A resonant type underwater electric field communication system and communication method

Abstract

The application belongs to the technical field of underwater radio communication, and discloses a resonant type underwater electric field communication system which comprises a signal generator, a pair of transmitting electrodes, a water environment, a packaging assembly and an oscilloscope; the packaging assembly comprises a direct current bias magnetic field assembly, a magnetoelectric gyroscope, a load resistor and a capacitor which are packaged together, a part of a piezoelectric layer protruding from a magnetostrictive layer serves as a receiving electrode and is in contact with the water environment, two wire ends of a coil serve as signal output ends and are connected to the oscilloscope; one end of each transmitting electrode is connected to the signal generator, and the other end is placed in water; the transmitting electrodes are connected to the receiving electrode in the packaging assembly through the water environment; the magnetoelectric gyroscope, the capacitor and the load resistor form a series circuit. Compared with the traditional electric field communication technology, the communication system has stronger signal response, higher signal-to-noise ratio, better stability, extended communication distance, excellent signal fidelity and anti-interference capability in underwater electric field communication.

Description

Technical Field

[0001] This invention belongs to the field of underwater radio communication technology, and relates to a resonant underwater electric field communication system and communication method. Background Technology

[0002] Underwater wireless communication is a key technology for realizing marine exploration, equipment control, and data transmission. Common underwater acoustic communication suffers from drawbacks such as large propagation delay, narrow bandwidth, and interference with marine life; underwater optical communication, on the other hand, requires extremely clear water and experiences rapid attenuation. Underwater electric field communication, as an emerging technology, utilizes seawater as a conductive medium to transmit information by establishing a time-varying electric field in the water. It possesses potential advantages such as low latency, moderate bandwidth, resistance to turbidity, and simple equipment.

[0003] However, existing underwater electric field communication technologies face a core challenge: seawater, as a low-impedance, high-attenuation medium, requires a sufficiently large alternating current to establish an electric field that can be detected over long distances. Existing underwater electric field communication devices lack precise resonant matching designs, making signals susceptible to environmental noise interference and resulting in poor transmission stability. These limitations fail to meet the demands of deep-sea exploration and collaborative underwater robot operations for miniaturized, highly reliable, and long-distance communication devices.

[0004] The magneto-electric gyrotron is a novel two-port non-reciprocal power device that can "transform" the capacitance of one port into the inductance of the other, or vice versa. Currently, there are no reports of using magneto-electric gyrotrons as auxiliary components to generate resonant electric fields for underwater communication. Summary of the Invention

[0005] This invention addresses the technical problems of low signal-to-noise ratio and poor stability in existing underwater communication technologies by providing a resonant underwater electric field communication system and method. By combining the signal enhancement characteristics of magneto-electric gyroscopes and resonant technology, the system achieves a larger signal response, higher signal-to-noise ratio, better stability, and extended communication distance. It also exhibits excellent signal fidelity and anti-interference capabilities in underwater electric field communication.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a resonant underwater electric field communication system, comprising a signal generator, a pair of transmitting electrodes, an underwater environment, a packaging assembly, and an oscilloscope; the packaging assembly includes a DC bias magnetic field assembly, a magneto-electric gyroscope, a load resistor, and a capacitor packaged together; the magneto-electric gyroscope is composed of a magneto-electric composite material and a coil tightly wound around the outside of the magneto-electric composite material; the magneto-electric composite material is a symmetrical structure composed of a piezoelectric layer and two magnetostrictive layers bonded to both sides of the piezoelectric layer; the portion of the piezoelectric layer protruding from the magnetostrictive layer serves as a receiving electrode and is in contact with the underwater environment; the two ends of the coil serve as signal output terminals and are connected to the oscilloscope; one end of each transmitting electrode is connected to the signal generator, and the other end is placed in the water; the transmitting electrode is connected to the receiving electrode in the packaging assembly through the underwater environment; the DC bias magnetic field assembly provides a DC bias magnetic field for the magneto-electric gyroscope; the magneto-electric gyroscope, capacitor, and load resistor form a series circuit; the capacitor and the inductive magneto-electric gyroscope are matched to generate resonance.

