An improvement of the wave concept iterative procedure (WCIP) is proposed that avoids excessive computational storage and simulation times for bulky devices. 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 allows implementation of fine features within the circuit area. These concepts are tested and validated through comparison between measurement and simulated results. This method is applied on multi-scale circuits that could not be simulated before because of memory storage limitation.