空间放电辐射脉冲的探测与定位

提出一种基于辐射场窄带测试的空间放电辐射信号探测系统,系统主要由8路定向性天线阵、高增益接收前端以及数据处理单元构成。基于该探测系统建立了空间平面4元阵列定位模型,研究了空间放电辐射源位置快速搜索算法,并对定位精度进行了试验验证。实验结果表明,该系统能对1 km以内的空间放电辐射源进行探测,阵元尺寸为10 m的空间平面4元阵列的距离定位误差小于2.5%。该探测定位系统可以用于复杂电磁环境下空间放电源位置的确定。     

电磁脉冲耦合效应的等效源建模及应用

结合二端口网络理论和频域电磁场混合势积分方程的矩量法,对带有电缆线屏蔽体的电磁脉冲耦合效应进行了等效源模型建模。采用全波分析提取外部电磁脉冲干扰的等效源参数,利用场路结合的方法,以调制高斯脉冲为例,实现了屏蔽体内电路板上电磁耦合效应的分析。仿真结果表明：在0.1～7.5 GHz频带范围内,构建的电磁干扰等效源模型与商业软件仿真结果吻合得很好,可以为复杂电磁脉冲耦合效应的定量分析提供了一种有效便捷的研究方法,为电路工作安全防护提供理论参考。     

Microwave radiation of the atmosphere induced by a pulsed gamma source

The model problem of the perturbation of the atmosphere by an isotropic gamma source (pulse width Δτ ≤ 100 ns) situated at various altitudes (0 ≤ h ≤ 100 km) and assumed to be a “point” source was solved. The action of emitted gamma quanta caused the formation of a spatial region in the atmosphere containing highly excited atoms and molecules, the emission from which was recorded over a certain microwave range (0.8–1.0 GHz). The amplitudes of the electric component intensity of the field of noise Rydberg radiation over the range specified were calculated. Rydberg radiation duration, type, and the degree of polarization were estimated. The shape of the emission line and the character of broadening of signals received by two receivers situated at an altitude of H ₁ = 20000 km and on the surface of the Earth (H ₁ = 0 km) were analyzed. During measurements, both receivers were situated on the axis perpendicular to the surface of the Earth.     

电磁脉冲耦合效应的等效源建模及应用

结合二端口网络理论和频域电磁场混合势积分方程的矩量法,对带有电缆线屏蔽体的电磁脉冲耦合效应进行了等效源模型建模。采用全波分析提取外部电磁脉冲干扰的等效源参数,利用场路结合的方法,以调制高斯脉冲为例,实现了屏蔽体内电路板上电磁耦合效应的分析。仿真结果表明:在0.1~7.5 GHz频带范围内,构建的电磁干扰等效源模型与商业软件仿真结果吻合得很好,可以为复杂电磁脉冲耦合效应的定量分析提供了一种有效便捷的研究方法,为电路工作安全防护提供理论参考。     

水下大功率电磁式脉冲声源设计与研究

建立了大功率电磁式脉冲换能器的时变振动数学模型,利用有限差分方法得到了该模型的数值解。分析了声源的电磁参数和物理结构对辐射声压大小的影响,确定了最优的参数。设计和制作了电磁式脉冲声源,进行了性能测试。结果表明,电容充电6 kV情况下距离换能器1 m处峰值声压226 dB,中心频率25 kHz,与模型结果(峰值声压225 dB,中心频率24.5 kHz)吻合较好。进而证明了本文提出的时变振动模型可以为设计和优化大功率电磁式脉冲声源提供理论指导。     

Transformation of radiation pulse in nonstationary conducting medium

The three-dimensional case of electromagnetic-field transformation as a result of permittivity and conductivity jumps is studied. Exact expressions for the field of an arbitrary vector source after a change in the electrodynamic parameters of the medium are obtained by a resolvent method. The space-time structure of this field is analyzed for a point source with an arbitrary dependence of current density on time. It is shown that a conductivity jump creates a continuous wave spectrum. A component appears in the transformed wave that does not have an analog in the case of a dielectric medium.Khar'kov State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 35, Nos. 3, 4, pp. 302–312, March–April, 1992.     