[0008] In the above technical solution, the packaging assembly further includes a packaging shell, which is divided into a water inlet area and a receiving area by a water-proof plate. A water inlet pipe and a DC bias magnetic field component are provided at one end of the packaging shell near the water inlet area, and an outlet pipe and a DC bias magnetic field component are provided at one end of the packaging shell near the receiving area. The magneto-electric gyroscope, load resistor, and capacitor are integrated on a PCB board. The PCB board is placed in the receiving area, and the piezoelectric layer of the magneto-electric gyroscope protrudes beyond the magnetostrictive layer, passes through the water-proof plate, and extends into the water inlet area. Wires are led out from the two ends of the coil of the magneto-electric gyroscope on the PCB board and from the outlet pipe.

[0009] In the above technical solution, the DC bias magnetic field assembly includes a magnetic pole fixing base and a permanent magnet fixed on the magnetic pole fixing base. The N pole and S pole of the permanent magnet are symmetrically arranged along the axial direction of the packaging shell to form an SN / NS polarity structure. The magnetic pole fixing base is movably connected to the end of the packaging shell.

[0010] In the above technical solution, a waterproof rubber ring is installed at the outlet pipe.

[0011] In the above technical solution, sealant is injected between the outlet tube and the waterproof rubber ring.

[0012] In the above technical solution, the outer surface of the packaging shell is coated with an anti-corrosion coating.

[0013] Secondly, the present invention provides a communication method based on the above-mentioned resonant underwater electric field communication system, comprising the following steps:

[0014] a. Place the encapsulation component in a water environment, allowing water to enter the encapsulation component and come into contact with the receiving electrode;

[0015] b. Start the signal generator and input the modulation signal to the transmitting electrode, which changes the surface potential of the transmitting electrode and forms an alternating electric field in the water. Ions in the water move back and forth with the alternating electric field and collide with the receiving electrode, which changes the potential of the receiving electrode and generates an alternating voltage, which is conducted to the piezoelectric layer. Through the inverse piezoelectric effect, mechanical energy is transferred to the magnetostrictive layer, which generates an alternating magnetic field through the piezomagnetic effect. The change in the magnetic field is induced by the coil, thereby outputting an alternating current. At the same time, the impedance transformation characteristics of the magneto-electric gyrotron resonate with the capacitor, efficiently converting the voltage signal into an alternating current.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] In this invention, the magneto-electric gyrotron structure essentially achieves resonance with an external capacitor through impedance conversion, generating a much larger electrode current than traditional voltage-driven methods, resulting in a stronger signal response. The signal is more stable, with the output current primarily determined by the input voltage and the capacitor matched to the magneto-electric gyrotron, making it less affected by load (seawater conductivity) variations. This leads to a more stable communication link, unaffected by obstructions or water turbidity, making it suitable for complex water environments. Resonance indicates a larger signal response, resulting in a higher signal-to-noise ratio and extended effective communication distance. It avoids the use of bulky, inefficient power amplifier stages for driving low-impedance loads, resulting in a simpler and more energy-efficient overall circuit. Through optimized magneto-electric gyrotron design, it maintains good current output characteristics over a wide frequency range, supporting higher data rates. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the resonant underwater electric field communication system of the present invention, wherein: (a) and (b) are schematic diagrams of the overall and partial aspects of the underwater communication system; (c) and (d) are schematic diagrams of the appearance and internal structure of the packaging component. In the figure: 1 is the packaging component, 101 is the packaging shell, 102 is the water inlet area, 103 is the receiving area, 104 is the PCB board, 105 is the water inlet pipe, 106 is the outlet pipe, 107 is the permanent magnet, 108 is the magnetic pole fixing base, 109 is the water isolation plate, 2 is the water environment, and 3 is the transmitting electrode.

