Barium titanate-based fiber film and preparation method thereof, antenna dielectric layer and antenna

Abstract

The application provides a barium titanate-based fiber membrane and a preparation method thereof, an antenna dielectric layer and an antenna, wherein the preparation method comprises the following steps: stirring and mixing a single-layer dispersed MXene and polyvinylpyrrolidone in an organic solvent, and then adding tetrabutyl titanate and barium acetate into the mixture to prepare a spinning precursor solution; taking the spinning precursor solution to electrospinning to obtain a PVP / BaTiO3 / MXene nanofiber membrane; and calcining the spun nanofiber membrane to obtain a BaTiO3 / MXene fiber membrane. The addition of MXene in the spinning precursor solution can optimize the conductive performance of the spinning precursor solution and reduce the calcination temperature of the material. The addition of MXene can obtain a flexible barium titanate film by calcination at 550 DEG C, thereby greatly reducing the energy loss. The dielectric loss of the finally prepared material is only 0.005, which is far lower than the dielectric loss of 0.02 of a common barium titanate film.

Description

Technical Field

[0001] This invention relates to the field of barium titanate-based dielectric materials, specifically to barium titanate-based fiber films and their preparation methods, antenna dielectric layers, and antennas. Background Technology

[0002] The advent of the 5G era, the rapid upgrading of electronic communication equipment, and the rise of the Internet of Things (IoT) have created demands for flexibility and wearability in intelligent wireless communication systems. Ultimately, the flexibility and wearability of intelligent wireless communication systems hinge on the flexibility of the substrate material within the system. Flexible barium titanate-based dielectric materials are a novel type of dielectric material. They possess excellent flexibility, a controllable dielectric constant, and low dielectric loss. Compared to traditional dielectric materials, flexible barium titanate-based dielectric materials offer both superior electromagnetic properties and physicochemical stability, making them widely used in microwave, infrared, and laser communications, particularly in the field of flexible antennas. As a next-generation dielectric material, flexible barium titanate-based dielectric materials offer superior dielectric properties, better meeting the performance requirements of flexible antennas.

[0003] There are various methods for preparing flexible barium titanate dielectric materials. Preparing materials with uniformly oriented barium titanate significantly improves their dielectric properties. Currently, there are diverse methods for preparing highly oriented barium titanate materials, including electrospinning, vapor deposition, and cryogenic casting. While cryogenic casting and vapor deposition can produce highly oriented barium titanate materials with high dielectric properties, their flexibility may not meet the requirements of wearable devices. Electrospinning is widely used due to the high strain tolerance of fibers, the versatility of raw materials, and the controllability of particle size. Because fiber diameters can be refined from the micrometer to the nanometer scale, it possesses unique mechanical and thermal properties. Flexible barium titanate materials prepared by electrospinning technology have broad application prospects. Properly controlling the precursor solution and the post-processing of the spun film is crucial for obtaining materials with both high flexibility and high dielectric properties.

[0004] The existing method for preparing flexible barium titanate thin films using electrospinning is as follows: organic matter and barium titanate are mixed uniformly in a precursor solution, and spinning voltage, flow rate, humidity, and temperature are appropriately set. A flexible nanofiber membrane with organic matter as the fiber skeleton and barium titanate particles as the dielectric modulator is then produced by electrospinning. To reduce the harmful effects of organic matter, an organic template method can also be used to prepare barium titanate fiber membranes. The organic matter is then removed by calcination at high temperatures, forming a nanofiber membrane with barium titanate as the skeleton. However, in the existing technology, calcination at a high temperature of 1050℃ is required to remove organic matter and maintain the high dielectric properties of the material, which places high demands on the experiment and consumes a lot of energy. Furthermore, barium titanate alone has limited dielectric properties and flexibility. To meet the requirements of flexible device substrate materials, the fiber membrane needs to be modified and improved. Summary of the Invention

[0005] In view of this, the present invention provides a barium titanate-based fiber membrane and its preparation method, an antenna dielectric layer and an antenna. The calcination temperature of the barium titanate-based fiber membrane prepared in the present invention is only 540-560℃, and the dielectric loss of the barium titanate-based fiber membrane is only 0.005.

