Research On Compact Dual Polarization Magneto-Electric Dipole Antenna For Base Station

Base station antenna is one of the crucial components in RF front end in wireless communication system.Its performance effects the quality and stability of the signals in base station system. With the rapid development of 4G communication system,it has a great significance to study and to design small size and dual-polarized base station antenna for the popularization of 4G communication system.Compact structure and dual-polarized base station antenna is studied in this thesis,the main work includes the following aspects.First,based on Magneto-electric Dipole complementary theory and the characteristic that the radiation pattern of electric and magnetic dipole is complementary^ single polarized compact Magneto-electric Dipole complementary antenna for base station is proposed.It is excited by coaxial balun in order to direct current (dc) grounded for lightning protection in outdoor applications.With the folded copper sheet,it achieves a compact and low altitude structure while the height is 16mm (0.13?).Through parameter analysis,it is fabricated and tested at the center frequency of 2.3GHz and the bandwidth (VSWR<2) is 1.94GHz-2.75GHz, both the gain(around 7dBi) and radiation pattern is stable in the working bandwidth and stay same as the simulation results.Secondly,on the base of design thought of single polarized antenna.a ±45° dual-polarized antenna is proposed and its height is 25.7mm (0.19?).The test results show that its bandwidth (VSWR?2) of port 1 and port 2 is 1.75GHz-2.62GHz and 1.59GHz-2.51GHz and other performances are sized up to the requirements of base station antenna.Thirdly,an improved feed structure for the dual-polarized antenna is proposed.which can broaden the bandwidth of port 2 from 1.66GHz-2.56GHz to 1.62GHz-2.80GHz while the bandwidth of port 1 maintains the same.Finally,the influence of units number and distance between units on the performance of dual-polarized antenna array is studied and an eight units dual-polarized antenna array is proposed. The gain of the array is 18dBi and the working bandwidth(VSWR?2) is 1.7GHz-2.5GHz. The half-power beamwidth of yoz and xoz plane is 60° and 8°, and the radiation performances also meet the requirements of base station antenna.