[0019] Figure 2 The diagram shows the communication principle of the resonant underwater electric field communication system of the present invention, wherein: (a) is an energy conversion flowchart, and (b) is a schematic diagram of efficient multi-field coupling conversion of electric field-mechanical energy-magnetic field-electric energy.

[0020] Figure 3 The impedance phase diagram (a) of the magneto-electric gyroscope output port after matching with the capacitor and the output voltage diagram (b) under different electric fields are shown.

[0021] Figure 4The curves of the positive magnetoelectric voltage coefficient of the magneto-electric gyrotron under different DC biases (a) and the response diagram of the input electric field to voltage under different load resistances (b) are shown.

[0022] Figure 5 This is a diagram showing the response direction of the resonant underwater electric field communication device of the present invention when receiving an electric field underwater.

[0023] Figure 6 The transmission and attenuation characteristics of the resonant underwater electric field communication system of the present invention are shown.

[0024] Figure 7 This is a timing diagram showing the underwater signal-to-noise ratio and amplitude shift keying modulation and demodulation of the underwater channel in the resonant underwater electric field communication device system of the present invention.

[0025] Figure 8 This invention relates to the underwater information communication capability of the resonant underwater electric field communication device system based on ASK modulation. Detailed Implementation

[0026] The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of protection of the present invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the test methods in the following embodiments are conventional methods.

[0027] Example 1

[0028] like Figure 1 As shown in -a and 1-b, the resonant underwater electric field communication system of the present invention includes a signal generator, a pair of transmitting electrodes 3, a water environment 2, a packaging assembly 1, and an oscilloscope. One end of each transmitting electrode 3 is connected to the signal generator, and the other end is placed in the water. The transmitting electrode 3 is connected to the receiving electrode in the packaging assembly 1 through the water environment. The packaging assembly 1 includes a DC bias magnetic field assembly, a magneto-electric gyroscope, a load resistor, and a capacitor packaged together, realizing the integration of the magneto-electric gyroscope, receiving electrode, capacitor, and DC bias. The DC bias magnetic field assembly is used to provide a DC bias magnetic field for the magneto-electric gyroscope. The magneto-electric gyroscope, capacitor, and load resistor form a series circuit, and the capacitor matches the inductive magneto-electric gyroscope to generate resonance.

[0029] In this invention, the magneto-electric gyrotron is composed of a magneto-electric composite material and a coil tightly wound around the outside of the composite material. The magneto-electric composite material is a symmetrical structure consisting of a piezoelectric layer and two magnetostrictive layers bonded to both sides of the piezoelectric layer. The portion of the piezoelectric layer protruding from the magnetostrictive layers serves as a receiving electrode and is in contact with the water environment. The two ends of the coil serve as signal output terminals and are connected to an oscilloscope. In one embodiment, the magnetostrictive layer is Ni. 0.9 Zn 0.1Fe2O4 (NZFO), length × width × thickness = 36 mm × 6 mm × 1 mm, NZFO is magnetized along the length direction (L); the piezoelectric layer is PZT-8, length × width × thickness = 40 mm × 6 mm × 1 mm, PZT-8 is polarized along the thickness direction (T), forming the LT mode. The magnetostrictive layer and the piezoelectric layer are bonded together with epoxy resin and then baked in a constant temperature oven at 120 °C for 2 h. Copper enameled wire (200 turns, r = 2 cm) is tightly wound on the magnetoelectric composite material to make a magnetoelectric gyroscope with an NZFO-PZT-NZFO sandwich structure.

