IFFT Algorithm Based On Mutual Coupling Compensation Matrix And Its Application

The wide-angle scanning phased array antenna has received extensive attention from researchers in the past few decades due to its wide field of view performance.Its basic goal is to broaden its beam scanning range while ensuring the basic performance of the array.In the early days,researchers mainly built wide-beam antenna elements to widen the scanning range of phased arrays.However,in addition to the element factor,the array factor also has a great influence on the radiation performance of wide-angle scanning phased array antennas,For example,as the scanning angle increases,high side lobes will be generated.Therefore,we need to analyze and synthesize the phased array to solve these problems.Array antenna synthesis refers to the design of the number,spacing,excitation amplitude and phase of the array elements given the radiation pattern of the antenna or certain characteristic parameters to achieve the desired effect.Classical array synthesis methods include Chebyshev synthesis method,Taylor synthesis method,etc.Later,intelligent optimization algorithms were proposed for array synthesis,such as genetic algorithm,particle swarm optimization algorithm,immune algorithm and so on.These methods have good results for the synthesis of small arrays,but they are not suitable for large arrays.Therefore,some methods that use the special properties of array factors to quickly analyze and synthesize arrays have been proposed,and the most representative one is the iterative fast Fourier transform technique.However,the application object of the IFFT technology is the array factor,and the mutual coupling effect between the arrays cannot be considered,which may cause a certain deviation between the optimization result and the actual result.Therefore,this paper analyzes the mutual coupling effect between the arrays,and introduces the mutual coupling compensation matrix to eliminate the mutual coupling effect caused by the low side lobe synthesis.In combination with the AEP method,the mutual coupling compensation matrix is solved and after verification,an IFFT technique based on mutual coupling compensation strategy is proposed.In order to verify the speed and reliability of the proposed algorithm,the algorithm was first applied to two examples composed of microstrip patch antennas for low-sidelobe synthesis,which achieved good results.Then the proposed algorithm is applied to the low-sidelobe synthesis of a wide-angle scanning phased array antenna,and the optimization results of the genetic algorithm are compared for different numbers of array elements.The comparison shows that the proposed algorithm takes much less time than the latter when the array performance is basically consistent.It should be noted that,unlike the AEP method,this paper uses a mutual coupling compensation matrix to calculate the coupling strength between the array elements,and uses the least squares method to solve,that is,the mutual coupling compensation matrix is used to extract the anisotropic parts of the array In addition to accumulating symbols,IFFT technology can be used for fast synthesis.