Surface acoustic wave temperature sensor and preparation method thereof

Abstract

The present invention discloses a surface acoustic wave temperature sensor and a preparation method thereof, and relates to the technical field of surface acoustic wave devices. The surface acoustic wave temperature sensor includes a sensing module and an antenna module that are electrically connected to each other, wherein the antenna module includes a first high temperature resistant substrate and a graphic antenna formed on the surface of the first high temperature resistant substrate, and a groove is formed on the first surface of the first high temperature resistant substrate, and the sensing module is fixed in the groove. The sensing module and the antenna module of the surface acoustic wave temperature sensor provided by the present invention form a whole, and compared with the prior art, the volume is greatly reduced, and the wireless passive monitoring of temperature in a high temperature and small space can be better realized. Moreover, the sensing module can be integrated in the antenna module, and this structure is more convenient for batch processing.

Description

Technical Field

[0001] The invention relates to the technical field of surface acoustic wave devices, and in particular to a surface acoustic wave temperature sensor and a preparation method thereof. Background Art

[0002] In recent years, as sensor products have become more and more functional and smaller in size, they need to be tested and applied in harsh environments such as high temperature, confined space and closed environments, such as aerospace vehicles and turbine engines. The operation of aerospace vehicles is often accompanied by harsh environments such as high temperature, especially in key parts such as the surface of hypersonic vehicles, aircraft engines and gas turbines, where the local temperature even exceeds 800°C. Therefore, in-situ real-time acquisition of temperature in harsh environments is of great significance for material selection, structural design and protective measures of aerospace vehicles.

[0003] Compared with traditional wired active devices, wireless passive sensor devices based on high temperature resistant materials have significant advantages in testing in harsh environments such as high temperature, small and closed environments. Surface acoustic wave technology can realize wireless passive monitoring of sensor signals over long distances. Due to the simple structure, small size, strong anti-interference performance, good stability, and the ability to perform wireless passive testing, surface acoustic wave sensors are currently a wireless monitoring technology with promising application prospects.

[0004] The existing surface acoustic wave temperature sensor adopts the structure of a sensor module and an external antenna module. The sensor module includes an interdigital transducer and a reflection grating. The sensor module and the antenna module exist separately, and most antenna modules adopt a dipole antenna structure, which is large in size. As a result, the entire surface acoustic wave temperature sensor is large in size and cannot be used in the above-mentioned environment with a small space. Summary of the invention

[0005] The present invention provides a surface acoustic wave temperature sensor and a preparation method thereof, which are used to overcome the technical problems existing in the above-mentioned prior art and can perform wireless passive monitoring of temperature in a high-temperature and narrow space.

[0006] A surface acoustic wave temperature sensor provided by the present invention includes a sensing module and an antenna module electrically connected to each other; the antenna module includes a first high temperature resistant substrate and a patterned antenna formed on the surface of the first high temperature resistant substrate; a groove is formed on the first surface of the first high temperature resistant substrate, and the sensing module is fixed in the groove.

[0007] Furthermore, the first high temperature resistant substrate is a high temperature co-fired ceramic substrate.

[0008] Optionally, the graphic antenna includes: a first base plate located on the first surface of the first high temperature resistant substrate, a second base plate located on the second surface of the first high temperature resistant substrate opposite to the first surface, and an inverted F antenna, the first base plate and the second base plate are electrically connected through a through hole on the first high temperature resistant substrate; the inverted F antenna includes a first horizontal branch, a second horizontal branch and a vertical branch, the first horizontal branch is connected to the second base plate, and is electrically connected to the ground end of the first surface through a through hole on the first high temperature resistant substrate, the second horizontal branch is electrically connected to the feeding end of the first surface through the through hole on the first high temperature resistant substrate, and the vertical branch is arranged around the second base plate.

[0009] Furthermore, an end of the vertical branch line is connected to the second bottom plate via a matching inductor.

[0010] Optionally, the sensing module includes a second high temperature resistant substrate and an interdigital transducer and a reflection grating formed on a surface of the second high temperature resistant substrate.

[0011] Furthermore, the second high temperature resistant substrate is a lanthanum gallium silicate substrate.

