Design of Low-Power Underwater Backscatter Sensor Node

In response to the challenges posed by high power consumption and the logistical difficulties of battery replacement in conventional underwater sensor nodes, we came up with a design that uses backscatter communication. The underwater sensor node comprises a piezoelectric transducer and node control circuit, which underwent simulation to validate its operational capabilities. A MCU governs the switching of the piezoelectric transducer between absorption and reflection states: during absorption, the transducer generates electrical energy to sustain the node; during reflection, the node transmits signals. Simulation results indicate that under 100kHz incident sound waves, the energy harvesting circuit in absorption mode reliably yields a stable 2.2V voltage, ensuring uninterrupted power for the MCU during sensor data retrieval. During the reflection state, the node modulates sensor data onto the reflected signal via backscatter technology, transmitting this signal back to the hydrophone. Operating autonomously without an external power source, this node supports prolonged underwater deployment, thus offering a viable solution for low-power underwater IoT applications.