PASSIVE TEMPERATURE SENSOR-ANTENNA AND ASSOCIATED MANUFACTURING METHOD

Abstract

The invention relates to a passive temperature sensor-antenna (10) comprising: - a plurality of layers of ferroelectric materials (12.1, 12.3, 12.4) arranged side by side on a support (11) made of an electrically conductive material, - said layers of ferroelectric materials (12.1, 12.3, 12.4) being made of different ferroelectric materials having different Curie temperatures, each associated with a peak in dielectric constant, so that said sensor-antenna (10) exhibits several resonance frequencies corresponding to the Curie temperatures to cover a temperature measurement range, and - a plurality of electrically conductive layers (13.1, 13.3, 13.4) each deposited on a corresponding layer of ferroelectric material (12.1, 12.3, 12.4). Figure 4

Description

Title of the invention: PASSIVE TEMPERATURE SENSOR-ANTENNA AND ASSOCIATED MANUFACTURING METHOD

[0001] The present invention relates to a passive temperature sensor-antenna and the associated manufacturing process. The invention relates to the technical field of instrumentation and structural monitoring, with a specific application in critical environments, such as aircraft engines. The invention can thus be used in strategic areas of engines, such as the combustion chamber, the high-pressure compressor, the high-pressure turbine, and the low-pressure turbine, which are subjected to significant temperature variations, as well as constant mechanical stresses and vibrations.

[0002] Current temperature monitoring systems in harsh engine environments are based on the use of wired temperature sensors, such as thermocouples. However, these sensors have major drawbacks, including high costs, risks of failure related to cables and connectors, and operational challenges under extreme conditions.

[0003] In the context of a transition to wireless alternatives, two categories of sensors are emerging: chip-based wireless sensors and chipless wireless sensors. The former are limited by temperature constraints, operating efficiently only at temperatures below 600°C due to the thermal sensitivity of electronic chips.

[0004] Among passive wireless sensors without a chip, we distinguish surface acoustic wave sensors (or SAW sensor for "Surface Acoustic Wave" according to Anglo-Saxon terminology), inductive coupling sensors, radio frequency identification sensors (or RFID sensor for Radio Frequency Identification) and antenna sensors.

[0005] Surface acoustic wave sensors use the phase transformation of piezoelectric materials to detect temperature variations. However, they are limited by the chemical stability of these materials, which can lead to long-term reliability problems.

[0006] Inductively coupled sensors use coils to exchange data wirelessly. Despite their simplicity, they encounter calibration difficulties, which can lead to measurement errors. Furthermore, their range is limited to a few centimeters due to the need for physical proximity between the sensor and the reader.

[0007] Wireless RFID sensors use radio frequency communication for data transmission. However, they are subject to calibration problems affecting the accuracy of measurements, and their interrogation distance is often limited to a few centimeters.

[0008] The sensor-antennas act as detection and communication elements. These sensor-antennas are adapted to the harsh environments of aircraft engines for monitoring temperature and deformation.

[0009] As illustrated in [Fig.1], a conventional sensor-antenna 1 comprises a layer of dielectric material 2 arranged between a ground plane 3 and a metallization layer 4. The sensor-antenna 1 constitutes a module called a "patch" according to Anglo-Saxon terminology.

[0010] The sensor-antenna 1 is associated with a horn antenna 5 and a vector network analyzer 6. The vector network analyzer 6 performs frequency sweeps by emitting a signal Se and measures the return signal Sr reflected by the sensor-antenna 1. This type of sensor is thus said to be "passive", insofar as it does not require any on-board power source to operate and is activated only upon reception of the signal Sr emitted by the antenna 5.

[0011] Since temperature and / or mechanical deformations modify the dielectric constant of the dielectric material constituting the sensitive layer 2, and since the resonant frequency of the sensor-antenna 1 depends on the dielectric constant, the sensor-antenna 1 can be used to measure temperature and / or deformations by monitoring the resonant frequency of the feedback signal Sr. The geometry of the sensor-antenna 1 changes under the effect of mechanical deformations, which causes a shift in the resonant frequency of the feedback signal Sr. Furthermore, temperature influences the dielectric constant of the dielectric material, resulting in a variation of the resonant frequency of the feedback signal Sr. These two phenomena are independent of each other.

