A dual-mode operation overmoded coaxial millimeter-wave generator with high power capacity and pure transverse electric and magnetic mode output
A dual-mode operation overmoded coaxial millimeter-wave generator with high power capacity and pure transverse electric and magnetic mode output
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DOI：
10.1063/1.4945645
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发表时间：
2016-04
影响因子：
2.2
通讯作者：
Zhen Bai;Jun Zhang;H. Zhong
中科院分区：
文献类型：
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作者：
Zhen Bai;Jun Zhang;H. Zhong
采用一种横截面尺寸大、内外导体间距小的同轴慢波结构，设计并实现了一种高功率容量、纯横向电磁输出的过模同轴毫米波发生器。发电机工作在双模运行机构中。电子束与准瞬变电子显微镜的7个π/8模同步相互作用，同时与3个π/8模进行能量交换。行波TM01模的存在不仅提高了注波互作用效率，而且提高了提取效率。同轴SWS的大横向尺寸使得其功率容量高于其他已报道的毫米波器件，而内外导体之间的距离很小，只允许两个方向对称的模式共存。SWS后的变流器保证了输出功率的模式纯度。粒子模拟结果表明，当二极管电压为400kV，束流为3.8kA时，获得了32.26 GHz的微波输出，输出功率为611 mW，转换效率为40%。在输出功率中，由瞬变模式携带的功率百分比达到99.7%。
An overmoded coaxial millimeter-wave generator with high power capacity and pure transverse electric and magnetic (TEM) mode output is designed and presented, by using a kind of coaxial slow wave structure (SWS) with large transversal dimension and small distance between inner and outer conductors. The generator works in dual-mode operation mechanism. The electron beam synchronously interacts with 7π/8 mode of quasi-TEM, at the meanwhile exchanges energy with 3π/8 mode of TM01. The existence of TM01 mode, which is traveling wave, not only increases the beam-wave interaction efficiency but also improves the extraction efficiency. The large transversal dimension of coaxial SWS makes its power capacity higher than that of other reported millimeter-wave devices and the small distance between inner and outer conductors allows only two azimuthally symmetric modes to coexist. The converter after the SWS guarantees the mode purity of output power. Particle-in-cell simulation shows that when the diode voltage is 400 kV and beam current is 3.8 kA, the generation of microwave at 32.26 GHz with an output power of 611 MW and a conversion efficiency of 40% is obtained. The power percentage carried by TEM mode reaches 99.7% in the output power.