In Td-scdma Smart Antenna Of Power Transfer Phase Shifter

With the rapid development of modern mobile communication technology, China has been stepping into the 3G era. The 3G international standard adopted by China is TD-SCDMA standard. The TD-SCDMA international standard is proposed by China itself, and it breaks the monopoly of Europe and US in high-tech area. Electrically adjustable antenna, as one of the key technologies in TD-SCDMA, has a significant influence on the performance of wireless communication system. And phase shifters which are widely used in base station electrically adjustable antenna arrays, always play crucial roles in the mobile communication system.In this thesis, the author adopted the way of studying the existent electrically adjustable antennas and variable phase shifters to understand the performance of them. A lot of studies on the shortcomings of them were carried out, in order to design some novel phase shifters with better performances. Particularly, considering the current phase shifters usually have problems such as large size, narrow phase shift range, high cost, etc, the author tried to design new phase shifters to overcome these problems. Two types of phase shifters were proposed and designed, which are much better in aspects of size, phase shift range and cost. Besides, aiming at the base station antenna's problem of big size, over weight, much cost and poor beam convergence, the author designed an antenna element which is much better in these aspects as compared to conventional base station antenna elements. Finally, a±45°polarization printed dipole fed by an inverted J balun was designed.The main contents and innovative points in this thesis are summarized as follows:1. The performances and shortcomings of existing phase shifters are analyzed, and the slow wave structure widely used in wave tubes are introduced into the phase shifter design.2. Two types of phase shifters were designed, including the phase shifter with a helical structure and the phase shifter with a comb-like structure. As compared to conventional phase shifters, both of them show better performance in terms of the size, cost and phase shift range. 3. A±45°polarization printed dipole fed by inverted J balun was designed. The dipole antenna has small size, light weight and low cost, and can be widely used in urban mobile communication base station antenna array.The two types of phase shifters and the printed dipole designed in this thesis have solved some problems existed in the existent electrically adjustable antennas, which have great practical value and good market prospects.