Active electret and active electret ultra-low frequency mechanical antenna

Abstract

The present invention discloses an active electret and an active electret ultra-low frequency mechanical antenna. The active electret includes a positive electrode plate, a negative electrode plate, an insulating dielectric layer, a positive electrode ring and a negative electrode ring. The insulating dielectric layer is located between the positive electrode plate and the negative electrode plate. The positive electrode plate is connected to the positive electrode ring, and the negative electrode plate is connected to the negative electrode ring. The positive electrode ring is used to connect to the positive pole of a power supply, and the negative electrode ring is used to connect to the negative pole of a power supply. The active electret ultra-low frequency mechanical antenna of the present invention uses a method of artificially applying voltage to make the electrode plate potential remain unchanged, thereby achieving a stable storage of a large amount of charge on the electrode plate. The active electret ultra-low frequency mechanical antenna of the present invention uses the electrode ring method so that the DC power supply does not move with the rotating mechanism, thereby reducing the overall weight of the antenna. The present invention can improve the charge storage capacity of the electrode plate by increasing the power supply capacity of the DC power supply and the dielectric constant of the insulating dielectric layer, thereby improving the radiation intensity of the antenna.

Description

Technical Field

[0001] The present invention relates to the technical field of ultra-low frequency transmitting antennas, and in particular to an active electret ultra-low frequency mechanical antenna. Background Art

[0002] Ultra-low frequency (ULF) communication technology utilizes the ultra-low and very low frequency bands of the radio spectrum for wireless communication. The ULF (30Hz-300Hz) band offers the following advantages: 1. Low path loss in water and soil; 2. Insensitive to unreliable propagation conditions, ensuring stable and reliable transmission; 3. Strong anti-interference capabilities. Based on these advantages, ULF communication offers the following advantages: 1. ULF signals experience much lower attenuation in the Earth's crust than other commonly used low-frequency signals, allowing for greater penetration depths; 2. ULF signals are insensitive to unreliable propagation conditions, ensuring stable and reliable transmission, making them one of the few communication methods impervious to electromagnetic interference; 3. Strong anti-interference capabilities. Any attempt to interfere with ULF communication requires a power output greater than that of the ULF signal.

[0003] Although ultra-low frequency communication has so many advantages, the biggest problem that still exists in ultra-low frequency communication is how to effectively generate ultra-low frequency electromagnetic waves.

[0004] Traditional ELF and ULF antennas are either electric field antennas or magnetic field antennas. Electric field antennas require electric dipoles to radiate electromagnetic waves, while magnetic field antennas require coils. In both cases, the radiation resistance is low, and generating significant radiated power requires large oscillating currents. The energy dissipated by these currents can only be minimized by using superconducting structures, but using superconducting structures incurs significant material and cooling costs. The large size of the antennas makes them vulnerable to damage during wartime, making them unsuitable for military use.

[0005] The introduction of "mechanical antennas" addresses the issues of large size and poor flexibility associated with ultra-low frequency (ULF) antennas. However, the magnetic energy density of rotating permanent magnets—radiation sources—is currently difficult to increase, requiring only increased volume to increase radiation intensity, posing significant challenges for rotating machinery. Rotating electret radiation sources—passive electrets—have poor charge storage capacity, making them difficult to achieve long-distance transmission requirements. Research conducted by Cui Yong's team at the Beijing University of Aeronautics and Astronautics on passive electrets has only achieved 0.1m@1nT communication. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an antenna electret and an ultra-low frequency mechanical antenna with small size and long transmission distance.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0008] The present invention first provides an active electret, which is characterized in that it includes a positive electrode plate, a negative electrode plate, an insulating dielectric layer, a positive electrode ring and a negative electrode ring, the insulating dielectric layer is located between the positive electrode plate and the negative electrode plate, the positive electrode plate is connected to the positive electrode ring, the negative electrode plate is connected to the negative electrode ring, the positive electrode ring is used to connect to the positive pole of the power supply, and the negative electrode ring is used to connect to the negative pole of the power supply.

[0009] The active electret of the present invention includes a positive electrode plate, a negative electrode plate, an insulating dielectric layer, a positive electrode ring, and a negative electrode ring. When the active electret rotates, it can generate a time-varying electric field in space. The positive electrode ring and the negative electrode ring provide a large amount of charge to the positive electrode plate and the negative electrode plate. The surface charge density of the electret is more than 20 times that of the passive electret of the same size, and the communication distance can be increased by 20 1 / 2 times.

