天线的阻抗分析与测量

【作者】 王峰；

【导师】 邹澎；

【作者基本信息】 郑州大学 ， 电磁场与微波技术， 2007， 硕士

【摘要】 当今，随着无线通信和电子技术的发展，使用的频率也越来越高，在电路设计时，对电路的匹配程度的要求也越来越高，其中天线和电路的匹配在电路设计中的应用更为广泛。因此，需要知道比较精确的天线的阻抗值，并在此基础上探索天线阻抗的匹配问题。然而不是所有的天线都能比较精确计算的，因此，设计一个快速的天线输入阻抗的测量方案来代替天线阻抗计算是电路设计的一个必要的基础。本课题的目的就是研究天线阻抗的分析，计算方法和匹配电路设计方法，并且针对安捷伦4396B网络分析仪，设计一个天线阻抗的测量方案，并验证该方案是可行的。为了比较测量结果，论文中分析和计算了线天线(对称振子天线和单极子天线)的阻抗，针对这两种天线，分别采取了解析法、改进型等效传输线法和时域有限差分法等多种计算方法计算天线的阻抗，并与测量结果进行比较，来验证测量方案的可行性。本课题又论述了宽带天线的匹配网络设计方法，深入分析了两种匹配网络元件的计算方法——直接优化法和驻波比法。在匹配优化程序设计中，提出两种匹配方法的算法，并且基于matlab开发平台优化出来了匹配网络所需的元件值。文中提出了把优化目标函数时采取的最小二乘法算法应用于驻波比法，计算出匹配电路的元件值。本文自制一环形天线，测量出该天线的输入阻抗和驻波比，并计算出该天线的驻波比，经比较进一步验证测量方案是可行的。在此基础上优化出匹配网络的元件值，连接电路，并测量出连接匹配网络后的天线的驻波比。比较前后结果，匹配方法改进了驻波比的值，提高了匹配程度。更多还原

【Abstract】 Today, as wireless communications and electronic technology development, the frequency of use increases. In circuit design, the extent of the matching circuit is increasingly demanding, especially antenna impedance matching circuit is more and more important when design circuit. Therefore, it is necessary to know more precise antenna input impedance, and explore the antenna impedance matching. Not all the antennas will be accurately calculated, and calculation antenna model is often ideal model, therefore, a quick antenna input impedance measurement program is a necessary foundation to circuit design.The purpose of this thesis is to design an antenna input impedance measurement programs aiming at the Agilent 4396B network analyzer, and certificate that the program is feasible. To compare measurements, Papers analyze and calculate the line antenna (Dipole Antenna and monopole antenna) input impedance, and against the two antennas, respectively, take the analytical method, Improved equivalent transmission electro circuit method and the finite difference time domain method. The results of calculation by a variety of methods and measurement results were compared to verify the feasibility of measuring programs. In this paper, I measured the laboratory standard antennas and two homemade antennas.This thesis carefully analyzes the broadband antenna matching network design methods, and discuss the two calculation methods of matching network elements -direct optimization and VSWR method. This paper presents two methods of matching algorithm, and optimizes matching networks components values basing on the matlab development platform. This paper innovational develope the least square algorithm of optimization objective function. This paper makes a loop antenna and measure the antenna input impedance and VSWR. and calculate the antenna VSWR ,which further tests measurement program is feasible. Based on this optimal design matching network components values, connect circuits, and measure the antenna VSWR which matching network is connected. Comparing both results, matching method improved VSWR values, and the matching degree.更多还原