[0006] To address the technical problems mentioned in the background section, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing a barium titanate-based fiber membrane, the method comprising the following steps:

[0008] S1: Add monolayer dispersed MXene and polyvinylpyrrolidone to an organic solvent and stir to mix. Then add tetrabutyl titanate and barium acetate to prepare a spinning precursor solution.

[0009] S2: Take the spinning precursor liquid described in S1, use a roller as an electrospinning receiver to perform electrospinning, and obtain a PVP / BaTiO3 / MXene nanofiber membrane.

[0010] S3: The PVP / BaTiO3 / MXene nanofiber membrane spun in S2 is calcined to obtain the BaTiO3 / MXene fiber membrane.

[0011] Furthermore, the organic solvent is a mixture of ethanol, acetic acid, and deionized water.

[0012] Further, after adding the barium acetate to S1, the mixture is stirred for 4 to 12 hours, and then the tetrabutyl titanate is added dropwise while stirring for 1 to 3 hours.

[0013] Furthermore, the spinning parameters in S2 are set as follows: spinning speed is 0.8-1.2 mL / h, voltage is 18-23 kV, spinning distance is 12-15 cm, the rotation speed of the roller is 100-500 rpm, and spinning time is 3-5 h.

[0014] Furthermore, the calcination described in S3 adopts a staged heating method. The staged heating conditions are as follows: the temperature is increased to 210-230°C at a heating rate of 1.5-2.5°C / min and maintained for 0.5-1.5 hours; then the temperature is increased to 440-460°C at a heating rate of 2-3°C / min and maintained for 1-3 hours; then the temperature is increased to 540-560°C at a heating rate of 1.5-3°C / min, and then the temperature is lowered.

[0015] Furthermore, the mass fraction of the monolayer dispersed MXene in the spinning precursor solution is 5–15 wt‰, and / or

[0016] The polyvinylpyrrolidone has a mass fraction of 4-6 wt%; and / or

[0017] The tetrabutyl titanate has a mass fraction of 12–16 wt%; and / or

[0018] The barium acetate has a mass fraction of 15–25 wt%.

[0019] Secondly, the present invention provides a barium titanate-based fiber membrane, which is prepared by the preparation method described above.

[0020] Thirdly, the present invention provides an antenna dielectric layer comprising a barium titanate-based fiber membrane as described above.

[0021] Furthermore, the antenna dielectric layer comprises three layers: the top and bottom layers are made of polyethylene terephthalate material, and the middle layer is a barium titanate-based fiber membrane.

[0022] Fourthly, the present invention provides an antenna comprising the antenna dielectric layer as described above.

[0023] The beneficial effects of the above-described technical solution of the present invention are as follows:

[0024] This invention provides a barium titanate-based fiber membrane and its preparation method, an antenna dielectric layer, and an antenna. The preparation method of the barium titanate-based fiber membrane includes the following steps: S1: Add monolayer dispersed MXene and polyvinylpyrrolidone to an organic solvent and stir to mix, then add tetrabutyl titanate and barium acetate to prepare a spinning precursor solution; S2: Take the spinning precursor solution in S1 and perform electrospinning using a roller as an electrospinning receiver to obtain a PVP / BaTiO3 / MXene nanofiber membrane; S3: Calcine the PVP / BaTiO3 / MXene nanofiber membrane spun in S2 to obtain the BaTiO3 / MXene fiber membrane.

