| Nowadays, mobile communication has been at a stage of multiple system co-existence, including 2G,3G and 4G, and developing towards next generation system. In order to upgrade systems steadily and decrease installation cost of base stations, it is an economic and effective method using one antenna to server multiple systems. This dissertation design a broadband dual-polarized annular ring base station antenna, which covers most frequency band of 2G/3G/LTE systems. The antenna is able to embed another antenna in its center, and together form a coaxial type multi-band dual-polarized base station antenna.Our design starts with optimizing antenna’s port characteristics. By employing techniques such as novel L-probe feeding structure and slot radiation patch, we successfully design an annular ring antenna operating from 1.7 GHz to 2.7 GHz with port isolation more than 35 dB. The antenna’s property is also verified by embedding a dual-polarized planar dipole element operating at higher frequency band in its center. Secondly, based on the mobile communication base station requirement on dual-polarized antennas, we designed a wave shape periodic metal pillar side wall, which greatly improve the annular ring’s radiation characteristics. The antenna element finally operates from 1.7GHz to 2.6GHz with stable HPBW of 65°±8°. The wave shape side wall is also optimized to improve the radiation characteristics of the designed embedded type dual-band antenna. At last, a four-element antenna array is designed base on the broad band annular ring antenna. The reason why array’s port characteristics decrease is discussed by analyzing the intercoupling and intracoupling of antenna elements. By installing wave shape side walls at every element and adjusting their structure parameters, a base station antenna array with favorable overall characteristics, which meet the mobile communication base station requirements, is finally obtained. |
PDF Full Text Request