Realization of a novel memcapacitor emulator and its applications in chaotic systems

The memristor, which is the fundamental member of the family of memory elements, was introduced into the literature by Prof. Leon O. Chua in 1971 as the fourth fundamental circuit element. Subsequent studies have brought the memcapacitor, which is based on the charge-voltage relationship, to the forefront in addition to the memory behavior associated with memristor-based systems. Investigating the contributions of memcapacitors to the field of electronics is of considerable interest to researchers. Since the memcapacitor has not yet been commercialized in an integrated form, the practical use of this element is achieved through emulator circuits that exhibit the same characteristic behavior. In this study, a charge-controlled, incremental/decremental, floating, and electronically tunable memcapacitor emulator is designed. The fact that it does not include a memristor in its structure, thereby avoiding circuit complexity, and that it can operate over a relatively wide frequency range are among the advantages of the proposed emulator. To examine the performance of the designed emulator, the memcapacitor was used instead of a conventional capacitor in low-pass filter, adaptive learning, and integrator circuits. It was observed that the memcapacitor emulator provided advantageous results in terms of several parameters, such as filtering performance, learning capability, power efficiency, and operating speed. The studies conducted to ensure the integrity of circuit theory were carried out theoretically, through simulations, and experimentally, and consistent results were obtained. The nonlinear characteristics of the memcapacitor make its use in chaotic circuits attractive and enable new studies in areas such as image encryption and communication security. In this context, a new four-dimensional Chua-like chaotic equation system was developed by incorporating the proposed memcapacitor emulator. Based on chaos tests, the system was analyzed as a hyperchaotic circuit with the advantage of a high level of complexity. Chaotic synchronization, which is important for secure communication applications, was achieved using two different methods. In addition, chaotic communication and image encryption applications were investigated through different methods based on the proposed system. Finally, chaos control was applied to suppress chaotic behavior and direct the system toward regular equilibrium points, and the obtained results demonstrated the effectiveness of the employed methods.