[0025] Adding MXene to the spinning precursor solution optimizes its conductivity and lowers the calcination temperature. Calcination at 550°C with MXene in place yields a flexible barium titanate film, significantly reducing energy loss. The resulting BaTiO3 / MXene fiber film exhibits a dielectric loss of only 0.005, far lower than the 0.02 dielectric loss of common barium titanate films. The method for preparing barium titanate-based fiber films provided in this invention lays the foundation for the application of flexible barium titanate dielectric materials. Antennas using the BaTiO3 / MXene fiber film as the antenna dielectric layer material achieved a high gain of 13 dBi at 10 GHz and a transmission efficiency exceeding 80%, effectively improving the transmission distance and efficiency of flexible antennas. Attached Figure Description

[0026] Figure 1 A flowchart illustrating the preparation and application of BaTiO3 / MXene fiber membranes;

[0027] Figure 2 This is a structural design diagram of a flexible barium titanate-based antenna;

[0028] Figure 3 This is a TEM image of the BaTiO3 / MXene fiber membrane prepared in Example 1;

[0029] Figure 4a This is a photograph of the BaTiO3 / MXene fiber membrane prepared in Example 1 being bent.

[0030] Figure 4b A photograph of the curled BaTiO3 / MXene fiber membrane prepared in Example 1 of this paper;

[0031] Figure 5 The image shows the S11 test curve of the flexible barium titanate-based antenna in Example 5.

[0032] BaTiO3 / MXene fiber membrane 1;

[0033] PET layer 2;

[0034] Radiation layer 3. Detailed Implementation

[0035] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the present invention.

[0036] The barium titanate-based fiber membrane and antenna dielectric layer provided in this invention will be further explained and described below with reference to the accompanying drawings and embodiments.

[0037] In a first aspect, the present invention provides a method for preparing a barium titanate-based fiber membrane, the method comprising the following steps:

[0038] S1: Add monolayer dispersed MXene and polyvinylpyrrolidone to an organic solvent and stir to mix. Then add tetrabutyl titanate and barium acetate to prepare a spinning precursor solution.

[0039] S2: Take the spinning precursor liquid described in S1, use a roller as an electrospinning receiver to perform electrospinning, and obtain a PVP / BaTiO3 / MXene nanofiber membrane.

[0040] S3: The PVP / BaTiO3 / MXene nanofiber membrane spun in S2 is calcined to obtain the BaTiO3 / MXene fiber membrane.

[0041] Currently, flexible barium titanate materials prepared using electrospinning technology still suffer from stringent spinning conditions. This is mainly due to the weak conductivity of barium titanate, which easily leads to needle blockage and dripping during the spinning process. Furthermore, the calcination temperature is too high, requiring 1050℃ to form barium titanate crystals, consuming a large amount of energy, and the dielectric loss of the material after calcination is high, failing to meet the requirements of flexible wearable devices. To address these issues, this invention provides an improved method for preparing barium titanate-based fiber membranes. A monolayer dispersed MXene, after etching, is stirred with PVP in a mixed solvent of ethanol, acetic acid, and deionized water for 3–12 hours. After homogenization, tetrabutyl titanate and barium acetate are added separately to prepare a spinning precursor solution. The inventors discovered that the addition of MXene can alter the conductivity of the spinning precursor solution, thus making it easier to optimize the electrospinning parameters of the flexible barium titanate material. Simultaneously, using a roller as a receiver for the electrospun membrane during preparation allows for the fabrication of large-area materials. Adding MXene to the spinning precursor solution optimizes its conductivity and lowers the calcination temperature. Calcination at 550°C with MXene yields a flexible barium titanate film, significantly reducing energy loss. The resulting BaTiO3 / MXene fiber film exhibits a dielectric loss of only 0.005, far lower than the 0.02 dielectric loss of common barium titanate films. The method for preparing barium titanate-based fiber films provided in this invention lays the foundation for the application of flexible barium titanate dielectric materials.

[0042] According to some embodiments of the present invention, the organic solvent is a mixture of ethanol, acetic acid and deionized water.

[0043] According to some embodiments of the present invention, after adding the barium acetate to S1, the mixture is stirred for 4 to 12 hours, and then the tetrabutyl titanate is added dropwise while stirring for 1 to 3 hours.

