基于光电导线性调控的可调谐强电磁脉冲源及其兆赫兹重频运行特性研究

高功率、高重复频率和宽参数调谐的强电磁脉冲源在国防和经济领域有重要的应用价值。现有的超高重频电磁脉冲源，主要通过固态电开关的快速导通或关断特性，直接产生时域冲激窄脉冲，其输出频谱表现为超宽谱且中心频率参数固定。本项目拟采用宽禁带钒掺杂碳化硅，利用其高功率容量和光电响应速度快的优异特性，基于其非本征光电导线性调控机制，产生可调谐中心频率、兆赫兹重复频率的电磁脉冲。通过理论、仿真与实验相结合的方式，研究该材料杂质能级在非本征光生载流子的产生、输运及复合过程中的影响机制，完善器件物理模型；通过模型优选材料并构筑全内反射光捕获器件结构，降低器件导通阻抗和匀化光生电流分布，提高器件功率容量和运行寿命；研究与之匹配的射频传输技术，完成初步系统实验，产生峰值功率10kW、重频MHz、脉宽5ns、中心频率多倍频程可调（0.5-5GHz）电磁脉冲。研究能为超高重频自适应电磁信息对抗系统提供技术支撑。

The frequency agile, high repetitive rate and high power are the trends promoting the development of high power electromagnetic pulse technology and high power microwave technology, to meet the civil and military requirements. The fast closing or opening (switching time at order of 100 ps) switches are widely used to generate a short pulse with an ultrawide spectrum and its central-frequency is fixed or difficult to change. In this study, the extrinsic linear photoconductive semiconductor devices are used to generate the high power electromagnetic pulse with tunable central-frequency and high repetitive rate. Vanadium compensated semi-insulating SiC is used because of its essential characteristics: high-power and fast photoelectric response speed. With a combined method of theoretical modeling, simulation and experimental research, this program firstly focuses on the effects of impurity energy level on the generation, transportation and recombination of the extrinsic photo induced carriers. The physical model of the device is constructed and the model parameters are improved based on the mechanism analysis. Then, the SiC material can be selected by the mechanism analysis and improved model to achieve high photoelectric conversion efficiency, and a total internal optical-reflection trapping device structure is proposed to increase the extrinsic light absorption and make the distribution of the photocurrent density uniform in the SiC material, so the lifetime and power of the device can increase. Meanwhile, the technology of the large power radio-frequency circuit should be matched to develop the preliminary system experiment. Based on those studies, electromagnetic pulses can be generated with 10 kW peak power, MHz repetitive rate, 5 ns pulse duration and a tunable broadband central-frequency (0.5-5 GHz) , and this work can lay the foundation and theoretical references for the research of frequency agile, high repetitive rate and high power electromagnetic pulse system.