[0012] The present invention provides a method for preparing a surface acoustic wave temperature sensor, comprising: preparing a sensing module; preparing an antenna module, wherein the antenna module comprises a first high temperature resistant substrate, a patterned antenna formed on the surface of the first high temperature resistant substrate, and a groove formed on the first surface of the first high temperature resistant substrate; fixing the sensing module in the groove; and electrically connecting the sensing module and the antenna module.

[0013] Optionally, the method for preparing the sensor module includes: coating a photoresist on a second high temperature resistant substrate; photolithography the photoresist using a sensor mask; developing the photoresist to form a patterned photoresist; forming a metal layer on the surface of the patterned photoresist; and removing the patterned photoresist to form an interdigital transducer and a reflection grating on the surface of the second high temperature resistant substrate.

[0014] Optionally, the method for preparing the first high temperature resistant substrate in the antenna module includes: cutting alumina raw porcelain tape to obtain M raw porcelain tape diaphragms of the same size; making positioning holes for positioning and through holes for lead connection on the raw porcelain tape diaphragms; filling metal in the through holes; making openings for forming the groove on N raw porcelain tape diaphragms among the M sheets; stacking the M raw porcelain tape diaphragms according to the positioning holes in a manner such that the N raw porcelain tape diaphragms are stacked at the bottom and the remaining raw porcelain tape diaphragms are stacked at the top; the opening position is filled with a sacrificial layer material; laminating and cutting the stacked M raw porcelain tape diaphragms to form an antenna substrate blank sample; sintering the antenna substrate blank sample to volatilize the sacrificial layer material to form the first high temperature resistant substrate having the groove.

[0015] Optionally, the method for forming a patterned antenna on the surface of the first high temperature resistant substrate includes: depositing metal slurry on the surface of the first high temperature resistant substrate using a screen printing template; and sintering the first high temperature resistant substrate at a high temperature to form the patterned antenna.

[0016] Optionally, the method of fixing the sensor module in the groove includes: coating alumina high temperature ceramic glue on the bottom of the groove; placing the sensor module in the groove so that the bottom of the sensor module without forming a device is bonded to the bottom of the groove.

[0017] Optionally, the method of electrically connecting the sensor module and the antenna module includes: welding a feeding terminal and a grounding terminal of the patterned antenna to an electrode port of the sensor module respectively using metal wires.

[0018] Furthermore, the preparation method further comprises: sintering the sensor module and the antenna module at high temperature.

[0019] In the surface acoustic wave temperature sensor and its preparation method provided by the present invention, since the patterned antenna of the antenna module is formed on the surface of the first high temperature resistant substrate, and a groove is also formed on the first surface of the substrate, the sensor module is fixed in the groove and electrically connected to the antenna module, so that the sensor module and the antenna module form a whole, compared with the prior art, the volume is greatly reduced, and the wireless passive monitoring of temperature in a high temperature and small space can be better realized. Moreover, the sensor module can be integrated in the antenna module, and this structure is more convenient for batch processing.

[0020] In addition, the antenna module uses a high temperature resistant substrate, which can significantly improve the high temperature resistance of the entire temperature sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0022] Figure 1 A schematic structural diagram of a first surface of a first high temperature resistant substrate in a surface acoustic wave temperature sensor provided by an embodiment of the present invention;

[0023] Figure 2 for Figure 1 A schematic diagram of the structure of the second surface of the first high temperature resistant substrate in the surface acoustic wave temperature sensor shown;

[0024] Figure 3 A schematic diagram of the structure of another graphic antenna provided by an embodiment of the present invention;

[0025] Figure 4 A schematic diagram of the structure of a sensor module provided by an embodiment of the present invention;

[0026] Figure 5 A schematic flow chart of a method for preparing an antenna module provided by an embodiment of the present invention;

[0027] Figure 6 A schematic flow chart of a method for preparing a sensor module provided by an embodiment of the present invention;

[0028] Figure 7 This is a simulation diagram of a graphic antenna in an antenna module provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] To make the technical solution of the present invention clearer, embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0031] The embodiment of the present invention provides a surface acoustic wave temperature sensor, such as Figure 1 and Figure 2 As shown, it includes a sensor module 11 and an antenna module 12 electrically connected to each other. The antenna module 12 includes a first high temperature resistant substrate 13 and a patterned antenna 14 formed on the surface of the first high temperature resistant substrate 13. A groove 15 is formed on the first surface A of the first high temperature resistant substrate 13, and the sensor module 11 is fixed in the groove 15.

