Abstract: A method for optimizing the design of a device includes interrogation means and a differential passive sensor, including a generator connected directly or indirectly to a reader antenna, a passive sensor including at least two resonators, a sensor antenna connected to the sensor.

Abstract: A method for optimizing the design of a device includes interrogation means and a differential passive sensor, including a generator connected directly or indirectly to a reader antenna, a passive sensor including at least two resonators, a sensor antenna connected to the sensor.

Abstract: A system comprises a cavity being reflecting for RF waves and comprises at least one acoustic wave sensor exhibiting a resonance frequency band, coupled to a sensor antenna; and an interrogation/reception device for the sensor. The interrogation/reception device comprises: means for transmitting/receiving an RF signal transmitting within an interrogation frequency band comprising the resonance frequency band of the sensor; at least a first transmission/reception antenna and a second transmission antenna/reception, positioned within the cavity; means for dividing the signal into at least a first RF signal and a second RF signal, the first signal being transmitted to the first transmission/reception antenna and the second signal being transmitted to the second transmission/reception antenna; means for creating a phase-shift between the first RF signal and the second RF signal; means for analysing the power level of the received signal. An interrogation method used in the system is also provided.

Abstract: A pressure and temperature sensor comprising comprises at least a first resonator of the SAW type comprising a piezoelectric substrate, thinned at least locally, of the membrane type, a second resonator of the SAW type comprising a piezoelectric substrate and a third resonator of the SAW type comprising a piezoelectric substrate, characterized in that the first, the second and the third resonators are respectively on the surface of first, second and third individual piezoelectric substrates, each of the individual substrates being positioned on the surface of a common base section, locally machined away under said first resonator in such a manner as to liberate the substrate from said resonator so as to render it operational for the measurement of pressure. A method of fabrication for such a sensor is also provided.

Abstract: A system comprises a cavity being reflecting for RF waves and comprises at least one acoustic wave sensor exhibiting a resonance frequency band, coupled to a sensor antenna; and an interrogation/reception device for the sensor. The interrogation/reception device comprises: means for transmitting/receiving an RF signal transmitting within an interrogation frequency band comprising the resonance frequency band of the sensor; at least a first transmission/reception antenna and a second transmission antenna/reception, positioned within the cavity; means for dividing the signal into at least a first RF signal and a second RF signal, the first signal being transmitted to the first transmission/reception antenna and the second signal being transmitted to the second transmission/reception antenna; means for creating a phase-shift between the first RF signal and the second RF signal; means for analysing the power level of the received signal. An interrogation method used in the system is also provided.

Abstract: A remotely interrogatable pressure and/or temperature measuring device includes at least an acoustic wave sensor including at least one resonator coupled to a first antenna element, and an interrogation system including a second antenna element for transmission and reception. The device further includes an expandable tubular structure, the structure integrating a biocompatible material, and the acoustic wave sensor is encapsulated in the biocompatible material. The second antenna element operates at frequencies above several tens of MegaHertz.

Abstract: A pressure and temperature sensor comprising comprises at least a first resonator of the SAW type comprising a piezoelectric substrate, thinned at least locally, of the membrane type, a second resonator of the SAW type comprising a piezoelectric substrate and a third resonator of the SAW type comprising a piezoelectric substrate, characterized in that the first, the second and the third resonators are respectively on the surface of first, second and third individual piezoelectric substrates, each of the individual substrates being positioned on the surface of a common base section, locally machined away under said first resonator in such a manner as to liberate the substrate from said resonator so as to render it operational for the measurement of pressure. A method of fabrication for such a sensor is also provided.

Abstract: A method of collective fabrication of remotely interrogatable sensors, wherein the method may include fabricating fabricating a first series of first resonators exhibiting a first resonant frequency at ambient temperature and a first static capacitance and fabricating a second series of second resonators exhibiting a second resonant frequency at ambient temperature and a second static capacitance. The method may also include performing a series of electrical measurements of the set of the first series of first resonators and of the set of the second series of second resonators, so as to determine first pairs and second pairs of resonant frequency and of capacitance of each of the first and second resonators and performing a series of matching of a first resonator and of a second resonator.

Abstract: The invention relates to a process for the collective fabrication of a remotely interrogable sensor having at least one first resonator and one second resonator. Each resonator exhibits respectively a first and a second operating frequency. A first series of first resonators are fabricated. The first resonators each have a first operating frequency belonging to a first set of frequencies centered on a first central frequency. A second series of second resonators are fabricated. The second resonators each having a second operating frequency belonging to a second set of frequencies centered on a second central frequency. A series of pairings of a first resonator and of a second resonator are conducted so as to form pairs of resonators exhibiting a difference of operating frequencies which is equal to the difference of the first and second central frequencies.

Abstract: A remotely interrogatable passive sensor is provided. The sensor comprises an antenna and at least one surface wave resonator including a transducer with inter-digitated electrodes with two ports on the surface of a piezoelectric substrate, in which the antenna comprises conducting elements connected to the two ports and integrated onto said piezoelectric substrate. Advantageously, the antenna elements are folded on the substrate to enhance compactness. The passive sensor can be used for medical applications such as tissue analysis or arterial pressure measurement.

Abstract: A remotely interrogatable pressure and/or temperature measuring device includes at least an acoustic wave sensor including at least one resonator coupled to a first antenna element, and an interrogation system including a second antenna element for transmission and reception. The device further includes an expandable tubular structure, the structure integrating a biocompatible material, and the acoustic wave sensor is encapsulated in the biocompatible material. The second antenna element operates at frequencies above several tens of MegaHertz.

Abstract: A method of collective fabrication of remotely interrogatable sensors, each sensor comprising at least one first resonator and one second resonator, each resonator comprising acoustic wave transducers designed such that they exhibit respectively a first and a second operating frequency, is provided.

Abstract: The invention relates to a process for the collective fabrication of a remotely interrogable sensor having at least one first resonator and one second resonator. Each resonator exhibits respectively a first and a second operating frequency. A first series of first resonators are fabricated. The first resonators each have a first operating frequency belonging to a first set of frequencies centered on a first central frequency. A second series of second resonators are fabricated. The second resonators each having a second operating frequency belonging to a second set of frequencies centered on a second central frequency. A series of pairings of a first resonator and of a second resonator are conducted so as to form pairs of resonators exhibiting a difference of operating frequencies which is equal to the difference of the first and second central frequencies.

Abstract: A device for measuring the brightness of a surface includes a light source to send an incident beam onto the surface and a polarizer and two analyzers one for analyzing the reflected light and the other for analyzing the diffuse reflection from the surface at a selected point of incidence; light-sensitive photodetector means are provided to receive light from the analyzers; the incident light impinges on the surface under examination at an angle of between 0.degree. and 90.degree. with the incident beam polarization being perpendicular to the plane of incidence; the analyzers are located to differentiate between parallel and perpendicular polarization to provide differences in the assessment of specular and diffuse brightness.

Abstract: A transmitting antenna radiates a micro-wave field through an opening in the form of a rectangular wave-guide applied against the separation surface between a first medium, in which it is located, and a second medium, in which an object is buried. The micro-wave radiation reflected by the object is collected through the opening of a receiving antenna, also in the form of a rectangular wave-guide, applied against the radiating opening of the transmitting antenna. The collected radiation is measured at a series of points by means of pinpoint antennae located in the collecting opening. Thanks to the antennae arrangement, the collected radiation can be used as such, without having to subtract therefrom the result of a reference measurement. The invention can be used particularly to obtain, non destructively, images of metal bars buried in reinforced concrete.