[0044] According to some embodiments of the present invention, the spinning parameters in S2 are set as follows: spinning speed of 0.8–1.2 mL / h, voltage of 18–23 kV, spinning distance of 12–15 cm, rotation speed of the roller of 100–500 rpm, and spinning time of 3–5 h. For the spinning precursor solution in the present invention, matching spinning parameters are provided. For example, the spinning speed can be set to 0.8 mL / h, voltage of 18 kV, spinning distance of 12 cm, rotation speed of the roller of 100–500 rpm, and spinning time of 3 h. The present invention uses electrospinning technology to prepare PVP / BaTiO3 / MXene nanofiber membranes. The reason for choosing a roller as the receiver is that it enables the preparation of large-area fiber membranes and facilitates the preparation of fiber membranes with consistent fiber orientation, thereby enhancing the mechanical properties of the fiber membrane. In the electrospinning process, spinning speed, voltage, and spinning distance all affect the diameter of the prepared fibers. Therefore, it is crucial to select appropriate spinning speed, voltage, and spinning distance. The interaction of these parameters ensures that the prepared spun membrane fibers have a suitable diameter, thereby enhancing the mechanical properties of the fiber membrane. Furthermore, spinning time affects the thickness of the prepared fiber membrane; generally, a longer spinning time results in a thicker fiber membrane. Therefore, it is necessary to select an appropriate spinning time to prepare a fiber membrane that meets the requirements of the device application.

[0045] According to some embodiments of the present invention, the calcination in S3 adopts a staged heating method, wherein the staged heating conditions are as follows: heating to 210-230°C at a heating rate of 1.5-2.5°C / min and maintaining calcination for 0.5-1.5h; then heating to 440-460°C at a heating rate of 2-3°C / min and maintaining calcination for 1-3h; then continuing to heat to 540-560°C at a heating rate of 1.5-3°C / min, and then immediately cooling down after heating to 540-560°C. This invention employs a staged heating method to calcine the PVP / BaTiO3 / MXene nanofiber membrane. The prepared PVP / BaTiO3 / MXene nanofiber membrane is calcined in a muffle furnace, with a maximum calcination temperature set at 550℃. The temperature is programmed with holding periods at 210–230℃ and 440–460℃. The holding period at 210–230℃ aims to ensure sufficient solvent evaporation, while the holding period at 440–460℃ provides sufficient time and a plateau for polymer decomposition and crystal phase formation. To allow for sufficient grain growth, the heating rate is maintained at 1.5–3℃ / min throughout the calcination process. The final calcination temperature is set at 550℃.

[0046] According to some embodiments of the present invention, the mass fraction of the monolayer dispersed MXene in the spinning precursor solution is 5-15 wt%, and / or the mass fraction of the polyvinylpyrrolidone is 4-6 wt%; and / or the mass fraction of the tetrabutyl titanate is 12-16 wt%; and / or the mass fraction of the barium acetate is 15-25 wt%. For example, the mass fraction of the monolayer dispersed MXene in the spinning precursor solution is 10 wt%, and / or the mass fraction of the polyvinylpyrrolidone is 5 wt%; and / or the mass fraction of the tetrabutyl titanate is 14 wt%; and / or the mass fraction of the barium acetate is 20 wt%.

[0047] Secondly, this invention provides a barium titanate-based fiber membrane, which is prepared by the method described above. The flexible, low-loss, and high-toughness dielectric substrate material provided by this invention can conform to any curved surface, thus having broad application prospects. Compared with traditional dielectric materials, flexible barium titanate-based dielectric materials combine excellent electromagnetic properties and physicochemical stability, and are therefore widely used in microwave, infrared, and laser communications, especially in the field of flexible antennas.

[0048] Thirdly, the present invention provides an antenna dielectric layer comprising a barium titanate-based fiber membrane as described above.

