磁绝缘线振荡器谐振腔的高频特性研究

 利用数值方法计算了磁绝缘线振荡器(MILO)主慢波结构谐振腔和扼流腔的谐振频率和场分布。结果表明：当主慢波结构腔内半径为4.6 cm,扼流腔内半径为4.2 cm，阴极半径为3 cm时，MILO工作在3.6~4.4 GHz频率范围，扼流片可以阻止微波功率向脉冲功率源泄漏，这有利于提高器件微波输出的功率；4.5~4.9GHz频段为慢波结构的阻带，微波在该频段截止。计算了C波段MILO开放腔的谐振频率，当模式分别为3π/8,π/2,5π/8,3π/4时，其谐振频率分别为3.18,3.76,4.00,4.11 GHz;并通过实验测出了开放腔的谐振频率,其相应的值分别为3.80,3.94,4.08.4.18 GHz, Q分别为194，143，231，468。数值计算的谐振频率与实验测出的频率基本一致。

Numerical analysis on high frequency characteristics of MILO

Through numerical calculation, the high frequency characteristics of magnetically insulated line oscillator (MILO) coaxial slow wave structure(SWS),the frequency of the eigen-modes and its distribution of coaxial SWS are presented. The sizes of MILO are:the inner radius of the primary SWS and RF choke 4.6 cm and 4.2 cm,respectively, the cathode radius 3 cm. When the frequency in MILO is from 3.6 to 4.4 GHz, the RF chock cavity stops leakage of microwaves toward the pulse power, unexpectedly increases the output power. The cutoff frequency of the primary SWS is from 4.5 to 4.9 GHz. A wave whose frequency is near cutoff is evanescent in the primary SWS. The eigen-frequency of MILO with open boundary was calculated and the Q-value in the cavity was given by the experimental results. The frequencies of the 3π/8,π/2, 5π/8, 3π/4 mode achieved in the simulation are 3.18, 3.76,4.00, 4.11 GHz, the corresponding frequencies in “cold” measurement are 3.80, 3.94,4.08,4.18 GHz and Q in the cavity are 194,143,231,468.The experimental results are in accordance with the results of the numerical solution.