Method of transmetallic communication, high frequency ultrasound transducer and method of manufacturing and system thereof

Abstract

The application discloses a cross-metal communication method, a high-frequency ultrasonic transducer and a preparation method and system thereof. The ultrasonic transducer used in the method comprises a piezoelectric layer and an epoxy conductive silver adhesive backing layer integrated with the piezoelectric layer, and the thickness of the piezoelectric layer is X, wherein 100 μm≤X<500 μm. The method comprises the following steps: generating a carrier signal, the frequency of the carrier signal is matched with the center frequency of the ultrasonic transducer; based on a data signal to be transmitted, a 2ASK modulation signal is generated by controlling the opening and closing of the carrier signal; the 2ASK modulation signal is power amplified, and a first ultrasonic transducer is driven to convert the 2ASK modulation signal into an ultrasonic wave signal, which is transmitted through a metal medium; the ultrasonic wave signal penetrating through the metal medium is received by a second ultrasonic transducer and converted back into an electric signal; and the electric signal is demodulated to restore the data signal. By thinning the piezoelectric layer and cooperating with the epoxy conductive silver adhesive backing layer, the working frequency of the transducer is fundamentally improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ultrasonic communication, in particular to a cross-metal communication method based on a high-frequency ultrasonic transducer, a high-frequency ultrasonic transducer and a preparation method and system thereof. BACKGROUND

[0002] In a cross-metal medium communication environment, due to the strong reflection and absorption of metal materials to electromagnetic waves, the traditional wireless communication method often has problems of signal attenuation and communication quality degradation when penetrating through metal shielding or metal structures. Therefore, how to realize high-speed and stable communication in a metal structure or metal environment has become an important issue to be solved in current communication technology. Compared with electromagnetic waves, ultrasonic signals have less transmission loss and stronger penetration in metals and other substances, which makes the ultrasonic communication method have wide application potential in metal structure environment.

[0003] At present, the research and development of ultrasonic communication technology mainly focuses on the innovation of the back-end system, such as signal processing, transmission algorithm, coding technology, etc., to improve the efficiency and stability of the communication system. However, the breakthrough and improvement of these back-end technologies are still restricted by the performance parameters of the front-end transducer. As the core component of the ultrasonic communication system, the transducer is responsible for converting electrical signals into ultrasonic signals, and its performance directly affects the transmission quality and reliability of the entire system. The application of ultrasonic probes in cross-metal communication is limited by bandwidth and resonance frequency, making it difficult to achieve high-speed communication performance. Specifically, the resonance frequency of existing ultrasonic probes is generally low, which cannot effectively support high-frequency signal transmission, and the narrow bandwidth of the transducer can only carry a small amount of data, which cannot meet the demand of high-speed communication for large data volume and high throughput. SUMMARY

[0004] In order to overcome the defects of the existing ultrasonic transducer that cannot support high-speed cross-metal communication due to low resonance frequency and narrow working bandwidth, the first purpose of the present application is to provide a cross-metal communication method based on a high-frequency ultrasonic transducer; the second purpose of the present application is to provide a high-frequency ultrasonic transducer for realizing the foregoing method; the third purpose of the present application is to provide a preparation method of the high-frequency ultrasonic transducer; and the fourth purpose of the present application is to provide a cross-metal high-speed communication system.

[0005] To achieve the above purposes, the technical solution adopted by the present application is:

[0006] In a first aspect, the present application provides a cross-metal communication method based on a high-frequency ultrasonic transducer, the ultrasonic transducer used in the method includes a piezoelectric layer and an epoxy conductive silver adhesive backing layer integrated with the piezoelectric layer, the thickness of the piezoelectric layer is X, wherein 100 μm≤X<500 μm, and the method includes the following steps:

[0007] A carrier signal is generated, the frequency of which is matched with the center frequency of the ultrasonic transducer;

[0008] Based on the data signal to be transmitted, a 2ASK modulated signal is generated by controlling the on and off of the carrier signal;

[0009] The 2ASK modulated signal is amplified and driven by the first ultrasonic transducer to convert it into an ultrasonic signal, which is transmitted through the metal medium.

[0010] The second ultrasonic transducer receives the ultrasonic signal that penetrates the metal medium and converts it back into an electrical signal;

[0011] The electrical signal is demodulated to recover the data signal.

[0012] It should be noted that the center frequency is matched with the resonant frequency of the ultrasonic transducer to ensure effective signal excitation and transmission. In this application, the center frequency usually refers to the operating frequency point with the highest electroacoustic conversion efficiency determined by the transducer impedance curve. For example, it can be a frequency between its series resonant frequency and parallel resonant frequency, such as the geometric average of the two, or the frequency corresponding to its maximum admittance.

[0013] Matching the carrier signal frequency to the center frequency of the ultrasonic transducer means setting the carrier frequency near the resonant frequency point where the transducer impedance is minimum and energy conversion efficiency is highest, to ensure effective signal excitation and transmission. The entire communication link constitutes a complete ultrasonic penetration communication system based on 2ASK modulation.

[0014] This application utilizes a high-frequency ultrasonic transducer comprising a piezoelectric layer (thickness 100μm ≤ X < 500μm) and an epoxy conductive silver paste backing layer integrated with the piezoelectric layer, significantly increasing the transducer's center frequency to the high-frequency range (e.g., up to 18MHz). The epoxy conductive silver paste backing layer suppresses clutter interference by optimizing acoustic damping characteristics and acts as a conductive path to ensure low-loss transmission of high-frequency signals, synergistically enhancing the high-frequency range with the thinned piezoelectric layer. In 2ASK modulation, data signals are encoded and transmitted by controlling the "on" and "off" states of the carrier wave. Based on the synergistic effect of the epoxy conductive silver paste backing layer and the thinned piezoelectric layer, the transducer's high-frequency bandwidth and signal integrity are significantly improved. The higher carrier frequency means a shorter symbol period, allowing more symbols to be transmitted per unit time, thereby directly increasing the data transmission rate.

[0015] In a second aspect, the application provides a method for cross-metal communication based on a high-frequency ultrasonic transducer. The ultrasonic transducer used in the method comprises a piezoelectric layer and an epoxy conductive silver adhesive backing layer integrated with the piezoelectric layer, and the thickness of the piezoelectric layer is X, where 100 μm≤X<500 μm. The method comprises the following steps:

[0016] generating a data stream to be transmitted;

[0017] mapping the data stream onto a plurality of orthogonal subcarriers to generate a baseband OFDM signal;

[0018] up-converting the baseband OFDM signal to a radio frequency to generate an OFDM modulated signal, wherein the carrier frequency of the radio frequency matches the center frequency of the ultrasonic transducer;

[0019] after amplifying the OFDM modulated signal, driving the first ultrasonic transducer to convert the electrical signal into an ultrasonic wave signal and transmit through the metal medium;

[0020] receiving the ultrasonic wave signal transmitted through the metal medium by the second ultrasonic transducer and converting it into an electrical signal;

[0021] down-converting and OFDM demodulating the electrical signal to restore the data stream.