[0030] In one implementation, such as Figure 1 -c and Figure 1 As shown in Figure -d, the DC bias magnetic field component, magneto-optical gyroscope, load resistor, and capacitor are encapsulated within a cylindrical housing 101. The housing 101 is divided into a water inlet area 102 and a receiving area 103 by a water-proof plate 109. A water inlet pipe 105 and the DC bias magnetic field component are located at one end of the housing 101 near the water inlet area 102, and an outlet pipe 106 and the DC bias magnetic field component are located at the other end of the housing 101 near the receiving area 103. The magneto-optical gyroscope, load resistor, and capacitor are integrated on a PCB board 104. The PCB board 104 is placed in the receiving area 103, and the portion of the piezoelectric layer of the magneto-optical gyroscope protruding from the magnetostrictive layer (i.e., the receiving electrode) passes through the water-proof plate 109 and extends into the water inlet area 102. Wires are led out from the two ends of the coil of the magneto-optical gyroscope on the PCB board 104 and from the outlet pipe 106. The wires are connected to an oscilloscope for signal transmission. The DC bias magnetic field assembly includes a magnetic pole holder 108 and a permanent magnet 107 fixed on the magnetic pole holder 108. The N pole and S pole of the permanent magnet are symmetrically arranged along the axial direction of the packaging shell to form an SN / NS polarity structure. The magnetic pole holder 108 is movably connected to the end of the packaging shell 101. Specifically, there is a protruding section at the center of the end of the water inlet area 102 of the packaging shell 101, and threads are opened on the outside of the protruding section. The magnetic pole holder 108 is a nut with internal threads. The nut is screwed on the protruding section, and the distance between the permanent magnet 107 and the magneto-electric gyroscope can be adjusted by adjusting the length of the nut screwed in or out of the protruding section, so as to provide the optimal DC bias magnetic field for the magneto-electric gyroscope.

[0031] The center lines of the water inlet pipe 105 and the cable outlet pipe 106 of this invention may or may not coincide with the center lines of the end plates on both sides of the encapsulation housing 101, as long as water inlet and cable outlet are satisfied. When the encapsulation assembly 1 is placed in water, water enters the water inlet area 102 from the water inlet pipe 105 and contacts the receiving electrode. In a preferred embodiment, end plates are provided on both sides of the encapsulation housing 101. After the internal components of the encapsulation housing 101 are installed, the end plates are fixed to the circular housing to achieve encapsulation. To achieve a more compact encapsulation structure and a better sealing effect, the center lines of the inlet pipe 105 and the outlet pipe 106 are aligned with the center lines of the end plates on both sides of the encapsulation housing 101. To adjust the distance between the permanent magnet 107 and the magneto-electric gyroscope, the permanent magnet 107 is a circular permanent magnet with a central hole. The permanent magnet 107 passes through the inlet pipe 105 or the outlet pipe 106 and is fixed to the magnetic pole fixing seat 108. To prevent water from entering the receiving cavity 103, a waterproof rubber ring is installed at the position where the receiving electrode exits the water-proof plate 109, and a waterproof rubber ring is installed at the position where the outlet pipe 106 exits the end plate. Sealant is injected between the receiving electrode, the outlet pipe 106, and the waterproof rubber ring to further achieve a seal. To improve the service life of the encapsulation component 1, the encapsulation housing 101 is made of corrosion-resistant titanium alloy material, and an anti-corrosion coating is applied to the outer surface of the encapsulation housing 101.

[0032] The communication method based on the above-mentioned resonant underwater electric field communication system includes the following steps:

[0033] a. Place the encapsulation component 1 into the water environment 2, so that water enters the encapsulation component 1 and comes into contact with the receiving electrode;

[0034] b. Start the signal generator and input the modulation signal to the transmitting electrode 3, which changes the surface potential of the transmitting electrode 3 and forms an alternating electric field in the water. Ions in the water move back and forth with the alternating electric field and collide with the receiving electrode, which changes the potential of the receiving electrode and generates an alternating voltage, which is conducted to the piezoelectric layer. Through the inverse piezoelectric effect, mechanical energy is transferred to the magnetostrictive layer, and through the piezomagnetic effect, an alternating magnetic field is generated. The change in the magnetic field is induced by the coil, thereby outputting an alternating current. At the same time, the impedance transformation characteristics of the magneto-electric gyrotron resonate with the capacitor, which efficiently converts the voltage signal into an alternating current.

