【作者】 张健穹；

【导师】 刘庆想；

【作者基本信息】 西南交通大学 ， 电磁场与微波技术， 2011， 博士

【摘要】 由于高功率微波辐射系统是高功率微波系统的终端,整个系统的效能均需通过高功率微波辐射系统体现出来,因此随着高功率微波技术的不断发展,高功率微波辐射系统在整个系统中发挥的作用日益为人们所重视,高功率微波辐射技术的研究也成为高功率微波技术的重要研究内容之一。虽然许多传统的微波辐射技术都已经成熟化,但高功率微波的固有特点带来的许多新问题使得传统的微波辐射技术不能在高功率微波中直接应用。这些新问题主要包括高功率容量、旋转轴对称模的定向辐射、高效率(低损耗和高口径效率)、小型化等。为了解决这些问题,国内外学者研究了波导模式变换器加辐射喇叭、模式转换天线、反射面天线、阵列天线等多种天线类型,这些天线都有其各自的特点和适用场合,都推动了高功率微波辐射技术的发展,但是,它们距离高功率微波对辐射技术的需求还有一定的差距。高功率微波现有辐射技术的不足,促使我们必须采取新的技术手段,新的方式方法,探索新型式的高功率微波天线,推进高功率微波辐射技术的发展,并与高功率微波技术的快速发展相适应。为了能更好地解决高功率微波对其辐射系统提出的诸多挑战,本文在借鉴国内外优秀研究成果的基础上,提出并研究一种新型的高功率微波辐射天线—高功率高增益径向线螺旋阵列天线。过去已有学者研究了径向线阵列天线用于高功率微波辐射,并取得了一定的研究进展,但这些研究并未没有最终实现高增益阵列,对高增益阵列实现过程中产生的新问题,如大型阵列的阵面密封、多级级联、子阵馈电等没有讨论。因此,基于径向线阵列天线实现高功率高增益的辐射天线系统,尚有许多关键技术问题有待研究。高功率高增益径向线螺旋阵列天线的设计思想为：采用多个径向线子阵组合形成高增益阵列,并由高功率多路功率分配器对各个子阵馈电；每个子阵采用高功率圆极化天线作为辐射单元,采用径向线作为馈电波导,由耦合探针实现从径向线到同轴波导的耦合,并对单元天线进行馈电；最后使用天线罩将阵列天线进行真空密封,同时需要考虑其他各处的密封问题,保证天线的功率容量。根据该设计思想中所包含的内容,对论文研究过程中所涉及的相关理论进行了系统的总结。在高功率高增益径向线螺旋阵列天线设计思想的基础上,对阵列天线的关键部件-高功率单元天线进行了研究。首先从螺旋天线理论入手阐述了螺旋天线的辐射特性,分析了短螺旋天线在圆极化辐射中的应用；然后依据阵列天线的特点,提出了一种基于单元级的短螺旋天线密封方案,解决了大型阵列的阵面密封问题；随后,分析了该方案下存在的功率容量较低的问题,并有针对性的进行了改进设计,获得了具有较高功率容量的新型高功率单元天线；最后,对新型高功率单元天线间的互耦大小进行了分析,并对此密封方案的真空密封特性进行了实验测试。研究结果表明,新型高功率单元天线相对于高功率短螺旋天线的功率容量提高了4倍,达8MW；单元间的互耦系数减小了约10dB；对单个辐射单元的真空密封测试结果表明,真空度可以达10-4Pa量级,验证了上述方案的可行性。然后对高功率径向线子阵进行了研究。高功率径向线子阵是高功率高增益径向线螺旋阵列天线的组成单位,子阵性能将很大程度上决定高增益阵列天线的性能。论文首先对16单元矩形栅格子阵进行了设计,该子阵采用第三章中所提出的新型高功率单元天线作为辐射单元,相关实验结果验证了该高功率单元天线应用于径向线子阵的可行性。其次对三角形栅格的径向线子阵进行了研究。三角形栅格的阵列栅格形式与矩形栅格相比,在相同的单元间距下具有更好的栅瓣抑制能力,可以节约单元个数。采用相同的单元天线,分别对3单元、4单元、6单元和8单元的三角形栅格子阵及其馈电系统进行了研究,分析了其匹配特性和辐射特性,认识到了改善子阵性能的方法；最后对性能较优的12单元三角形栅格径向线子阵进行了设计,采用两种耦合探针实现了子阵馈电系统,对加载短螺旋天线后的天线辐射特性进行了分析研究,并通过实验验证了多单元三角形栅格径向线子阵的可行性。接着对同高功率多路功率分配器进行了研究。高功率多路功率分配器主要实现对各个高功率径阳线子阵进行馈电,其核心问题包括高功率容量、多路等幅同相输出和等路径馈电等。为了满足此要求,论文探讨了两种实现高功率多路功率分配的方案。第一种功率分配方案采用径向线功率分配器和同轴连接波导实现。但由于阵列天线对等路径馈电的需求,使得该方案下连接波导结构较为复杂,连接长度较长,影响了整个天线系统的效率和结构紧凑性。第二种功率分配方案由同轴波导-4路矩形波导、HT波导和波导同轴转换等三个元件采用4级级联构成,功率分配在平面内进行,轴向尺寸短，结构紧凑且满足等路径馈电要求。相关研究结果表明,对16个排列为4×4的子阵馈电时,采用第二种高功率16路功率分配方案更具优势,实验结果验证了其可行性。最后对高功率高增益径向线螺旋阵列天线进行了集成和实验。基于前面各章对高功率高增益径向线螺旋阵列天线各分系统的研究结果,采用16个16单元矩形栅格子阵构成256单元阵面,采用第二种功率分配方案中所述的高功率16路功率分配器对各子阵进行馈电,首次实现了具有较高增益的高功率径向线阵列天线模型,通过实验验证了该天线设计思想的合理性。相关的实验和分析结果表明：天线轴向增益约30dB,圆极化轴比约为1dB,功率容量大于1GW。更多还原

