In this paper, we consider some techniques to reduce the bend losses. We apply the method of moments to analyse the reflection of millimeter waves from the right-angle bend. The global basis functions were used to reduce the number of unknowns per metal post and the necessary computer memory is also reduced. Furthermore, the Galerkin method was used to obtain a sytem of linear equations. Therefore, the resulting matrix is symmetric. Since the objects were confined to circular metallic posts, the elements of matrix were calculated in closed form and no numerical integration is needed. It will be shown that only a few additional posts are set at appropriate positions in the post wall waveguide, almost all incident waves go around the corner and the bend losses are minimized. Especially, only one additional metallic post is enough to minimize the bend losses.