[0035] like Figure 2 The energy conversion flowchart shown in -a shows the process from signal input to transmitting electrode 3. The input electrical signal is modulated by a signal generator, transmitted through an underwater electric field, and the receiving electrode senses the electric field. A voltage is generated on the receiving electrode through the electrophoretic effect produced by the reciprocating motion of underwater ions. The voltage is transmitted to the piezoelectric layer, and through the inverse piezoelectric effect, mechanical energy is transferred to the magnetostrictive material. Through the piezomagnetic effect, a magnetic field is generated, which is captured by the coil to generate a current signal.

[0036] The piezoelectric effect of the piezoelectric layer and the magnetostrictive effect of the magnetostrictive layer in this invention are the core mechanisms for achieving multi-field coupling, such as... Figure 2 -b shows a schematic diagram of efficient multi-field coupling conversion of electric field, mechanical energy, magnetic field, and electrical energy. During operation, the piezoelectric layer converts the electric field into an electrical signal through electrophoresis, driving the piezoelectric layer to generate mechanical strain; this strain is transmitted to the magnetostrictive layer through interfacial stress, inducing a change in its magnetization intensity and generating a magnetic field.

[0037] The core of the magneto-electric gyrotron lies in impedance transformation, such as... Figure 2 As shown in -c, without an external capacitor, the signal received by a single electrode plate has a small amplitude because the output voltage is determined solely by the direct induction of the electric field. With an external capacitor, the capacitor and the magneto-electric gyroscope resonate. The impedance transformation of the magneto-electric gyroscope "transforms" the capacitive impedance of the transmitting electrode at its input end (mainly the parallel connection of the resistance of seawater and the double-layer capacitance of the electrode) into an inductive impedance, which resonates with the capacitor, significantly increasing the amplitude of the received voltage.

[0038] This invention utilizes the capacitive / inductive non-reciprocal characteristics of a magneto-electric gyro to generate resonance in series with a capacitor. By adjusting the circuit topology (e.g., introducing an external capacitor C), the system achieves resonance and impedance matching at the target frequency. The required capacitor parameters are designed based on the series resonance condition. The measuring device includes an impedance analyzer (model: KEYSIGHT E4990A) and a desktop computer with its corresponding software system. The resonant frequency satisfies... Therefore, the formula for calculating capacitance can be obtained: Substitute the equivalent inductance L eq =1.80531×10 -4 H and resonant frequency f r =58.87 kHz, calculated to be C≈4.049×10 -8 Since F≈40.49 nF, a matching capacitor value of 40.5 nF is selected, which enables the system to reach a series resonance state at 58.87 kHz. At this time, the imaginary part of the impedance is zero, and the electrode induced voltage shows a peak value. Figure 3 -a is the impedance phase diagram of the output port of the magneto-electric gyroscope of the present invention. It can be seen that under the circuit structure with external capacitor, the device exhibits obvious resonant behavior in the frequency range of 57-61 kHz. The phase curves reach matching at about 58.87 kHz, at which point the impedance is about 16Ω. Figure 3 -b represents the relationship between the output voltage and the electric field strength and frequency. The figure shows that when the electric field strength increases to 2.36-3.93 V / m and the frequency is close to 58.87 kHz, the output voltage increases significantly, reaching a maximum of over 0.52 V.