[0012] Fig. 2 illustrates the shift in a resonance frequency fr of the sensor-antenna 1 corresponding to an increase in the temperature T of the environment from 25°C to 1600°C.

[0013] The analytical model below makes it possible to understand the relationship between, on the one hand, the resonance frequency and, on the other hand, the permittivity of the dielectric layer and the geometry of the sensor-antenna.

[0014] Assuming that a rectangular sensor-antenna 1 operates in TM010 mode, its resonant frequency fr can be calculated on the basis of the following transmission line model: Or: - c is the speed of light and er is the dielectric constant of the dielectric material, - Le is the electrical length of the sensor-antenna 1 which is approximately equal to a physical length L of the sensor, i.e. Le ~ L.

[0015] The variation in resonance frequency ôfr can then be expressed in terms of variations in the dielectric constant of the substrate er and the length of the sensor L as follows: ôf = (2)

[0016] It is also possible to deduce from equation (1) that: _ / I \ f and f (3&4) ôer - f ~2t'r}Jr SL - \ ~L )jr

[0017] By substituting equations (3) and (4) into (2) and normalizing the difference in resonant frequency with the resonant frequency of the antenna, we obtain: _ 1 OL (5) 4 “ - 2 - L

[0018] For the purposes of temperature detection, equation (5) can be expressed in terms of temperature change ôtT as follows: ^ = -4^7 - 0^7 = (4^, -^)57 = ^7(6) Or: - aE is the thermal coefficient of the dielectric constant of the substrate; - aT is its coefficient of thermal expansion; - Kt is defined as the temperature sensitivity of the normalized frequency shift and is a linear function of ae and aT.

[0019] It can be observed from the above equations that the dielectric constant is an essential element in the determination of the resonance frequency of the sensor-antenna 1, so that its change due to the variation of the stimuli (temperature and / or deformation) is associated with the change of the resonance frequency of the sensor-antenna L. Therefore, a temperature and / or a deformation of the part carrying the sensor-antenna 1 can be measured wirelessly by measuring the shift of the resonance frequency fr of the sensor-antenna 1 under a given variation of temperature and / or deformation.

[0020] Known sensor-antennas attached to a support by an intermediate adhesive are susceptible to detachment due to severe environmental stresses, such as temperature, vibration and humidity, which compromises their stability and their operation. In addition, the rigid and flat structure of the sensors makes them difficult to integrate onto curved supports.

[0021] Moreover, the limitation of the sensitivity of current sensors is clearly manifested through the graphs of [Fig.3] illustrating the variation, as a function of temperature, of the dielectric constant of dielectric materials commonly used in the manufacture of high temperature sensor-antennas, such as alumina (Al2O3), SiCN, and SiôBl ceramic.

[0022] This variation in dielectric constant remains relatively limited in percentage terms. Furthermore, it is accompanied by a very low initial dielectric constant. These characteristics result in limited sensitivity of known sensor-antennas, making them less responsive to subtle variations in ambient temperature. However, good sensor sensitivity is essential for accurate temperature monitoring in aircraft engines.

[0023] The invention aims to effectively remedy the aforementioned drawbacks by proposing a passive temperature sensor-antenna comprising: - a plurality of layers of ferroelectric materials arranged side by side on a support made of an electrically conductive material, - said layers of ferroelectric materials being made of different ferroelectric materials having different Curie temperatures, each associated with a peak in dielectric constant, so that said sensor-antenna exhibits several resonant frequencies corresponding to the Curie temperatures to cover a temperature measurement range, and - a plurality of electrically conductive layers, each deposited on a corresponding layer of ferroelectric material.

