slot length, and cavity dielectric constant on the input impedance are discussed. Measurements were carried out to verify the theory, and very good agreement between theory and experiment is obtained. In addition, the zonal slot antenna on a spherical cavity with a conducting backing shell is studied. The effect of the shell radius on the input impedance is investigated and, again, very good agreement between theory and experiment is found.  相似文献   

14.
The rectangular cavity backed slot is excited by a current source connected across its center. The longitudinal voltage variation across the slot is obtained from the variational solution of an integral equation. For shallow and narrow cavities the slot appears inductive and the voltage is rapidly attenuated along the slots. The slot may resonate for deeper and/or wider cavities, when the voltage along the slot is approximated by a half-cycle of a sine wave. The resonant cavity depth and the antenna bandwidth are examined for various cavity and Slot parameters. Dielectric cavity loading is shown to decrease both the resonant cavity depth and the antenna bandwidth.  相似文献   

15.
Most modern aircraft are designed to withstand a direct lightning strike. To accomplish this protection, the aircraft must have an external conductive path with a given skin thickness and a minimum amount of exposed areas and antennas that could allow energy coupling to the inside. Additionally, some modern military aircraft are also designed to operate in a nuclear electromagnetic pulse (NEMP) environment. This paper provides experimental lightning data and NEMP scalemodel data to characterize both phenomena. The lightning data were obtained by measuring the surface electromagnetic fields on a CV-580 research aircraft during an actual lightning strike. The aircraft was struck by lightning 48 times in central Florida between 1500- and 18 000-ft altitude during the summers of 1984 and 1985. One of these lightning events, for which an extensive set of data was available, has been analyzed. For this event, the maximum measured values were as follows: time rate of change of the surface magnetic flux density, 3750 T/s; total normal current density, 20 A/m2; peak current, 4.7 kA; and rate of rise of the current, 38 kA/ps. The NEMP data were obtained by measuring the surface electromagnetic fields during a simulated NEMP test in a 1:74 scale model of the same aircraft. During scale-model NEMP simulation, the maximum values measured were as follows: time rate of change of the surface magnetic flux density, 40 000 T/s; and total normal current density, 90 A/m2. The analyses of these results should provide new insights for combined lightning and NEMP protection.  相似文献   

16.
The input admittance of the rectangular cavity-backed slot antenna   总被引:1,自引:0,他引:1  
The input admittance of the rectangular cavity-backed slot antenna is investigated. The slot is assumed narrow so that the voltage distribution in its aperture is sinusoidal. Equations which represent the input admittance of this slot, backed by a rectangular cavity in which a single propagating wave is assumed to exist, are given. Calculations based on these representations are compared to available measured data. As the depth of the cavity increased the resonant frequency decreased and the bandwidth became narrower. Input admittance curves as a function of electrical slot length are also presented for several size cavities.  相似文献   

17.
In bipolar coordinates, a nonuniform conducting cylindrical cavity with a slot in a uniform electric field E0 is analyzed. The authors investigate the electric field penetration of a slotted cylindrical cavity through the slot and the electric field perturbation of an incomplete conducting cylinder. A family of objects are included by changing the structural parameters of the nonuniform cylindrical cavity with a slot. Both analytical expressions and numerical results of some special structures are given  相似文献   

18.
应用时域有限差分法(FDTD)模拟计算了微波脉冲与带缝非金属腔体的线性耦合过程.在正弦波凋制的高斯脉冲源激励下,分析了耦合场在腔体内的分布情况,总结了相对介电常数、腔壁厚度、孔缝尺寸等因数对耦合特性影响的基本规律.结果表明:在入射电场方向腔体中心轴线上的耦合场基本保持不变,垂直于入射电场截面上耦合场关于截画中心点呈对称分布;耦合进腔体的能量随厚度的增加和介电常数的增大而减小,但介电常数的影响更加明显,且随孔缝面积的增大而增大,面积一定时,随纵横比的增大而增大;孔缝中心处的电场耦合系数峰值随介电常数的增大呈近似线性下降,而腔体中心处呈振荡减小,在相对介电常数为6左右电场时域峰值达到最大;腔体内耦合磁场的变化规律与电场的类似.  相似文献   

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