小型化大功率波导定向耦合器的研究与设计

发布时间：2018-03-28 09:28

本文选题：二级定向耦合器　切入点：椭圆孔　出处：《电子科技大学》2015年硕士论文

【摘要】：定向耦合器是测量微波功率的重要器件。当测量大功率微波时,需要使用大功率弱耦合定向耦合器。通常耦合度越弱,耦合孔的尺寸越小。但是过小的耦合孔会降低定向耦合器的峰值功率。针对弱耦合与大功率的矛盾可以采用多级耦合方式解决。但是多级定向耦合器通常体积庞大,不方便搬运。为了解决以上问题,本文需设计一种大功率,小型化,弱耦合的矩形波导定向耦合器。本文主要研究内容如下:1.矩形波导定向耦合器是通过公共壁上的小孔或缝隙进行功率耦合的,所以详细研究了小孔耦合理论,推导了小孔耦合公式。为了增加整体的峰值功率,本设计采用二级耦合方式,明确每一级定向耦合器需要达到的指标:整体的耦合度由第一级和第二级共同承担,整体的方向性由第一级承担。2.研究第一级定向耦合器设计方案,第一级定向耦合器采用多孔波导转波导的耦合方式。分别详细地推导了圆孔和椭圆孔的耦合计算公式,并在CST软件中建立模型。如果两种耦合结构想要达到相同的指标,需要椭圆孔的数目更少。为了实现小型化的目的,最终选择耦合度为-25dB波导转波导双排6椭圆孔为第一级定向耦合器。3.研究第二级定向耦合器设计方案,第二级定向耦合器采用单缝隙波导转带状线的耦合方式。分别介绍了菱形长缝隙和窄槽缝隙的耦合结构,并在CST软件中建立模型得到相应的仿真结果。考虑到承载大功率,加工方便以及小型化等因素,最终选择了耦合度为-25dB的窄槽缝波导转带状线为第二级定向耦合器,其中标准的N型同轴接头垂直插入第二级定向耦合器的副线。第二级定向耦合器实测结果满足技术指标。4.考虑到生产厂商的限制要求,最终设计耦合度为-49.4—-50.5dB,方向性小于-25dB的新型二级定向耦合器。理论峰值功率大于3.5MW。新型二级定向耦合器实测结果满足各项技术指标。
[Abstract]:Directional coupler is an important device for measuring microwave power. When measuring high power microwave, it is necessary to use high power weakly coupled directional coupler. The smaller the size of the coupling hole, the smaller the coupling hole will reduce the peak power of the directional coupler. The contradiction between the weak coupling and the high power can be solved by multi-stage coupling. But the multistage directional coupler is usually large. It is not convenient to carry. In order to solve the above problem, we need to design a kind of high power, miniaturization, Weakly coupled rectangular waveguide directional couplers. The main contents of this paper are as follows: 1. The rectangular waveguide directional couplers are power coupled through small holes or gaps in the common wall, so the theory of small hole coupling is studied in detail. In order to increase the peak power of the whole system, the design adopts the two-stage coupling method, which specifies the target to be achieved by each stage directional coupler: the coupling degree of the whole system is shared by the first stage and the second stage. The first stage directional coupler design scheme is studied. The first stage directional coupler adopts the coupling mode of porous waveguide rotating waveguide. The coupling formulas of circular hole and elliptical hole are derived in detail. In order to achieve the same target, the number of elliptical holes is less. In order to achieve the purpose of miniaturization, Finally, the coupling degree of -25dB waveguide is chosen as the first stage directional coupler. 3. The design scheme of the second stage directional coupler is studied. The second stage directional coupler adopts the coupling mode of single slot waveguide rotating strip line. The coupling structure of diamond long slot and narrow slot slot is introduced, and the corresponding simulation results are obtained by establishing the model in CST software. Finally, the narrow slot waveguide with a coupling degree of -25dB is selected as the second stage directional coupler because of its convenient processing and miniaturization. The standard N-type coaxial connector is inserted vertically into the secondary directional coupler's secondary line. The measured results of the second stage directional coupler meet the technical specifications .4. taking into account the limited requirements of the manufacturer, Finally, a new type of directional coupler with a coupling degree of -49.4--50.5 dB and a directivity of less than -25 dB is designed. The theoretical peak power is greater than 3.5 MW. The measured results of the new two-stage directional coupler meet various technical specifications.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN622

【参考文献】