Research On Key Technologies Of Frequency-controlled Arra

It can be formed a time-varying beam with angle,distance,and time dependence for frequency diverse array,which overcomes the shortcomings of traditional phased-array beams that without contain distance and time variables and brings many unique application advantages.However,the traditional frequency diverse array exists distance-angle coupling problem.Therefore,the frequency diverse array beam optimization algorithms based on a uniform circular array structure and a uniform concentric circular array structure are proposed in this paper to solve the beam coupling problem.The distance and angle coupling problem can be solved by using linear frequency offset in the proposed methods,and the beam performance is superior.The main research contents and innovations of this paper as follows:1.The basic principles and beam characteristics of the frequency diverse array are analyzed and the periodic characteristics of the frequency diverse array beam with respect to distance,angle and time variables are discussed.Through mathematical formula derivation,the reason for the distance-angle coupling of the frequency diverse array is analyzed,and the idea of solving the coupling problem is explained.2.The methods to solve the beam coupling problem are discussed.First,the beam decoupling algorithms based on the optimized frequency offset method is analyzed,including:logarithmic frequency deviation method,exponential frequency offset method,genetic algorithm decoupling method,multi-carrier mode decoupling algorithm,etc.Then the frequency diverse array decoupling algorithm based on the array structure is analyzed,and the advantages of the frequency diverse array based on the uniform circular array are discussed.Finally,in order to optimize the beam performance of the circular array structure frequency diverse array,the frequency diverse array based on uniform circular array with the multi-carrier mode is proposed.3.Discussed the beam optimization algorithms of the concentric frequency diverse array,the advantages of the concentric structure frequency diverse array are analyzed.In order to further optimize the beam performance,the improved concentric structure frequency diverse array beam optimization algorithm and the multi-carrier mode concentric structure frequency diverse array beam optimization algorithm are proposed to optimize the performance of the beam in the distance dimension,and the frequency diverse array beam optimization algorithm based on concentric structure with the same number of array elements is created to optimize the performance of the beam in the angle dimension.Theoretical and simulation results indicate that the frequency diverse array beam optimization algorithm based on the uniform circular array structure and the concentric circular array structure,proposed in this paper,can solve the coupling problem and achieve the purpose of beam focusing by using the linear frequency offset,which overcomes the shortcomings of traditional methods that the non-linear frequency offset must be used to realize the beam focusing.The beam performance results show that the series of beamforming and optimization algorithms proposed in this article have superior beam performance.