Dual-Frequency/Dual-polarization Antenna For 3G Mobile Communication Base Station

This paper primary introduces the design of the dual-frequency/dual-polarization antenna which is used in the base station and operated in two frequency band:820～960MHz and 1710～2170MHz. The demand of this design: every index should stand strictly to the country standard.It is composed of that: the design of the element of the antenna, the design of the feeding circuit network, the design of the array of the antenna.The probes and patches were used in the element. The mechanism has been studied and the choice has been made as this:The probe: we have analyzed the T probe and L-probe by simulation and trial-production.The patch: considering the configuration and the capability index,the single patch was adopted in the low frequency and the double patch was adopted in the high frequency.The cable and PCB, by which the power divider was made, were both adopted in the feeding circuit net work. This paper has introduced the design process of the power divider in detail: to compute micro strip line's width and length, to simulate, to product, to adjust to the good capability index.The antenna array was assigned in the same space and the same phase, to achieve the highest gain and to achieve the demand that different frequency have different element space, a mass of experiments have been made, the prime space was determined ultimately. Finally the technique how to control the radiation pattern was studied, and it is the needed of optimizing the network, which is that the upper side lobe was controlled and the lower first null was filled.This design has completed the dual-frequency/dual-polaried base station antenna with eight high frequency elements and four low frequency elements. The result perfectly achieved the country index. It includes both 2G and 3G frequency. So it is ready for the transition from 2G to 3G.