[0022] The application uses a high-frequency ultrasonic transducer comprising a piezoelectric layer (thickness 100 μm≤X<500 μm) and an epoxy conductive silver adhesive backing layer integrated with the piezoelectric layer, and combines OFDM modulation technology. OFDM technology decomposes a high-speed data stream into a plurality of low-speed sub-data streams, and modulates each sub-data stream onto a series of mutually orthogonal subcarriers for parallel transmission. This modulation method can effectively resist frequency-selective fading caused by multipath effects. The high-frequency transducer used in the application has a wider absolute bandwidth through the synergistic structure of the thinned piezoelectric layer and the epoxy conductive silver adhesive backing layer: the thinned piezoelectric layer directly raises the center frequency to the high-frequency band (such as 18 MHz), and the epoxy conductive silver adhesive backing layer suppresses spurious interference and reduces high-frequency signal attenuation by optimizing acoustic damping characteristics. A wider absolute bandwidth means that more OFDM subcarriers or higher subcarrier modulation orders can be accommodated, and the epoxy conductive silver adhesive backing layer improves the integrity of high-frequency signal transmission and reduces inter-carrier interference (ICI), thereby greatly improving the spectral efficiency and total data throughput of the system. Matching the carrier frequency to the center frequency of the ultrasonic transducer aligns the spectral center of the OFDM modulated signal with the efficient operating frequency band of the transducer, and the epoxy conductive silver adhesive backing layer improves the frequency stability of the transducer to ensure long-term matching of the spectral center and the resonance frequency, so as to fully utilize the bandwidth advantage.

[0023] In a third aspect, the application provides a high-frequency ultrasonic transducer for cross-metal communication, comprising:

[0024] a piezoelectric layer having a thickness X, 100 μm≤X<500 μm;

[0025] an epoxy conductive silver adhesive backing layer, bonded to a first surface of the piezoelectric layer and serving as a first electrical connection terminal;

[0026] a second electrical connection terminal, disposed on a second surface of the piezoelectric layer opposite to the first surface;

[0027] a housing, accommodating the piezoelectric layer and the epoxy conductive silver adhesive backing layer;

[0028] an encapsulation layer, filled between the epoxy conductive silver adhesive backing layer and the housing;

[0029] a high-frequency connection interface, fixed to the housing, having an inner core electrically connected to the first electrical connection terminal and an outer conductor electrically connected to the second electrical connection terminal.

[0030] According to the physical principle that the resonant frequency of a piezoelectric ceramic is inversely proportional to its thickness, thinning the piezoelectric layer is the most direct and effective means to increase the central resonant frequency. By thinning the thickness from millimeter level of traditional transducers to hundred-micron level, the working frequency is successfully increased to MHz or even tens of MHz high frequency band. The conductive backing layer serves as an acoustic backing for absorbing the backward propagating acoustic waves, suppressing spurious interference and shortening the pulse length, and also as an electrical connection terminal. The second electrical connection terminal and the first electrical connection terminal are used together to apply an excitation electric field on both sides of the piezoelectric layer. The housing provides mechanical protection and shielding for the internal precision structure. The high-frequency connection interface ensures low-loss transmission of high-frequency signals and reliable electrical connection.

[0031] Epoxy conductive silver adhesive is a composite material composed of epoxy resin and silver powder. The epoxy resin matrix provides structural support and curability, while the silver powder particles form a conductive path. The backing layer meets the dual functions of electrical conductivity and acoustic damping. In actual use, other conductive composites with the same function can also be used.

[0032] Optionally, the second electrical connection terminal is a conductive electrode layer formed on the second surface of the piezoelectric layer. One specific implementation of the second electrical connection terminal is to form a layer of firm conductive film on the surface of the piezoelectric layer by silver plating, silver paste coating or other conductive materials as an electrode. This structure is simple and reliable, and can ensure that the electric field is uniformly applied to the piezoelectric layer.

[0033] Optionally, the material of the piezoelectric layer is PZT-5H piezoelectric ceramic. PZT-5H is a soft lead zirconate titanate piezoelectric ceramic with high piezoelectric constant, electromechanical coupling coefficient and dielectric constant. These characteristics make PZT-5H particularly suitable for manufacturing high-frequency broadband transducers, because it can achieve high electro-acoustic conversion efficiency and wide operating bandwidth, which is crucial for high-speed communication. It can be understood that other types of piezoelectric ceramic or piezoelectric single crystal materials with the same function can also be used in actual use.

[0034] Optionally, it further comprises a packaging layer filled between the conductive backing layer and the shell. The packaging layer mainly has the following functions: insulation, preventing short circuit between the conductive backing layer and the metal shell; fixation, firmly packaging the internal components in the shell, improving the mechanical strength and reliability of the transducer; acoustic isolation, further optimizing the acoustic performance, reducing unnecessary vibration and acoustic reflection.

[0035] In a fourth aspect, the application provides a preparation method of a high-frequency ultrasonic transducer, comprising the following steps:

[0036] Providing a piezoelectric material and thinning it to a predetermined thickness X, 100 μm≤X<500 μm, to form a piezoelectric layer;

[0037] Forming a conductive backing layer on the first surface of the piezoelectric layer and arranging a conductive connecting piece in the conductive backing layer, the conductive backing layer serving as a first electrical connection end, and the conductive backing layer being an epoxy conductive silver adhesive backing layer;

[0038] Forming or arranging a second electrical connection end on the second surface of the piezoelectric layer;

[0039] Assembling the assembly composed of the piezoelectric layer, the conductive backing layer and the conductive connecting piece into a shell;

[0040] Filling an insulating material to achieve insulation and fixation between the internal components and the shell;

[0041] Installing a high-frequency connection interface, with its signal inner core electrically connected to the conductive connecting piece and its external conductor electrically connected to the second electrical connection end.

[0042] By forming a conductive backing layer on the first surface of the piezoelectric layer and embedding a conductive connecting piece, the functions of acoustic backing and electrical lead-out are integrated in one step. Pre-assembling the piezoelectric layer, the backing and the like into an assembly before assembling into the shell is a reasonable and efficient assembly process, which is conducive to ensuring the alignment accuracy of the internal structure. Filling an insulating material ensures the electrical safety and structural integrity of the product. Finally, installing a high-frequency connection interface completes the transition from the internal small structure to the external standard interface, making the transducer easy to integrate into the communication system.

