| High-frequency communication is widely used in Military and Civil products due to its advantages.Antenna is an essential part of the wireless communication system. With the developing progress of science and technology and the growing requirements of high capacity and accurate real-time communication, and the shrinking communication equipments, the large physical size、low gain and efficiency of the high frequency antenna can not meet the request, this makes the broadband antenna miniaturization research become significative. Wire antenna is widely used for it’s potential broadband characteristics, loading resonant circuits and suitable matching networks make it possible to realize miniaturization with broadband characteristics at the same time.This article starts with the fundamental theory of wire antenna,and researches the broadband and miniaturized methods of the high frequency antenna. Firstly, a brief review is given to show the historical process of the analysis theory of wire antenna. Based on this, the research survey in the field of high frequency antenna miniaturization at home and abroad is analyzed to confirm the research contents of this article. A series of uniform cylindrical section is adopted to approximate the electrically small wire antenna’s geometry shape, and methods for analysising the simulation of the geometric structure is confirmed. Several technology which can be used to broaden the bandwidth and miniaturize wire antennas is researched. Several softwares are used to optimize the simulation. A broadband miniaturized antenna which works in the frequency range3MHz-30MHz and have the size of10.4metres×2.3metres is designed. It is obtained by loading the LC Series and parallel resonant circuit with hybrid resistive in double folded monopole structure and optimized by genetic algorithm At the same time, a series of10:1,50:1,100:1scaled model is designed according to the same method. A design scheme is put forward for improving the indicators of the antenna and is implemented in100:1and50:1scaled model.When the antenna is increased to the opposite2-unit model, the band feed impedance is about100ohms.When the antenna is increased to the "cross" four-unit model, matching network can be saved, and the antenna is directly connected with the50ohm coaxial line to realize matching. For the solution of the100:1scaled model, the antenna size is0.106m×0.046m×0.046m,wire radius r=0.0008m,the maximum physical size is nearly1/9.4lower part of the band. The Antenna’s Φ-average gain in horizontal plane is more than-1.5dB not only in the concerned band of300MHz-3000MHz but also until5000MHz, and it realized a good omnidirectional radiation.The designed antenna generates enough uniform radiation at different elevation for the entire HF frequency range. Finally, a50:1scaled model is manufactured and VSWR is measured, the theory is consistent with the actual result.In this article, the geometric structure simulation and analysis of simulation structure of high-frequency electrical small wire antenna are researched. Various broadband antenna miniaturization are the analysised and comparised. The strategy to get small broadband high-frequency wire antenna is put forward, and the antenna designed by this strategy has the advantages of easy construction,wide frequency band, small size, simple structure, easy matching, high gain, uniform radiation levels,convenient using and maintenance. |
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