[0024] The invention thus makes it possible, thanks to ferroelectric materials having a significant variation in dielectric constant around the Curie temperature, to obtain a more pronounced modulation of the antenna's resonant frequency in response to temperature changes. Furthermore, the multilayer assembly of ferroelectric materials increases the sensor's sensitivity over a wide temperature measurement range. The invention therefore enables precise monitoring of temperature variations in harsh environments, such as aircraft engines. The invention can be implemented using advanced printing techniques for the ferroelectric and conductive layers, allowing the sensor-antenna to be integrated onto flat or curved surfaces while ensuring good adhesion and increased durability.

[0025] According to one embodiment of the invention, the different layers of ferroelectric materials have different geometries.

[0026] According to one embodiment of the invention, the ferroelectric materials are chosen from the following materials: BaTiO3; SrTiO3; Pb(Zr,Ti)O3; Pb(Zr,Ti)O3; (Pb,La)(Zr,Ti)O3; LiTaO3; CaCu3Ti4O12; BiFeO3; LiNbO3; Nd2Ti2O7.

[0027] According to one embodiment of the invention, the electrically conductive layers are made using a conductive ink based on high-temperature resistant conductive particles, such as platinum or tungsten particles.

[0028] According to one embodiment of the invention, the support is constituted by a portion of a part whose temperature is to be measured.

[0029] The invention also relates to a method for manufacturing a passive temperature sensor-antenna comprising: - a step of depositing, on an electrically conductive support, a plurality of layers of ferroelectric materials arranged side by side, said layers of ferroelectric materials being made of different ferroelectric materials having different Curie temperatures, each associated with a peak in dielectric constant, so that said passive temperature sensor-antenna has several resonant frequencies corresponding to the Curie temperatures to cover a temperature measurement range, and - a step of depositing a plurality of electrically conductive layers, each arranged on a corresponding layer of ferroelectric material.

[0030] According to one embodiment of the invention, the deposition of a layer of ferroelectric material is carried out by: - a step of depositing a high-temperature resistant ink containing ferroelectric material particles, and - a high-temperature resistant ink curing step.

[0031] According to one embodiment of the invention, the deposition of an electrically conductive layer is carried out by: - a step of depositing a high-temperature resistant ink containing particles of electrically conductive material and - a high-temperature resistant ink curing step.

[0032] According to one embodiment of the invention, the deposition of the high-temperature resistant ink containing particles of ferroelectric materials or of the high-temperature resistant ink containing particles of electrically conductive material is carried out according to a contact deposition technology by means of a pneumatic or endless piston type distributor or according to a non-contact deposition technology by aerosol jet or piezoelectric jet.

[0033] The invention also relates to an assembly comprising an aircraft engine part constituting a support and a passive temperature sensor-antenna as previously defined.

[0034] The present invention will be better understood and other features and advantages will become apparent upon reading the following detailed description, which includes embodiments given by way of illustration with reference to the accompanying figures, presented by way of non-limiting examples, which may serve to complete the understanding of the present invention and the explanation of its implementation and, where appropriate, contribute to its definition, on which:

[0035] [Fig-1] Fig. 1, already described, is a schematic representation of a system of wireless detection of temperature and / or deformation by means of a sensor-antenna integrated on a conductive surface;

[0036] [Fig.2] Fig.2, already described, illustrates the shift of a resonance frequency of a sensor-antenna according to the state of the art corresponding to an increase in the temperature of the environment;

[0037] [Fig.3] Fig.3 shows graphical representations illustrating the variation, in function of temperature, of a dielectric constant of dielectric materials commonly used in the manufacture of high temperature sensor-antennas according to the state of the art;

[0038] [Fig. 4] Fig. 4 is a cross-sectional view of a passive temperature sensor-antenna according to the invention comprising an assembly of several ferroelectric materials in a single module ("patch" in English);

[0039] [Fig. 5] [Fig. 5] is a top view of a passive temperature sensor-antenna according to the invention without the electrically conductive layers;

[0040] [Fig. 6] [Fig. 6] is a top view of a passive temperature sensor-antenna according to the invention showing electrically conductive layers deposited respectively on the different ferroelectric materials;

