Comment on ´Application of OSRC operator of third order to electromagnetic scattering from conducting or dielectric cylinder´

For original paper, see Z.-H. Cheng and W.X. Zheng, ibid., vol.27, no.10, p.806-8 (1991). The original authors presented the third order OSRC operator to improve the calculation accuracy of scattering by 2-D objects and seemed to suggest that for all 2-D objects the accuracy can be improved by employing a higher order OSRC operator. The commenter would like to point out that the third order OSRC operator can be much more easily developed by the recursion relationship. The efficiency of higher order OSRC operators has been demonstrated in detail by applying OSRC operators of different orders to both conducting cylinders and impedance cylinders. Other doubts about the original paper are expressed.