| The antenna arrays have always played an important role in antenna applications.All kinds of antenna arrays play an irreplaceable role in various communication systems.Especially in the emerging millimeter wave communication,the path loss and the absorption of air and rainwater are serious.So the transmission attenuation caused by this need to be compensated by more sufficient signal power to complete the communication process normally.In the application of millimeter-wave antennas,antennas are usually constructed in arrays and beamformed to get high gain and relay strong losses and attenuation.Among them,the circular microstrip antenna array has been widely used in radar and other communication systems because it can provide omnidirectional angle and provide the same beam at different angles in azimuth plane.In the research of beamforming,the mutual coupling between array antenna elements often leads to the deviation with the designed radiation characteristics.The active element pattern is a kind of pattern which includes the influence of coupling between elements and the physical environment of the array.So in the pattern synthesis of antenna arrays,if the active element pattern can be introduced into the calculation,the precise array radiation pattern that close to the actual value can be obtained.Applying the obtained pattern of active elements to the calculation of beam synthesis can effectively improve the deviation caused by mutual coupling and some other reasons.Based on the above problems and analysis,the decoupling technology in beamforming of circular microstrip antenna array is studied in this paper.The main contents of this paper are as follows.Firstly,aiming at the decoupling technology based on the active element pattern,the pattern synthesis formulas of uniform linear array,uniform rectangular planar array and uniform circular array are analyzed from the theory of wave superposition,and then the pattern synthesis formulas of numerical synthesis calculation based on the active element pattern are obtained.On this basis,a validation study is carried out.Then,the selection of dielectric substrate material,antenna size calculation and feeding mode in microstrip antenna design are also studied.And microstrip antenna element with resonant frequency of 26 GHz is designed and optimized.Based on this array element,microstrip array antennas such as linear array,rectangular planar array and annular array are designed as research objects of pattern synthesis and beamforming.Finally,two kinds of circular microstrip antenna arrays with 8 and 64 elements are designed,and the beamforming of cosecant square beam and flat-top beam in 64 elements circular antenna array is designed on the basis of active element pattern. |
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