[0043] Optionally, the step of thinning the piezoelectric material comprises:

[0044] temporarily fixing the piezoelectric material on the support substrate using hot-melt paraffin;

[0045] mechanically grinding the exposed surface of the piezoelectric material to a predetermined thickness;

[0046] heating and melting the paraffin to remove the piezoelectric layer and perform cleaning.

[0047] The hot-melt paraffin serves as a temporary adhesive, providing stable support during grinding to prevent the brittle and thin piezoelectric ceramic from breaking. After processing is completed, the paraffin can be melted by simply heating, achieving non-damaging demolding. Mechanical grinding is a practical method for controlling thickness and achieving surface flatness. The subsequent cleaning step is used to completely remove paraffin residues, ensuring the interface quality of subsequent processes.

[0048] Optionally, the step of forming the conductive backing layer comprises:

[0049] Mixing the A and B components of the epoxy conductive silver paste in a mass ratio of 3:1, pouring onto the first surface of the piezoelectric layer and curing. This mass ratio is an optimized ratio that can ensure sufficient curing of the epoxy resin to form a strong skeleton while maintaining a high enough silver powder content to ensure good electrical conductivity. The pouring process can well fill the mold and form a tight bond with the surface of the piezoelectric layer.

[0050] Optionally, the step of forming or providing the second electrical connection comprises:

[0051] Applying conductive silver paste to the second surface of the piezoelectric layer and electrically connecting the conductive silver paste to the housing. Coating conductive silver paste is a simple and low-cost method of forming electrodes. By contacting the silver paste with the metal housing, the housing itself is used as a conductor to lead the second electrical connection to the outside, simplifying the internal lead structure and improving reliability.

[0052] Optionally, the step of installing the high-frequency connection interface comprises:

[0053] Welding the conductive connector to the signal inner core of the high-frequency connection interface, and using conductive glue to fix the external conductor of the high-frequency connection interface to the housing. Welding ensures a low-resistance and highly reliable electrical connection between the signal inner core and the conductive connector leading from the backing, which is crucial for the transmission of high-frequency signals. The conductive glue, on the other hand, achieves mechanical fixation of the interface's external conductor to the housing and establishes a good electrical connection.

[0054] In a fifth aspect, a cross-metal high-speed communication system comprises:

[0055] Two high-frequency ultrasonic transducers are arranged on two sides of the metal medium as a transmitting end and a receiving end respectively, and the high-frequency ultrasonic transducers are the high-frequency ultrasonic transducers described above.

[0056] A signal generating and modulating unit is used for generating a carrier signal and generating a 2ASK or OFDM modulated signal according to the data to be transmitted, and is electrically connected with the transmitting end.

[0057] A signal receiving and demodulating unit is electrically connected with the receiving end, and is used for demodulating the received electrical signal to restore the data.

[0058] By using the above technical scheme, the present application has the following advantages compared with the prior art:

[0059] 1. The piezoelectric layer thickness of the ultrasonic transducer is thinned to 100 μm≤X<500 μm, and the acoustic damping characteristics of the epoxy conductive silver adhesive backing layer are matched, so that the center resonant frequency and the working bandwidth are significantly improved. The thinning of the piezoelectric layer directly improves the high frequency band through the thickness-frequency inverse relationship, and the epoxy conductive silver adhesive backing layer further expands the effective bandwidth by suppressing spurious interference and optimizing acoustic impedance matching, and the two work together to break through the technical bottleneck that the traditional transducer cannot support high-speed communication due to low frequency and narrow bandwidth.

[0060] 2. Based on the high-frequency transducer, the two communication methods (2ASK and OFDM) provided by the present application can fully utilize the high frequency and wide band advantages, and significantly improve the data transmission rate of the cross-metal communication.

[0061] 3. The transducer structure of the present application is reasonable, the preparation method is clear and has strong operability, especially the paraffin temporary fixation thinning process effectively solves the problem of fragile and difficult processing of thin layer piezoelectric ceramic, and ensures the consistency and reliability of product performance.

[0062] In order to make the above and other objects, features and advantages of the present application more obvious and easy to understand, the following preferred embodiments are described in detail below, and the accompanying drawings are described as follows. BRIEF DESCRIPTION OF DRAWINGS

[0063] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creating laborious work.

[0064] Figure 1 The structure diagram of the high-frequency ultrasonic transducer in the embodiment of the present application is shown in the figure.

[0065] Figure 2Impedance phase angle curve diagram for 100 μm transducer with piezoelectric layer;

[0066] Figure 3 Impedance phase angle curve diagram for 200 μm transducer with piezoelectric layer;

[0067] Figure 4 Impedance phase angle curve diagram for 300 μm transducer with piezoelectric layer;

[0068] Figure 5 Impedance phase angle curve diagram for 400 μm transducer with piezoelectric layer;

[0069] Figure 6 Impedance phase angle curve diagram for 500 μm transducer with piezoelectric layer;

[0070] Figure 7 Flow chart of 2ASK communication system;

[0071] Figure 8 Communication rate and bit error rate relation diagram under 2ASK modulation mode;

[0072] Figure 9 OFDM communication system test platform;

[0073] Figure 10 Communication rate and EVM relation diagram under 64QAM modulation mode.

[0074] Reference signs of the above drawings: 1, high frequency connection interface; 2, shell; 3, encapsulation layer; 4, piezoelectric layer; 5, second electric connection end; 6, first electric connection end; 7, conductive connecting piece; 8, conductive backing layer. DETAILED DESCRIPTION

[0075] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work are within the protection scope of the present application.

[0076] Embodiment, see Figure 1As shown, a high-frequency ultrasonic transducer comprises a piezoelectric layer 4 with a thickness of X, 100 μm≤X<500 μm; a conductive backing layer 8 bonded to a first surface of the piezoelectric layer 4 and serving as a first electrical connection end 6; a second electrical connection end 5 provided on a second surface of the piezoelectric layer 4 opposite to the first surface; a housing 2 accommodating the piezoelectric layer 4 and the conductive backing layer 8; and a high-frequency connection interface 1 fixed to the housing 2, with an inner core thereof electrically connected to the first electrical connection end 6 and an outer conductor thereof electrically connected to the second electrical connection end 5. By thinning the piezoelectric layer 4 to the order of 100 μm, the working frequency of the transducer is fundamentally improved; meanwhile, the integrated structural design highly integrates the acoustic backing, electrical connection and mechanical packaging, which not only ensures the reliability of high-frequency signal transmission, but also simplifies the overall assembly process.

