【作者】 刘鲁伟；

【导师】 魏彦玉；

【作者基本信息】 电子科技大学 ， 物理电子学， 2013， 博士

【摘要】 螺旋线行波管具有宽频带、高功率、高效率以及高增益等特点，尤其可与固态放大器件和电子功率调谐器一起形成超级性能的微波功率模块(MPM)，被大量应用于雷达、电子对抗、通信等领域。螺旋线慢波结构是行波管的核心部件之一，其作用是降低电磁波的相速以使其相速与电子注速度同步，从而实现能量交换，但是由于其散热能力的限制，螺旋线行波管一般工作在中小功率的水平。随着军事电子技术的发展，需要螺旋线行波管具有更宽的频带，更高的功率，更高的频率，更长的寿命以及更小的尺寸等特点，因此深入而详细地对螺旋线慢波结构进行研究具有重要的理论价值和现实意义。本论文主要采用模拟仿真和实验测试的手段对新型螺旋线慢波结构进行深入的研究。主要工作和创新点如下：1、为了提高螺旋线慢波结构的散热能力，从而提高毫米波螺旋线行波管的平均输出功率，提出了一种开槽螺旋线慢波结构，建立了该结构的热分析模型，并对其热形变情况进行模拟分析。热分析结果表明：在相同条件下，开槽螺旋线慢波结构比常规螺旋线慢波结构具有更高的散热能力，更小的热形变。设计了Ka波段开槽螺旋线行波管的慢波结构、耦合结构，并采用CST软件建立了具有集中衰减器和切断的三维注-波互作用模型，对非线性的注-波互作用过程进行了模拟计算。计算结果表明：在27.5GHz~32.5GHz范围内，开槽螺旋线行波管的平均输出功率大于700W，对应的增益和电子效率分别大于41.1dB和19%。该结构的提出，对研制大功率高可靠的毫米波螺旋线行波管具有积极的推动作用。另外，为提高开槽螺旋线慢波结构的耦合阻抗，在本章的最后提出了一种双夹持开槽螺旋线慢波结构，并对其注-波互作用特性进行了研究。2、为克服介质夹持杆易断以及宽带螺旋线行波管增益波动大等难题，提出了一种具有金属内芯的介质夹持杆。本章详细研究了这种新型夹持杆的加工方法，并把这种夹持杆应用到螺旋线慢波结构中。利用该新型夹持杆螺旋线慢波结构完成了V波段互作用电路的设计。研究结果表明：与常规夹持杆相比，该新型夹持杆具有更好的柔韧性，因此在慢波结构装配时不容易断裂；同时，夹持杆中加载的金属内芯还起到翼片加载的作用，可以改善慢波结构的色散特性。当电子注电压为13100V，电流为60mA时，在53GHz~68GHz范围内，输出功率大于80W，增益大于39dB，电子效率大于10.3%，最重要的是在15GHz范围内，增益波动只有0.7dB。该结构的提出为发展宽频带低增益波动以及高可靠毫米波行波管提供了一个新的解决方案。3、为解决毫米波螺旋线行波管不易加工、装配的困难，并结合平面微带曲折线慢波结构的特点，创新性地提出了一种卷绕微带曲折线慢波结构。详细研究了这种结构的加工方法，并利用该结构完成了V波段互作用电路的设计。计算结果表明：在58GHz~63GHz范围内，卷绕微带曲折线行波管的峰值输出功率大于130W,相应的增益和电子效率分别大于31.6dB和8.2%。4、采用T型夹持杆螺旋线慢波结构，并利用螺距跳变技术，成功地设计了低谐波倍频程螺旋线行波管的慢波电路。计算结果表明：在一个倍频程带宽内，基波输出功率大于250W，二次谐波小于-7dB。对所设计的无截获栅控电子枪进行了热分析和热应力分析，给出了电子枪的装配距离等关键参数。最后，我们提出了一种新的抑制二次谐波的方法—磁场跳变技术。计算结果表明：该技术可把低频端的二次谐波抑制到-11.32dB以内，对应的基波功率大于300W。5、低谐波倍频程螺旋线行波管的实验测试。根据本文设计的方案，分别加工和装配了电子光学样管和整管。首先，对电子光学样管的流通率进行了实验测试。结果表明：样管的流通率达到了98.2%，尤其是无截获栅控电子枪发射性能良好，控制栅电流为2μA。其次，对整管的传输特性进行了测试。最后，对整管进行了热测试。实验测试结果表明：在工作带宽内，基波输出功率大于250W，二次谐波小于-7dB，电子效率大于13%。更多还原

