【作者】 纪卫莉；

【导师】 施卫；

【作者基本信息】 西安理工大学 ， 物理电子学， 2005， 硕士

【摘要】 半导体光电导开关(简称PCSS’s)作为一种新型的高功率超宽带电磁脉冲源,具有传统开关不能比拟的优点,其产生的线性电磁脉冲上升前沿为亚纳秒或皮秒量级、相对带宽超过25%,用宽带天线发射时其频谱可以从几十MHz伸展到儿GHz乃至几十GHz。而且光电导开关具有可以用较低能量的光脉冲激励和具有高增益特性的优点,从而使制成全固态化的微型高功率超宽带微波脉冲产生器系统成为可能。然而,当开关工作于线性模式时,开关的输出电脉冲的宽度与偏置电压和触发条件的关系、开关的转换效率与触发条件及偏置电压确切关系还需进一步研究。另外,非线性模式下的辐射还未见有报导;用以解释非线性模式的光激发电荷畴理论尚需进一步的完善。 本论文对半绝缘GaAs光电导开关产生超宽带电磁辐射的机理及测试结果进行了分析研究,结合线性模式下的实验,主要分析了影响光电导开关产生超快电磁脉冲的时间特性的因素,并且对频域特性和时域特性之间的关系进行了分析,得出输出电脉冲的频宽主要决定于电脉冲的上升沿和下降沿,电脉冲上升沿决定频谱的高频部分,其下降沿决定频谱的低频部分。实验中获得了国内同类型开关最好的实验结果。对触发光、开关结构及开关材料对脉冲时域的影响进行理论模拟和分析,分析表明在高偏置电压工作的情况下,为了提高输出电脉冲幅值和上升速率,应使开关工作在饱和状态下,激励光脉冲应尽量窄;深能级的引入有效的减小了材料载流子寿命,使脉宽更窄。窄间隙开关使脉冲在不损失上升时间的前提下,辐射效率相更多还原

【Abstract】 Photoconductor Semiconductor Switches (PCSS’s), as a new kind of high power ultra-wide-band electromagnetic pulse emitter, offer unique properties comparing with traditional switches. The rise time of electromagnetic pulse is on sub-nanosecond and picosecond level, the relative wide of band exceed 25%, its frequency band is range from tens MHz to several and even maybe to tens of GHz. Especially, PCSS’s can be excited by lower energy laser pulse and have high-gain output, so it is possible to make the all-solid state mini-size high power ultra-wide-band electromagnetic pulse emitter system. However, when the switches are working as linear mode, the relations between the wide output electromagnetic pulse and biased dc voltage, trigging condition, and a function between the transforming efficiency and biased dc voltage, trigging condition need father research. Furthermore, the radiation at non-linear mode has not been reported, the theory of optically activated charge domain, what is used to explain the non-linear mode, need to be improved father.This article gives the research on the mechanism and application of Semi-insulating (SI) GaAs PCSS’s generating ultra-wide-band electromagnetic radiation, combining with linear mode experiment, mainly analyzing the factor whichinfluencing the time characteristic of PCSS’s generating ultra-fast electromagnetic pulse characteristic, and analyzing the connection between the characteristic of time and the characteristic of frequency. The article indicates the output pulse band of frequency is mainly determined by the rise time and the fall time of electromagnetic pulse. The rise time of electric pulse determine the high-frequency component of output electromagnetism pulse, the fall time determine the low-frequency component, and get the best experiment result in our nation at present. The influence factor is simulated by exciting optical pulse and the structure of switch to the time resolved electromagnetic pulse. We indicate that, to enhance the peak value of the output of electromagnetic pulse, the trigging optical pulse should be sufficiently narrow and the switch should work on the saturated mode on the condition of proper biased dc voltage; The importing of deep energy level effectively shortens the recombination time of the photo generated carriers, and the width of pulse become narrower. The narrow gap switches make the radiate relatively high efficiency of electromagnetic pulse on the premise of that there is no loss of the rise time of electric pulse. All these provide the theoretical foundation for the design and research of PCSS’s in the linear mode. The article presents the hypothesis that the maintaining phase of nonlinear pulse is envelope of the narrow pulses on the base of the nonlinear radiation of pulse experiments and the theory of optically activated charge domain. In the end, preliminarily analyse the hypothesis.更多还原