[0041] [Fig.7] Fig.7 shows a characteristic of the evolution, as a function of the temperature, of the dielectric constant of a ferroelectric material illustrating the Curie transition phenomenon;

[0042] [Fig.8] Fig.8 shows a distribution of complementary Curie temperatures of different ferroelectric materials used in a passive sensor-antenna according to the invention to cover a wide temperature measurement range;

[0043] [Fig.9] Fig.9 shows a variation in the resonance frequency of the different ferroelectric materials used in a passive sensor-antenna according to the invention in the temperature measurement range;

[0044] [Fig. 10a] [Fig. 10b] [Fig. 10c] Figures 10a, 10b and 10c illustrate the different manufacturing stages of a sensor-antenna according to the invention directly on an aircraft engine blade by 3D printing.

[0045] [Fig. 11] The [Fig. 11] is a schematic representation illustrating the deposition of ink by contact on a support by means of a pneumatic or endless piston type distributor;

[0046] [Fig. 12] The [Fig. 12] is a schematic representation illustrating the non-contact deposition of ink onto a substrate by means of a piezoelectric jet;

[0047] [Fig. 13] The [Fig. 13] is a schematic representation illustrating the non-contact deposition of ink onto a substrate by means of an aerosol jet.

[0048] It should be noted that, in Figures 4 and following, the structural and / or functional elements common to the different embodiments may have the same reference numerals. Thus, unless otherwise stated, such elements have identical structural, dimensional and material properties.

[0049] Figures 4, 5, and 6 show a support 11 made of an electrically conductive material. The support 11 is advantageously constituted by a portion of a part whose temperature is to be measured, such as a high-pressure compressor blade, a high-pressure turbine blade, a low-pressure turbine blade, or any other part of an aircraft engine. The support 11 is, for example, made of steel or any other electrically conductive material suitable for the application.

[0050] A passive temperature sensor-antenna 10 that can be used in place of The sensor-antenna of [Fig. 1] comprises a plurality of layers of ferroelectric materials 12.1-12.5 arranged side by side on the support 11. The layers 12.1-12.5 can be connected side by side or separated from each other. The acceptable separation distance is such that all the layers 12.1-12.5 remain within the field of view of the antenna reader.

[0051] Ferroelectric materials exhibit a high dielectric permittivity er, meaning they have a capacity to store a large amount of electrical energy. Ferroelectric materials are characterized by their ability to undergo a phase transition at a given temperature called the Curie temperature (TC), at which these materials lose their ferroelectric properties, as illustrated in [Fig. 7].

[0052] At temperatures below the Curie temperature TC, these materials, which are in a ferroelectric state (denoted Et_ferro in [Fig. 7]), exhibit an increase in dielectric permittivity due to ferroelectric polarization. Above the Curie temperature TC, these materials, which are in a paraelectric state (denoted Et_para in [Fig. 7]), exhibit a decrease in dielectric permittivity. This phenomenon, known as the "Curie transition," significantly influences the dielectric constant of the material around this critical temperature.

[0053] The invention takes advantage of the significant variation of the dielectric constant er around the Curie temperature TC. This characteristic allows for a more pronounced modulation of the antenna's resonant frequency in response to temperature changes.

[0054] Indeed, in the invention, the ferroelectric material layers 12.1-12.5 visible in [Fig. 5] are made of different ferroelectric materials having different Curie temperatures TC1-TC5, each associated with a dielectric constant peak. [Fig. 8] thus shows the distribution of the Curie temperatures TC1-TC5 over a temperature measurement range PT.

[0055] The sensor-antenna 10 has several resonant frequencies frl-fr5 corresponding to the Curie temperatures TC1-TC5 to cover the temperature measurement range, as illustrated in [Fig. 9]. Indeed, when a vector network analyzer detects a very low level of the return signal Sr for a given resonant frequency frl-fr5, the Curie temperature at which this resonance is observable, and therefore the temperature of the environment, can be deduced. In the example shown, the sensor-antenna 10 comprises five layers of different ferroelectric materials. Alternatively, the sensor-antenna 10 may have fewer than five layers of ferroelectric materials 12.1-12.5, or more than five. The number of layers of ferroelectric materials 12.1-12.5 can be adapted, in particular, according to the temperature measurement range to be covered.

