双指数纳秒脉冲场测试系统研究

发布时间：2019-03-04 10:01

【摘要】：电磁脉冲作用范围广危害大,为了模拟电磁脉冲环境,参照国内外相关标准对瞬态电磁场辐射敏感度测量的要求,构建了一种小型的双指数纳秒脉冲场测试系统。测试系统主要由高压脉冲源、GTEM小室、电阻分压器、场强探头和示波器组成,高压脉冲源向GTEM小室放电在小室内部产生强瞬态电磁场,电阻分压器和场强探头分别用来监测脉冲电压和电场的变化。本文的主要工作包括以下几个方面：1)对GTEM、室的馈电接头进行了耐高压优化设计,优化后的小室接头可以耐受20kV的脉冲电压。GTEM小室从低频到2GHz频率范围内电压驻波比稳定在1.6,在605MHz附近电压驻波比为1.73。对电阻分压器性能进行了调试提高了其3dB带宽,从直流到400MHz范围内衰减值稳定在65.5dB；在方波脉冲响应测试中,上升时间稳定在1ns附近,可以用于高压脉冲的测量。2)在高压脉冲源的设计中,提出了高压脉冲源的设计方案。分析了电容器和负载电阻对串级发生器的电压纹波和电压降的影响,完成了串级发生器、气体火花开关及其触发电路的结构设计。对脉冲源进行了静态击穿试验和触发击穿试验,在试验的基础上分析了气体压力、电极间距、电极形状对脉冲波形的影响。脉冲源在自击穿工作状态下,输出电压峰值可达到20kV、平均上升时间约2.46ns、平均半峰值脉宽约30ns,输出波形和标准波形拟合良好。3)在原有场强探头的基础上,通过调整分压电容器的取值和单极子天线的杆长来减小电路的输入信号,去除光纤传输模块以充分利用运算放大器的工作范围,从而提高了探头的最大可测电场强度。分析了分压电容对场强探头频带宽度的影响,完成了探头的结构设计和仿真分析。对探头的天线系数分别在时域和频域进行了校准,确定了探头在不同分压电容取值和天线杆长时的3dB带宽、线性度和可测场强范围。整个测试系统的功能基本满足了标准要求,但是仍然存在一些不足需要改进。
[Abstract]:In order to simulate the environment of electromagnetic pulse, a small double exponential nanosecond pulse field testing system is constructed according to the requirements of the relevant standards at home and abroad for the measurement of transient electromagnetic field radiation sensitivity. The test system consists of a high voltage pulse source, a GTEM chamber, a resistance divider, a field strength probe and an oscilloscope. The discharge of the high voltage pulse source into the GTEM chamber produces a strong transient electromagnetic field inside the chamber. Resistance divider and field strength probe are used to monitor the change of pulse voltage and electric field respectively. The main work of this paper includes the following aspects: 1) the optimal design of high voltage resistance for the feed joint of GTEM, chamber is carried out. The optimized chamber joint can withstand the pulse voltage of 20kV. The VSWR of GTEM chamber is stabilized at 1.6 from low frequency to 2GHz frequency and is 1.73 near 605MHz. The performance of resistive divider is debugged and the bandwidth of 3dB is improved. The attenuation value is stable at 65.5dB from DC to 400MHz. In the square wave pulse response test, the rising time is stable near the 1ns, which can be used to measure the high voltage pulse. 2) in the design of the high voltage pulse source, the design scheme of the high voltage pulse source is put forward. The influence of capacitor and load resistance on voltage ripple and voltage drop of cascade generator is analyzed, and the structure design of cascade generator, gas spark switch and trigger circuit is completed. The static breakdown test and trigger breakdown test of the pulse source are carried out. The effects of gas pressure, electrode spacing and electrode shape on the pulse waveform are analyzed on the basis of the experiment. Under the condition of self-breakdown, the peak output voltage can reach 20 kV, the average rising time is about 2.46 ns, and the average half-peak pulse width is about 30 ns. The output waveform and standard waveform fit well. 3) on the basis of the original field strength probe, the output wave is fitted well with the standard waveform. The input signal of the circuit is reduced by adjusting the value of the voltage divider capacitor and the length of the pole of the monopole antenna, and the optical fiber transmission module is removed to make full use of the operating range of the operational amplifier, thus increasing the maximum measurable electric field intensity of the probe. The influence of partial voltage capacitance on the frequency band width of the field strength probe is analyzed, and the structure design and simulation analysis of the probe are completed. The antenna coefficients of the probe are calibrated in time domain and frequency domain, respectively, and the 3dB bandwidth, linearity and measurable field intensity range of the probe at different partial voltage capacitance values and the length of antenna rod are determined. The function of the whole test system basically meets the standard requirements, but there are still some shortcomings that need to be improved.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TP274

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