Long-Range Wireless Interrogation of Passive Humidity Sensors Using Van-Atta Cross-Polarization Effect and Different Beam Scanning Techniques

This paper presents a method for the remote interrogation of batteryless humidity sensors based on statistical estimations and 3-D beam scanning techniques. As a proof-of-concept demonstration, a Van-Atta reflectarray sensor is interrogated with a 24-GHz frequency-modulated continuous-wave transceiver at various reading ranges. The extension of the proposed approach to passive or moving sensors is...