放射性同位素伽玛源准直照射辐射场模拟研究

针对各向同性伽玛源参考辐射场尺寸关键技术问题,GB/T 12162系列标准虽然进行了相关规定,但是该规定并未对准直照射状态下照射室尺寸提出具体要求。为减小用于辐射检测或监测类仪器仪表检定与量值校准时伽玛参考辐射场内散射影响,本文采用蒙特卡罗方法,研究了同位素放射源准直照射时,照射室尺寸变化对检验点处的剂量率值与能量分布的影响情况,获得了准直照射时伽玛辐射场照射室尺寸的边界条件,建立并完善了伽玛参考辐射场边界研究方法及相关标准细节,为准直照射状态下照射室尺寸设计提供了一种新方法或途径。     

芯片-系统电磁脉冲耦合的高性能全波电磁模拟

目的是研究高性能的电磁场仿真软件,对真实的芯片-系统电磁脉冲耦合过程进行高分辨率、高置信度的电磁仿真。研究重点是针对多尺度问题,突破算法的并行计算瓶颈。基于自主软件平台快速研发出仿真软件,在高性能计算平台上完成对真实复杂问题的全波电磁仿真。通过对某真实机箱内部芯片的电磁脉冲耦合仿真分析,验证了本文提出的算法的高性能、高效率的特性。     

新型宽谱电磁脉冲试验系统

 研制了一套新型宽谱电磁脉冲试验系统,该系统采用全电感隔离型重复频率Marx发生器产生高压冲击脉冲,经双极脉冲形成线馈入宽带天线进行宽谱辐射。介绍了发生器工作原理和双极脉冲形成原理。实验结果表明：发生器输出脉冲电压500 kV,脉冲前沿20 ns,重复频率20 Hz,宽谱辐射因子195 kV,辐射中心频率200 MHz,频谱宽度37%。该试验系统结构紧凑、操作灵活,并具有方位辐射方向360°旋转和运程控制等功能。     

新型宽谱电磁脉冲试验系统

研制了一套新型宽谱电磁脉冲试验系统,该系统采用全电感隔离型重复频率Marx发生器产生高压冲击脉冲,经双极脉冲形成线馈入宽带天线进行宽谱辐射。介绍了发生器工作原理和双极脉冲形成原理。实验结果表明：发生器输出脉冲电压500 kV,脉冲前沿20 ns,重复频率20 Hz,宽谱辐射因子195 kV,辐射中心频率200 MHz,频谱宽度37%。该试验系统结构紧凑、操作灵活,并具有方位辐射方向360°旋转和运程控制等功能。     

Microwave pulse compression using diffraction gratings

Electromagnetic pulse compressors employing gratings of high breakdown strength in the autocollimation regime at the center frequency of the pulse for p polarization are investigated theoretically. A theory is devised on the basis of a numerical solution of the electromagnetic field equations in an integral-equation formulation. The case of the aberrationless approximation of the compression of a bell-shaped pulse with a quadratically modulated phase is considered analytically. A numerical experiment demonstrates the presence of strong distortions in the pulse after compression, which are caused by the cubic and higher terms in the expansion of the frequency dependence of the phase acquired by the wave in the compressor. The conditions for optimal pulse compression with allowance for aberrations are investigated. Zh. Tekh. Fiz. 68, 82–90 (February 1998)     

Double-resonant extremely asymmetrical scattering of electromagnetic waves in non-uniform periodic arrays

