Optimal Design Of Smart Circular Array Antenn

With the continuous development of 5G mobile communication technology,outdoor communication services can no longer meet people’s normal needs,and better indoor communication services are needed to provide support.Therefore,indoor base station smart antennas are becoming more and more important in mobile communications.In order to achieve full-area coverage of indoor communication signals and reduce the large attenuation of energy during communication,indoor base station antennas usually adopt a circular array structure with vertical polarization characteristics.The main research contents of this paper are:1.Based on the monopole,two eight-element intelligent circular array antennas with a working center frequency of 3.4 GHz are designed,and the element is composed of a monopole Yagi antenna.The two array antennas adopt different metal ground structures,and two working modes can be realized in the azimuth plane: one is omnidirectional radiation mode,that is,each port of the array antenna is given equal amplitude in-phase excitation,and when the two antennas work in this mode,they not only have good omnidirectional performance,but also have omnidirectional gain greater than 3.6 dBi;The other is directional radiation mode,by presetting the receiving antenna at the far field of the array antenna to build a wireless power transmission system,and using the maximum power transmission efficiency method to optimize the optimal excitation distribution of the array antenna,continuously changing the position of the receiving antenna,obtaining the excitation distribution of the array antenna at each position,the array antenna finally realizes a 360°continuous and stable beam scanning function in the radiation azimuth plane,and the gain fluctuation during beam scanning is less than 0.5 dBi.The array antenna with a complete floor structure has a beam upturned of 20° due to the ground induced current,and the peak gain reaches 12.0 dBi.The maximum radiation direction of the array antenna with slotted local floor structure is in the horizontal plane,and the peak gain is 11.1 dBi.2.Based on the magnetic dipole,a sixteen-element intelligent circular array antenna with an operating frequency of 3.4 GHz is designed,and the element is composed of a microstrip Yagi antenna,and the array antenna could achieve vertical polarization at a height of only0.045 λ in profile.The array antenna can also realize two working modes: omnidirectional radiation mode and directional radiation mode,when working in omnidirectional radiation mode,the array gain is 2.0 dBi,the circularity is less than 0.5 dB,and it has good omnidirectional performance;When operating in directional radiation mode,using the same beamforming method,the array antenna can achieve 360° continuous and stable beam scanning in the horizontal azimuth plane,with a gain fluctuation of less than 0.2 dBi and a peak gain of 13.1 dBi during beam scanning.