[0077] In an optional embodiment, the piezoelectric layer 4 serves as a transducing element of the transducer and is responsible for the mutual conversion between electrical signals and ultrasonic signals. Optionally, the piezoelectric layer 4 can be made of PZT-5H piezoelectric ceramic, because it has high piezoelectric constant (d33) and high electromechanical coupling coefficient (Kt), which helps to achieve efficient energy conversion.

[0078] In an optional embodiment, the piezoelectric layer 4 has a thickness of X, where 100 μm≤X<500 μm, such as 100 μm, 200 μm, 300 μm, 400 μm or any value between 100 μm and 500 μm. According to the physical principle that the fundamental resonant frequency of piezoelectric ceramic is inversely proportional to its thickness (fr=N / t, where N is the frequency constant and t is the thickness), by thinning the piezoelectric layer 4 from the millimeter level of the conventional transducer to the order of 100 μm, the working frequency of the high-frequency ultrasonic transducer can be significantly improved, for example, to the high-frequency band of MHz or even tens of MHz.

[0079] In an optional embodiment, the conductive backing layer 8 is tightly bonded to the first surface (e.g. the lower surface) of the piezoelectric layer 4. In a preferred scheme, the conductive backing layer 8 can be made of epoxy conductive silver adhesive, which is a composite material composed of an epoxy resin matrix and dispersed silver powder.

[0080] The conductive backing layer 8 has both acoustic and electrical functions. Acoustically, it can act as an acoustic backing to absorb the backward propagating acoustic energy by its acoustic impedance property, thus helping to suppress spurious and shorten pulse; electrically, it directly serves as the first electrical connection 6. In forming the conductive backing layer 8, a conductive connection 7 can be pre-embedded, which, after the conductive backing layer 8 material is cured, forms an electrical connection with the conductive backing layer 8 and the lower surface of the piezoelectric layer 4, for signal input or output. The conductive connection 7 can be a piece of silver-plated copper wire, which is pre-set before pouring the conductive backing layer 8, with one end extending to the outside of the backing layer for subsequent soldering, and the other end being solidified inside the backing layer to ensure stable and low-resistance electrical contact with the lower surface of the piezoelectric layer 4. This structure combines mechanical fixation and electrical connection, simplifies the internal lead structure, and improves the reliability of the high-frequency signal transmission path.

[0081] In an optional embodiment, the second electrical connection 5 is provided on the second surface (e.g. upper surface) of the piezoelectric layer 4 opposite to the first surface. The second electrical connection 5, together with the first electrical connection 6, forms an excitation electric field on both sides of the piezoelectric layer 4. In a specific embodiment, the second electrical connection 5 can be a conductive electrode layer formed on the second surface of the piezoelectric layer 4, for example by coating conductive silver paste and curing. This way is simple in process and low in cost, and can help to ensure that the electric field is uniformly applied to the piezoelectric layer 4.

[0082] In an optional embodiment, the housing 2 is used to accommodate the piezoelectric layer 4 and the conductive backing layer 8, providing mechanical protection and structural support for them. Optionally, the housing 2 can be made of metal material, such as brass. In addition to protection, brass can also serve as part of the conductive path.

[0083] In an optional embodiment, the high-frequency connection interface 1 is fixed to the housing 2, for connecting the high-frequency ultrasonic transducer to external circuits. For example, an SMA radio frequency head can be used as the high-frequency connection interface 1.

[0084] The connection can be as follows: the signal inner core of the high-frequency connection interface 1 is electrically connected to the first electrical connection 6 (e.g. the conductive connection 7 leading out from the conductive backing layer 8), for example by soldering; and the outer conductor is electrically connected to the second electrical connection 5. This connection mode helps to ensure low-loss and reliable transmission of high-frequency signals.

[0085] In an optional embodiment, an encapsulation layer 3 is filled between the conductive backing layer 8 and the housing 2. The encapsulation layer 3 can be made of an insulating material, such as epoxy AB glue. The encapsulation layer 3 can serve the following purposes: 1. electrical insulation, to prevent short circuit between the conductive backing layer 8 and the metal housing 2; 2. mechanical fixation, to securely encapsulate the internal components within the housing 2, and to improve the overall structural strength; 3. acoustic isolation, which can help to reduce unwanted vibration and acoustic reflection, and to optimize the acoustic performance.

[0086] The application further discloses a preparation method of the high-frequency ultrasonic transducer.

[0087] S101, a piezoelectric material is provided and is thinned to a preset thickness X (100 μm≤X<500 μm) to form a piezoelectric layer.

[0088] Specifically, first, hot melt paraffin is used as a temporary adhesive to fix the PZT-5H piezoelectric ceramic sheet with an initial thickness of ≥500 μm on a clean glass substrate. During the operation, the glass substrate is placed on a heating table, and the temperature is raised to about 70 ℃, which is higher than the melting point of paraffin (about 65 ℃), so that the paraffin is completely melted. Then the piezoelectric ceramic sheet is smoothly immersed in the molten paraffin, and the interface bubbles are removed by slight extrusion, and the excess paraffin is removed by absorbing the paraffin paper. After the heating table is turned off, the piezoelectric ceramic sheet is firmly fixed on the glass substrate after the paraffin is cooled and solidified.

[0089] After the fixing is completed, the exposed surface of the piezoelectric ceramic sheet is mechanically ground and thinned. Preferably, 2000 mesh or finer sandpaper is used, and the piezoelectric ceramic sheet is gradually thinned to a target thickness, such as 100 μm, 200 μm, 300 μm or 400 μm, by accurately controlling the grinding time, the applied pressure and keeping uniform movement. During the grinding process, special attention should be paid to maintaining the surface flatness and uniformity.

[0090] After the grinding is completed, the above paraffin-glass-piezoelectric ceramic composite structure is heated again to above the melting point of paraffin, so that the softened paraffin can be used to take off the thinned piezoelectric layer from the glass substrate. Then, the piezoelectric layer is thoroughly cleaned with paraffin water and anhydrous alcohol in sequence to completely remove the paraffin residue and ensure the surface cleanliness, thereby providing good interface conditions for subsequent process steps.

[0091] In this thinning process, the hot melt paraffin acts as a temporary fixing medium to provide reliable mechanical support for the brittle and thin piezoelectric ceramic at room temperature, effectively preventing fragmentation during the grinding process. At the same time, it is easy to demold after heating, realizes the safe and lossless processing of the thin layer piezoelectric ceramic, and has good process feasibility.