A new type of Bragg scattering – double-resonant extremely asymmetrical scattering (DEAS) of optical waves in oblique, non-uniform, periodic Bragg arrays is analysed theoretically and numerically. Steady-state DEAS is demonstrated to occur in the extremely asymmetrical geometry where the scattered wave propagates parallel to the front array boundary. The non-uniform array is represented by two joint uniform, strip-like, periodic arrays with different phases (and amplitudes) of the grating. DEAS is characterised by a unique combination of two simultaneous resonances with respect to frequency and phase variation at the interface between the joint arrays. As a result, a strong resonant increase in the scattered wave amplitude compared with the amplitude of the incident wave is predicted and investigated theoretically. The amplitude of the incident wave inside the array is also shown to increase resonantly in the middle of the array where the step-like variation in the phase of the grating takes place. The effect of different widths of the joint arrays, and magnitudes of the grating amplitudes on DEAS is analysed. Physical explanations of this type of scattering, based on the diffractional divergence of the scattered wave from one of the joint arrays into another, are presented.     

双极型晶体管损坏与强电磁脉冲注入位置的关系

利用时域有限差分法,对双极型晶体管(BJT)在强电磁脉冲作用下的瞬态响应进行了2维数值模拟,研究了电磁脉冲从不同极板注入时BJT的响应情况,根据温度分布的集中程度分析了发生烧毁的难易程度。模拟得出：发射极注入最容易导致烧毁,集电极注入次之,基极注入相对不易导致烧毁;发射极注入烧毁所消耗能量随着脉冲电压上升而下降,到30 V以后基本与电压的升高无关,集电极注入烧毁所消耗的能量则随着电压上升而上升,到100 V以后由于BE结上热点的出现而开始下降。     

Splitting of an electromagnetic pulse on resonant reflection from a plasma film

It is found theoretically that the temporal profile of a quasimonochromatic electromagnetic pulse is strongly distorted on reflection from a thin (on the wavelength scale) film of a plasma-like (semiconductor, metallic) medium under plasma-resonance conditions. It is shown that an incident Gaussian pulse splits with time (completely or partially) into two reflected pulses, whose amplitudes can be controlled by varying the relationships among the parameters of the incident pulse and the film. Zh. Tekh. Fiz. 67, 65–68 (June 1997)     

双极型晶体管损坏与强电磁脉冲注入位置的关系

 利用时域有限差分法,对双极型晶体管(BJT)在强电磁脉冲作用下的瞬态响应进行了2维数值模拟,研究了电磁脉冲从不同极板注入时BJT的响应情况,根据温度分布的集中程度分析了发生烧毁的难易程度。模拟得出：发射极注入最容易导致烧毁,集电极注入次之,基极注入相对不易导致烧毁;发射极注入烧毁所消耗能量随着脉冲电压上升而下降,到30 V以后基本与电压的升高无关,集电极注入烧毁所消耗的能量则随着电压上升而上升,到100 V以后由于BE结上热点的出现而开始下降。     

电磁脉冲辐射场试验技术

针对电磁脉冲辐射场试验的特点和参试电子设备对辐射场试验的需求,介绍了利用辐射波电磁脉冲模拟器进行效应试验过程中,总触发信号、环境场监测信号等的选取原则及获取方法。结合电磁脉冲孔缝耦合效应和穿透耦合效应,分析了试验状态设置在辐射场试验中的重要性。测量结果表明：所给出的总触发信号具有信号稳定、幅值大、到达时刻可以精确计算的特点,适合作为触发信号,用于记录设备的触发;所给出的环境场监测信号具有波形特性好、幅值适中、易于读数等特点,适合作为基准波形,用于对环境场变化的监测和归一化处理。     

电磁脉冲模拟器电磁场计算

 利用电磁场张量法计算了平行板电磁脉冲模拟器内的电磁场并推导了其时域解析表达式。按照模拟器的平行板段和前后三角板的结构将平板近似为线网格。场的幅值由各线段元的不同滞后时间叠加来确定,其方向由线段元和场点的单位矢量经简单矢量运算来确定。计算结果表明：平行板段内的场具有横电磁分布特性,而靠近三角板处由于各线段元的非对称性贡献将使场出现其它分量。通过对模拟器的电场测量值与理论计算值相比较可知,两者大致相同。