[0032] Specifically, Figure 1 The first surface A of the first high temperature resistant substrate 13 is shown. Figure 2 The second surface B of the first high temperature resistant substrate 13 is shown, and patterned antennas (17, 21, 22) are formed on both surfaces. A groove 15 is formed on one side of the patterned antenna 14 and close to the first surface A of the patterned antenna 14, and a sensor module 11 is fixed in the groove 15. The metal wires (161, 162) between the groove 15 and the patterned antenna 14 are used to electrically connect the sensor module 11 and the patterned antenna 14 in the antenna module 12.

[0033] In the surface acoustic wave temperature sensor provided by the embodiment of the present invention, since the patterned antenna of the antenna module is formed on the surface of the first high temperature resistant substrate, and a groove is also formed on the first surface of the substrate, the sensor module is fixed in the groove and electrically connected to the antenna module, so that the sensor module and the antenna module form a whole, compared with the prior art, the volume is greatly reduced, and the wireless passive monitoring of temperature in a high temperature and small space can be better realized. Moreover, the sensor module can be integrated in the antenna module, and this structure is more convenient for batch processing.

[0034] In addition, the antenna module uses a high temperature resistant substrate, which can significantly improve the high temperature resistance of the entire temperature sensor.

[0035] In the above embodiment, the first high temperature resistant substrate 13 may be a high temperature co-fired ceramic (HTCC) substrate, which is a new type of high thermal conductivity substrate and packaging material, having the characteristics of high thermal conductivity, low thermal expansion coefficient, high dielectric constant, etc. The antenna module prepared with this material has excellent high temperature resistance.

[0036] In addition, according to the antenna resonant frequency formula: f r ≈c / [2L(ξ r ) 1 / 2 ], where c is the speed of light in a vacuum, L is the length of the rectangular patch of the antenna, ξ r is the relative dielectric constant of the substrate material. From the formula, we know that the resonant frequency is inversely proportional to the dielectric constant. Therefore, using a HTCC substrate with a high dielectric constant can reduce the resonant frequency. Moreover, when the resonant frequency remains unchanged, the length of the rectangular patch can be reduced.

[0037] In the prior art, antennas mostly use printed circuit boards as substrates. Since the dielectric constant of the ceramic substrate is much higher than that of the printed circuit board, the embodiment of the present invention can effectively reduce the size of the antenna.

[0038] In the above-mentioned surface acoustic wave temperature sensor, the patterned antenna can be as follows Figure 1 and Figure 2 As shown, it includes: a first bottom plate 17 located on the first surface A of the first high temperature resistant substrate 13, a second bottom plate 21 located on the second surface B of the first high temperature resistant substrate 13 opposite to the first surface A, and an inverted F antenna 22, and the first bottom plate 17 and the second bottom plate 21 are electrically connected through a through hole C on the first high temperature resistant substrate.

[0039] The inverted F antenna 22 is shaped like an inverted letter "F", and includes a first horizontal branch 221, a second horizontal branch 222 and a vertical branch 223. The first horizontal branch 221 is connected to the second base plate 21, and is electrically connected to the ground terminal 18 of the first surface A through the through hole C on the first high temperature resistant substrate 13. The second horizontal branch 222 is electrically connected to the feeding terminal 19 of the first surface A through the through hole C on the first high temperature resistant substrate 13, and the vertical branch 223 is arranged around the second base plate 21.

[0040] It should be noted that the feeding terminal 19 and the grounding terminal 18 are formed simultaneously with the first base plate of the first surface A, and are also part of the patterned antenna 14 .

[0041] The inverted F antenna has a low-profile structure, and the radiation field has both horizontal and vertical polarizations. Due to its compact structure and isotropic radiation characteristics, its good grounding design can effectively improve the working efficiency of the antenna and increase the transmission distance.