[0056] Advantageously, the different layers of ferroelectric materials 12.1-12.5 have different geometries. The different layers 12.1-12.5 can thus have different surface areas. According to an advantageous embodiment, the different layers 12.1-12.5 have rectangular or square shapes with different surface areas to adapt the resonance frequency of the different layers of ferroelectric materials 12.1-12.5. Alternatively, the layers 12.1-12.5 of ferroelectric materials can have another shape such as a triangular, round, oval, hexagonal, or more generally polygonal shape, or any other shape suitable for the application.

[0057] The ferroelectric materials of layers 12.1-12.5 can be selected from the following materials: Ferroelectric Materials Curie Temperature (TC) Dielectric Constant @ TC BaTiO3 120 1700 SrTiO3 105 2000 Pb(Zr,Ti)O3 320 1000 Pb(Zr,Ti)O3, (Pb,La)(Zr,Ti)O3 450 2500 LiTaO3 610 3000 CaCu3Ti4O12 Varies 80 000 BiFeO3 830 20000 LiNbO3 1140 800 Nd2Ti2O7 1480 800

[0058] The sensor-antenna 10 also comprises a plurality of electrically conductive layers 13.1-13.5, each deposited on a corresponding layer of ferroelectric material 12.1-12.5. The electrically conductive layers 12.1-12.5 are distinct from one another. In other words, an electrically conductive layer 13.1-13.5 is deposited on a corresponding layer of ferroelectric material 12.1-12.5 without touching the adjacent electrically conductive layer(s) 13.1-13.5. The electrically conductive layers 13.1-13.5 are made using a conductive ink based on high-temperature resistant conductive particles, such as platinum or tungsten particles.

[0059] The assembly "layers of ferroelectric materials 12.1-12.5-electrically conductive layers 13.1-13.5" form a compact module called "patch" according to Anglo-Saxon terminology.

[0060] The method for manufacturing a passive temperature sensor-antenna 10 according to the invention is described below with reference to Figures 10a-10c. The sensor-antenna 10 is intended to be placed on the electrically conductive support 11 shown in [Fig. 10a]. In this case, the support 11 is an aircraft engine blade.

[0061] As illustrated in [Fig. 10b], the process comprises a step of depositing, on the support 11, a plurality of layers of ferroelectric materials 12.1-12.5 arranged side by side. As previously stated, the layers of ferroelectric materials 12.1-12.5 are made of different ferroelectric materials having different Curie temperatures TC1-TC5, each associated with a dielectric constant peak, so that said passive temperature sensor-antenna 10 has several resonant frequencies fr1-fr5 corresponding to the Curie temperatures TC1-TC5 to cover a temperature measurement range PT.

[0062] The deposition of the ferroelectric material layers 12.1-12.5 is carried out by a step of depositing a high-temperature resistant ink 17 containing particles of ferroelectric material and a step of curing the high-temperature resistant ink 17. The deposition of the ink 17 containing the particles of ferroelectric material can be carried out by means of a deposition head 15 mounted on a 5-axis motion system to enable 3D printing allowing a deposition of ferroelectric material layers 12.1-12.5 on non-planar surfaces, including a curved surface of a blade.

[0063] As illustrated in [Fig. 10c], the method further comprises a step of depositing a plurality of electrically conductive layers 13.1-13.5, each arranged on a corresponding layer of ferroelectric material 12.1-12.5. The deposition of the electrically conductive layers 13.1-13.5 is carried out by a step of depositing a high-temperature resistant ink 17 containing particles of electrically conductive material and a step of curing the high-temperature resistant ink 17. The deposition of the ink 17 containing the particles of electrically conductive material can be performed by means of a deposition head 15 mounted on a 5-axis motion system to enable 3D printing, allowing the electrically conductive layers 13.1-13.5 to be deposited on non-planar surfaces, in particular a curved surface of a blade.

