Optimal Desigln Of Base Station Smart Antenna Array

With the rapid development of mobile communication,base station antenna is an important part of base station system,which plays a vital role in mobile communication.Three representative base station smart antennas are designed in this paper and the main research contents include:1.Firstly,a 2.45GHz monopole antenna is designed and the monopole is folded twice.The overall height of the antenna is reduced to one tenth of the wavelength.The sleeve ground with a height of one-quarter wavelength is used to tune the direction of maximum radiation to horizontal plane.The antenna model is optimized by using HFSS simulation software and the optimal excitation is optimized by using the method of maximum power transmission efficiency.In the feed part,a voltage control circuit is designed to provide the optimal excitation for the antenna array.The experimental results show that the antenna has a good omnidirectional and directional characteristic.Compared with the same structure of the electronically steerable passive array(ESPAR)antenna,the four-element antenna with the optimal excitation is more than 2.7dBi with the same type of seven-element ESPAR antenna.2.Given the good direction and high gain of the Yagi antenna,two Yagi smart antenna arrays operating at 830MHz and 1800MHz are proposed in this paper respectively.Taking the center frequency of 830MHz for example,q quarter of a wavelength is 90 mm,the sleeve ground which applied in the antenna will increase the height of the antenna.So in the antenna array,Yagi antenna structure is introduced into the antenna design to tune the direction of maximum radiation to horizontal plane.To obtain the optimal distribution of excitations for the arrays,the gain of the array systems is optimized by using the method of maximum power transmission efficiency.The experimental results show that the design can achieve beam scanning in horizontal plane over 3 60°range in the directional radiation state and has good directionality.3.In order to reduce antenna height and transverse distance to install and maintain easily,a low profile dual-mode smart antenna array operating at 2.45 GHz is proposed in this paper.In order to make full use of the substrate,we choose four circular dipoles of the planar dipole to form an antenna array and a circular reflector is added to the antenna to adjust the directional gain.To obtain the optimal distribution of excitations for the arrays,the gain and front-back ratio of the array systems are optimized by using the same method.The experimental results show that the design is in dual-mode operation,switching between omnidirectional and directional radiation states and can realize the beam scanning of different angles.