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

• Published in: IEEE transactions on microwave theory and techniques Vol. 65; no. 12; pp. 5345 - 5354
• Main Authors: Henry, Dominique, Hester, Jimmy G. D., Aubert, Herve, Pons, Patrick, Tentzeris, Manos M.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.12.2017; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antennas arrays; batteryless sensors; chipless sensors; Clutter; direction-of-arrival (DoA) analysis; flexible electronics; Humidity; Internet of Things; Interrogation; Mechanical sensors; microstrip antenna arrays; Polarization; Position sensing; Questioning; Radar; Radar antennas; Radar echoes; radar imaging; radio-frequency identification (RFID) sensors; Relative humidity; remote sensing; Remote sensors; Scanning; Sensor arrays; Sensors; Statistical analysis; Wireless sensor networks
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2017.2769055

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 reported, and the measurement results are discussed. The relative humidity (RH) is derived from the statistical analysis of multidimensional radar echoes, while method is proposed to detect the sensor among clutter without knowing its exact position. Moreover, it is demonstrated that the cross-polarization effect of the Van-Atta reflectarray combined with the 3-D beam scanning technique allows the indoor measurement of the RH up to 58 m.