CN108736146B

CN108736146B - Ultra-small U L F/V L F rotating current antenna and signal amplitude-frequency modulation method

Info

Publication number: CN108736146B
Application number: CN201810351505.0A
Authority: CN
Inventors: 王宗新; 曹振新; 杨非
Original assignee: Southeast University
Current assignee: Southeast University
Priority date: 2018-04-19
Filing date: 2018-04-19
Publication date: 2020-07-31
Anticipated expiration: 2038-04-19
Also published as: CN108736146A

Abstract

The invention discloses a subminiature U L F/V L F rotating current antenna, which comprises a light-emitting device and a turntable, wherein the turntable comprises an anode metal layer, a P-type semiconductor layer, an N-type semiconductor layer and a cathode metal layer which are sequentially arranged, an unthreaded hole is formed in the anode metal layer, a conductive coil is further arranged on the turntable, and two ends of the conductive coil are respectively connected with the anode metal layer and the cathode metal layer.

Description

Ultra-small U L F/V L F rotating current antenna and signal amplitude-frequency modulation method

Technical Field

The invention relates to a subminiature U L F/V L F rotating current antenna and a signal amplitude-frequency modulation method.

Background

The Very low Frequency (Very L ow Frequency-V L F, the Frequency range is 3-30 kHz) is also suitable for military communication, an electromagnetic wave waveguide with a V L F Frequency band is formed between the ground and an ionized layer which is 70-85 kilometers above the earth surface, and the attenuation of the electromagnetic wave signal of V L F transmitted in the earth-ionized layer waveguide is Very small, so that the Ultra-long distance communication can be realized.

Although underwater acoustic communication systems are very effective for joint tactical activities between surface warships and submarines, and between submarines and submarines, these underwater acoustic communication systems are only suitable for short-range communication, up to 10-30 km at most, and problems arise if the submarines work outside of normal waters, far from the areas covered by national defense and communication systems.

At present, a receiver with high sensitivity is not lacked in a U L F/V L F frequency band, however, the wavelength of an electromagnetic wave in a free space of the U L F and V L F frequency bands can reach hundreds to thousands of kilometers, a U L F/V L F transmitting system designed by a conventional antenna method is very large in size and generally needs to be erected on a plurality of high towers as shown in FIG. 1, for example, a V L F transmitter with the strongest function in the world built by Katler in the state of America occupies 2000 acres and is erected on 26V L F transmitters with the height of 1000 feet, which are easy to destroy and are not easy to maintain in a plurality of operation environments, and are extremely inconvenient to maintain, especially when needing to move, the transmitting system needs to be carried by an air ball or a satellite tower and is extremely impractical.

Disclosure of Invention

The invention aims to provide a subminiature U L F/V L F rotating current antenna and a signal amplitude-frequency modulation method, which can greatly reduce the volume of the antenna.

The technical scheme is as follows: in order to achieve the purpose, the invention adopts the following technical scheme:

the microminiature U L F/V L F rotating current antenna comprises a light-emitting device and a rotary table, wherein the rotary table comprises an anode metal layer, a P-type semiconductor layer, an N-type semiconductor layer and a cathode metal layer which are sequentially arranged, an unthreaded hole is formed in the anode metal layer, a conductive coil is further arranged on the rotary table, and two ends of the conductive coil are respectively connected with the anode metal layer and the cathode metal layer.

Furthermore, the light-emitting device comprises a light source disc, and a light emitter is arranged on the light source disc.

Further, the light source disc and the rotating disc are coaxially arranged, but the light source disc is fixed.

Furthermore, the turntable also comprises an insulating layer which is arranged on the surface and is close to the negative metal layer, an insulating support is arranged on the insulating layer, and the conducting coil is wound on the insulating support.

Furthermore, a current limiting resistor is arranged between the conductive coil and the anode metal layer. This prevents the conductive coil from being burnt out by excessive current.

Further, the turntable comprises a motor for driving the turntable to rotate.

By adopting the amplitude modulation method of the signals emitted by the subminiature U L F/V L F rotating current antenna, the turntable is controlled to rotate at a constant speed, and the intensity of light emitted by the light-emitting device is controlled by using the modulation signals.

By adopting the frequency modulation method of the signals emitted by the subminiature U L F/V L F rotating current antenna, the rotating speed of the turntable is controlled by the modulation signals, and the intensity of light emitted by the light-emitting device is controlled to be constant.

The subminiature U L F/V L F rotating current antenna and the signal amplitude-frequency modulation method have the advantages that electromagnetic waves are emitted in the U L F frequency band and the V L F frequency band by utilizing the rotating motion of magnetic dipole moment formed by a spiral current loop, the antenna designed by the invention has extremely small electric size, can be realized by meter-level volume in the U L F/V L F frequency band, is far smaller than the antenna with the volume of kilometer level in the prior art, and cannot influence the radiation efficiency of the antenna.