[0042] The end of the vertical branch 223 of the inverted-F antenna can be as follows Figure 2 As shown, it can also be Figure 3 As shown, it is connected to the second bottom plate B through a matching inductor 31. In order for the patterned antenna to obtain the highest transmission frequency, the impedance of the patterned antenna needs to match the impedance of the signal source end. If the impedance matching is not done well, a part of the power will be reflected back to the signal source end, thereby reducing the transmission power of the patterned antenna. The impedance of the RF signal source end is mostly 50Ω. For the designed patterned antenna, the impedance is not 50Ω. At this time, a matching inductor 31 needs to be connected in series to obtain impedance matching. .

[0043] The patterned antenna in the surface acoustic wave temperature sensor provided by the embodiment of the present invention is not limited to the above structure, and any other patterned antenna that can realize the function of transmitting and receiving electromagnetic wave signals can be used in the present invention.

[0044] like Figure 1 and Figure 4 As shown, the sensing module 11 of the surface acoustic wave temperature sensor may include a second high temperature resistant substrate 41 and an interdigital transducer 42 and a reflective grating 43 formed on the surface of the second high temperature resistant substrate 41. When the external temperature changes, the material properties of the second high temperature resistant substrate 41 change due to the change of thermal stress, resulting in a slight change in the distance from the interdigital transducer 42 to the reflective grating 43, and a slight change in the interdigital spacing of the interdigital transducer 42, thereby affecting the propagation speed of the surface acoustic wave. The sensing characteristics of the surface acoustic wave temperature sensor are represented by the resonant frequency, and the shift of the resonant frequency can represent the change of temperature, so wireless passive measurement of temperature can be achieved.

[0045] The second high temperature resistant substrate 41 is mostly made of a lanthanum gallium silicate substrate, and of course other materials known to those skilled in the art may also be used.

[0046] The embodiment of the present invention further provides a method for preparing a surface acoustic wave temperature sensor, which comprises the following steps.

[0047] Step 1: Prepare Figure 1 to Figure 4 The sensor module 11 is shown.

[0048] Step 2: Prepare Figure 1 to Figure 4 The antenna module 12 shown includes a first high temperature resistant substrate 13 , a patterned antenna 14 formed on the surface of the first high temperature resistant substrate 13 , and a groove 15 formed on the first surface A of the first high temperature resistant substrate 13 .

[0049] Step three: fix the sensor module 11 in the groove 15 .

[0050] Step 4: electrically connect the sensor module 11 and the antenna module 12.

[0051] In the method for preparing the surface acoustic wave temperature sensor provided by the embodiment of the present invention, since the patterned antenna of the antenna module is formed on the surface of the first high temperature resistant substrate, and a groove is also formed on the first surface of the substrate, the sensor module is fixed in the groove and electrically connected to the antenna module, so that the sensor module and the antenna module form a whole, compared with the prior art, the volume is greatly reduced, and the wireless passive monitoring of temperature in a high temperature and small space can be better realized. Moreover, the sensor module can be integrated in the antenna module, and this structure is more convenient for batch processing.

[0052] In addition, the antenna module uses a high temperature resistant substrate, which can significantly improve the high temperature resistance of the entire temperature sensor.

[0053] In the above method, the method for preparing the sensor module 11 is as follows Figure 6 As shown, the specific steps may include the following steps.

[0054] 601 . Coat a photoresist 61 on the second high temperature resistant substrate 41 .

[0055] First, pretreatment can be performed, and the surface of the second high-temperature resistant substrate 41 (which can be a lanthanum gallium silicate substrate) is cleaned with acetone, anhydrous ethanol, and deionized water, and blown dry with nitrogen. Then, a layer of positive photoresist 61 is evenly applied on the surface of the cleaned second high-temperature resistant substrate 41 using a photoresist spreader, and post-baking is performed to fully volatilize the organic solvent in the photoresist 61 to improve the quality of photolithography.

[0056] 602. Photolithography the photoresist 61 using a sensor mask.

[0057] 603 . Develop the photoresist to form a patterned photoresist 62 .

[0058] The sensor mask plate engraved with the interdigital electrodes and the reflective grating can be photolithographically processed using an ultraviolet lithography machine, and the second high temperature resistant substrate 41 after photolithography is developed in a matching developer of the positive photoresist 61 to remove the excess photoresist and leave the patterned photoresist 62 with the interdigital electrodes and the reflective grating pattern.

[0059] 604 . Form a metal layer 63 on the surface of the patterned photoresist 62 .