[0039] To determine the optimal DC bias magnetic field and output power for the magneto-electric gyrocoil, the test setup included: a lock-in amplifier (model: Zurich MFLI-500kHz), a desktop computer with the corresponding Labone software, and an adjustable DC bias magnetic rail. By setting the excitation voltage to 282.8 mV and the sweep frequency range to (57~60 kHz), and changing the DC bias, the amplitude-frequency response graphs of the output voltage versus frequency at the two output ports under different DC biases could be measured. Figure 4 -a is a set of graphs showing the positive magnetoelectric voltage coefficient curves of the magnetoelectric gyroscope under different DC bias magnetic fields. It can be seen that when the magnetic field strength increases from 10 Oe to 31 Oe, the inverse magnetoelectric voltage coefficient gradually increases, reaching a maximum value of about 140 G / V at 31 Oe; when the magnetic field strength continues to increase to 69 Oe, the inverse magnetoelectric voltage coefficient decreases instead, indicating that there is an optimal magnetic field strength (about 30 Oe) that maximizes the magnetoelectric response of the device. Figure 4 -b represents the effect of different load resistances on the output power of the magneto-electric gyrotron. It can be seen that, with the same input electric field strength, changing the load resistance increases the output power gradually from 10 Ω to 16 Ω, reaching a maximum of approximately 84 μW at 16 Ω. When the load resistance continues to increase to 60 Ω, the output power gradually decreases. The ratio of output voltage to input electric field, and the ability to convert the electric field into voltage, continuously increase with increasing load resistance.

[0040] The device for testing the response values ​​of the magneto-electric gyroscope in each plane of the present invention includes a magneto-electric gyroscope, a lock-in amplifier (model: Zurich MFLI-500kHz), and a desktop computer with the corresponding Labone software system. The excitation voltage is set to 282.8 mV and the DC bias is 30 Oe. The response values ​​of the magneto-electric gyroscope in each plane are measured, and the data are normalized using Origin-2023 software. Figure 5 Anisotropic control of the electric field response was achieved by observing the receiving response of the magnetoelectric composite layer of the magnetoelectric gyroscope at different angles under an electric field. Figure 5 -a is a schematic diagram of the three-dimensional coordinate system for each plane test. When the alternating electric field is applied along the Z-axis, the normalized output voltage of the device exhibits a distinct elliptical distribution with respect to the electrode direction angle φ. Figure 5-b represents the yz plane direction. The normalized output voltage reaches its maximum value (approximately 1.0) at φ=0° and φ=180°, and drops to its minimum value (approximately 0.5) at φ=90° and φ=270°. Therefore, by adjusting the electrode orientation angle, the output voltage of the device can be precisely controlled, achieving maximum response in a specific direction while significantly decreasing in other directions. This characteristic makes the device of this invention valuable for applications in directional electric field sensing, energy harvesting, and other fields, enabling improvements in output performance and enhancing the system's sensitivity and directionality according to actual needs.

[0041] To test the underwater transmission performance of the resonant underwater electric field communication system of this invention, an Agilent 33250A signal generator and a pair of transmitting electrodes (40 mm long, 10 mm wide, and 1 mm thick metal plates) were used. A Tektronix TDS 2012B oscilloscope was used. The distance between the transmitting and receiving electrodes was d, and the water environment was municipal tap water. During system operation, the signal generator produces a low-frequency baseband signal (e.g., 20 Hz) and a high-frequency carrier signal (e.g., 58.87 kHz). After modulation by the modulation unit, the signal is radiated into the water environment by the underwater transmitting electrodes. The magneto-electric gyrocopter receives the signal underwater and transmits it to the oscilloscope. After demodulation processing by the oscilloscope, the original baseband signal is recovered. Figure 6 The transmission and attenuation characteristics of the underwater electric field communication system of this invention show that when the transmitting electrode is working, the electric field strength exhibits a significant nonlinear attenuation with increasing distance: at a distance of 0 cm, the electric field strength reaches its maximum value of approximately 4.2 V / m; as the distance increases, the electric field strength decreases rapidly, dropping to approximately 2.5 V / m at 10 cm; when the distance exceeds 20 cm, the attenuation rate slows significantly, stabilizing at approximately 1.4 V / m at 30 cm. This electric field attenuation characteristic is the result of the combined effects of the conductivity of the water environment, the electrode spacing, and the transmitting voltage. At close range, the electric field lines are mainly concentrated near the electrodes, resulting in high electric field strength and rapid attenuation; at long distances, the electric field lines gradually diffuse, and the electric field strength tends to stabilize. By adjusting the electrode layout, transmitting voltage, or water environment parameters, the transmission distance and coverage of the electric field can be effectively controlled, providing crucial performance data for applications such as underwater electric field communication and target detection.