【Abstract】 The high power microwave (HPM) radiation system is terminal of HPM system, and efficiency of the whole system should be reflected by radiation system eventually, so more attention has been progressively paid to the function of HPM radiation system with the development of high power microwave technology, and HPM radiation techniques have become one of the important research content of HPM technology.Although many of the traditional microwave radiation technology has matured, the inherent characteristics of high power microwave brought many new problems, which make the traditional microwave radiation technology cannot be used in high power microwave directly. These new problems include that: high power handling capacity, the directional radiation of axisymmetric mode, high efficience, compact structure and so on. Therefore, many researches have been made at home and abroad, and such HPM antennas as mode converter with radiant horn, Vlasov antenna and mode-transducing antenna (like COBRA antenna, etc.), array antenna have been put forward. However, they are subject to some disadvantages more or less, and they can not perfectly meet the requirements of HPM system that become greater. The shortage of existing high power microwave radiation technology make us to adopt new techniques, new methods and explore new type of high power microwave antennas, which will promote the development of high power microwave radiation technology, also adapte with the fast development of high power microwave technology.In order to overcome the challenge of HPM radiation system, this paper puts forward and study a novel high power microwave radiation antenna-high-power high-gain radial line array antenna.The design thought of high-power high-gain radial line array antenna is that: adopting several subarrays to form a high-gain array and each subarray is feeded by high power mutil-way power divider; the subarray adopt high power circularly-polarized antenna as radiation unit, uses the radial line as feeding waveguide, and applies coupling probes to feed energy from radial line to unit antenna; Finally using antenna radome to make the whole array at vacuum state and reaching comparatively high power-handling capacity. Theoretical principle related to the antenna are summarized and ameliorated systemically based upon the basic principle of high-power high-gain radial line array antenna.Base on the design thought of high-power high-gain radial line array antenna, the paper focuses on the key component of the array antenna-high power unit antenna. First, the paper gives the description of radiation mechanism and far-field radiation characteristic of cylinder helical antenna, analyzes the physical foundation of axial mode helical antenna as phase shifter. Second, proposeing a vacuum sealed scheme of short helical antenna based on the unit cell, which solves the sealed problem of high-gain array. Third, analyzing the power-handling capacity of antenna in the vacuum sealed scheme, and improving the performance of the unit antenna beased on the initial design. Finally, analyzing the mutual coupling between the two novel high-power unit antennas, and experiment on the vacuum properties of the sealed scheme, which verify the feasibility of the scheme.Then the paper studies the high-power radial line rectangular subarray. The high-gain array antenna can be formed by combination of several subarrays, and the performance of which can depend largely on the performance of the subarray. First, the paper describes the design of16-element rectangular lattice subarray, which use the novel high-power unit antenna as its radiation unit. The experiment result verifies the feasibility of the unit antenna. Then, research on the triangular lattice radial line subarray, which can save16%numbers of unit antenna compare to the rectangular lattice subarray. With the same unit antenna, the paper research on the3-element,4-element,6-element and8-element subarray, analyzing the matching condition and polarization characteristic, also realizing the methods to improve the performance of subarray. Finially, designing on12-element triangular lattice radial line subarray, and the feasibility of the subarray is verified by experiment.Afterwards, the paper studies the high-power muti-way power divider, which is used to feed the subarray. The key questions include that:high-power handling capacity, muti-way equal magnitude and phase output and equal patch feeding. In order to satisfy this requirement, the paper discusses two schemes. The first scheme is realized by radial line power divider and coaxial connection waveguide. Because of the requirements on equal patch feeding, which causes the coaxial connection waveguide complex and longer, also affects the high efficience and compact sturucture of the whole system. The second scheme is composed of coaxial-4way rectangular waveguide, HT waveguide and R-C converter, the power divider is in the same plane, so it have the advangates of short axial length, compact structure, alao meet the requirements on equal patch feeding, and the experiment verify the feasibility of the second schemes.At last, the high-power high-gain radial line array antenna is integrated and tested, which adopt16number of16-element subarray to form256units array antenna, and uses the second schemes of high-power16-way power divider to feed the subarray. The experiment and analysis realize that: the antenna gain is about30dB, axial radio is about ldB and power-handling capacity exceeds1GW.更多还原