【作者】 王君；

【导师】 张福顺；

【作者基本信息】 西安电子科技大学 ， 电磁场与微波技术， 2006， 硕士

【摘要】 本文研究了在VHF波段机载定向天线的设计理论和工程实现方法，给出了满足电指标的工程可用的对数周期天线形式。采用基于矩量法的IE3D分析软件，分别对印刷平面对数周期天线、常规对数周期天线和双对数周期天线进行了优化仿真设计，给出了相应的天线尺寸，比较了天线的方向图指标，筛选出只有双对数周期天线可以满足机载天线的工程要求。由于机载天线对重量和尺寸有着非常苛刻的要求，在上述设计的基础上，必须对天线的重量和尺寸进行重新设计，为此，文中利用相同的分析软件对天线尺寸进行了二次设计，并采取振子折叠的方法缩小对数周期天线的横向尺寸实现了满足工程要求的天线尺寸；研究结果表明，印刷平面对数周期天线，与常规对数周期天线相比较，具有重量轻、体积小的特点，但是其馈电端集合线尺寸太窄，因此，在工程实现中有许多不好解决的问题，例如馈电电缆焊接，并且该天线的驻波系数在工作频带内总有个别点达不到指标要求，而线状管形双对数周期天线具有良好的电指标。在前述研究工作的基础上，我们研制了两种形式的双对数周期天线实物样机，对其电性能进行了测量；测试结果表明，线状管形双对数周期天线具有宽带(2倍频)、高增益(9dBi)、小型化(580×580×1000mm~3)等特点，完全满足了机载状态下对天线的要求，同时也表征了本文研究方法的正确性和研究工作的实用价值。更多还原

【Abstract】 The design theory and implementation method of the directional airborne antenna on very high frequency (VHF) band are discussed. Two types of the log-periodic antennas, the traditional log-periodic antenna (LPA) and the printed planar version, are designed for the specified electrical and mechanical specifications. The size and electric parameters of printed planar and traditional log-periodic antennas are respectively simulated and optimized as well as dual LPA by the commercial software IE3D based on the method of moment (MOM), and the corresponding dimensions are obtained. Then their radiation characteristics are compared, and the results indicate that the dual LPA is a probable candidate which can meet the requirements of airborne antenna. Due to rigorous limitations of the weight and size, the antenna is redesigned using the same software, and the dipoles should be folded to shorten the width of the antenna. Compared with the traditional log-periodic antenna, the printed planar one has the advantages of light weight and small size. But the feed line of the printed planar LPA is too narrow, some troublesome problems appear during the engineering realization such as the coaxial cable jointing. Moreover, the antenna has no a good impedance match on some frequency points. However, dual traditional LPA with linear and tubular dipoles has good electrical characteristics. Based on the aforementioned, the two types of dual LPAs are manufactured and measured. The measured results show that dual log-periodic antenna with linear and tubular dipoles is of wide band (2:1 bandwidth )、high gain (9dBi)、small size (580×580×1000mm~3), and fully satisfies the requirements of airborne antenna, and that this research method is valid and the work is valuable practically.更多还原