Drawings

FIG. 1 is a schematic diagram of a prior art V L F antenna;

FIG. 2 is a schematic illustration of calculating a rotating charge radiation field;

FIG. 3 is a time domain waveform of a rotating charge radiation electromagnetic wave at a constant rotation speed;

FIG. 4 is a frequency spectrum of a rotating charge at a constant rotational speed;

FIG. 5 is a time domain waveform of a charge radiation electromagnetic wave rotating at variable speeds;

FIG. 6 is a frequency spectrum of a charge radiation electromagnetic wave rotating at variable speeds;

FIG. 7(a) is a schematic view of a rotating current antenna according to an embodiment of the present invention;

FIG. 7(b) is a schematic diagram of another view of a rotating current antenna in accordance with an embodiment of the present invention;

FIG. 8 is a schematic cross-sectional view of a turntable according to an embodiment of the present invention;

fig. 9 is a schematic diagram of an amplitude modulation process for an antenna transmission signal according to an embodiment of the present invention;

fig. 10 is a schematic diagram of a process of modulating the frequency of a signal transmitted from an antenna according to an embodiment of the present invention.

Detailed Description

The technical solution of the present invention will be further described with reference to the following detailed description and accompanying drawings.

The present embodiment discloses a subminiature U L F/V L F rotating current antenna, and the design principle is described first.

It is well known that a changing electric field can induce a magnetic field, which in turn induces an electric field. The electric field and the magnetic field are mutually induced in sequence to form the electromagnetic wave which can be transmitted. The electric charges generate an electric field in the space, and if the electric charges are driven to make a certain specific motion, a changing electric field is generated in the space, and then a magnetic field which is mutually induced with the electric field is generated, so that the radiation electromagnetic wave can be generated. The electric field and magnetic field generated by the charge moving at low speed (v < c) in vacuum are shown as formula (1) and formula (2):

in the formula, mu₀And₀is the permeability and permittivity of the vacuum, q is the amount of charge, v is the velocity of charge movement, c is the speed of light, and r is the radial dimension of the charge to the field point, respectively.

The numerical value and 1/r of the first term of formula (1)²Proportional, the integral at infinity is zero, so the field represented by this term cannot radiate; the value of the second term is proportional to 1/r, and the integral at infinity is not zero, which represents the radiation field. The radiation field generated by the moving charge can be expressed as:

as can be seen from expressions (3) and (4), even if the velocity of the moving charge is low, electromagnetic waves can be radiated as long as it has a certain acceleration.

If a pair of charge amounts is + q and-q, respectively, as shown in FIG. 2, the distance is d₀The rotation angle is ω, because the negative charge and the positive charge are opposite in polarity, but because the acceleration of the negative charge and the acceleration of the positive charge are opposite in direction, the radiation field generated by the negative charge and the radiation field generated by the positive charge are approximately equal according to equation (3) and considering that the distance between the two charges is far less than the distance between the two charges and the field point of the far zone, so the intensity of the radiation electromagnetic wave generated by the two charges in the far zone is as shown in equation (5):

in the formula: q d₀Is the electric dipole moment of the positive and negative charges,

is the unit vector of positive charge pointing to the center of the rotation.

The electronic equipment can only work normally within a certain frequency range, and the frequency of electromagnetic waves is an important parameter of the electronic equipment, so that the determination and control of the frequency of the electromagnetic waves of the rotating current antenna are an important part for researching the antenna. The research shows that the frequency of electromagnetic wave radiated by the electric dipole moment rotating at a constant speed is the same as the rotating frequency of the driving motor. Fig. 3 and fig. 4 are time domain curves of the radiation field of the rotating electric dipole moment excited by the constant dc voltage and rotating at a constant speed (the rotation speed is 500 rpm) and the frequency spectrum thereof, respectively, and it can be seen that the electromagnetic wave frequency of the electrode moment rotating at the constant speed is equal to the rotation frequency thereof. The frequency of the electromagnetic wave radiated by the rotating electric dipole moment which performs variable speed motion changes with the rotation speed of the motor, assuming that the rotation acceleration of the motor is ω' 750rad/s2, the initial rotation speed is 280 rpm, and the rotation speed is accelerated to 300 rpm, and the time domain waveform and the frequency spectrum of the radiated electromagnetic wave are obtained through simulation calculation and are respectively shown in fig. 5 and fig. 6.

In electromagnetism, what corresponds to electric dipole moment is magnetic dipole moment, and according to the electromagnetic dual principle of electromagnetism, the magnetic induction intensity in the magnetic dipole moment radiation field can be easily obtained from formula (6) as follows:

wherein m is a magnetic dipole moment,

is the vector per unit area of the current loop that generates the magnetic dipole moment.

In reality, there is no magnetic charge, i.e. there is no magnetic dipole, but the electromagnetic behavior of the current-carrying coil is consistent with that of the magnetic dipole, so the current-carrying coil can be regarded as a magnetic dipole in electromagnetic application.