[0060] Platinum metal may be sputtered on the surfaces of the interdigital electrodes and the reflective grid by using a magnetron sputtering method, and other metal materials known to those skilled in the art may also be used.

[0061] 605 , removing the patterned photoresist 62 to form an IDT 42 and a reflective grating 43 on the surface of the second high temperature resistant substrate 41 .

[0062] The patterned photoresist 62 can be removed by acetone, the interdigital electrodes form the interdigital transducer 42, and the remaining parts form the reflective grating 43, and finally the structure is formed as shown in FIG. Figure 4 The surface acoustic wave temperature sensor shown. Figure 6 Only a portion of the interdigital transducer 42 and a portion of the reflection grating 43 are shown.

[0063] 606 . Depositing a protective film 64 on the surface of the second high temperature resistant substrate 41 .

[0064] Afterwards, a pulsed laser deposition system can be used to plate a 200 nm aluminum oxide film on the surface of the fabricated surface acoustic wave temperature sensor, with the parameters set at a substrate temperature of 200° C., a vacuum environment, a laser intensity of 500 mJ, and a frequency of 3 Hz.

[0065] In a high temperature environment, the exposed interdigital electrodes and reflective grids may aggregate, crack, or even break. Therefore, depositing an aluminum oxide film on the interdigital electrodes and reflective grids can prevent these phenomena from occurring.

[0066] In the above-mentioned method for preparing the surface acoustic wave temperature sensor, the method for preparing the first high temperature resistant substrate 13 in the antenna module 12 is as follows: Figure 5 As shown, the following steps are included.

[0067] 501. Cut the alumina green porcelain tape to obtain M green porcelain tape membranes of the same size.

[0068] The alumina green porcelain tape can be cut into 8×8 inch green porcelain tape membrane sheets 51, the protective film can be removed, and the surface of the green porcelain tape membrane sheets 51 can be cleaned by air shower or the like.

[0069] 502. A positioning hole 52 for positioning and a through hole C for lead connection are made on the green porcelain tape diaphragm.

[0070] A laser drilling machine can be used to drill positioning holes 52 and through holes C for lead connection at the four corners of the alumina green ceramic tape diaphragm 51 , and the green ceramic tape diaphragm can be accurately placed on the lamination mold through the positioning holes 52 .

[0071] It should be noted that the figure corresponding to step 502 to step 506 is a cross-sectional schematic diagram of M pieces of green porcelain tape membranes stacked together, and Figure 1 and Figure 2 Since the number of M is different in different application scenarios, the figure does not show each piece of raw porcelain tape membrane, but shows M pieces of raw porcelain tape membrane as a whole.

[0072] 503. Fill the through hole C with metal.

[0073] 504. An opening D for forming a groove 15 is made on N pieces of raw porcelain tape diaphragms among the M pieces, and the M pieces of raw porcelain tape diaphragms are stacked according to the positioning holes 52 in a manner that N pieces of raw porcelain tape diaphragms are stacked at the bottom and the remaining pieces of raw porcelain tape diaphragms are stacked at the top; the opening D is filled with a sacrificial layer material 53, and then the stacked M pieces of raw porcelain tape diaphragms are laminated and cut to form an antenna base blank sample 54.

[0074] The number of M can be 8, the number of N can be 4, and an opening D needs to be set on the four raw porcelain tape diaphragms placed on the lower layer. The size of the opening D can be 0.9cm×0.7cm×0.5mm (slightly larger than the sensor module 11). During the lamination process, it is necessary to fill the opening with a sacrificial layer material 53 to prevent the cavity from collapsing during the subsequent lamination process. According to the debonding time and thickness of the raw porcelain tape diaphragm, a carbon film can be selected as the sacrificial layer material 53 to fill the cavity. The stacked raw porcelain tape diaphragms 51 are sealed using vacuum packaging technology and laminated. The lamination temperature is set to 75°C, the pressure is set to 21MPa, and the pretreatment and lamination times are both set to 10 minutes. After lamination, the raw porcelain tape diaphragms are physically bonded to form a whole. Thereafter, the laminated raw porcelain tape is cut into a sample to form an antenna blank sample 54.

[0075] 505 . Sinter the antenna substrate blank 54 to volatilize the sacrificial layer material 53 to form a first high temperature resistant substrate 13 having a groove 15 .

