Fringing-Effect-Based Capacitive Proximity Sensors

Proximity sensing technology, which can obtain information without physical contact, has become an ideal choice in scenarios where physical contact is not feasible. Despite substantial advancements in tactile sensing, proximity sensing technology still holds great potential and has yet to be fully developed. Among numerous proximity sensing technologies, the fringing-effect-based capacitive proximity sensor (FE-CPS) has garnered considerable attention due to its low cost, low power consumption, wide sensing range, and flexible and versatile structural design. However, research on FE-CPS has not yet formed a complete system, and its development and intellectualization are still in their infancy, urgently requiring a systematic review to advance its development. This paper systematically summarizes the recent advances in FE-CPS, from basic theory to practical applications. The working principle and typical structure of FE-CPS are first introduced, followed by a discussion of methods for optimizing device performance. Furthermore, the application scenarios of FE-CPS in intelligent pre-alarm systems, intelligent control systems, and intelligent material perception systems are reviewed. Finally, the future development and challenges faced by FE-CPS are prospected.