To fast and accurately calculate the EM scattering problems like radiation of antenna around complex objects, many different techniques have been performed. However, these techniques (exact solution methods) either have a long calculation time or they (hybrid methods) tend to fail when the antenna is near or adjacent to structures. In this study, to make the scattering analysis of antennas fast and accurately, proposed stationary phase method (SPM) based hybrid MoM-PO method is implemented. For the geometrical modelling part, the antenna and its close vicinity is modelled with triangular facets, and the rest of the structure is modelled with non-uniform rational b-spline (NURBS) surfaces which provides efficient and accurate modeling. Maximum 1.7 dB of difference in the radiation pattern is observed for an antenna positioned around a curvy plate, when the results are obtained by using MoM and the proposed method. Despite that little difference, the calculation time for MoM is around 41 minutes; whereas for the proposed hybrid method it is 9 seconds. Overall, this hybrid formulation and NURBS modeling allow a substantial reduction of computation time and memory requirement to analyze radiation of antennas that are even close or connected to structure surfaces.