A compact P-band coaxial relativistic backward wave oscillator with only three periods slow wave structure
A compact P-band coaxial relativistic backward wave oscillator with only three periods slow wave structure
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DOI：
10.1063/1.3646519
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发表时间：
2011-10
影响因子：
2.2
通讯作者：
Liang Gao;B. Qian;X. Ge
中科院分区：
文献类型：
--
作者：
Liang Gao;B. Qian;X. Ge
对一种仅具有三个周期慢波结构的紧凑型P波段同轴相对论返波管进行了理论和数值研究。分析了同轴慢波结构由外导体涟漪结构变为内外导体波纹结构时的特性。结果表明，内导体涟漪的存在可以减小同轴慢波结构的周期长度，从而保持返波管的工作频率不变，并可以大大提高器件的时间生长率和空间生长率。在此基础上，利用粒子模拟方法研究了慢波系统周期数对P波段相对论返波管微波产生的影响。结果表明，三周期慢波结构不仅使器件结构更加紧凑，而且在较宽的二极管电压范围内具有较宽的单频工作区域和较大的效率及输出功率。典型的模拟结果表明，在0.8T螺线管场引导下，585 kV、7.85 kA的电子束在900 MHz频率下产生了1.65 GW的微波，互作用效率约为36%。与传统的P波段同轴相对论返波管相比，该返波管的轴向长度减小了一半，仅为38.4cm，微波信号的饱和时间缩短了约10ns。
A compact P-band coaxial relativistic backward wave oscillator(BWO) with only three periods slow wave structure (SWS) is investigated both theoretically and numerically. The characteristics of the coaxial SWS are analyzed when the SWS is changed from the structure with only outer conductor ripple to the structure with both inner and outer conductor ripples. It is found that the existence of the inner conductor ripple can reduce the period length of coaxial SWS to maintain the same operating frequency of the BWO and can largely increase the temporal growth rate and the spatial growth rate of the device. Then, the effects of SWS period numbers on the generation of the microwave in the P-band relativistic BWO are studied by PIC simulations. The results show that three periods SWS cannot only make the device more compact but also has a wide region of single-frequency operation and relatively large efficiency and output power in a wide range of the diode voltage. Typical simulation results show that, with a 585 kV and 7.85 kA electron beam guided by a 0.8 T solenoidal field, the microwave of 1.65 GW is generated at the frequency of 900 MHz, and the interaction efficiency is about 36%. Compared with the conventional P-band coaxial relativistic BWO with five periods SWS, the axial length of the SWS is reduced by about one half, which is only 38.4 cm, and the saturation time of the microwave signal is reduced by about 10 ns.