[0092] S102、In the first surface of the piezoelectric layer, a conductive backing layer is formed, and a conductive connecting piece is arranged in the conductive backing layer. The conductive backing layer serves as a first electrical connection end.

[0093] The purpose of this step is to construct a composite structure with both acoustic backing function and electrical connection function on the first surface of the piezoelectric layer. The specific operation process is as follows:

[0094] First, the piezoelectric layer after thinning is placed in a silicone mold with its first surface facing up. The depth of the silicone mold is adjusted according to the target backing thickness, for example, when the piezoelectric layer is 100 μm thick, a mold with a depth of 5.1 mm can be selected.

[0095] Then, the epoxy conductive silver paste is prepared. The resin component (component A) and the curing agent component (component B) of the epoxy conductive silver paste are accurately weighed in a mass ratio of 3:1, and are placed in a container and stirred until they are evenly mixed. This ratio is optimized to ensure that the epoxy resin is fully cured to form a stable three-dimensional network structure while maintaining a high silver powder filling fraction, thereby ensuring that the cured material has good mechanical strength and excellent electrical conductivity.

[0096] Next, the mixed epoxy conductive silver paste is poured into the silicone mold containing the piezoelectric layer, so that it completely covers the first surface of the piezoelectric layer. When the epoxy conductive silver paste has not yet cured, one end of a conductive connecting piece (such as a silver-plated copper wire) is inserted vertically into the paste, and the insertion depth is sufficient to form a stable mechanical anchor and reliable electrical contact. The other end of the conductive connecting piece should be long enough to extend outside the mold for subsequent welding to the signal core of the high-frequency connection interface.

[0097] Finally, the epoxy conductive silver paste is allowed to cure at room temperature for a period of time. After curing, the conductive backing layer, the first surface of the piezoelectric layer, and the conductive connecting piece form a stable whole. The conductive backing layer serves as an acoustic backing, absorbing the reverse-propagating acoustic waves and improving the impulse response of the transducer, and as a first electrical connection end, allowing the electrical signal to be extracted through the embedded conductive connecting piece. Through a one-step molding process, both acoustic damping and electrical connection functions are achieved, simplifying the internal structure of the transducer.

[0098] S103、In the second surface of the piezoelectric layer, a second electrical connection end is formed or arranged.

[0099] The purpose of this step is to establish a reliable electrical connection on the second surface of the piezoelectric layer, providing a complete electrical field excitation path for the transducer. The specific implementation process is as follows:

[0100] Place the assembly completed in S102 horizontally, ensure the second surface of the piezoelectric layer faces upwards and remains clean. Apply conductive paste evenly to the entire second surface of the piezoelectric layer to form a continuous electrode layer using appropriate coating process. The thickness and uniformity of the paste should be controlled during the coating process to ensure the consistent conductivity of the electrode and not affect the vibration characteristics of the transducer.

[0101] After the coating is completed, transfer the assembly to a curing environment and allow the conductive paste to fully cure under appropriate conditions. The cured paste layer constitutes the second electrical connection end, which forms good electrical contact with the second surface of the piezoelectric layer, ensuring effective transmission of electrical signals.

[0102] S104, assemble the assembly consisting of the piezoelectric layer, conductive backing layer and conductive connecting piece into the shell.

[0103] The purpose of this step is to precisely assemble the core functional assembly formed by the above process with the shell to establish a complete mechanical structure. The specific operation process is as follows:

[0104] Prepare a metal shell and an inner square outer circular silicone positioning ring. The inner hole size of the silicone positioning ring matches the planar size of the piezoelectric layer, and the outer contour matches the inner cavity of the shell. For example, if the thickness of the silicone positioning ring is 3mm, the inner hole is a square with a side length of 5mm, and the outer circle diameter is 14mm.

[0105] Assemble in the order from inside to outside: first place the silicone positioning ring flat on the workbench, then precisely embed the assembly completed in S103 into the inner hole of the silicone positioning ring, and finally axially cover the silicone positioning ring with the metal shell to complete the preliminary assembly.

[0106] This assembly scheme realizes radial positioning through the silicone positioning ring, ensuring the coaxiality between the piezoelectric layer and the shell, and providing an accurate assembly basis for subsequent packaging processes.

[0107] S105, fill with insulating material to achieve insulation and fixation between the internal components and the shell.

[0108] The purpose of this step is to achieve reliable fixation of the internal components by filling insulating material and ensure electrical insulation between the conductive components. The specific implementation method is as follows:

[0109] Prepare epoxy AB glue as the insulating packaging material, accurately weigh the A component and B component according to a mass ratio of 3:1, fully mix and stir, and then perform vacuum degassing treatment to obtain a bubble-free mixed glue solution.

[0110] Use a syringe to draw the mixed glue solution, slowly inject it along the annular gap between the shell and the internal components, and make sure that the glue solution can fully fill all the gaps between the conductive backing layer and the shell. Control the injection speed during the injection process to avoid air bubbles.

[0111] After the perfusion is completed, the entire assembly is left to stand and wait for the epoxy AB glue to fully cure at room temperature. The encapsulation layer formed by curing provides reliable electrical insulation to prevent short circuits between the conductive backing layer and the metal shell, while also serving as a mechanical fixing to enhance the stability of the overall structure.

[0112] S106, install the high-frequency connection interface, make its signal inner core electrically connected with the conductive connecting piece, and make its external conductor electrically connected with the second electrical connection end.

[0113] The purpose of this step is to complete the reliable connection of the high-frequency ultrasonic transducer and the external circuit. The specific installation process is as follows:

[0114] Signal inner core connection: weld the reserved end of the conductive connecting piece extending to the outside of the shell with the signal inner core of the SMA connector to form a low-resistance signal transmission channel.

[0115] External conductor connection: use conductive silver glue to bond and fix the external conductor of the SMA connector at the mounting position of the metal shell. Since the second electrical connection end has been electrically connected with the metal shell through the coated conductive silver paste, this step also establishes the electrical connection between the external conductor of the SMA connector and the second electrical connection end.

[0116] This connection scheme ensures signal transmission quality through welding and mechanical fixation and ground loop establishment through conductive glue bonding, ensuring the reliability of the high-frequency ultrasonic transducer under high-frequency working conditions.

[0117] The embodiments of the present application also disclose two cross-metal communication methods based on the above high-frequency ultrasonic transducer. Both methods place one transducer of the present application on each side of the metal barrier to be communicated, respectively as the transmitting end and the receiving end. The transmitting end converts electrical signals into ultrasonic waves and penetrates the metal, and the receiving end restores the received ultrasonic waves into electrical signals.

