Studies On Micro Base Station Atenna Techniques In New Genneration Wireless Mobile Communication

With the global commercial popularity of 3G and the beginning of 4G massive deployment, micro base stations are receiving more and more attentions in modern wireless communication system. Due to their merits such as small volume, easy to install, and easy for maintenance, micro base stations can be used to compensate for those short backs of traditional macro base stations in many aspects, such as locations of base stations, environmental protection and network coverage. However, due to the small volume of mini base stations, the antennas, as one of the core devices, have to behave better antenna performance. In micro base stations, miniaturization and broadband are even more required, while difficulty becomes more distinct in the port isolation improvement. Microstrip antenna and printed dipole antenna are always the primary choice for a micro base station antenna due to the advantages of low cost, easy to integrate and light weight. In this thesis, several microstrip antennas and dipole antennas which can be applied to micro base stations are proposed and designed for studies on some techniques such as miniaturization, broadband and high port isolation. The main contents are as follows:Firstly, the research background, development of micro base station antenna techniques and some dual-polarized antenna theories are successively presented and reviewed in the first two chapters.Secondly, a novel dual-polarized double E-shaped microstrip antenna element is proposed in the third chapter. The design process and performance analysis is described in detail. The proposed antenna element achieves the advantages of low profile and high port isolation.Thirdly, the proposed element is successfully extended to a 1×2 antenna element and a 2×4 antenna array according to the demands of LTE micro base stations. Through simulation and optimization, the antenna arrays behave good performances and are thus suitable for LTE micro base stations.Fourthly, some basics of full duplex and the technical difficulties of antennas used for full duplex are introduced in the fifth chapter, and a novel dual-polarized microstrip antenna fed by magnetic-coupled loop is proposed and designed. Based on the proposed element, a 1×2 antenna array with gradual shorted metal strips between the elements is designed. Simulated and measured results show that both the antenna element and the array achieve high port isolation characteristics and can be used in the full duplex system.Finally, a novel linearly-polarized printed dipole is proposed in the sixth chapter, with its mechanism analyzed and then extended to a dual-polarized antenna. Both the linearly-polarized and dual-polarized antennas achieve more compact sizes than those conventional dipole antennas. Besides, other advantages like wide bandwidth and high port isolation are also obtained. The proposed dual-polarized dipole antenna can be extended to antenna arrays for the IMT-Advanced system.