Abstract: To further improve the ability of analyzing electromagnetic scattering from electrically large perfect electric conducting objects, an efficient domain decomposition method is presented. In this method, the approximated current density is expanded with the phase-extracted basis functions defined over curvilinear triangular patches, and the number of unknowns to be solved is significantly reduced. Meanwhile, to further reduce the memory requirement, the original problem domain is divided into a number of small overlapped sub-domains and the sub-domain problems are solved one by one. In addition, the buffer regions introduced in this method are limited to only a single layer of jagged triangular mesh cells whose edges are about half a wavelength long, leading to a simplified construction process of buffer zones as well as a smaller number of additional variables to be solved. A good convergence behavior is observed. The multilevel fast multipole algorithm is applied to accelerate the matrix-vector products. Numerical examples are given to show the efficiency and robustness of the proposed approach.