A Comparison of Lightning Electromagnetic Fields with the Nuclear Electromagnetic Pulse in the Frequency Range 104-107 Hz

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.     

Investigation on the Frequency Range of Validity of Electroquasistatic RC Models for Semiconductor Substrate Coupling Modeling

Electroquasistatic analysis is currently the dominant approach for the modeling of semiconductor substrate noise coupling. The electroquasistatic (EQS) approximation is considered acceptable for frequencies such that the distances over which substrate interactions are considered are a small fraction of the wavelength. Yet, with clock bandwidths in state-of-the-art and future designs extending to multiple tens of gigahertz, it is necessary to accurately investigate and quantify the range of validity of the EQS approximation. This investigation is carried out in this paper by means of a rigorous electrodynamic model for the induced surface voltage due to an elementary dipole source in various types of commonly used semiconductor substrates for digital and radio-frequency integrated circuits. In addition to enabling a quantitative assessment of the frequency range of the validity of the electroquasistatic approximation and, hence, the RC models used commonly in computer-aided design tools for substrate noise coupling, the proposed electrodynamic model is used to investigate the prominence of inductive-like characteristics in noise propagation through the substrate. Through these investigations, it is demonstrated that the electrodynamic model used in this paper provides for a unified rigorous electromagnetic analysis of substrate noise coupling over the entire frequency bandwidth of interests to practical applications, from DC to multiple tens of gigahertz.     

用于30MHz～1GHiz电磁辐射骚扰测量的全电波暗室场地校验方法

详细介绍了最新国际标准CISPR 16-1-4:2004第5.8条给出的两种评估方法-场地参考法(site reference method)和归一化场地衰减法NSA.为评估全电波暗室的性能提供重要技术依据.     

高频电子电路中的耦合系数及耦合电容

在高频电路中,有时用到电容耦合回路,其调谐特性和频率特性与耦合系数直接相关.因此,耦合系数的确定与耦合电容的选择是该电路设计中的一个重要问题.在现有高频电路教材中,一般对电容耦合回路耦合系数的确定与耦合电容的选择这一重要问题未作深入讨论.为此,本文归纳总结了电容耦合回路设计中,耦合系数的确定与耦合电容的选择这个重要问题.     

用于30MHz～1GHz电磁辐射骚扰测量的全电波暗室场地校验方法

详细介绍了最新国际标准CISPR16-1-4∶2004第5.8条给出的两种评估方法—场地参考法(sitereferencemethod)和归一化场地衰减法NSA。为评估全电波暗室的性能提供重要技术依据。     

Design of 24-GHz 0.8-V 1.51-mW Coupling Current-Mode Injection-Locked Frequency Divider With Wide Locking Range

A 0.8-V CMOS coupling current-mode injection-locked frequency divider (CCMILFD) with 19.5% locking range and a current-injection current-mode logic (CICML) frequency divider have been designed and fabricated using 0.13-$mu{hbox{m}}$ 1p8m CMOS technology. In the proposed CCMILFD, the current-mode technique to minimize the loss of input signals and the coupling circuit to enlarge the phase response have been designed to increase the locking range. The locking range of the fabricated CCMILFD is 4.1 GHz with a power consumption of 1.51 mW from a power supply of 0.8 V. In the proposed CICML frequency divider, the current-injection interface is applied to the current inputs to make the circuit operated at a higher frequency with low power consumption under a low voltage supply. The operation frequency of the fabricated CICML frequency divider can divide the frequency range from CCMILFD and consume 1.89 mW from a 0.8-V voltage supply. The chip core areas of the CCMILFD and CICML frequency divider without pads are 0.23 and 0.015 $ {hbox{mm}}^{2}$, respectively. The proposed circuits can be operated in a low supply voltage with the advantages of a wider locking range, a higher operation frequency, and lower power consumption.      

超视距空战领先能力研究

运用数值仿真法研究了电子对抗条件下歼击机超视距空战中的领先能力.提出了超视距空战效能指标,利用蒙特卡罗法建立了超视距空战仿真流程图.通过算例评估了领先探测效能、领先发射效能、领先击毁效能,分析了脉冲积累、脉冲重复频率、远距支援干扰、自卫干扰以及机载自卫干扰定位技术对效能指标的影响,指出了歼击机在不同电子对抗环境下探测、...     

歼击机雷达综合瞄准系统超视距空战中的效能

探讨了在超视距空战中歼击机雷达综合瞄准系统(RLPK)的效能评估方法问题。通过分析雷达综合瞄准系统在超视距空战中的典型工作状态,采用概率分析法提出了效能指标。运用概率论相关知识,分别建立了雷达综合瞄准系统在远距导引阶段、搜索与发现/识别阶段、威胁评估/火力分配阶段、小区搜索/截获/跟踪阶段以及空空导弹制导阶段的效能模型。算例表明:系统的工作周期越短,抗干扰能力越强,系统在超视距空战中的效能越大;目标与火力分配环节对单机单目标空战影响不大,但对单机多目标与多机多目标空战影响较大。     

A New Edge-Mode Isolator in the Very High Frequency Range

An edge-mode isolator, using a magnetostatic surface mode operates in the very high frequency (VHF) range below the gyromagnetic resonance.     

