Bragg J-W B, Sullivan W W, Mauch D, Neuber A A, Dickens J C
Department of Electrical and Computer Engineering, Center for Pulsed Power and Power Electronics, Texas Tech University, Lubbock, Texas 79409, USA.
Rev Sci Instrum. 2013 May;84(5):054703. doi: 10.1063/1.4804196.
An all solid-state, megawatt-class high power microwave system featuring a silicon carbide (SiC) photoconductive semiconductor switch (PCSS) and a ferrimagnetic-based, coaxial nonlinear transmission line (NLTL) is presented. A 1.62 cm(2), 50 kV 4H-SiC PCSS is hard-switched to produce electrical pulses with 7 ns full width-half max (FWHM) pulse widths at 2 ns risetimes in single shot and burst-mode operation. The PCSS resistance drops to sub-ohm when illuminated with approximately 3 mJ of laser energy at 355 nm (tripled Nd:YAG) in a single pulse. Utilizing a fiber optic based optical delivery system, a laser pulse train of four 7 ns (FWHM) signals was generated at 65 MHz repetition frequency. The resulting electrical pulse train from the PCSS closely follows the optical input and is utilized to feed the NLTL generating microwave pulses with a base microwave-frequency of about 2.1 GHz at 65 MHz pulse repetition frequency (prf). Under typical experimental conditions, the NLTL produces sharpened output risetimes of 120 ps and microwave oscillations at 2-4 GHz that are generated due to damped gyromagnetic precession of the ferrimagnetic material's axially pre-biased magnetic moments. The complete system is discussed in detail with its output matched into 50 Ω, and results covering MHz-prf in burst-mode operation as well as frequency agility in single shot operation are discussed.
介绍了一种全固态兆瓦级高功率微波系统，该系统采用碳化硅（SiC）光电导半导体开关（PCSS）和基于亚铁磁的同轴非线性传输线（NLTL）。一个面积为1.62平方厘米、50 kV的4H-SiC PCSS被硬开关，以在单次和突发模式操作中产生半高全宽（FWHM）为7 ns、上升时间为2 ns的电脉冲。当用355 nm（三倍频Nd:YAG）的约3 mJ激光能量在单个脉冲中照射时，PCSS的电阻降至亚欧姆。利用基于光纤的光传输系统，以65 MHz的重复频率产生了四个7 ns（FWHM）信号的激光脉冲串。来自PCSS的电脉冲串紧密跟随光输入，并被用于馈入NLTL，以65 MHz的脉冲重复频率（prf）产生基微波频率约为2.1 GHz的微波脉冲。在典型实验条件下，NLTL产生的输出上升时间锐化至120 ps，并产生2 - 4 GHz的微波振荡，这是由于亚铁磁材料轴向预偏置磁矩的阻尼旋磁进动产生的。详细讨论了整个系统，其输出匹配到50 Ω，并讨论了突发模式操作中MHz - prf的结果以及单次操作中的频率捷变。
