Studies On Dual-polarization And High Isolation Microstrip Array Antenna

In the recent 10 years, more common users have been obtaining access to the internet. With the rapid development of the mobile internet, antennas transmitting high-speed signal are increasingly demanded. 3G technology has matured, 4G is also increasingly ubiquitous to be put into commercial use, and micro base station for radio signal transmission also plays a key role. The micro base station has the characteristics of low profile, low transmission power and low cost as compared to traditional base station.In micro base station,due to the small distance between antenna elements,there is an interference between each other. Thus, improving the isolation between antenna elements in such a confined area has important research significance.The high isolation and low cross polarization of the micro base station antennas are discussed in this paper. The main work of this thesis includes the following aspect.First of all, the research background and development status are introduced in the first two chapters of the thesis, including a discussion of the key parameters of high isolation and dual polarization antennas.Secondly, a new type of dual polarized patch antenna element loaded V-slot is designed. The design process and experimental results are given in details.The antenna element has a high port isolation and a low profile, which is suitable for base station antenna arrays.In the fourth chapter, a 4x4 antenna array is designed and simulated. Compared to traditional structures, the cross polarization performances of the antenna array loaded with fence are improved obviously, because of changing the current direction at the fence. In addition, design and simulation of a 1x4 antenna array are presented. The defected ground structure is used to reduce the direct coupling between the array elements.Finally, the 1x4 antenna array is fabricated and measured, and the test results are consistent with simulation results. The isolation of antenna array is better than 50 d B. The structure can improve isolation of co-polarization and cross-polarization port.The structure can be used in micro base station system.