The tapered incident wave is introduced into the classical Kirchhoff approximation (KA), and the shadowing effect is also taken into account to make the KA results have a high accuracy.

• 首先，将入射锥形波引入到传统的基尔霍夫近似中，并且考虑了遮蔽效应，对基尔霍夫近似进行修正，使其计算结果精度更高。