An improvement of the wave concept iterative procedure (WCIP) is implemented for bulky devices without involving excessive computational storage and simulation times. The description of such features has been a major difficulty since both small and large dimensions exist which led to hardened constraints when accuracy is required. An alternative consists in the use of appropriate modifications and interfaces of coarse numerical meshes (Macropixel) which allow implementation of fine feature within circuit area. These concepts were validated through comparison between measurement and simulated results performed by classical and improved WCIP method, for patch antennas.