变频调技术在铁路范围内的应用

介绍了变频调速在铁路范围内的应用，重点叙述了变频技术在铁路锅炉房鼓引风、行车、恒压供水、空压机和冲洗泵方面应用。     

65nm及以下IC制造挑战

全球IC制造业在2004年取得辉煌业绩,销售总额达到2180亿美元,提前完成了国际半导体技术发展路线图(ITRS)的90nm节点进程,十多座300mm晶圆厂正在投产或共建,全球以Intel为首的十大IC供应商都在加紧研发65nm工艺,Intel、TI、三星、东芝、台积电开始小批量生产65nm工艺的IC,谋求技术领先,抢占市场.根据2004的修正的ITRS最新技术进程可知,90nm节点正好在2004年完成了DRAM指标,65nm节点预定在2007年和45nm节点预定在2010年达到DRAM的生产水平,因为存储器IC的制造工艺最成熟,而且单元电路相同,比较容易设计和测试.对于电路单元更复杂的逻辑IC和混合IC来说,65nm节点和45nm节点的完成时间要推后两年,分别至2009年和2012年完成.     

分形粗糙表面涂覆目标太赫兹散射特性

该文采用物理光学法方法研究了具有分形粗糙表面的涂覆目标太赫兹散射特性。基于分形粗糙面建立表面粗糙目标模型,根据菲涅尔反射系数得出表面电流分布进而得到涂覆粗糙目标的雷达散射截面。对比分析了具有粗糙表面和光滑目标的散射结果,详细讨论了不同频率、不同涂层厚度的表面粗糙钝锥目标模型的太赫兹散射特性,计算结果表明在太赫兹波段目标表面的粗糙度对散射有显著的影响。      

NU—FDTD在腔体孔缝电磁耦合分析中的应用

由电磁学的基本规律麦克斯韦方程差分形式即时域有限差分（Finite Different Time Domain,FDTD）导出不均匀网格的FDTD差分形式,即不均匀网格的时域有限差分法（Non Uniform Grid Finite Different Time Domain,NU—FDTD）,并提出了在腔体孔缝电磁耦合分析中采用NU—FDTD时,网格和时间步长划分的原则是：导体边界采用局部均匀细网格法,其它空间采用渐变不均匀法。实验结果表明,这种方法不仅节省计算时间,而且精度高。     

变频控制系统的电磁兼容探讨

抑制电磁干扰的影响是一项复杂的系统工程,为了抑制变频控制系统的电磁干扰。根据电磁干扰的基本构成、干扰的种类,探讨了变频传动系统中功率器件开关干扰的抑制、元器件的布局与布线、接地设计、屏蔽和隔离、滤波、计算讥控制系统的电磁兼容问题。从一般电气系统的电磁兼容性的问题探讨,结合变频调速电气系统电磁干扰产生原因的具体情况,探讨了采取的相应抑制措施。     

频响范围对语言清晰度的影响

通过主观评价实验来分析频响范围对语言清晰度的影响。将测试得到的不同频响范围的清晰度平均值进行比较后发现,高于4kHz的信号对语言清晰度仍有较大影响,特别是4~6kHz频率段的信号影响最大。而对于下限频率来说,至少可以认为只要不低于300Hz,对语言清晰度不会有太大的影响。根据声母及韵母的频谱特性对实验结果进行了分析。     

扫频非线性对线性调频连续波雷达测距精度和距离分辨力的影响

线性调频连续波（ＬＦＭＣＷ）雷达在理论上具有很高的测距精度和距离分辨力,但实际的ＬＦＭＣＷ雷达由于其固有的扫频非线性而使其实际的测距精度和距离分辨力下降,本文根据ＬＦＭＣＷ雷达回波功率谱的特性,从理论上分析了扫频非线性对ＬＦＭＣＷ雷达测距精度和距离分辨力的影响,为实际ＬＦＭＣＷ雷达扫频非线性的外部校正提供一个精确的理论依据。     

The Coupling of Electromagnetic Waves Through Long Slots

The problem of a plane wave incident upon one or more long, parallel slots in an infinite plane screen is treated by the method of moments. A Galerkin's solution with triangular expansion and weighting functions is used. The complete solution for aperture fields, transmission coefficients, near and far fields is formulated and programmed. Arbitrary polarization and arbitrary angles of incidence are treated. Where comparison is possible, there is good agreement with classical results. Wide slots, and multiple slots, which cannot be treated by classical methods, are readily handled by the method of moments procedure. Two separate computer programs have been prepared for a) single slot and b) double slots. The theory is outlined; the computer program is described briefly, and representative examples are given.