【作者】 王文；

【导师】 胡玉禄；

【作者基本信息】 电子科技大学 ， 工程硕士（专业学位）， 2017， 硕士

【摘要】 不论是应对半导体放大器件的挑战还是行波管自身的发展,宽频带和高功率一直是行波管行业前进的重要方向。频带的拓宽和功率的提高不仅带来行波管性能上的提升,还将产生重大的经济效益。本文基于输出功率和二次谐波抑制这两个指标,对超宽带行波管注波互作用的优化进行研究,论文的主要工作体现在以下几个方面:一、系统地探讨了慢波特性受高频结构影响的规律。对慢波特性影响显著的是螺旋线内径、螺距、翼片内径及翼片夹角,影响微弱的是螺旋线的厚度和宽度以及夹持杆的宽度和外径。二、提出并验证了翼片内径跳变对抑制超宽带行波管二次谐波的可行性和高效性。传统的螺距正跳变无法使超宽带行波管大部分频点的二次谐波得到很好的抑制,而采用翼片内径负跳变的技术,二次谐波抑制效果比无跳变和单螺距跳变都要好。三、研究了归一化相速对输出功率的影响,得出了4GHz和18GHz的相速取值范围。相速须稍小于电子注速度,但并没有对小多少进行量化。不同频段的行波管,相速小多少的程度是不一样的,通过研究4-18GHz超宽带行波管的最佳同步相速,为了尽可能地提高输出功率,探讨了两种色散反常度下边频点的归一化相速范围。四、提出一种高效的互作用分布来优化全频带的输出功率。保证边频点相速在工作三的范围内,输入段色散平坦且耦合阻抗大,便于更好地同步和缩短互作用长度;输出段色散反常度大,便于更彻底地抑制二次谐波。五、利用成熟的速度再同步技术,有效地提高了电子效率。在输出功率饱和点前的某个位置,适当地减小螺距,设计标准就是保证18GHz的电子效率达到最大。六、结合前述的优化技术和方法,参考宽带行波管的设计流程,完成4-18GHz超宽带螺旋行波管高频结构的设计和注波互作用的优化设计。实现了4-18GHz全频带内输出功率不小于150W、二次谐波抑制不大于-3.5dBc且电子效率高于15%。更多还原

【Abstract】 Wideband and high power is a main tendency of traveling wave tube(TWT)production,no matter the challenge from semiconductor amplifying device or the development of TWT itself.With the expansion of bandwidth and the improvement of output power,not only the performance of TWT will be enhanced,but also brings great economic benefits.The article will show some researches on beam-wave interaction of ultra-wideband TWT based on the demand of output power and secondary resonance wave restrain.The content of the article contain the following aspects:1.Research of the discipline about diversification of slow wave characteristics caused by transformation of high frequency structure.Helix diameter,pitch,wing diameter and wing angle will obviously influence slow wave characteristics.Adjusting the thickness and width of helix,the outside diameter and width of support rod could slightly change dispersion and coupling impedance.2.Proposing and verifying the feasibility and high-efficiency that using the mutation of wing diameter restrain the second harmonic of ultra-wideband TWT.Applying the traditional mutation of pitch,second harmonic of most frequency point can’t be restrained but the effect of mutation of wing diameter will be better.3.Researching the influence of normalized phase velocity on output power,at the same time,obtaining the value range of phase velocity at 4GHz and 18 GHz.As we all know,in order to obtain an efficient beam-wave interaction,we should let phase velocity less than the speed of electronic beam,however,there is still no accurate figure.The TWT in different frequency actually need different phase velocity.Referring to the best phase velocity at 4GHz to 18 GHz,the article will show the range of normalized phase under two different anomaly degree of dispersion to improve the output power as much as possible.4.Coming up with an efficient distribution of interaction that can improve output power of the full band.Firstly,ensuring phase velocity of frequency point at edge belong to the range of the third works,besides,in order to make electronic beam and electromagnetic wave are synchronous,dispersion should be more flat and coupling impedance should be bigger on input section.Finally,abnormality of dispersion are supposed to be more intensive on output segment to restrain second harmonic.5.Increasing electronic efficiency with mature speed synchronize again technology.To make the biggest electronic efficiency at 18 GHz,reducing pitch properly in a position in front of saturation point of output power,additionally,ensuring pitch and starting point in a right place.6.Fulfilling calculation on high frequency structure and beam-wave interaction of ultra-wideband at 4GHz to 18 GHz,which is based on the methods above and design process for wideband TWT.In the article,output power at 4GHz to 18 GHz will exceed 150 watt and electronic efficiency will exceed 15%,what is more,rejection ratio of second harmonic will less than-3.5dBc.更多还原