Optimal Design Of Circularly Polarized Reconfigurable Array Antennas

With the rapid development of global communications services,various services have increasingly demanded bandwidth.Therefore,broadening bandwidth has become the top priority of the electronic information industry.Antenna is an indispensable and important part of the information industry,and the overall design requirements are also developing in the direction of miniaturization and high integration.In addition,in order to meet more people’s needs,circularly polarized antennas have begun to be favored.Circularly polarized waves have significant advantages in anti-multipath interference and reducing polarization mismatch,and have been widely used in satellite communications and military communications.However,a single microstrip antenna unit has low gain and narrow bandwidth.In order to pursue higher gain and achieve more functions,the best choice is to combine multiple antenna units to form an array.The microstrip array antenna can realize the polarization reconfigurable function of the antenna,and the phased array antenna that controls the excitation can also realize the large-angle scanning function,which has great applications in the field of terminal antennas.To this end,this article designed three circular polarization array antennas,the main research content includes: 1.First,we design one new low-profile 36-element microstrip array antennas.The difference from the ordinary microstrip antenna array is that the component unit of the antenna is not a rectangular patch,but the rectangular patch is cut corners to turn it into a left-handed circularly polarized microstrip unit,and then 36 The units are placed on the surface of the substrate at equal intervals to form an array.The design works at19.7GHz-20.2GHz respectively,using the Maximum Power Transmission Efficiency Method(MMPTE),by placing a circularly polarized receiving antenna with known polarization characteristics in the far field to obtain the frequency optimize the excitation distribution and bring into the array to artificially control the polarization characteristics and deflection direction of the array emitted wave.2.Secondly,in order to find out whether the above design method is applicable at low frequencies,a 16-element antenna array is designed with a center frequency of 2.45 GHz.The maximum power transmission efficiency method is also used to obtain the excitation distribution,and the reasons for the large gain difference that affect its different polarization characteristics are analyzed,and another 16-element circular polarization antenna array is designed by replacing the material.The same method obtains the optimal excitation distribution and gain the difference does not exceed 1dBi.Finally,the actual object is made,and compared with the experimental results,the experiment shows that the array antenna can realize the circular polarization reconfigurable and scanning function of the beam.3.Finally,design a double-layer dual-band array antenna that can work at19.7GHz-20.2GHz and 29.5GHz-30 GHz at the same time,and use the maximum power transmission efficiency method to obtain the excitation distribution.In addition to realizing dual frequency bands,the antenna can also greatly reduce the size of the array antenna and realize the miniaturization and compactness of the antenna array.The simulation experiment results show that the antenna array can achieve gain greater than 16 dBi in both frequency bands,while the scanning angle can reach 60°,and the axial ratio of each angle can be guaranteed to be less than 4dB.