改进型IE-FFT结合物理光学的宽带分析方法

将物理光学方法与改进型积分方程-傅里叶变换方法相结合，通过引入基于Stoer-Bulirsch(SB)算法的自适应有理插值技术，快速分析电大载体平台上天线的宽带辐射特性．首先，提出基于子域快速傅里叶变换(FFT)的改进型单层FFT算法对格林函数插值，通过引入空组概念，加速迭代求解中的矩阵与矢量相乘计算，减少矩阵求解存储量，避免了对插值不准确的近场进行修正．同时，对于电流频率响应，根据SB算法的循环准则，利用阶数可变的有理函数作为替代模型，实现频域插值的快速计算．基于以上的改进，混合算法在频域分析时不仅减少了矩阵方程中未知量的个数，同时大大降低了内存需求和计算时间．数值结果表明，该方法可以快速有效地分析大型载体平台上天线的宽带特性．

Wide-band analysis using the modified IE-FFT and physical optical hybrid method

A highly efficient computational electromagnetic technique based upon the well known PO formulation combined with the modified IE-FFT and adaptive Stoer-Bulirsch frequency-sampling method is applied to wide-band analysis of antennas radiating in the presence of electrically large conducting platforms. By interpolating Green's function and introducing the concept of empty groups, the modified single-level FFT algorithm which is based on the subdomain FFT acceleration is employed to reduce matrix storage and to accelerate all the matrix-vector multiplications in both the linear system for moments and the iterative solver. Otherwise, the correction of the near-interaction is avoided. For the frequency response of electric currents, the SB algorithm using the rational approximation solution and the recursive rules is utilized to achieve fast frequency sweeping. Due to the above modifications, the PO hybrid method utilizes fewer unknowns and requires less solution time. Numerical examples are given to verify its validity.