【作者】 周亮；

【导师】 许锋；

【作者基本信息】 南京邮电大学 ， 电子与通信工程（专业学位）， 2021， 硕士

【摘要】 在射频微波系统中,为了分别实现功率分配或功率组合,以及相位的调控的功能,通常采用功分器、耦合器、移相器等无源器件来设计。而微带线由于具有结构简单、成本低等优势被广泛应用于无源器件的设计中,但由于其非屏蔽结构,存在串扰和散射的问题。基片集成波导(Substrate Integrated Waveguide,SIW)继承了微带线的优点,具有较高Q值、易加工的优点,但其不能传播TEM模,在宽频带的无源器件设计中不适合。基片集成同轴线(Substrate Integrated Coaxial Line,SICL)继承了SIW的损耗小、成本低且具有屏蔽结构等优点,是一种将同轴线平面化的技术。同时SICL结构能传播TEM模,适合在宽频带的无源器件设计中,又可以与其它平面电路集成。因此,SICL具有很大的应用价值。本文的主要工作有如下几个方面:第一,在SICL的理论基础上,设计了3d B的定向耦合器。该3d B定向耦合器在普通的定向耦合器的基础上结合交指耦合线结构来实现3d B的强耦合。第二,在对交指耦合线研究的基础上,结合三线平行耦合线的原理对交指耦合线结构进一步研究,发现采用双交指耦合线结构能使传统的SICL分支线耦合器的体积减小了一半多的前提下,还能保持强耦合的效果。因此,最终设计了小型化的SICL分支线耦合器。第三,本文基于SICL技术,结合传输线型移相器的基本原理,设计了两种改进的Schiffman移相器。其中一种相比于传统的Schiffman移相器工作在第一相位周期,而它工作在第二相位周期。并且使其该Schiffman移相器实现了90°的相移且实现了41.3%的相对相移带宽。另一种,通过改进传统的Schiffman移相器的主线,在主线上通过加载阶梯形的开路枝节线的方法来实现宽带上的相位变化。而参考线通过弯折的方法来减小体积。进而来计了一种工作在4-8GHz频带上的枝节加载型宽带移相器,也可称为改进的Schiffman移相器。实现了90°的相移和50%的相对相移带宽。该移相器带宽宽、体积小、相位稳定,非常适合用于固定相位差的相控阵天线中。更多还原

【Abstract】 In RF microwave systems,power dividers,couplers,phase shifters and other passive devices are usually designed to achieve power allocation or power combination and phase control functions.Microstrip line is widely used in passive device design because of its simple structure and low cost.However,due to its unshielded structure,crosstalk and scattering problems exist.Substrate Integrated Waveguide(SIW)inherits the advantages of microstrip line,and has the advantages of high Q value and easy processing.However,it can not propagate TEM mode and is not suitable for broadband passive device design.Substrate Integrated Coaxial Line(SICL)inherits the advantages of low loss,low cost and shielding structure of SIW.It is a technology for planarization of coaxial lines.At the same time,the SICL structure can propagate the TEM mode,which is suitable for the design of broadband passive devices,and can be integrated with other planar circuits.Therefore,SICL has great application value.The main work of this paper is as follows:Firstly,the directional coupler of 3d B is designed based on the theory of SICL.The 3d B directional coupler realizes the strong coupling of 3d B based on the common directional coupler and the interdigital coupling line structure.Secondly,based on the research of interdigital coupling line,combined with the principle of three parallel coupling lines,the structure of interdigital coupling line is further studied.It is found that the double interdigitated coupling structure can maintain a strong coupling effect on the premise that the volume of the conventional SICL branch coupler is reduced by more than half.Therefore,a miniaturized SICL branch line coupler is finally designed.Thirdly,based on the SICL technology and the basic principle of the transmission line phase shifter,two improved Schiffman phase shifters are designed.One of them works in the first phase period compared with the traditional Schiffman phase shifter,and it works in the second phase period.It makes the Schiffman phase shifter achieve a 90 degree phase shift and achieves 41.3%relative phase shift bandwidth.Another way is to improve the traditional Schiffman phase shifter’s main line and realize the phase change on the main line by loading ladder shaped open branch line.The volume of the reference line is reduced by bending.In addition,a branch loaded broadband phase shifter operating on the 4-8GHz frequency band is also introduced,which is also called an improved Schiffman phase shifter.The 90 degree phase shift and 50% relative phase shift bandwidth are achieved.The phase shifter has wide bandwidth,small volume and stable phase.It is very suitable for phased array antenna with fixed phase difference.更多还原