[0042] To test the ASK modulation effect of the resonant underwater electric field communication system of this invention, the test apparatus included a signal generator (model: Agilent 33250A) and an oscilloscope (model: Tektronix TDS 2012B). During the test, the DC bias magnetic field was set to 30 Oe, and the distance d between the transmitting and receiving electrodes was 10 cm. The signal generator was set to output a 20Hz square wave as the fundamental frequency, a 58870 Hz sine wave with an amplitude of 10 V as the carrier wave, and an amplitude-shift keying (APS) modulation wave with 100% depth. When the system was working, the signal generator produced a low-frequency baseband signal (e.g., 20 Hz) and a high-frequency carrier signal (e.g., 58.87 kHz). After ASK modulation by the modulation unit, the signal was radiated into the water environment by the underwater transmitting electrode and then received by the magneto-electric gyrocoil. Figure 7 -a represents the underwater signal-to-noise ratio of the resonant underwater electric field communication system of this invention. It can be seen that the underwater electric field communication system based on ASK modulation of this invention has a resonance enhancement effect of the magneto-electric gyroscope at the carrier frequency (58.87 kHz), which causes the received signal to form a significant voltage peak at this frequency. This result can effectively suppress communication noise and improve the sensitivity and reliability of signal detection. Figure 7 -b is a timing diagram of amplitude shift keying modulation and demodulation in the underwater channel of the resonant underwater electric field communication system of this invention. From top to bottom, it shows the fundamental waveform of the channel, the modulated waveform, the received waveform of the magneto-electric gyrotron, and the demodulated waveform. It can be seen that after the received signal is acquired in real time by the oscilloscope, the data processing unit performs spectrum analysis and demodulation processing, successfully recovering the original baseband signal. The demodulated signal waveform is highly consistent with the original baseband signal, indicating that the system has excellent signal fidelity and anti-interference capability in underwater electric field communication applications.

[0043] To test the underwater information communication capability of the resonant underwater electric field communication device based on ASK modulation, the encoding unit converts information such as letters and numbers into unique "hyphen (-)" and "dot (·)" encoding sequences (e.g., ...). Figure 8 -a, 8-b). In the signal transmission experiment, the coded sequence (e.g., "UP") is modulated onto a 58.87 kHz carrier wave by the modulation unit, radiated into the water environment by the underwater electric field transmitting electrode, and then received by the magneto-electric gyrocoil. After processing by the demodulation and decoding unit, the original coded sequence and information are successfully recovered. The demodulated signal waveform is highly consistent with the original coded sequence (e.g., ...). Figure 8 -c). Figure 8 -d represents the change in the underwater transmission distance of the "UP" command. As the distance increases, the output voltage decreases and the signal distortion gradually increases. Distortion occurs at a distance of 80cm, but the waveform data of the signal is still present, proving that the system still has reliable signal transmission over long distances. Figure 8-e represents the variation of the system's signal-to-noise ratio (SNR) with transmission distance. The SNR gradually decreases as the transmission distance increases. The underwater transmission analysis of the "UP" command reveals the corresponding SNR at different distances, proving that the system can accurately recover the transmitted information. Distance-related performance shows that the SNR decreases as the transmission distance increases: at close range (approximately 20 cm), the SNR can reach approximately 41.63 dB, while at long distance (approximately 90 cm), it still maintains above approximately 20 dB, indicating that the system has reliable communication capabilities over a wide transmission distance range.

[0044] In summary, the resonant underwater electric field communication system of this invention significantly improves the reliability and anti-interference capability of underwater signal transmission by combining the resonance enhancement effect with ASK modulation technology.