[0076] The antenna base blank sample 54 is placed on an alumina ceramic sintering plate and covered with a hollow thin ceramic plate to prevent the antenna base blank sample 54 from warping during sintering. The antenna base blank sample 54 is placed in a muffle furnace and a sintering curve is set. During the sintering process, organic matter is discharged and the carbon film 53 is volatilized. The carbon film 53 is drained before the ceramic forms a dense base structure. Grooves are formed on the antenna base blank sample 54, and the ceramic particles in the antenna base blank sample 54 are tightly bonded by an inorganic adhesive to form a dense ceramic base structure.

[0077] In the method for preparing the surface acoustic wave temperature sensor, the method for forming the patterned antenna 14 on the surface of the first high temperature resistant substrate 13 is as follows: Figure 5 As shown in the figure corresponding to step 506 in , it specifically includes the following steps.

[0078] Step 1: depositing metal slurry on the surface of the first high temperature resistant substrate 13 using a screen printing template.

[0079] Step 2: Sintering the first high temperature resistant substrate 13 at high temperature to form a patterned antenna 14.

[0080] Specifically, a customized screen printing template can be used to deposit platinum paste on the surface of the first high temperature resistant substrate 13. Since the platinum paste contains a large amount of binder and impurities, the organic solvent evaporates and is discharged during the high temperature sintering process, and the platinum paste forms a conductor, thereby forming a patterned antenna 14.

[0081] In the method for preparing the surface acoustic wave temperature sensor, the method for fixing the sensor module 11 in the groove 15 may include the following steps.

[0082] Step 1: Coat the bottom of the groove 15 with alumina high temperature ceramic glue.

[0083] Step 2: Place the sensor module 11 in the groove 15 so that the bottom of the sensor module 11 without a device formed thereon is bonded to the bottom of the groove 15 .

[0084] In the method for preparing the surface acoustic wave temperature sensor, the method for electrically connecting the sensor module 11 and the antenna module 12 can be as follows: Figure 1 As shown, the following steps are included.

[0085] The feeding terminal 19 and the grounding terminal 18 of the patterned antenna 14 are respectively welded to the electrode ports of the sensor module 11 by using metal wires (161, 162).

[0086] The electrode ports of the sensor module 11 are ports of two electrodes on the interdigital transducer. The feeding terminal 19 and the grounding terminal 18 of the patterned antenna 14 are formed on the first surface A at the same time as the first base plate 17 is formed.

[0087] The method for preparing the surface acoustic wave temperature sensor may further include: sintering the sensing module 11 and the antenna module 12 at high temperature.

[0088] Specifically, alumina high-temperature ceramic glue is used to fix the sensor module 11. In addition, metal platinum slurry is used to electrically connect the sensor module and the antenna module. Therefore, by placing the device in a muffle furnace for sintering, the high-temperature ceramic glue and the platinum slurry are sintered at high temperature, making the high-temperature glue tightly bonded and making the platinum slurry conductive.

[0089] like Figure 7 As shown, it is a simulation curve of the graphic antenna in the antenna module provided by the embodiment of the present invention. The simulation curve is generated after testing using HFSS (High Frequency Structure Simulator) software. By analyzing the simulation curve, it can be seen that the resonant frequency of the graphic antenna provided by the embodiment of the present invention is 750MHz, and the S11 parameter can meet the performance requirements. The return loss of the graphic antenna at the center frequency is -19.5dB, indicating that the antenna has good performance.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A surface acoustic wave temperature sensor, characterized in that: It comprises a sensing module and an antenna module which are electrically connected to each other; the antenna module comprises a first high temperature resistant substrate and a patterned antenna formed on the surface of the first high temperature resistant substrate; A groove is formed on the first surface of the first high temperature resistant substrate, and the sensor module is fixed in the groove; the graphic antenna includes: a first base plate located on the first surface of the first high temperature resistant substrate, a second base plate located on the second surface of the first high temperature resistant substrate opposite to the first surface, and an inverted F antenna, the first base plate and the second base plate are electrically connected through a through hole on the first high temperature resistant substrate; the inverted F antenna includes a first horizontal branch line, a second horizontal branch line and a vertical branch line, the first horizontal branch line is connected to the second base plate, and is electrically connected to the ground end of the first surface through a through hole on the first high temperature resistant substrate, the second horizontal branch line is electrically connected to the feeding end of the first surface through the through hole on the first high temperature resistant substrate, and the vertical branch line is arranged around the second base plate. 2 . The surface acoustic wave temperature sensor according to claim 1 , wherein the first high temperature resistant substrate is a high temperature co-fired ceramic substrate. 3 . The surface acoustic wave temperature sensor according to claim 1 , wherein an end of the vertical branch line is connected to the second bottom plate via a matching inductor. 4 . The surface acoustic wave temperature sensor according to claim 1 , wherein the sensing module comprises a second high temperature resistant substrate and an interdigital transducer and a reflection grating formed on a surface of the second high temperature resistant substrate. 5 . The surface acoustic wave temperature sensor according to claim 4 , wherein the second high temperature resistant substrate is a lanthanum gallium silicate substrate.

