Analysis Of Large Phased Array Using Equivalent Electromagnetic Current Method

The high directivity antenna in microwave band mainly consists of reflector antenna,lens antenna,horn antenna and so on.Because of the high directivity,they have wide application in radar applications,however,they also have disadvantages in size,portability and Integration.Phased array has been widely used in radar communications and become the main development direction of radar in recent years for its adaptability,strong anti-interference ability,high flexibility,multi beam and large target capacity.Therefore,the accurate analysis of phased array is particularly important.The scale and complexity of modern electromagnetic systems have been greatly improved,and the accurate simulation design of large antenna arrays has brought great challenges to the conventional numerical methods in computational electromagnetics.With the rapid development of high performance computing technology,supercomputers have provided a powerful computing platform for the accurate simulation and design of phased array antennas,and can solve most of the problems of medium scale phased array antennas.However,supercomputers can do nothing for larger complex arrays because of the huge unknowns.At present,the main methods are approximate methods,so that the radiation characteristics of the whole array can not be accurately analyzed.In this paper,based on the idea of subarray and combining the advantages of Mo M,the total electromagnetic field of large array is solved by using the surface equivalent electromagnetic current of subarray.For simple arrays,Mo M can be used to calculate the surface electromagnetic current of the sub array in one time when all elements fed individually.The units from different location are processed separately and then accumulateed.The coupling between the elements and the elements environment in the array can be considered accurately by using the proposed method.Traditional methods can be used only to analyze array patterns.Differently,by using the surface equivalent electromagnetic currents of small arrays,the field at any points in the space can be calculated,which provides a new method for analyzing the electromagnetic environment around the array.In this paper,the reflection effect of ground is considered using the Image Theory,the array radiation characteristics of the array are analyzed,and the rotation of a small array surface electromagnetic flow is derived in detail,which provides an effective approach to the analysis of conformal arrays.In conclusion,In the case of effectively reducing the computational complexity,the proposed method takes into account the influence of the coupling between elements accurately,and is suitable for arrays of arbitrary types of antenna elements.Therefore,it is of great value to predict the radiation field of large array antenna in engineering practiceAt last,some small phased arrays are simulated and compared with the full wave simulation method.The results are in good agreement.The linear array pattern of 2000 elements are analyzed;The radiation characteristics of planar array containing 80x80 units are analyzed;the radation characteristics of the array at the actual attitude and the electromagnetic environment around the array are analyzed;the influence of the ground on the radiation characteristics of the array is analyzed by using image theory;A three-dimensional pattern of a spherical array consisting of 30 thousand elements is provided,the results were in line with expectations.The method provides accurate theoretical basis and efficient analysis means for the design and optimization of large phased array in practical engineering,and also provides a new method for testing the electromagnetic environment around the array.