Soil moisture wireless sensing with analog scatter radio, low power, ultra-low cost and extended communication ranges

The measurement of the soil moisture is critical in agriculture. In this work a joint analog design of wireless transmitter with scatter radio and capacitive sensor for soil moisture is presented. The design is based on a custom microstrip capacitor, exploits bistatic analog scatter radio principles and is able to wirelessly convey soil moisture percentage by mass (% MP) with RMS error of 1.9%, power consumption and communication range on the order of 100 uWatts and 100 meters, respectively. It is tailored for ultra-low cost (5 Euro per sensor) agricultural sensor network applications for soil moisture.