Calibration of Passive UHF RFID Tags Using Neural Networks to Measure Soil Moisture

Figure 9

Normalized RSSI data from tag number 81, number 07, and number 16 which was buried at 5, 10, and 15 cm from box bottom. Scatter blue and black represent RSSI signal and from which channel it was chosen. Red line represents the signal phase estimate, using I and Q channel data. Green line is the moisture measure from reference sensor multiplied by 300 so it can fit the scale.