[0118] The first communication method based on 2ASK modulation:

[0119] This method is suitable for application scenarios that are sensitive to system complexity and cost, and require high communication rate. The specific implementation steps include:

[0120] S201, signal generation and modulation:

[0121] A carrier signal matching the center frequency of the transmitting high-frequency ultrasonic transducer is generated by a sine wave signal generator. The carrier signal is input to an analog switch circuit controlled by a microprocessor. The microprocessor controls the on-off state of the analog switch according to the data signal to be transmitted received from the host computer, thereby generating a 2ASK modulated signal.

[0122] S202, power amplification and ultrasonic wave transmission:

[0123] The generated 2ASK modulated signal is sent to a power amplification circuit for signal amplification. The amplified signal drives the transmitting high-frequency ultrasonic transducer, which converts it into an ultrasonic wave signal and transmits it through the metal medium.

[0124] S203, signal reception and demodulation:

[0125] The receiving high-frequency ultrasonic transducer receives the ultrasonic wave signal that has penetrated the metal medium and converts it into an electrical signal. The electrical signal is amplified in amplitude by a variable gain amplifier, and then the signal envelope is extracted by an envelope detection circuit. Finally, the voltage comparator compares it with a reference threshold to restore the original data signal and upload it to the host computer.

[0126] To evaluate the performance of the communication method, the application provides a corresponding test scheme:

[0127] Under certain channel conditions (including specific metal barrier thickness, transducer spacing, etc.), the communication baud rate is increased in a step-by-step manner by program control. At each rate test point, the system sends a predetermined test data sequence, and the error rate is counted at the receiving end. When the error rate is continuously below 1%, the highest communication rate corresponding to the test condition is recorded as the maximum communication rate. This test method provides a quantitative basis for evaluating the communication performance of transducers with different thicknesses of piezoelectric layers.

[0128] Second communication method based on OFDM modulation:

[0129] This method is suitable for high-speed communication scenarios that pursue extremely high data throughput. The specific implementation steps include:

[0130] S301, OFDM signal generation:

[0131] The data stream to be transmitted is converted from serial to parallel by a vector signal generator or a host computer, and each sub-data stream is modulated onto multiple orthogonal subcarriers through constellation mapping to generate a baseband OFDM signal containing a cyclic prefix. Then the signal is shifted to a radio frequency carrier matching the center frequency of the high-frequency ultrasonic transducer through up-conversion.

[0132] S302, amplification and ultrasonic wave transmission:

[0133] The OFDM modulated signal is amplified by power amplifier, and drives the high-frequency ultrasonic transducer of the transmitting end to convert it into an ultrasonic signal and transmit it through the metal medium.

[0134] S303, receiving the OFDM demodulation:

[0135] The high-frequency ultrasonic transducer of the receiving end converts the received ultrasonic signal into an electrical signal, which is recovered to a baseband OFDM signal after frequency down-conversion, and then through digital signal processing operations such as removing the cyclic prefix, fast Fourier transform, channel equalization and subcarrier demapping, the original data stream is finally recovered.

[0136] To evaluate the limit performance of the communication method, the application provides a corresponding test scheme:

[0137] By gradually increasing the bandwidth of the OFDM signal, while monitoring the error vector magnitude of the demodulated signal at the receiving end. During the test, keep other system parameters unchanged, when the EVM reaches the predetermined tolerance value (such as 8%), record the signal bandwidth at this time. According to the signal bandwidth, the number of subcarriers, the modulation order and the coding rate at this time, the theoretical maximum communication rate of the system can be calculated. This test method provides an effective means for evaluating the performance potential of high-frequency ultrasonic transducers in wideband communication scenarios.

[0138] The embodiment also discloses a cross-metal high-speed communication system, comprising:

[0139] Two high-frequency ultrasonic transducers, respectively as the transmitting end and the receiving end, arranged on both sides of the metal medium, the high-frequency ultrasonic transducer is the high-frequency ultrasonic transducer described above;

[0140] A signal generation and modulation unit for generating a carrier signal and generating a 2ASK or OFDM modulated signal according to the data to be transmitted, electrically connected with the transmitting end;

[0141] A signal receiving and demodulation unit electrically connected with the receiving end, for demodulating the received electrical signal to restore the data.

[0142] To specifically illustrate the preparation process and show the technical effect of the application, the preparation and performance of the transducer with different thicknesses of piezoelectric layer are described in detail through multiple examples and comparative examples. Among them, examples 1-4 show the application scheme, and comparative example 1 represents the prior art scheme without using the thinning process of the application.

[0143] Example 1:

[0144] S101, take a piece of clean round glass, place it on a 70°C heating table. Place an appropriate amount of paraffin with a melting point of 65°C in the middle of the glass, after the paraffin is completely melted, take a PZT-5H piezoelectric ceramic piece with an initial size of 5mm x 5mm x 500μm (length x width x thickness), use tweezers to push it smoothly into the molten paraffin, make sure the paraffin is fully infiltrated between the piezoelectric ceramic piece and the glass. Slightly squeeze the piezoelectric ceramic piece to remove the interface bubbles, use a wax absorbing paper to absorb the excess paraffin. Turn off the heating table, wait for the paraffin to cool and solidify, complete the temporary fixing of the piezoelectric ceramic piece. Use 2000 mesh sandpaper to mechanically grind the exposed surface of the piezoelectric ceramic piece, gradually thin it to the target thickness of 100μm by controlling the grinding parameters, and perform surface polishing treatment. Place the fixed assembly on the 70°C heating table again to melt the paraffin, remove the thinned piezoelectric layer, and use wax cleaning water and anhydrous alcohol to thoroughly clean and remove paraffin residue, and dry for use.

[0145] S102, place the cleaned piezoelectric layer with its unground surface facing up in a silicone mold with an inner hole size of 5mm x 5mm x 5.1mm (deep). Weigh the resin component (A component) and the curing agent component (B component) of the epoxy conductive silver adhesive, mix them in a mass ratio of 3:1 and stir thoroughly. Pour the mixed epoxy conductive silver adhesive into the silicone mold, making sure it completely covers the lower surface of the piezoelectric layer, and insert a conductive connecting piece (such as silver-plated copper wire) before the glue solidifies. Let it stand until the epoxy conductive silver adhesive is completely cured, forming a conductive backing layer with both acoustic backing and electrical connection functions.

[0146] S103, after completing the shell assembly, evenly coat the conductive silver paste on the upper surface (i.e. the second surface) of the piezoelectric layer, so that after solidification it forms a second electrical connection end and realizes electrical conduction with the brass shell through the conductive silver paste.