[0045] The embodiments described above are merely preferred embodiments of the present invention and are only used to explain the present invention. They are not intended to limit the scope of the present invention. For those skilled in the art, other implementation methods can be easily made by substitution or modification based on the technical content disclosed in this specification. Therefore, all changes and improvements made on the principle of the present invention should be included within the scope of the patent application of the present invention.

Claims

1. A resonant underwater electric field communication system, characterized in that, The device includes a signal generator, a pair of transmitting electrodes, a water environment, a package assembly, and an oscilloscope. The package assembly includes a DC bias magnetic field assembly, a magneto-electric gyroscope, a load resistor, and a capacitor packaged together. The magneto-electric gyroscope is composed of a magneto-electric composite material and a coil tightly wound around the outside of the composite material. The magneto-electric composite material is a symmetrical structure consisting of a piezoelectric layer and two magnetostrictive layers bonded to both sides of the piezoelectric layer. The portion of the piezoelectric layer protruding from the magnetostrictive layers serves as a receiving electrode and is in contact with the water environment. The two ends of the coil serve as signal output terminals and are connected to the oscilloscope. One end of each transmitting electrode is connected to the signal generator, and the other end is placed in the water. The transmitting electrode is connected to the receiving electrode in the package assembly through the water environment. The DC bias magnetic field assembly provides a DC bias magnetic field for the magneto-electric gyroscope. The magneto-electric gyroscope, capacitor, and load resistor form a series circuit, and the capacitor resonates with the inductive magneto-electric gyroscope.

2. The resonant underwater electric field communication system according to claim 1, characterized in that, The encapsulation assembly also includes an encapsulation housing, which is divided into a water inlet area and a receiving area by a water-proof plate. A water inlet pipe and a DC bias magnetic field component are provided at one end of the encapsulation housing near the water inlet area, and an outlet pipe and a DC bias magnetic field component are provided at one end of the encapsulation housing near the receiving area. The magneto-electric gyroscope, load resistor, and capacitor are integrated on a PCB board. The PCB board is placed in the receiving area, and the piezoelectric layer of the magneto-electric gyroscope protrudes beyond the magnetostrictive layer, passes through the water-proof plate, and extends into the water inlet area. Wires are led out from the two ends of the coil of the magneto-electric gyroscope on the PCB board and out from the outlet pipe.

3. The resonant underwater electric field communication system according to claim 1 or 2, characterized in that, The DC bias magnetic field assembly includes a magnetic pole fixing base and a permanent magnet fixed on the magnetic pole fixing base. The N pole and S pole of the permanent magnet are symmetrically arranged along the axial direction of the packaging shell to form an SN / NS polarity structure. The magnetic pole fixing base is movably connected to the end of the packaging shell.

4. The resonant underwater electric field communication system according to claim 2, characterized in that, A waterproof rubber ring is installed at the outlet pipe.

5. The resonant underwater electric field communication system according to claim 4, characterized in that, Sealant is injected between the outlet pipe and the waterproof rubber ring.

6. The resonant underwater electric field communication system according to claim 2, characterized in that, The outer surface of the encapsulation housing is coated with an anti-corrosion coating.

7. A communication method based on the resonant underwater electric field communication system according to any one of claims 1 to 6, characterized in that, Includes the following steps: a. Place the encapsulation component in a water environment, allowing water to enter the encapsulation component and come into contact with the receiving electrode; b. Start the signal generator and input the modulation signal to the transmitting electrode to change the surface potential of the transmitting electrode and form an alternating electric field in the water; Ions in the water reciprocate with the alternating electric field and collide with the receiving electrode, causing a change in the potential of the receiving electrode and generating an alternating voltage, which is conducted to the piezoelectric layer. Through the inverse piezoelectric effect, mechanical energy is transferred to the magnetostrictive layer, where an alternating magnetic field is generated through the piezomagnetic effect. The change in the magnetic field is induced by the coil, thereby outputting an alternating current. At the same time, the impedance transformation characteristics of the magneto-electric gyrotron resonate with the capacitor, efficiently converting the voltage signal into an alternating current.

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