【作者】 陈小强；

【导师】 任恩恩；

【作者基本信息】 兰州交通大学 ， 交通信息工程及控制， 2010， 博士

【摘要】 脊波导作为微波通信器件广泛应用于微波传输,空间技术、电磁兼容与电子对抗等领域。随着我国铁路信息化和现代化的发展,由脊波导构成的微波器件被广泛应用于铁路交通信息系统及控制系统领域。例如用双脊波导制作的铁路驼峰测速雷达,以及应用于高速铁路无线通信系统中的波导器件等。论文以复杂结构脊波导为主要研究对象,首次提出了三角形和倒梯形两种新型脊波导。利用有限元数值方法,在Matlab环境下求解了具有复杂横截面结构脊波导的传输特性。系统研究了矩形脊波导、梯形脊波导、倒梯形脊波导和三角形脊波导的截止特性、单模传输带宽、阻抗特性、衰减特性和功率容量。研究结果表明：倒梯形脊波导具有高的归一化截止波长和单模带宽,低的特性阻抗,高的功率容量,适用于微波传输；窄边和三角形双脊波导的单模带宽小,不适用于单模信息传输,可应用于制作微波滤波器；非对称双脊波导双脊平移和单脊平移时,其单模带宽和截止波长变化与脊对称时的变化相接近,但错脊波导归一化截止波长较大,单模带宽变化范围较小,所以错脊波导不适.用于宽带传输系统,可用于窄带传输系统和制作微波滤波器。复杂结构脊波导传输特性的研究,使得有相同传输特性的微波器件的结构尺寸减小,易于实现微波器件的小型化和集成化。考虑到脊波导器件在使用和制造中可能产生的结构变形,论文重点研究了变形对常规单脊波导与双脊波导传输特性的影响。研究结果表明：错位变形时,只要变形在工程允许的10%范围内,其对截止特性和单模带宽的影响小于3%,这类变形对参数的影响在工程应用中可以不予考虑。单脊、双脊波导双边受力变形时,对传输特性的影响较大,且使特性变差,应用时应尽量避免；对不同的受力变形,只要保证变形程度不超过相应结构尺寸的8%时,可保证工程实际应用中主要传输特性的变化小于10%。本论文通过对复杂结构脊波导传输特性的系统分析,为设计新型微波、毫米波脊波导器件及拓展脊波导的工程应用范围提供了坚实的理论基础。得到的相关结论,将为脊波导器件的设计和工程应用提供指导。更多还原

【Abstract】 As one of the important high-frequency communication device, ridged waveguides have been widely used as microwave transmission lines in wireless communications, space technology, electromagnetic compatibility (EMC), and electronic counter-measures (ECM). With the increasing modernization and informationization of Chinese railway system, microwave components such as ridged waveguides have been employed in railway transportation information system and control system. For example, the double-ridged hump radar speed meter has been equipped in most of the railway yards. Ridged waveguide components have been widely employed in microwave wireless communication system in high-speed rail (HSR).The purpose of the present study is to determine the transmission characteristics of ridged metallic waveguides with complex cross-sections. Two novel ridged waveguides with triangular ridges and inverted-trapezoidal ridges were first proposed in this thesis. Finite element method was implemented in Matlab, and transmission characteristics such as cut-off wavelength, single-mode bandwidth, characteristic impedance, attenuation and power handling capability for ridged rectangular waveguides, ridged trapezoidal waveguides, ridged inverted trapezoidal waveguides and ridged triangular waveguides have been analyzed systematically. The inverted-trapezoidal waveguide is especially suitable for single-mode transmission because of its large cutoff wavelength of dominant mode, lower characteristic impedance and higher power handling capability. Double ridged waveguide with ridges on the narrow side and ridged triangular waveguides are ideally suitable for microwave filters because of their narrow single-mode bandwidth. Dependence of transmission characteristics on asymmetrical ridged structures have been studied which is almost the same as those of symmetrical structures. The antipodal ridge waveguide has larger cutoff wavelength and smaller single-mode bandwidth. It is suitable for the case where narrowband operations are required. Ridged waveguides with complex cross-sections provide a possible way for waveguide miniaturization. It should be possible to fabricate microwave components at considerable saving in size and weight with high integration.Another important contribution of this thesis is in studying the dependence of waveguide deformation on the transmission characteristics of normal single- and double-ridged waveguides. For the case of dislocation deformation, the influence on the cutoff wavelength and single-mode bandwidth is about 3% and can be ignored if the critical deformation is within 10%。For the case of deformation due to the external force, the transmission characteristics will be changed dramatically and the performance becomes worse. From practical engineering point of view, the variation of major transmission characteristics can be within 10% if the mechanical deformation doesn’t exceed 8%.Through the detailed numerical study of various ridged waveguides with complex cross-sections, this thesis presents systematic information for design of novel microwave and millimeter-wave ridged waveguide devices and provides a solid theoretical basis for expanding their application area. Numerical results in thesis are considered to be highly helpful in the design of various ridged waveguides in practical microwave engineering.更多还原