Autonomous Nonlinear Passive Transmit-Receive Switch for Compact IoT Devices: A Three-Port Agile Network

Recent advancements in RF technologies, especially Internet of Things (IoT) devices, require compact and integrated RF circulators or transmit-receive (T/R) switches for efficient resource use. Although conventional techniques are crucial in managing signal flow to prevent signal interference to sensitive receiver components, they have some drawbacks, such as limited isolation, low switching speed, complex circuitry, bulkiness, and high cost. This work presents a smart, miniaturized, nonlinear T/R switch capable of operating over a wide frequency range (0.8~1.3 GHz), making it suitable for IoT frequency bands. The switch achieves the high isolation, low insertion loss, and intelligent transitions between transmitter and receiver without requiring external control or bias pins.