Ultra-Low Power Temperature Sensing Node Powered by Low RF Power Harvesting for Long-Range Communication

This paper proposes an ultra-low power temperature data sensing node with long-range communication capability based on low RF power harvesting. The sensor node can operate stably at input power levels as low as -20 dBm. By utilizing the characteristics of a linear voltage regulator, whose output is controlled by the temperature-dependent resistance of a thermistor, a voltage-controlled oscillator (VCO) is created. This VCO generates an output frequency that directly corresponds to the ambient temperature. The system enables temperature sensing and data transmission without the need for a microcontroller, leading to significant power savings. Its ultra-low power consumption allows for self-powering in low power harvesting environments. Experimental results demonstrate that the proposed sensor node can transmit temperature data over a distance greater than 10 meters.