The carbon nanotube (CNT)-based materials can be used as vacuum device cathodes. Owing to the excellent field emission properties of CNT, it has great potentials in the applications of an explosive field emission ca...The carbon nanotube (CNT)-based materials can be used as vacuum device cathodes. Owing to the excellent field emission properties of CNT, it has great potentials in the applications of an explosive field emission cathode. The falling off of CNT from the substrate, which frequently appears in experiments, restricts its application. In addition, the onset time of vacuum breakdown limits the performance of the high-power explosive-emission-cathode-based diode. In this paper, the characteristics of the CNT, electric field strength, contact resistance and the kind of substrate material are varied to study the parameter effects on the onset time of vacuum breakdown and failure mechanism of the CNT by using the finite element method.展开更多
文摘利用2.5维粒子模拟软件Karat对一种无导引磁场X波段Cerenkov型高功率微波振荡器开展了仿真研究,利用冷腔色散曲线模型与Superfish电磁场分布模拟软件选择了工作点,设计了基本模型。在基本模型的基础上进行仿真优化,通过采用内外约束阴极环提高电子束质量,采用锥变型收集极优化器件Q值、增加模转效率、纯化输出微波模式,优化非均匀锥形慢波结构增强束波作用,最终使器件效率从17%优化到30%,输出功率达到1.8GW,输出微波模式为TEM模,频率9.1GHz,对应二极管工作电压620k V、电流9.4k A.
基金supported by the National Natural Science Foundation of China(Grant Nos.11305263 and 61401484)
文摘The carbon nanotube (CNT)-based materials can be used as vacuum device cathodes. Owing to the excellent field emission properties of CNT, it has great potentials in the applications of an explosive field emission cathode. The falling off of CNT from the substrate, which frequently appears in experiments, restricts its application. In addition, the onset time of vacuum breakdown limits the performance of the high-power explosive-emission-cathode-based diode. In this paper, the characteristics of the CNT, electric field strength, contact resistance and the kind of substrate material are varied to study the parameter effects on the onset time of vacuum breakdown and failure mechanism of the CNT by using the finite element method.