[0147] S104, take a silicone positioning ring with a thickness of 3mm, an inner hole of 5mm x 5mm, and an outer diameter of 14mm, and place it flat on the workbench. Assemble the assembly containing the piezoelectric layer and the conductive backing layer, the silicone positioning ring, and the brass shell in order, ensuring accurate alignment between each component.

[0148] S105, weigh the components of the epoxy resin AB glue in a mass ratio of 3:1, mix and stir, then vacuum degassing. Use a syringe to slowly inject the mixed glue between the conductive backing layer and the brass shell, making sure it is fully filled. After curing, turn over the transducer, remove the silicone positioning ring, and fill the gap again with epoxy resin AB glue to complete the insulation and overall packaging of the internal components.

[0149] S106, the reserved end of the conductive connecting piece is welded with the signal inner core of the SMA high-frequency connecting interface to realize the signal path connection. At the same time, the external conductor of the SMA interface is adhered and fixed to the rear end of the brass shell using conductive silver glue to ensure the electrical conduction between the external conductor and the shell, thereby completing the assembly of the entire high-frequency ultrasonic transducer.

[0150] Example 2:

[0151] The preparation process of this example is basically the same as that of Example 1, the difference is that in step S101, the PZT-5H piezoelectric ceramic sheet is thinned to a target thickness of 200 μm; correspondingly, in step S102, a silicone mold with a depth of 5.2 mm is selected.

[0152] Example 3:

[0153] The preparation process of this example is basically the same as that of Example 1, the difference is that in step S101, the PZT-5H piezoelectric ceramic sheet is thinned to a target thickness of 300 μm; correspondingly, in step S102, a silicone mold with a depth of 5.3 mm is selected.

[0154] Example 4:

[0155] The preparation process of this example is basically the same as that of Example 1, the difference is that in step S101, the PZT-5H piezoelectric ceramic sheet is thinned to a target thickness of 400 μm; correspondingly, in step S102, a silicone mold with a depth of 5.4 mm is selected to adapt to the different thickness requirements of the backing layer.

[0156] Comparative Example 1:

[0157] This comparative example simulates the preparation method without using the thinning process of the present application. The preparation process omits step S101 (piezoelectric ceramic thinning process) of Example 1, and directly uses a PZT-5H piezoelectric ceramic sheet with an initial thickness of 500 μm for subsequent assembly. Correspondingly, in step S102, a silicone mold with a depth of 5.5 mm is selected, and the remaining steps S103 to S106 are consistent with Example 1.

[0158] The high-frequency transducers prepared in Examples 1-4 and Comparative Example 1 are subjected to systematic performance characterization and communication testing. The specific test contents and results are as follows:

[0159] Frequency performance test: the impedance characteristic curve of each transducer is measured using a vector network analyzer. Specifically, the vector network analyzer and the transducer are connected through a radio frequency line, the S parameter is measured, and the series resonance frequency and the parallel resonance frequency are obtained. The detailed data of the test results (see Table 1) are as follows: Figures 2-6

[0160] ​Example 1 (piezoelectric layer thickness 100 μm): parallel resonance frequency f a = 20.73 MHz, series resonance frequency f = 16.56 MHz;

[0161] Example 2 (piezoelectric layer thickness 200 μm): parallel resonance frequency f a = 11.64 MHz, series resonance frequency f = 8.97 MHz;

[0162] Example 3 (piezoelectric layer thickness 300 μm): parallel resonance frequency f a = 7.7 MHz, series resonance frequency f = 6.24 MHz;

[0163] Example 4 (piezoelectric layer thickness 400 μm): parallel resonance frequency f a = 5.91 MHz, series resonance frequency f = 5.04 MHz;

[0164] Comparative Example 1 (piezoelectric layer thickness 500 μm): parallel resonance frequency f a = 4.63 MHz, series resonance frequency f = 3.93 MHz;

[0165] The test data clearly shows that as the piezoelectric layer thickness is thinned, the resonance frequency of the high-frequency ultrasonic transducer is significantly improved. From the 500 μm of Comparative Example 1 to the 100 μm of Example 1, the parallel resonance frequency is improved from 4.63 MHz to 20.73 MHz, with an improvement of about 348%; the series resonance frequency is improved from 3.93 MHz to 16.56 MHz, with an improvement of about 321%. The center frequency of Example 1 is improved to about 18 MHz.

[0166] Communication rate test: an aluminum plate with a thickness of 20 mm is used as the metal medium to test the cross-metal communication performance.

[0167] 2ASK modulation performance test: the test system connection relationship is as shown in Figure 7 The transmitting end is connected to the host computer through a serial port, the host computer sends the data to be transmitted to the modulation circuit board, and after 2ASK modulation and power amplification, the high-frequency ultrasonic transducer of the transmitting end is driven; after the high-frequency ultrasonic transducer of the receiving end receives the signal, the signal is processed through the demodulation circuit board, and finally the restored data is transmitted back to the host computer through the serial port. The test results are shown in Figure 8As shown in the test results, the highest communication rate of each embodiment under the condition of bit error rate less than 1% is: 4.2 Mbps for embodiment 1 (100 μm), 3.8 Mbps for embodiment 2 (200 μm), 2.8 Mbps for embodiment 3 (300 μm), 2.3 Mbps for embodiment 4 (400 μm), and 1.7 Mbps for comparative example 1 (500 μm). Embodiment 1 is improved by about 147% compared with comparative example 1.

[0168] OFDM modulation performance test: the connection relationship of the test platform is as shown in Figure 9 The transmitting end generates an OFDM modulated waveform through a vector signal generator, and connects the high-frequency ultrasonic transducer through a radio frequency line; after the high-frequency ultrasonic transducer of the receiving end receives the signal, it is connected to a spectrum analyzer through a radio frequency line for demodulation analysis. The test results are shown in Figure 10 As shown in the test results, the theoretical maximum communication rate of each embodiment is: 13.05 Mbps for embodiment 1 (100 μm), 5.85 Mbps for embodiment 2 (200 μm), 5.175 Mbps for embodiment 3 (300 μm), 4.05 Mbps for embodiment 4 (400 μm), and 3.15 Mbps for comparative example 1 (500 μm). Embodiment 1 is improved by about 314% compared with comparative example 1.

