| A radome-antenna system is an important part of major information equipment such as ultra-high-speed aircraft.The radome seriously affects sum and difference beams of an antenna,and thus results in aiming error.Electromagnetic computation is a modern way to analyze such kind of problems.The analysis of aiming error is very demanding on high computational accuracy,but the numerically accurate methods,such as the method of moments(Mo M),are too computationally intensive and require large storage,which prohibit them from accurate and efficient optimizing of aiming error.In order to solve the problem of high computational cost in the radome-antenna simulation using Mo M,the higher-order basis functions are used to reduce the size of the complex dense Mo M matrix by one order of magnitude(compared to the RWG basis functions),and meanwhile the large-scale parallel computing technique is employed to significantly improve the computing capability.Compared with the fast multipole method and other fast methods based on iterative solvers,the direct solver based on the lower/upper decomposition is used to solve the matrix equation,avoiding issues of slow convergence and divergence that iterative solvers may encounter.Aiming at the optimization of radome-antenna systems,to ensure that the multidimensional optimization fast and accurately converges to the optimal solution,a mutation operator and an adaptive weight are introduced to improve the global optimization performance of the particle swarm optimization algorithm.Combining the electromagnetic simulation algorithm with the optimization algorithm,the optimization method of sum and difference beams of the radome-antenna system based on the amplitude and phase control is studied,where the bottleneck is too much time taken to repeatedly solve the Mo M matrix equation in the iterative process.To eliminate this bottleneck,an optimization method using the eigen solution of the antenna array is designed.By using the linear combination of the eigen solution,the radiation characteristics of the antenna array can be efficiently computed after the adjustment of array element amplitudes and phases,which greatly improves the efficiency of the method.Extracting the eigen solution of the antenna array is essentially to solve the Mo M matrix equation with multiple right-hand vectors,and the matrix needs to be decomposed only once,which is also a advantage of the direct solver.In engineering applications,the optimization of a base station antenna is first taken as an example.The antenna radiation pattern is optimized by adjusting the spacing of the antenna elements,the amplitude and phase of each element,and the sizes of the substrate to reach the desired target.Then,for the radome-enclosed antenna array with larger sizes and more variables,the parallel higher-order Mo M is used to extract the eigen solution of each element,and the efficient optimization of the sum and difference beams of the large-scale radome-enclosed antenna system is realized to meet the engineering requirements.This method has been applied to the rapid optimization of the aiming error of large-scale radome-antenna systems in the aerospace field,which was a long-term challenging problem. |