[0064] As illustrated in [Fig. 11], the deposition of the ink 17 containing particles of ferroelectric material or particles of electrically conductive material can be carried out according to a contact deposition technology by means of a pneumatic or endless piston type distributor 18.

[0065] The pneumatic-type distributor 18 shown on the left in [Fig. 11] operates by applying a variable pressure P inside a chamber containing the ink 17 in order to eject the ink 17 via the deposit head 15.

[0066] The endless piston-type dispenser 18 shown on the right in [Fig. 11] uses an eccentrically moving rotor 19 and a stator 20 adapted to reliably transport and meter liquids with precise volume control. The volume of ink 17 deposited is proportional to the rotation angle of the rotor 19, with the possibility of changing the direction of movement by reversing the rotation. This allows for precise metering of the ink 17 as a function of the rotation angle of the rotor 19.

[0067] This technology allows for the management of an ink viscosity range up to 1,000,000 mPas without any limit on the size of charged particles. This technology is therefore compatible with most screen printing inks. The fineness of the deposition lines is greater than 300 µm. The thickness of the deposition lines is between 10 and 30 µm. Due to the requirement for contact between the deposition head 15 and the substrate 11, there is a limitation in a vertical direction relative to the deposition area. The deposition rate is on the order of 0.05 to 6 ml / min or 750 g / min.

[0068] Alternatively, as illustrated in [Fig. 12], the deposition of the high-temperature resistant ink 17 containing particles of ferroelectric material or of the high-temperature resistant ink 17 containing particles of electrically conductive material can be carried out using a non-contact piezoelectric jet deposition technology.

[0069] According to this so-called "PiezoJet" technology (registered trademark), the dispensing head 15 of the piezoelectric system incorporates a piezoelectric actuator 23 to generate a piezoelectric movement. This movement is transmitted to a ceramic sealing rod 24 associated with a valve seat 25. The sealing rod 24 is translationally movable between a closed position and an open position. In the closed position, the sealing rod 24 cooperates with the valve seat 25 so as to block the flow of ink 17. When the sealing rod 24 is raised, ink 17 can pass through the valve seat 25, and when the sealing rod 24 returns to the closed position, a droplet of ink 17 is ejected via the dispensing head 15. The piezoelectric jet system can be controlled by a controller equipped with a human-machine interface, for example, in the form of a touchscreen interface.

[0070] This technology allows for a viscosity range of 50 to 200,000 mPas with a charged particle size of up to 1 OPM. The fineness of the deposition lines is greater than 300 µm. The thickness of the deposition lines is between 10 and 30 µm. The distance from the substrate 11 is between 3 and 5 mm. The deposition speed is on the order of 0.25 ms / drop. This technology offers ease of handling and cleaning. It is also possible to change the ink viscosity by heating the deposition head 15.

[0071] Alternatively, as illustrated in [Fig.13], the deposition of the high-temperature resistant ink 17 containing particles of ferroelectric material or of the high-temperature resistant ink 17 containing particles of electrically conductive material can be carried out using a non-contact aerosol jet deposition technology.

[0072] This technology uses aerodynamic focusing to precisely deposit an ink 17. The ink 17 is atomized in an ultrasonic atomizer 27 by means of an atomizing gas 28 (generally nitrogen), which creates droplets of 1 to 5 microns. The atomizer 27 includes a transducer 29 disposed within a volume of water 30.

[0073] The droplets are focused by a protective gas 31 via a profiled dispensing head 15. The dispensing head 15 is in fluidic communication with the atomizer via a conduit 32.

[0074] The protective gas (generally air) isolates the dispensing head 15 from the material to prevent clogging. The flow of ink droplets 17 remains focused over 2 to 5 mm, ensuring high resolution, even on non-uniform three-dimensional substrates.

