基于磁场积分方程法(MFIE),对脊波导传输特性进行研究,详细推导出脊波导的截止模式波数、模式电流、模式电磁场、TE和TM模式及衰减系数和特性阻抗等解析表达式,完善了其理论依据,为脊波导在微波通信工程中的应用提供理论基础.最后以双脊波导为例,仿真计算给出了双脊波导(a=2b)中TE10 模式随着 s/a和d/b 变化的电场等高线示意图.

利用等离子体对电磁波的独特响应,设计了一种可工作于30～512 MHz的新型超宽带等离子体天线.给出了等离子体天线的设计方法,说明了天线的系统组成,采用新形式及阻抗匹配网络实现了天线良好匹配;分析了等离子体天线的低雷达散射截面(RCS)特性;突破关键技术,研制了一套超宽带等离子体天线样机,测试了天线的匹配和辐射特性,测试结果与仿真结果互相吻合.研究成果可推广应用于各类低RCS载体平台的微波通信天线系统中.

The analysis on the transmission coefficients of frequency selective surface by the spectral domain Galerkin method is introduced briefly,which is based on the outspread of the plane wave and Fourier transform.The equation in spectral-domain is established by applying the Floquet's theorem.The surface current is expressed by using roof-basis function.The surface current and transmission coefficients can be got by this method.The transmission coefficients of a single ring frequency selective surface are measured and calculated.A good agreement between them is given.

The antenna feeder is an important part of an antenna.The antenna feeder design has great influence on the antenna performance.This thesis firstly found out the reason of the undesired aberrant pattern of the L/S dual-band antenna,and then presented an innovative antenna feeder of L/S dual-band antenna by applying skin effect and the impedance property of the short-circuited coaxial transmission line.The test results provee that the design is effectual and simple.

海面属于强反射平面,如何在强反射信道中抑制多径分量,实现信号可靠传输,工程中已积累了许多经验和方法.本文从圆极化天线抑制反射信号的原理、使用和安装的角度出发,提出了在海面强多径传播环境下,采用圆极化天线可以改善图像传输质量.试验结果表明:该方法切实可行,效果明显.