The Research And Design Of One Broadband Dual-polarized Base Station Antenna

Base station antenna is the receiving and launching device of mobile communication system, and the pros and cons of its performance will directly affect the quality of the whole communication system. With the continuous development of mobile communication,2G,3G,4G systems will co-exist for a long time. Broadband antennas can provide services to multi-systems simultaneously, which effectively reduce the sum of antennas, thus solving the issues of site selection and greatly lowering the cost.This paper is done under the project of researching the broadband dual polarization antenna, which is launched by Liaoning Putian Digital Limited Company and processed in the Institute of Microwave and Antenna of Dalian Maritime University and the main work is as follows:(1) A broadband dual polarization antennas is designed, which is simple, small size and suitable for 2G/3G/LTE(4G) communication system. The antenna with symmetrical structure, consists of two rectangular dipoles which lie on both sides of substrate. It is fed by an open circuit micro-strip line and matched with a short circuit micro-strip line, with a U-shaped slot on the surface of rectangular dipoles to reduce the antenna size. The antenna has 49%(1.66 to 2.73 GHz) relative bandwidth(S11<15dB), and Gain is about 8dBi.(2) A broadband dual polarization antenna with asymmetric structure is designed. Based on the design of the first one, the second change the structure of dipoles which broaden the bandwidth and improves the isolation. The antenna has 49%(1.66 to 2.73 GHz) relative bandwidth(S11<15dB), with stable radiation pattern in the whole frequency range, and Gain is about 8dBi.(3) A broadband ±45° dual-polarization base station antenna array with eight units is designed, array unit using the asymmetric broadband dual polarized antenna which has 53% relative bandwidth. An eight-way equal-split Wilkinson power divider is designed for antenna array feed. The results show that 58% relative bandwidth is obtained by antenna array, covering 1.65-2.99 GHz. Within the working frequency band, the minimum isolation is about 22 dB, and the radiation pattern is stable with 3-dB beam-width 69±5°. Thus the antenna array can be applied to 2G/3G/LTE communication system in the city.