[0075] This technology allows for handling a viscosity range up to 20 mPa with a charged particle size of less than 100 nm. The fineness of the deposition lines is less than 20 pm. The thickness of the deposition lines is between 6 nm and greater. 6 pm. The distance from the substrate is between 3 and 5 mm. The dispensing head has an elongated shape adapted for complex three-dimensional printing.

[0076] Of course, the different features, variants and / or embodiments of the present invention can be combined with each other in various ways insofar as they are not incompatible or mutually exclusive.

[0077] Furthermore, the invention is not limited to the embodiments described above and provided solely by way of example. It encompasses various modifications, alternative forms, and other variants that a person skilled in the art may consider within the scope of the present invention, and in particular all combinations of the different modes of operation described above, which may be taken separately or in combination.

Claims

Demands

1. Passive temperature sensor-antenna (10) characterized in that it comprises: - a plurality of layers of ferroelectric materials (12.1-12.5) arranged side by side on a support (11) made of an electrically conductive material, - said layers of ferroelectric materials (12.1-12.5) being made of different ferroelectric materials having different Curie temperatures (TC1-TC5) each associated with a peak of dielectric constant, so that said sensor-antenna (10) has several resonance frequencies (fr1-fr5) corresponding to the Curie temperatures to cover a temperature measurement range (PT), and - a plurality of electrically conductive layers (13.1-13.5) each deposited on a corresponding layer of ferroelectric material (12.1-12.5).

2. Passive temperature sensor-antenna according to claim 1, characterized in that the different layers of ferroelectric materials (12.1-12.5) have different geometries.

3. Passive temperature sensor-antenna according to claim 1 or 2, characterized in that the ferroelectric materials are selected from the following materials: BaTiO3; SrTiO3; Pb(Zr,Ti)O3; Pb(Zr,Ti)O3; (Pb,La)(Zr,Ti)O3; LiTaO3; CaCu3Ti4O12; BiFeO3; LiNbO3; Nd2Ti2O7.

4. Passive temperature sensor-antenna according to any one of claims 1 to 3, characterized in that the electrically conductive layers (13.1-13.5) are made using a conductive ink based on high-temperature resistant conductive particles, such as platinum or tungsten particles.

5. Passive temperature sensor-antenna according to any one of claims 1 to 4, characterized in that the support (11) is constituted by a portion of a part whose temperature is to be measured.

6. Method of manufacturing a passive temperature sensor-antenna (10) characterized in that it comprises: - a step of depositing, on an electrically conductive support (11), a plurality of layers of ferroelectric materials (12.1-12.5) arranged side by side, said layers of ferroelectric materials (12.1-12.5) being made of different ferroelectric materials having different Curie temperatures (TC1-TC5) each associated with a peak of dielectric constant, so that said passive temperature sensor-antenna (10) has several resonance frequencies (fr1-fr5) corresponding to the Curie temperatures (TC1-TC2) to cover a temperature measurement range (PT), and - a step of deposition of a plurality of electrically conductive layers (13.1-13.5) each disposed on a corresponding layer of ferroelectric material (12.1-12.5).

7. A method according to claim 6, characterized in that the deposition of a layer of ferroelectric material (12.1-12.5) is carried out by: - ​​a step of deposition of a high-temperature resistant ink (17) containing particles of ferroelectric material (12.1-12.5), and - a step of baking the high-temperature resistant ink (17).

8. Method according to claim 6 or 7, characterized in that the deposition of an electrically conductive layer is carried out by: - ​​a step of deposition of a high-temperature resistant ink (17) containing particles of electrically conductive material and - a step of baking the high-temperature resistant ink (17).

9. A method according to claim 7 or 8, characterized in that the deposition of the high-temperature resistant ink (17) containing particles of ferroelectric material or of the high-temperature resistant ink (17) containing particles of electrically conductive material is carried out according to a contact deposition technology by means of a pneumatic or endless piston type dispenser or according to a non-contact deposition technology by aerosol jet or piezoelectric jet.

10. Assembly comprises an aircraft engine part constituting a support and a passive temperature sensor-antenna (10) defined according to any one of claims 1 to 5.

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