[0049] According to some embodiments of the present invention, the antenna dielectric layer comprises three layers: the top and bottom layers are made of polyethylene terephthalate (PET), and the middle layer is a barium titanate-based fiber membrane. In this invention, the barium titanate-based fiber membrane described above is used as the material for the antenna dielectric layer to design a sandwich-structured antenna dielectric layer. Specifically, the barium titanate-based fiber membrane (i.e., BaTiO3 / MXene fiber membrane) is used as the middle layer of the antenna dielectric layer, which provides high flexibility and high dielectric properties. The top and bottom layers are composed of PET layers that encapsulate the BaTiO3 / MXene fiber membrane to form a sandwich structure. The PET layer serves both as a protective layer to reduce physicochemical corrosion and as a carrier for the patterned design of the antenna.

[0050] According to some embodiments of the present invention, the method for preparing the antenna dielectric layer is as follows: a BaTiO3 / MXene composite nanofiber film of a certain thickness is taken as the middle layer of the antenna dielectric layer, and the upper and lower layers are respectively encapsulated with PET (polyethylene terephthalate) material.

[0051] Fourthly, this invention provides an antenna comprising the antenna dielectric layer as described above. The antenna's structural design employs a 1-to-2 power divider to equally divide the input signal, and utilizes a series-parallel feed structure. The main structure of the antenna consists of three parts: a radiating patch, an antenna dielectric layer, and a ground plane.

[0052] Specifically, see the schematic diagram of the antenna structure. Figure 2 The antenna dielectric layer is a flexible BaTiO3 / MXene fiber film 1 with a thickness of 0.4 mm, and the upper and lower layers are encapsulated with PET layers 2 with a thickness of 0.1 mm. A stretchable conductive silver paste is used as the conductive material for patterning using a screen printing process that offers rapid prototyping, good conductivity, and high mechanical strength. The conductive layer with the array structure pattern is the radiating layer 3 of the entire antenna. To ensure the structural stability of the entire antenna, the upper and lower PET layers 2 are fixed together with adhesive.

[0053] The present invention will be further described below through some specific embodiments.

[0054] Example 1: Preparation of BaTiO3 / MXene fiber membrane

[0055] (1) Preparation of monolayer dispersed MXene solution

[0056] 1 g LiF was added to 20 mL of HCl (37 wt%) solution and stirred at a constant speed for half an hour. Then, 0.1 g Ti3AlC2 was added slowly to the solution in 10 portions over 30 minutes each time. The mixture was stirred continuously in an oil bath at 35°C for 24 hours to remove Al. The resulting suspension was washed several times with deionized water until neutral (pH = 6), and centrifuged to obtain multilayer Ti3C2T. x Precipitate. Then, in Ti3C2T x Add 150 ml of deionized water to the precipitate and sonicate in an ice bath for 90 min. Finally, centrifuge the sonicated solution at 3500 rpm for 1 h and collect the solution containing the layered Ti3C2T. x The dark green supernatant of the nanosheets (i.e., a monolayer dispersed MXene solution) was frozen and stored.

[0057] (2) Preparation of PVP / BaTiO3 / MXene nanofiber membrane

[0058] Weigh 0.3158g of polyvinylpyrrolidone (PVP) (M w ≈1.3×10 6The sample was dried in a vacuum drying oven for 2 hours. 3.8 mL of anhydrous ethanol, 2.3 mL of acetic acid, and 0.6 mL of 2 mg / mL MXene were mixed thoroughly to obtain an MXene mixed solution. The dried polyvinylpyrrolidone was added to the MXene mixed solution while stirring for 6 hours until the solution was homogeneous. Then, 0.9 g of barium acetate was added, and stirring continued for 6 hours. Finally, 1.2 g of tetrabutyl titanate was added dropwise while stirring for 2 hours until the solution became clear and transparent (i.e., the spinning precursor solution), ready for electrospinning. A roller was used as the electrospinning receiver, and the PVP / BaTiO3 / MXene nanofiber membrane was prepared by electrospinning using the spinning precursor solution. The spinning parameters were set as follows: spinning speed 1 mL / h, voltage 20 kV, spinning distance 15 cm, and roller speed 100 rpm.