6. A method for preparing a surface acoustic wave temperature sensor, characterized in that: include: preparing a sensor module; Prepare an antenna module, the antenna module comprising a first high temperature resistant substrate, a patterned antenna formed on a surface of the first high temperature resistant substrate, and a groove formed on a first surface of the first high temperature resistant substrate; The graphic antenna comprises: a first bottom plate located on the first surface of the first high temperature resistant substrate, a second bottom plate located on the second surface of the first high temperature resistant substrate opposite to the first surface, and an inverted F antenna, wherein the first bottom plate and the second bottom plate are electrically connected through a through hole on the first high temperature resistant substrate; the inverted F antenna comprises a first horizontal branch line, a second horizontal branch line and a vertical branch line, wherein the first horizontal branch line is connected to the second bottom plate and is electrically connected to the ground end of the first surface through a through hole on the first high temperature resistant substrate, the second horizontal branch line is electrically connected to the feeding end of the first surface through a through hole on the first high temperature resistant substrate, and the vertical branch line is arranged around the second bottom plate; Fixing the sensor module in the groove; The sensor module and the antenna module are electrically connected.

7. The method according to claim 6, characterized in that The method for preparing the sensor module comprises: coating a photoresist on the second high temperature resistant substrate; Photolithography the photoresist using a sensor mask; developing the photoresist to form a patterned photoresist; forming a metal layer on the surface of the patterned photoresist; The patterned photoresist is removed to form an interdigital transducer and a reflective grating on the surface of the second high temperature resistant substrate.

8. The method according to claim 6 or 7, characterized in that: The method for preparing the first high temperature resistant substrate in the antenna module comprises: Cutting the alumina green porcelain tape to obtain M green porcelain tape membranes of the same size; Making positioning holes for positioning and through holes for lead connection on the green porcelain tape membrane; Filling the through-holes with metal; Making openings for forming the grooves on N green porcelain tape membrane sheets among the M sheets; According to the positioning holes, the M pieces of green porcelain tape membranes are stacked in such a manner that the N pieces of green porcelain tape membranes are stacked at the bottom and the remaining green porcelain tape membranes are stacked at the top; the opening positions are filled with sacrificial layer materials; The stacked M pieces of green ceramic tape films are laminated and cut into samples to form an antenna base blank sample; The antenna substrate green sample is sintered to volatilize the sacrificial layer material to form the first high temperature resistant substrate having the groove.

9. The method according to claim 6, characterized in that The method for forming a patterned antenna on the surface of the first high temperature resistant substrate comprises: Depositing metal slurry on the surface of the first high temperature resistant substrate using a screen printing template; The first high temperature resistant substrate is sintered at a high temperature to form the patterned antenna.

10. The method according to claim 6, characterized in that The method for fixing the sensor module in the groove includes: Coating alumina high temperature ceramic glue on the bottom of the groove; The sensor module is placed in the groove, so that the bottom of the sensor module without forming a device is bonded to the bottom of the groove.

11. The method according to claim 6, characterized in that The method for electrically connecting the sensor module and the antenna module comprises: welding the feeding end and the grounding end of the patterned antenna to the electrode port of the sensor module respectively by using metal wires.

12. The method according to claim 6, characterized in that Also includes: The sensor module and the antenna module are sintered at high temperature.

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