In this paper, a 3D model for studying electromagnetic wave propagation in 2D guided-wave photonic crystals is presented. The model is based on the resolution of the integral-differential Green equation associated with the Helmholtz wave equation in cylindrical coordinates, in order to provide a simple and time-efficient vectorial representation of the field components. The model, used for the investigation of a photonic crystal waveguide which operates at a wavelength of 1300 nm, is validated through a comparison with other well-known algorithms. Results show a good agreement together with a significant reduction of computational time and memory requirements.