[0059] (3) Preparation of BaTiO3 / MXene fiber membrane

[0060] The spun PVP / BaTiO3 / MXene nanofiber membranes were cut to the same size and placed in a crucible within a muffle furnace. A specific temperature curve was programmed for staged heating. The staged heating process was as follows: First, the PVP / BaTiO3 / MXene nanofiber membrane was heated to 220°C at a rate of 2°C / min and held for 1 hour to allow for sufficient solvent evaporation. Then, the temperature was increased to 450°C at a rate of 2°C / min and held for 2 hours to provide sufficient time and a plateau for polymer decomposition and crystal phase formation. To allow for sufficient grain growth, the temperature was again increased to 550°C at a rate of 2°C / min. Heating was then stopped, and the membrane was allowed to cool naturally within the muffle furnace.

[0061] test:

[0062] 1. Figure 3 This is a TEM image of the BaTiO3 / MXene fiber membrane prepared in this embodiment. Figure 1 It can be seen that the prepared fiber has a relatively smooth surface and a dark black interior, which means that the fiber contains abundant carbon, thus making the fiber highly flexible.

[0063] 2. Figure 4a and Figure 4b The figures show photos of the BaTiO3 / MXene fiber membrane prepared in this embodiment being bent and rolled up. As can be seen from the figures, the prepared BaTiO3 / MXene fiber membrane has excellent flexibility.

[0064] 3. Test the dielectric loss of the BaTiO3 / MXene fiber membrane prepared in this embodiment:

[0065] Test method: The resonant frequency and Q value of the resonator equipped with the fiber membrane were measured using a vector network analyzer, and the measurement data were converted into material data using QWED software;

[0066] Test results: The dielectric loss of the BaTiO3 / MXene fiber membrane prepared in this embodiment is 0.005.

[0067] Example 2

[0068] (1) Preparation of monolayer dispersed MXene solution: Same as in Example 1.

[0069] (2) Preparation of PVP / BaTiO3 / MXene nanofiber membrane:

[0070] The spinning parameters were set as follows: spinning speed of 0.8 mL / h, voltage of 18 kV, spinning distance of 12 cm, and roller speed of 100 rpm. The rest of the preparation method was the same as in Example 1.

[0071] (3) Preparation of BaTiO3 / MXene fiber membrane: Same as in Example 1.

[0072] The dielectric loss of the BaTiO3 / MXene fiber membrane prepared in this embodiment was tested using the same method as in Example 1.

[0073] The dielectric loss of the BaTiO3 / MXene fiber membrane prepared in this embodiment was tested to be 0.008.

[0074] Example 3

[0075] (1) Preparation of monolayer dispersed MXene solution: Same as in Example 1.

[0076] (2) Preparation of PVP / BaTiO3 / MXene nanofiber membrane:

[0077] The spinning parameters were set as follows: spinning speed of 1.2 mL / h, voltage of 23 kV, spinning distance of 15 cm, and roller speed of 500 rpm. The rest of the preparation method was the same as in Example 1.

[0078] (3) Preparation of BaTiO3 / MXene fiber membrane: Same as in Example 1.

[0079] The dielectric loss of the BaTiO3 / MXene fiber membrane prepared in this embodiment was tested using the same method as in Example 1.

[0080] The dielectric loss of the BaTiO3 / MXene fiber membrane prepared in this embodiment was tested to be 0.009.

[0081] Example 4

[0082] (1) Preparation of monolayer dispersed MXene solution: Same as in Example 1.

[0083] (2) Preparation of PVP / BaTiO3 / MXene nanofiber membrane: Same as in Example 1.

[0084] (3) Preparation of BaTiO3 / MXene fiber membrane: Same as in Example 1.