[0010] The present invention also provides an active electret ultra-low frequency mechanical antenna, including an electret and an electret rotating clamp, wherein the electret is fixed on the electret rotating clamp, and the electret includes a positive electrode plate, a negative electrode plate, an insulating dielectric layer, a positive electrode ring and a negative electrode ring, wherein the insulating dielectric layer is located between the positive electrode plate and the negative electrode plate, the positive electrode plate is connected to the positive electrode ring, the negative electrode plate is connected to the negative electrode ring, the positive electrode ring is used to connect to the positive pole of the power supply, and the negative electrode ring is used to connect to the negative pole of the power supply.

[0011] The active electret ultra-low frequency mechanical antenna of this invention rotates the active electret, achieving rotation of the positive and negative charges on the electrode plates, i.e., rotation of the electric dipole moment, thereby generating a time-varying electromagnetic field. This mechanical antenna avoids the traditional practice of applying an excitation voltage to the feeder port to generate oscillating electromagnetic fields within the conductor. Furthermore, this solution addresses the low charge density of the natural electret and the inability to increase the magnetic energy of the permanent magnet, which are common problems in similar mechanical antennas.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] 1. The signal transmission module in the device of the present invention can realize a time-varying electric field with the same operating frequency as the motor.

[0014] 2. The device of the present invention uses an active electret as the emission source, which can be used permanently without considering impedance matching issues. Amplitude modulation can be achieved by changing the external power supply, and frequency modulation can be achieved by changing the rotation speed. Amplitude modulation can be achieved by changing the externally applied voltage waveform, and a high surface charge density can be achieved by applying a high voltage. Based on communication requirements, only the external excitation voltage can be changed without changing the source, thus avoiding resource waste.

[0015] 3. The active electret in the device of the present invention uses a material with a high dielectric constant (such as barium titanate) to achieve high charge density capability, and the radiation capability of the active electret in the present invention can be controlled.

[0016] 4. The device of the present invention adopts ultra-low frequency communication, which has small propagation loss, long transmission distance and strong anti-interference ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 Schematic diagram of the active electret structure of the present invention;

[0019] Figure 2 yes Figure 1 A top view of

[0020] Figure 3 yes Figure 1 Side view of;

[0021] Figure 4 yes Figure 3 AA cross-section diagram.

[0022] Figure 5 This is a structural block diagram of the active electret mechanical antenna of the present invention.

[0023] Figure 6 This is a diagram showing the overall structure of the active electret mechanical antenna device of the present invention.

[0024] Figure 7 Schematic diagram of the active electret rotating fixture of the present invention, wherein a is the overall structure diagram, b is the main view, c is the side view, and d is the top view.

[0025] Figure 8 These are the time-varying magnetic field strength curves of the pre-experiment of the active electret mechanical antenna of the present invention, where a is the experimental result curve of the rotating active electret at 0.6 m, and b is the experimental result curve of the rotating active electret at 5 m.

[0026] Figure 9 Schematic diagram of amplitude keying (ASK) of active electret mechanical antenna, where a is the time domain waveform of the rotating active electret and b is the spectrum of the rotating active electret.

[0027] Figure 10Schematic diagram of frequency modulation (FSK) of active electret mechanical antenna, where a is the time domain waveform of the rotating active electret, and b is the time domain spectrum of the rotating active electret. The modulation frequencies are 75Hz and 125Hz.

[0028] Reference numerals:

[0029] 10-electret; 101-positive electrode plate; 102-negative electrode plate; 103-insulating dielectric layer; 104-positive electrode ring; 105-positive electrode ring; 106-wire; 107-T-slot; 20-electret rotating fixture; 201-base; 202-fixture wall; 203-motor connecting shaft; 204-groove. DETAILED DESCRIPTION

[0030] The following embodiments of the technical solution of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention and are therefore only examples and are not intended to limit the scope of protection of the present invention.

