红外/微波波束合成器近场均匀性分析

针对矩量法（MoM）计算电大尺寸介质近场分布的低效率，提出使用口径场积分法（AFIM）分析红外/微波波束合成器近场均匀性，对比表明，AFIM相对MoM偏差小于10%，计算时间从数小时缩短至数秒.以电场分布曲线的标准差为均匀性指标，计算表明波束合成器近场均匀性关于D2/λL成负幂函数关系（D为波束合成器口径，L为近场距离，λ为波长）.将该负幂函数用于波束合成器外形尺寸优化，优化结果通过MoM进行验证，相对偏差小于10%. 

Near Field Uniformity of IR/MW Beam Combiner

The method of moment (MoM) is inefficient in near field calculation of electrically large dielectric object, so that the aperture field integration method (AFIM) is employed for evaluating near field uniformity of IR/MW beam combiner. Compared to MoM, the calculation error of AFIM was less than 10% while the calculation time was shortened from hours to a few seconds. Standard deviation of electric field distribution was chosen as the evaluation criteria, and calculation showed that, the near field uniformity of beam combiner was a negative power function of D2/λL, where D was the size of beam combiner, L was the distance of calculated field, and λ was the wave length. The negative power function was used for optimization of size and shape of beam combiner. Optimized beam combiner was validated by MoM and the calculation error was less than 10%.