【Abstract】 Helix traveling-wave tubes (TWT) with wide-bandwidth, high power, highefficiency and high gain, which especially can be chained with solid state poweramplifier (SSPA) and electronic power conditioner (EPC) to form superior MicrowavePower Module (MPM), are attractive for many applications, such as radar, electroniccountermeasures and communication. Helix slow-wave structure (SWS) which canreduce the phase velocity of electromagnetic wave to be equal to the velocity of theelectron beam is the key component of the TWT. Because its heat dissipation capabilityis limited, the average-power of the TWT is low. As the development of the militaryelectronic technology, the helix TWTs with wider bandwidth, higher power, higherfrequency, longer life and smaller size are urgent. In this paper, analog simulation andexperimental measurement are used to study the novel helix SWS. The important worksand innovation points are listed below:1. To improve the heat dissipation capability of the helix SWS, and then enhance theaverage power of millimeter-wave TWT, the slotted helix SWS has been proposed by us.The thermal analysis model is constructed and the thermal deformation analysis is alsostudied. Our preliminary thermal analysis of this structure shows that it has better heatdissipation capability and smaller thermal deformation than those of the conventionalhelix SWS in the same conditions. The slotted helix SWS operating in the Ka band isdesigned. The model with concentrated attenuators and sever is constructed by usingCST software and the beam-wave interaction simulations of the novel slotted helixslow-wave circuit are conducted by utilizing CST Particle Studio. The results show thatthis novel circuit can produce over700W average output power in a frequency rangefrom27.5GHz to32.5GHz, the corresponding conversion efficiency and gain over19%and41.1dB. At the end of this chapter, the double-slotted helix slow-wave structure isproposed to improve the coupled impedance of the SWS whose beam-wave interactioncharacteristic is studied also.2. To overcome the difficulties of ceramic dielectric rods easily brittle and decreasethe fluctuation of gain, a kind of dielectric rods with metal inner core is proposed. Theprocess method of this kind of rods is studied, and the rods are applied in the helix SWS.The beam-wave interaction circuit of the helix SWS operating in V-band is designed. The results show that the flexibility of these rods with metal core is better than that ofthe conventional rods; therefore, they are not easily fractured. Meanwhile, the metalcore in the rod can also improve the dispersion characteristics of the helix SWS. Fromour calculations, when the designed beam voltage and beam current are set to be13.1kVand0.06A, respectively, this novel TWT can produce over80-W average output powerin a frequency range from53GHz to68GHz, and the corresponding gain and conversionefficiency can reach over39dB and10.3%.3. To solve the problem of processing and assembling difficulties, a novel windingmicrostrip meander-line SWS is proposed. The processing method of this structure isstudied and the interaction circuit of the SWS operating in the V-band is investigated.The results show that this novel winding microstrip meander-line TWT can produceover130W peak power output in a frequency range from58GHz to63GHz, thecorresponding conversion efficiency values and gain over8.2%and31.6dB.4. The slow wave circuit of octave helix TWT with T-shaped dielectric rods isdesigned. The calculated results show that the output power of fundamental wave in oneoctave band values over250W, the gain of second harmonics is lower than-7dB. Thethermal analysis and thermal stress analysis of the nonintercepting gridded electron gunmodel are studied and the assembling distance of the electron gun is also calculated.The method (magnetic field taper technology) of restraining second harmonics isproposed. The gain of second harmonics is restrained to-11.32dB, the correspondingfundamental power is over300W.5. The experimental research of the low harmonics octave TWT is carried out. Theelectronic optical sample tube and whole tube according to the designed scheme areassembled respectively. First, the flow rate experimental test in the optical sample tubehas been done. The test results show that the flow rate of the sample tube can reach to98.2%, the emission characteristics of the nonintercepting gridded electron gun is good,and the current of the control gate is only2μA. Second, the transmission property of thewhole tube is tested. At last, the hot test of the whole tube is also tested. The resultsshow that the output power of fundamental wave in one octave band values over250W,the gain of second harmonics is lower than-7dB and the electronic efficiency is over13%.更多还原