[0085] The spun PVP / BaTiO3 / MXene nanofiber membranes were cut to the same size and placed in a crucible within a muffle furnace. A specific temperature curve was programmed for staged heating. The staged heating process was as follows: First, the PVP / BaTiO3 / MXene nanofiber membrane was heated to 220°C at a rate of 2.5°C / min and held for 1 hour to allow for sufficient solvent evaporation. Then, the temperature was increased to 450°C at a rate of 3°C / min and held for 2 hours to provide sufficient time and a plateau for polymer decomposition and crystal phase formation. To allow for sufficient grain growth, the temperature was again increased to 550°C at a rate of 3°C / min. Heating was then stopped, and the membrane was allowed to cool naturally within the muffle furnace.

[0086] The dielectric loss of the BaTiO3 / MXene fiber membrane prepared in this embodiment was tested using the same method as in Example 1.

[0087] The dielectric loss of the BaTiO3 / MXene fiber membrane prepared in this embodiment was tested to be 0.009.

[0088] Comparative Example 1

[0089] (1) Preparation of monolayer dispersed MXene solution: Same as in Example 1.

[0090] (2) Preparation of PVP / BaTiO3 / MXene nanofiber membrane: Same as in Example 1.

[0091] (3) Preparation of BaTiO3 / MXene fiber membrane: The spun PVP / BaTiO3 / MXene nanofiber membrane was cut into the same size and placed in a crucible, which was then calcined in a muffle furnace. The specific calcination method was to heat the membrane to 550℃ at a heating rate of 2℃ / min and hold it for 3 hours.

[0092] The dielectric loss of the BaTiO3 / MXene fiber membrane prepared in this comparative example was tested using the same method as in Example 1.

[0093] The dielectric loss of the BaTiO3 / MXene fiber membrane prepared in this comparative example was tested to be 0.015.

[0094] Comparative Example 2

[0095] (1) Preparation of monolayer dispersed MXene solution: Same as in Example 1.

[0096] (2) Preparation of PVP / BaTiO3 / MXene nanofiber membrane:

[0097] The spinning parameters were set as follows: spinning speed of 1.5 mL / h, voltage of 25 kV, spinning distance of 15 cm, and roller speed of 100 rpm. The rest of the preparation method was the same as in Example 1.

[0098] (3) Preparation of BaTiO3 / MXene fiber membrane: Same as in Example 1.

[0099] The dielectric loss of the BaTiO3 / MXene fiber film obtained in this comparative example was tested using the same method as in Example 1.

[0100] The dielectric loss of the BaTiO3 / MXene fiber membrane prepared in this comparative example was tested to be 0.015.

[0101] Example 5: Fabrication of a Flexible Barium Titanate-Based Antenna

[0102] In this embodiment, a sandwich dielectric layer was designed based on flexible barium titanate material, which is the BaTiO3 / MXene fiber membrane prepared in Example 1.

[0103] The middle layer of the sandwich structure's dielectric layer is a BaTiO3 / MXene composite nanofiber film, with four layers stacked to a thickness of 0.4 mm. The top and bottom layers are 0.1 mm thick PET (polyethylene terephthalate) material. To ensure the structural stability of the entire antenna, the top and bottom PET layers are fixed together with adhesive. The antenna's structural design employs a 1-to-2 power divider to equally divide the input signal, using a series-parallel feed structure. The main structure of the antenna consists of three parts: a radiating patch, a dielectric layer, and a ground plane. A stretchable conductive silver paste is used as the conductive material for patterned design using a screen printing process with rapid prototyping, good conductivity, and high mechanical strength. The conductive layer with the array structure pattern is the radiating layer of the entire antenna. Simultaneously, HFSS simulation software was used to design the antenna, with a size of 6 cm × 5 cm and a dielectric layer thickness of 0.6 mm. The antenna structure is designed as an array antenna.

[0104] Testing the echo performance of a flexible barium titanate-based antenna:

[0105] The antenna fabricated in Example 5 was subjected to S11 performance testing and analysis using vector network analysis, and the results were compared with those of the antenna designed using HFSS simulation software. The antenna structure fabricated using Flexible Printed Circuit Board (FPCB) technology is more precise, and theoretically, the measured results should be better. A clear resonant point can be observed in the vector network analysis; however, due to the thinner thickness of the flexible BaTiO3 / MXene nanofiber film dielectric material compared to the simulation design (indicating experimental error), the frequency shifts to higher frequencies. The theoretical resonant point is 10 GHz, while the actual measured resonant point is approximately 10.3 GHz. This difference between theory and practice can be resolved later by minimizing experimental errors.