[0031] It should be noted that, unless otherwise specified, the technical or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0032] In this application, unless otherwise specified or limited, the terms "electrode," "connecting shaft," "electrode ring," and "dielectric plate" should be interpreted broadly. For example, a positive electrode plate can be a negative electrode plate; a negative electrode ring can be a positive electrode ring; and a connecting shaft connecting an electrode can be a connecting shaft connecting another rotating mechanism. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0033] like Figure 5 As shown in FIG, a structural block diagram of an active electret mechanical antenna provided by the present invention includes a driving module and a radiation source module. The driving module includes a power supply, a driving motor and a Figure 7 The active electret rotating fixture shown; the radiation source is as shown Figure 1 The active electret shown.

[0034] The surface charge density of the active electret can be expressed as formula (1), and its unit is C / m 2 The active electret is supplied with a high voltage through a power supply and is made of a high dielectric constant material (such as barium titanate) to have a high surface charge density, thereby improving the radiation capability of the active electret mechanical antenna.

[0035]

[0036] where ε ris the dielectric constant of the insulating medium layer; U is the external voltage; k0 is the electrostatic constant; d is the thickness of the insulating medium layer

[0037] The driving motor drives the active electret fixture to rotate through its rotating shaft, which in turn causes the active electret to rotate, forming a time-varying electric field, thereby generating a time-varying electromagnetic field with the same frequency as the rotation frequency. The time-varying magnetic field intensity and time-varying electric field generated by the rotating active electret at a distance R are respectively expressed as Equations (2) and (3). These are consistent with the expression mechanism of the magnetic induction intensity and electric field generated by traditional antennas. Therefore, it is reasonable and feasible to use the rotating active electret as an ultra-low frequency mechanical antenna transmitting unit.

[0038]

[0039]

[0040] Where θ is the polar angle of the field point; Φ is the azimuth angle of the field point; q0 is the charge; l is the distance between the positive and negative charges, that is, the direction from the negative charge to the positive charge; R is the distance between the field point and the source point; a R is the unit vector of the radiation direction.

[0041] like Figure 1-4 The figure shows a structure diagram of an electret provided by the present invention. The electret provided by the present invention is an active electret, including a positive electrode plate 101, a negative electrode plate 102, an insulating dielectric layer 103, a positive electrode ring 104, a negative electrode ring 105, a wire 106 and a T-slot 107. The positive electrode ring 104 and the negative electrode ring 105 are located at the edges of both sides of the insulating dielectric layer 103. The insulating dielectric layer 103 is located between the positive electrode plate 101 and the negative electrode plate 102, thereby improving the anti-breakdown capability of the positive electrode plate 101 and the negative electrode plate 102 and increasing the amount of charge stored in the electrode plate. The connection between the electrode ring and the power supply is completed through a brush and a T-slot 107 to reduce the electrostatic effect generated during the rotation process.

[0042] Positive electrode ring 104 is connected to positive electrode plate 101, providing a continuous positive potential to positive electrode plate 101 by connecting to the positive terminal of the power supply. Negative electrode ring 105 is connected to negative electrode plate 102, providing a continuous negative potential to negative electrode plate 102 by connecting to the negative terminal of the power supply. The electrode plates and rings, each with corresponding electrical properties, are connected by welding. During the rotation of the active electret, the positive electrode plate is always connected to the positive terminal of the power supply, and the negative electrode plate is always connected to the negative terminal of the power supply.

[0043] The outer diameters of the positive electrode plate 101 and the negative electrode plate 102 are smaller than the inner diameter of the rotating fixture. The rotating fixture is cylindrical in shape to reduce wind resistance during rotation.

[0044] The positive electrode ring 104 and the negative electrode ring 105 are both circular rings with T-slots 107, which provide continuous energy to the rotating electret and ensure that the power supply is placed statically to facilitate providing a larger voltage to the electrode plates.

[0045] The insulating dielectric layer 103 is made of a high dielectric constant insulating material to enhance the breakdown resistance of the active electret. By adjusting the material, thickness and area of ​​the intermediate insulating dielectric layer, the voltage limit value on both sides of the active electret can be adjusted.

[0046] Both the positive electrode ring 104 and the negative electrode ring 105 are made of graphene material to reduce the probability of electrostatic effects occurring during rotation.

