Abstract: An H2S sensor includes at least one acoustic wave transducer and a film having a polymer matrix. The polymer matrix includes carboxylate functional groups and lead or zinc cations. The film may have a thickness of between a hundred nanometres and a 2 microns The H2S sensor optionally includes an antenna to remotely interrogate the H2S sensor.

Abstract: A surface elastic wave resonator comprises a piezoelectric material to propagate the surface elastic waves and a transducer inserted between a pair of reflectors comprising combs of interdigitated electrodes and having a number Nc of electrodes connected to a hot spot and an acoustic aperture W wherein the relative permittivity of the piezoelectric material is greater than about 15, a product of Nc·W/fa for the transducer being greater than 100 ?m·MHz?1, where fa is the antiresonance frequency of the resonator. A circuit comprises a load impedance and a resonator according to the invention and having an electrical response manifesting as a peak in the coefficient of reflection S11 at a frequency of a minimum value of the parameter S11 that is lower than ?10 dB, the antiresonance peak of the resonator being matched to the impedance of the load.

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 of interrogating sensors of SAW type, which allows notably the gathering of physical measurements of parameters carried out by SAW sensors, the method for gathering the measurement of an SAW sensor comprising a first step of generating and emitting an electromagnetic signal corresponding to the dilated time-reversal of a dilation coefficient k, of an impulse response signature which is characteristic of the SAW sensor, a second step of gathering a signal received as echo originating from the SAW sensor, a third step of determining a maximum of cross-correlation of the signal received as echo during the second step, the first step being applied with a set of values of the dilation coefficient k in a determined domain, the measurement of a physical parameter then being determined by the dilation coefficient k for which the power or the amplitude of the signal gathered as echo is a maximum.

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 method of interrogating a surface acoustic wave differential sensor formed by two resonators is provided, wherein the method allows the measurement of a physical parameter by determination of the difference between the natural resonant frequencies of the two resonators, which difference is determined on the basis of the analysis of a signal representative of the level of a signal received as echo of an interrogation signal, for a plurality of values of a frequency of the interrogation signal in a domain of predetermined values; the analysis can be based on the cross-correlation of the said signal representative of the level according to a splitting into two distinct frequency sub-bands. An advantage is that it may be implemented in a radio-modem.

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 transponder including a first resonator and a series of one or more second resonators with coupling of evanescent waves exhibiting at least one first resonant mode and one second resonant mode, said first resonator being connected via a first port, to a first means allowing an interrogation, wherein said second resonators are connected via at least one second port, to at least one variable load element capable of modifying coupling conditions of the resonant modes and consequently a response measured on said first port.

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 interrogating a surface acoustic wave differential sensor formed by two resonators is provided, wherein the method allows the measurement of a physical parameter by determination of the difference between the natural resonant frequencies of the two resonators, which difference is determined on the basis of the analysis of a signal representative of the level of a signal received as echo of an interrogation signal, for a plurality of values of a frequency of the interrogation signal in a domain of predetermined values; the analysis can be based on the cross-correlation of the said signal representative of the level according to a splitting into two distinct frequency sub-bands. An advantage is that it may be implemented in a radio-modem.

Abstract: A method of interrogating sensors of SAW type, which allows notably the gathering of physical measurements of parameters carried out by SAW sensors, the method for gathering the measurement of an SAW sensor comprising a first step of generating and emitting an electromagnetic signal corresponding to the dilated time-reversal of a dilation coefficient k, of an impulse response signature which is characteristic of the SAW sensor, a second step of gathering a signal received as echo originating from the SAW sensor, a third step of determining a maximum of cross-correlation of the signal received as echo during the second step, the first step being applied with a set of values of the dilation coefficient k in a determined domain, the measurement of a physical parameter then being determined by the dilation coefficient k for which the power or the amplitude of the signal gathered as echo is a maximum.

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 remotely interrogating a passive sensor, comprising at least one resonator, so as to determine the resonant frequency of said resonator, having a resonant frequency response defined by the design of said resonator, includes: a preliminary frequency-scan step for interrogating said resonator over a frequency range allowing for the rapid determination of a first resonant frequency (fr0) of said resonator by detecting the amplitude of the response signal of said resonator; a first step of a first couple of interrogations of said resonator at a first frequency (f11) and a second frequency (f21) such that: f11=fr0?fm/2 and f21=fr0+fm/2, fm being smaller than the width at half-maximum of the resonant frequency response defined by the design, allowing a first couple of amplitudes (Pf11, Pf21) of first and second reception signals to be defined; a second step of determining the amplitude difference (?(Pf11?Pf21)), said difference being signed; a third step allowing a first resonant frequency (fr1), contro

Abstract: The invention relates to a stress gauge of the type having an acoustic resonant structure, including a piezoelectric transducer (10) connected to a holder (20), the holder (20) including opposite the piezoelectric transducer (10) an imbedded reflecting portion (40). The imbedded reflecting portion (40) reflects the volume acoustic waves generated by the piezoelectric transducer (10) when it is excited according to a harmonic mode of the structure and propagating into said holder (20), the reflecting portion (40) being arranged at a distance from the piezoelectric transducer (10) such that the integral of the stress on the propagation distance of the volume acoustic waves up to their reflection is different from zero.

Abstract: A method for interrogating a passive sensor comprising at least one piezoelectric resonator includes the following steps: the identification of the characteristic width of the resonant frequency band of the resonator; the determination of a scan interval equal to a third of the measured bandwidth; a first series of three interrogation measurements with signals respectively at a first frequency, at a second frequency and at a third frequency making it possible to define a first resonance value, a second resonance value and a third resonance value; the determination by a parabolic fitting operation of the resonator response curve on the basis of said first, second and third resonance values, so as to calculate a first value of the frequency in real time of the resonator. The invention also relates to an electronic device for interrogating a passive sensor comprising at least one piezoelectric resonator and comprising a micro-controller implementing the interrogation method of the invention.

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 transponder including a first resonator and a series of one or more second resonators with coupling of evanescent waves exhibiting at least one first resonant mode and one second resonant mode, said first resonator being connected via a first port, to a first means allowing an interrogation, wherein said second resonators are connected via at least one second port, to at least one variable load element capable of modifying coupling conditions of the resonant modes and consequently a response measured on said first port.

Abstract: The invention relates to a surface acoustic wave resonator produced on a cut substrate with propagation axes for which a nonzero directivity exists and comprising at least one central transducer (Tc) exhibiting a central axis, a first array of reflectors (R1) and a second array of reflectors (R2), said arrays being situated on either side of said transducer, characterized in that the two arrays of reflectors exhibit nonsymmetric configurations with respect to the central axis of said central transducer. The introduction of an asymmetry makes it possible to strongly attenuate the parasitic resonances which may appear when the resonators are produced notably on piezoelectric substrates of quartz type or any other material and cut with propagation axes for which there exists a natural directivity (LiTaO3, LiNbO3, langasite, GaPO4, LiB4O7, KNbO3, etc.).