Dominique Henry

3D scanning and sensing technique for the detection and remote reading of a passive temperature sensor

This paper presents a novel technique for the detection and remote reading of passive temperature sensors. This technique is based on a 3D beam scanning performed by a FMCW radar for measuring the echo level of sensors distributed in a scene. The carrier frequency is 24GHz and two frequency modulation bandwidths are investigated (2 GHz and ISM 250 MHz). The fluctuation of the measured echo level is analyzed by using appropriate estimators and the derived temperature variation is displayed by using a convenient three dimensional representation of isosurfaces.

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 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.

3D scanning radar for the remote reading of passive electromagnetic sensors

This communication reports for the first time the remote reading of passive electromagnetic sensors using a 24GHz Frequency Modulated Continuous Wave (FMCW) scanning radar. It shows that the detection, identification and reading of such sensors are possible by the analysis of 3D radar images.

Long range wireless interrogation of passive humidity sensors using Van-Atta cross-polarization effect and 3D beam scanning analysis

This paper reports for the first time a long-range interrogation (> 50 meters) of wireless and batteryless humidity sensors combining a Van-Atta retrodirective array and a 3D beam scanning using a 24GHz Frequency-Modulated Continuous-Wave radar. Van-Atta cross-polarization properties, as well as the use of dedicated statistical estimators and Synthetic Aperture Radar technique allow the long-range measurement of the relative humidity at a distance of 58 meters. A measurement sensitivity of 0.2dB to 0.4dB per %RH was measured as a linear variation of the proposed estimator with a standard error of ±0.005dB.

Remote estimation of intra-parcel grape quantity from three-dimensional imagery technique using ground-based microwave FMCW radar

For better benefits and yields, a good estimation of the quantity of grapes in a vineyard is necessary. In this paper, a three-dimensional (3D) imagery technique using conventional 24 GHz frequency-modulated continuous- wave (FMCW) radar is applied for detecting and remotely estimating the intra-parcel quantity of grapes. An estimation is possible even in the presence of natural or artificial clutters such as leaves, wood, or irrigation hoses. The microwave sensing is performed from the radar beam scanning of a vineyard, and an estimator is defined to derive the quantity of grapes in grapevines from the radar echoes distribution in the interrogated 3D scene. An algorithm based on contour detection is applied to the 3D radar image and a new parameter, called the spread factor, is defined for classifying the echo levels of grapes. The quantity of grapes is finally deduced from an appropriate estimator. This remote sensing approach brings a new and flexible solution for precision viticulture by estimating the grape quantity even for grapes hidden by leaves.

Technique for wireless reading of passive microfluidic sensors

This letter focuses on the remote reading of high-resolution microfluidic and passive (i.e., batteryless and chipless) temperature sensors. These sensors are remotely interrogated from a 24GHz Frequency-Modulated Continuous-Wave radar performing a mechanical beam scanning for locating the sensors and measuring the variation of sensors electromagnetic echo level due to temperature fluctuation. From radar measurement data an estimator is proposed here for determining the meniscus position of the fluid inside the sensors microchannel and for deriving the temperature at the sensors location. It is shown that the estimator presents a convenient linear dependence with the meniscus position at the sensor location. The smallest measurable variation of the meniscus position is of 40µm.