[0106] Although there is a certain gap between the simulation results and the test results of the antenna, from Figure 5 It can be seen that the basic waveforms of the antennas are consistent, and their errors are within the allowable range. Simulation results using HFSS show that the antenna's S11 is as low as -23dB at a 10GHz operating frequency, indicating that only a small portion of the energy is reflected at this frequency, resulting in the highest transmission efficiency. This is mainly due to the good impedance matching between the antenna's radiating layer and the external electrical components. Test results show that at approximately 10.3GHz, the antenna's S11 increases slightly to -16dB. The operating frequency shifts to the right compared to the simulated 10GHz, with the shaded area representing the measured effective bandwidth (BW). Compared to traditional flexible antennas, this antenna is only 6cm x 5cm in size and achieves a high gain of 13dBi at 10GHz with a transmission efficiency exceeding 80%, effectively improving the transmission distance and efficiency of flexible antennas and providing potential for future applications in wearable antennas.

[0107] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship also changes accordingly.

[0108] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a barium titanate-based fiber membrane, characterized in that, The preparation method includes the following steps: S1: Add monolayer dispersed MXene and polyvinylpyrrolidone to an organic solvent and stir to mix. Then add tetrabutyl titanate and barium acetate to prepare a spinning precursor solution. S2: Take the spinning precursor liquid described in S1, use a roller as an electrospinning receiver to perform electrospinning, and obtain a PVP / BaTiO3 / MXene nanofiber membrane. S3: The PVP / BaTiO3 / MXene nanofiber membrane spun in S2 is calcined to obtain the BaTiO3 / MXene fiber membrane after calcination. The calcination described in S3 employs a staged heating method, and the conditions for the staged heating are as follows: The temperature is increased to 210-230 ℃ at a heating rate of 1.5-2.5 ℃ / min and held for 0.5-1.5 h; then the temperature is increased to 440-460 ℃ at a heating rate of 2-3 ℃ / min and held for 1-3 h; then the temperature is increased to 540-560 ℃ at a heating rate of 1.5-3 ℃ / min and then cooled down.

2. The preparation method according to claim 1, characterized in that, The organic solvent is a mixture of ethanol, acetic acid and deionized water.

3. The preparation method according to claim 1, characterized in that, After adding the barium acetate to S1, stir for 4 to 12 hours, then add the tetrabutyl titanate dropwise while stirring for 1 to 3 hours.

4. The preparation method according to claim 1, characterized in that, The spinning parameters in S2 are set as follows: The spinning speed is 0.8~1.2 mL / h, the voltage is 18~23kV, the spinning distance is 12~15 cm, the rotation speed of the roller is 100~500 rpm, and the spinning time is 3~5 h.

5. The preparation method according to claim 1, characterized in that, The mass fraction of the monolayer dispersed MXene in the spinning precursor solution is 5~15 wt‰, and / or The polyvinylpyrrolidone has a mass fraction of 4-6 wt%; and / or The tetrabutyl titanate has a mass fraction of 12-16 wt%; and / or The barium acetate has a mass fraction of 15-25 wt%.

6. A barium titanate-based fiber membrane, characterized in that, The barium titanate-based fiber membrane is prepared by the preparation method according to any one of claims 1 to 5.

7. An antenna dielectric layer, characterized in that, The antenna dielectric layer includes the barium titanate-based fiber membrane as described in claim 6.

8. The antenna dielectric layer according to claim 7, characterized in that, The antenna dielectric layer comprises three layers: the top and bottom layers are made of polyethylene terephthalate, and the middle layer is a barium titanate-based fiber membrane.

9. An antenna, characterized in that, The antenna includes the antenna dielectric layer as described in any one of claims 7 to 8.

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