According to the above design principle, the present embodiment discloses a subminiature U L F/V L F rotating current antenna, as shown in fig. 7(a) and 7(b), comprising a light source disc 5 and a turntable 3 coaxially disposed, wherein the light source disc 5 is fixed, the turntable 3 can rotate along with a rotating shaft 4, the rotating shaft 4 is driven by a motor 1, and the motor 1 is controlled by a motor controller 2.

As shown in fig. 8, the turntable 3 includes an anode metal layer 34, a P-type semiconductor layer 32, an N-type semiconductor layer 33, a cathode metal layer 35, and an insulating layer 31, which are sequentially disposed, the anode metal layer 34 is provided with an optical aperture 341, the insulating layer 31 is provided with an insulating support 36, a conductive coil 37 is wound on the insulating support 36, and two ends of the conductive coil 37 are respectively connected to the anode metal layer 34 and the cathode metal layer 35 through a wire 38 embedded inside the turntable 3. The conducting wire 38 between the conducting coil 37 and the positive metal layer 34 is also connected in series with a current limiting resistor 381.

As shown in fig. 7(a), the light source tray 5 is provided with a light emitter 51, a support plate 52, and a light emitter control plate 53.

The working principle of the antenna is described as follows:

the light emitter control board 53 is powered on to drive the light emitter 51 to work, and light is emitted to irradiate the turntable 3 and the PN junction formed by the P-type semiconductor layer 32 and the N-type semiconductor layer 33 through the light hole 341. Due to the photovoltaic effect, a voltage is generated between the positive metal layer 34 and the negative metal layer 35, and a current is generated in the conductive coil 37 connected between the positive metal layer 34 and the negative metal layer 35. When the motor 1 is in operation, the rotating shaft 4 connected to the shaft of the motor drives the rotating disc 3 to rotate, and the conductive coil 37 carrying current rotates along with the rotating disc, and the rotating current radiates electromagnetic waves according to the principle.

As shown in fig. 9, the amplitude modulation signal controller 7 is controlled by a modulation signal, and the intensity of light emitted by the illuminator 51 is controlled by the amplitude modulation signal controller 7, so that the voltage between the positive metal layer 34 and the negative metal layer 35 changes synchronously with the intensity of the light, and the current on the conductive coil 37 also changes synchronously with the intensity of the light, so that the intensity of the radiated electromagnetic wave also changes synchronously with the amplitude of the modulation signal, and at this time, the envelope curve of the time domain waveform of the electromagnetic wave is consistent with the amplitude curve of the modulation signal, thereby realizing amplitude modulation.

As shown in fig. 10, the intensity of light emitted by the light emitter 51 is controlled to be constant, and the motor controller 2 is controlled by using the modulation signal to control the rotation speed of the motor 1, so that the frequency of the rotating current radiation electromagnetic wave is changed along with the rotation speed, thereby realizing frequency modulation.

Claims

1. The microminiature U L F/V L F rotating current antenna is characterized by comprising a light-emitting device and a turntable (3), wherein the turntable (3) comprises an anode metal layer (34), a P-type semiconductor layer (32), an N-type semiconductor layer (33) and a cathode metal layer (35) which are sequentially arranged, an optical hole (341) is formed in the anode metal layer (34), a conductive coil (37) is further arranged on the turntable (3), and two ends of the conductive coil (37) are respectively connected with the anode metal layer (34) and the cathode metal layer (35).

2. The subminiature U L F/V L F rotating current antenna of claim 1, wherein the light emitting device comprises a light source disk (5), and the light source disk (5) is provided with a light emitter (51).

3. The subminiature U L F/V L F rotating current antenna of claim 2, wherein the light emitting device comprises a rotating shaft (4), the rotating shaft (4) penetrates through the center of a light source plate (5) and is connected with a rotating disc (3), and the light source plate (5) is fixed relative to the ground.

4. The subminiature U L F/V L F rotary current antenna of claim 1, wherein the turntable (3) further comprises an insulating layer (31) disposed on the surface and abutting against the negative metal layer (35), the insulating layer (31) is provided with an insulating support (36), and the conductive coil (37) is wound on the insulating support (36).

5. The subminiature U L F/V L F rotary current antenna of claim 1, wherein a current limiting resistor (381) is further disposed between the conductive coil (37) and the positive metal layer (34).

6. The subminiature U L F/V L F rotating current antenna of claim 1, further comprising a motor (1) for driving the turntable (3) in rotation.

7. The amplitude modulation method for transmitting signals by using the subminiature U L F/V L F rotating current antenna according to claim 1 is characterized in that the rotating disc (3) is controlled to rotate at a constant speed, and the intensity of light emitted by the light-emitting device is controlled by using the modulation signal.

8. The frequency modulation method for transmitting signals by using the subminiature U L F/V L F rotating current antenna according to claim 1, wherein the intensity of light emitted from the light emitting device is controlled to be constant by controlling the rotation speed of the turntable (3) by using the modulation signal.