Simulation-based design of modular QCA Circuits

The design of quantum-dot cellular automata (QCA) circuits and systems is still in an infancy stage; a modular technique which relies on building blocks referred to as tiles, is proposed in this paper. This approach consists of first analyzing the logic capabilities of the basic tiles (inclusive of simulation) followed by logic mapping and connecting the tiles to form the desired circuit. The 3×3 QCA grid is presented as an example of basic block. Five types of tiles can be constructed using the 3×3 grid. A logic characterization of these tiles is presented by using a coherence vector simulation engine. It is shown that the 3×3 grid is not only area efficient, but it also offers versatile logic operation. Various QCA circuits designed using the tile-based method are presented and compared with conventional gate-based design as well as the SQUARES methodology.