[0169] The above test results fully show that the thickness of the piezoelectric layer is reduced from 500 μm (comparative example 1) to 100 μm to 400 μm (embodiments 1-4), and the acoustic damping and conductive synergies of the epoxy conductive silver adhesive backing layer can significantly improve the center resonant frequency and working bandwidth of the high-frequency ultrasonic transducer. Among them, the thinning of the piezoelectric layer directly improves the high frequency band through the thickness-frequency inverse relationship, while the epoxy conductive silver adhesive backing layer further expands the effective bandwidth by suppressing spurious interference and optimizing acoustic impedance matching, and the two work together to fundamentally enhance the data transmission capability of the cross-metal communication. The test data clearly shows the performance improvement under the synergistic effect of the thickness of the piezoelectric layer and the epoxy conductive silver adhesive backing layer: the smaller the thickness (100 μm≤X<500 μm), the higher the resonant frequency (such as the parallel resonant frequency of embodiment 1 reaches 20.73 MHz), and the epoxy conductive silver adhesive backing layer further improves the communication rate by reducing signal attenuation and ensuring the integrity of high-frequency signals. In particular, embodiment 1 (100 μm piezoelectric layer + epoxy conductive silver adhesive backing layer) exhibits optimal performance under two modulation modes, fully verifying the effectiveness of the "100-micron piezoelectric layer + epoxy conductive silver adhesive backing layer integration" technical solution of the present application.

[0170] The principles and implementation manners of the present application are described by using specific examples, and the above examples are only used for helping to understand the method of the present application and its core idea; meanwhile, for the general technical personnel in the art, according to the idea of the present application, the specific implementation manners and application ranges will be changed, and on the basis of the above, the content of the specification should not be understood as the limitation of the present application.

Claims

1. A high-frequency ultrasonic transducer for cross-metal communication, characterized in that, include: A piezoelectric layer with a thickness of X, where X = 100 μm, is made of PZT-5H piezoelectric ceramic. An epoxy conductive silver paste backing layer is bonded to the first surface of the piezoelectric layer and serves as the first electrical connection terminal. The epoxy conductive silver paste backing layer is prepared by mixing the resin component and curing agent component of epoxy conductive silver paste in a mass ratio of 3:1 and then pouring it into a silicone mold with a depth of 5.1 mm where the piezoelectric layer is placed and curing it. Its acoustic impedance matches that of the piezoelectric layer to suppress noise. The second electrical connection terminal is disposed on the second surface of the piezoelectric layer opposite to the first surface, and is a conductive electrode layer formed on the second surface of the piezoelectric layer; The outer casing houses the piezoelectric layer and the epoxy conductive silver paste backing layer; An encapsulation layer is filled between the epoxy conductive silver paste backing layer and the outer shell; A high-frequency connection interface is fixed to the housing, with its signal core electrically connected to the first electrical connection terminal and its outer conductor electrically connected to the second electrical connection terminal.

2. A cross-metal communication method based on the high-frequency ultrasonic transducer of claim 1, characterized in that, The communication method includes the following steps: A carrier signal is generated, the frequency of which is matched with the center frequency of the ultrasonic transducer; Based on the data signal to be transmitted, a 2ASK modulated signal is generated by controlling the on and off of the carrier signal; The 2ASK modulated signal is amplified and driven by the first ultrasonic transducer to convert it into an ultrasonic signal, which is transmitted through the metal medium. The second ultrasonic transducer receives the ultrasonic signal that penetrates the metal medium and converts it back into an electrical signal; The electrical signal is demodulated to recover the data signal.

3. A cross-metal communication method based on the high-frequency ultrasonic transducer of claim 1, characterized in that, The communication method includes the following steps: Generate the data stream to be transmitted; The data stream is mapped onto multiple orthogonal subcarriers to generate a baseband OFDM signal; The baseband OFDM signal is upconverted to radio frequency to generate an OFDM modulated signal, wherein the carrier frequency of the radio frequency is matched with the center frequency of the ultrasonic transducer. After amplifying the OFDM modulated signal, the first ultrasonic transducer is driven to convert the electrical signal into an ultrasonic signal, which is then transmitted through the metal medium. The ultrasonic signal that penetrates the metal medium is received by the second ultrasonic transducer and converted into an electrical signal; The electrical signal is down-converted and OFDM demodulated to restore the data stream.

4. A method for fabricating a high-frequency ultrasonic transducer, characterized in that, Includes the following steps: A piezoelectric material is provided and thinned to a preset thickness X, where X = 100 μm, to form a piezoelectric layer; A conductive backing layer is formed on the first surface of the piezoelectric layer, and a conductive connector is disposed in the conductive backing layer. The conductive backing layer serves as the first electrical connection terminal. The conductive backing layer is an epoxy conductive silver paste backing layer. The epoxy conductive silver paste backing layer is prepared by mixing the resin component and the curing agent component of the epoxy conductive silver paste at a mass ratio of 3:1, and then pouring it into a silicone mold with a depth of 5.1 mm where the piezoelectric layer is placed and curing it. A second electrical connection terminal is formed or disposed on the second surface of the piezoelectric layer; The assembly consisting of the piezoelectric layer, the conductive backing layer, and the conductive connector is assembled into the housing; Insulating material is filled in to achieve insulating fixation between the internal components and the housing; Install a high-frequency connection interface so that its signal core is electrically connected to the conductive connector and its outer conductor is electrically connected to the second electrical connection terminal.

5. The method for preparing a high-frequency ultrasonic transducer according to claim 4, characterized in that, The steps for thinning piezoelectric materials include: The piezoelectric material is temporarily fixed to the support substrate using hot-melt paraffin wax; The exposed surface of the piezoelectric material is mechanically ground to a preset thickness; The paraffin wax is heated and melted to remove the piezoelectric layer and then cleaned.

6. The method for preparing a high-frequency ultrasonic transducer according to claim 4, characterized in that, The step of forming or setting the second electrical connection terminal includes: coating the second surface of the piezoelectric layer with conductive silver paste and electrically connecting the conductive silver paste to the housing.

7. The method for preparing a high-frequency ultrasonic transducer according to claim 4, characterized in that, The steps for installing the high-frequency connection interface include: welding the conductive connector to the signal core of the high-frequency connection interface, and using conductive adhesive to fix the outer conductor of the high-frequency connection interface to the housing.

8. A high-speed cross-metal communication system, characterized in that, include: Two high-frequency ultrasonic transducers, serving as a transmitter and a receiver respectively, are arranged on both sides of a metal medium. The high-frequency ultrasonic transducer is the high-frequency ultrasonic transducer as described in claim 1. The signal generation and modulation unit is used to generate a carrier signal and generate a 2ASK or OFDM modulated signal according to the data to be transmitted, and is electrically connected to the transmitting end; The signal receiving and demodulation unit is electrically connected to the receiving end and is used to demodulate the received electrical signal to restore the data.

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