[0047] It should be noted that the active electret positive electrode plate 101 and negative electrode plate 102 are identical in size, shape, and material, and face each other. The dimensions of the positive and negative electrode plates 101, 102 are slightly smaller than the insulating dielectric layer 103 to prevent edge electrical breakdown. The active electret insulating dielectric layer 103 requires a high-dielectric-constant material.

[0048] like Figure 6 FIG. 1 is a structural diagram of an active electret mechanical antenna provided by the present invention, comprising an electret 10 and an electret rotating fixture 20 . The electret 10 is fixed in the electret rotating fixture 20 .

[0049] like Figure 7 As shown, it is a structural diagram of an active electret rotating fixture provided by the present invention, including a base 201, a fixture wall 202 and a motor connecting shaft 203, and a groove 204 is provided on the fixture wall 202. The groove 204 is used to clamp the active electret 10 to prevent the active electret 10 from moving during the rotation process. The fixture wall 202 has two functions, one is to increase the strength of the rotating fixture 20, and the other is to reduce the wind resistance during the rotation process. The motor connecting shaft 203 is connected to the driving motor and rotates synchronously with the driving motor, thereby driving the active electret to rotate. It should be noted that the active electret rotating fixture 20 requires an insulating material with a low dielectric constant.

[0050] like Figure 8 The figure shows the preliminary experimental results provided by the present invention, including detection distances of 0.6m and 5m, and the preliminary experimental operating frequency is 16Hz.

[0051] In order to improve the transmission capability of the active electret mechanical antenna, the present invention realizes ASK and FSK modulation by controlling the DC source and the motor speed respectively. The time domain waveform and spectrum of the radiated electromagnetic wave are obtained through simulation calculation and experiment. Figure 9 and Figure 10 shown.

[0052] like Figure 9As shown in FIG, the ASK amplitude modulation provided by the present invention has an operating frequency of 75 Hz and is achieved by changing the size of the DC source. Figure 10 As shown, it is 2FSK of FSK frequency modulation provided by the present invention, and the modulation frequency is 75Hz and 125Hz, which is achieved by changing the motor speed.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some or all of the technical features therein can be replaced with equivalents. However, these modifications or replacements do not cause the corresponding technical solutions to essentially deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An active electret, characterized in that: It includes a positive electrode plate, a negative electrode plate, an insulating dielectric layer, a positive electrode ring and a negative electrode ring. The insulating dielectric layer is located between the positive electrode plate and the negative electrode plate. The positive electrode plate is connected to the positive electrode ring, and the negative electrode plate is connected to the negative electrode ring. The positive electrode ring is used to connect to the positive pole of the power supply, and the negative electrode ring is used to connect to the negative pole of the power supply.

2. The active electret according to claim 1, wherein: The positive electrode ring and the negative electrode ring are located on both sides of the insulating medium layer in a height direction.

3. The active electret according to claim 1, wherein The positive electrode ring and the negative electrode ring are arranged on the insulating medium, and the positive electrode plate and the negative electrode plate are located between the positive electrode ring and the negative electrode ring.

4. An active electret ultra-low frequency mechanical antenna, comprising an electret and an electret rotating fixture, wherein the electret is fixed on the electret rotating fixture, characterized in that: The electret is the active electret according to any one of claims 1 to 3.

5. The active electret ultra-low frequency mechanical antenna according to claim 4, characterized in that: The electret rotating fixture is provided with a fixture groove, and the active electret is located in the groove.

6. The active electret ultra-low frequency mechanical antenna according to claim 5, characterized in that: The insulating dielectric layer of the active electret is located in the groove.

7. The active electret ultra-low frequency mechanical antenna according to claim 6, characterized in that: The electret rotating fixture includes a base, a fixture arm and a motor connecting shaft. The fixture arm is arranged at the upper end of the base, and the motor connecting shaft is arranged at the lower end of the base; the groove is arranged on the fixture arm.

8. The active electret ultra-low frequency mechanical antenna according to any one of claims 4 to 7, characterized in that: The ultra-low frequency mechanical antenna also includes a driving motor and a power supply; the driving motor is connected to the electret rotating fixture to drive the electret rotating fixture to rotate; the power supply supplies power to the driving motor and the positive electrode ring and negative electrode ring of the electret; the insulating dielectric layer is located between the positive and negative electrode plates, thereby improving the anti-breakdown capability of the positive and negative electrode plates and increasing the amount of charge stored in the electrode plates.

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