Efficient IE-FFT and PO Hybrid Analysis of Antennas Around Electrically Large Platforms

An efficient hybrid analysis that combines integral equations (IE) with physical optics (PO) approximation is presented for antennas around an electrically large platform. In the analysis, the whole surface of the platform and antennas is divided into two regions, namely, the full-wave region and the PO region. In the full-wave region, the IE is modified by coupling into the PO contribution. Similar to the fast IE method, the modified impedance matrix is decomposed into the near-field couplings and the well-separated group couplings, respectively. By interpolating the Green´s function, the couplings between two well-separated groups can be computed using fast Fourier transform (FFT). Due to the PO approximation, the hybrid method utilizes fewer unknowns and requires less solution time than the conventional IE-FFT.