QCA-based Single-bit Comparator Circuit

Quantum-dot cellular automata (QCA), which consists of a group of cells is a new growing technology and is confirmed to be an advanced alternative of complementary metal oxide semiconductor (CMOS) technology. When the cells of QCA are combined and ordered in a certain way, it can perform various computational tasks. Since, comparators are one of the most vital and widely used circuits and used to compare input voltages, currents, and some other measurable quantities. This paper proposes a novel design for comparator in QCA nanotechnology. The proposed comparator is designed using 39 quantum cells and covers an area of almost 0.07 square micrometers. Further, the proposed design is compared with the previous works. The comparison concludes that the proposed comparator is designed utilizing much lesser number of cells and requires much smaller area than the previous works as also specified in the paper. The proposed comparator has been designed in a single layer.