CN105978840B - Rotating electromagnetic wave trajectory angular momentum wireless transmitting system - Google Patents

Abstract

The invention discloses a wireless transmission system of rotating electromagnetic wave orbital angular momentum, which converts different orbital angular momentum state numbers of electromagnetic waves at the transmitting end into different frequency offsets of electromagnetic waves at the receiving end through a rotating spiral phase plate, and then can form an orthogonal frequency at the receiving end. multiplexing signals. Transforming the orbital angular momentum electromagnetic wave from the space domain reception to the time domain orthogonal reception can overcome the free space divergence problem caused by the beam angle of the traditional electromagnetic wave with orbital angular momentum, and realize the long-distance, large-capacity, and high-spectrum efficiency transmission of electromagnetic wave orbital angular momentum. In the present invention, the baseband signal is modulated, up-converted to a radio frequency, and then fed into the transmitting antenna. After being converged by the lens, it is incident on the helical phase plate to generate orbital angular momentum electromagnetic waves, and then the rotation of the helical phase plate is controlled by the rotating device, thereby generating the orbital angle of the rotation. Momentum electromagnetic waves. After the receiving end receives part of the electromagnetic wave, it is down-converted and sent to the demodulator, and the demodulation is completed by using the orthogonal frequency division multiplexing signal demodulation method.

Description

Wireless Transmission System of Rotating Electromagnetic Wave Orbital Angular Momentum

technical field

The invention relates to the technical field of wireless transmission, in particular to a wireless transmission system for orbital angular momentum of rotating electromagnetic waves.

Background technique

Electromagnetic wave orbital angular momentum (OAM) has been widely concerned and deeply researched in academia since it was derived by Allen et al. using Maxwell's equations theory in 1992 and verified by experiments in 1994. The angular momentum of electromagnetic waves includes two parts: spin angular momentum and orbital angular momentum. Spin angular momentum corresponds to the polarization of electromagnetic waves. It has two degrees of freedom, left and right. It has been developed rapidly since it was proposed in the early 1950s. Today's research and products on polarization are very mature. As a new degree of freedom, the orbital angular momentum of the electromagnetic wave advances helically around the propagation axis.

Electromagnetic waves have used amplitude as a means of information transmission since the time of Marconi. Among them, the frequency indicates how fast the amplitude changes, and the phase indicates when the amplitude changes. The use of electromagnetic wave amplitude as the means of transmission of information carriers has not changed so far. What exactly is the electromagnetic wave, people's understanding of it has only stayed in the Marconi era. However, orbital angular momentum, as another typical physical quantity of electromagnetic waves, provides people with a new perspective to study and develop electromagnetic waves. It has potential applications in many ways. In terms of transmission, different orbital angular momentums of electromagnetic waves are orthogonal to each other. By multiplexing different orbital angular momentums and transmitting or receiving through the same aperture, the transmission spectrum efficiency can be greatly improved. In astronomy, electromagnetic waves with orbital angular momentum can be used to detect the vortex characteristics of the electromagnetic layer. In terms of particle manipulation, light waves with orbital angular momentum act as an optical wrench and can rotate particles. Therefore, different from conventional electromagnetic waves, orbital angular momentum provides a new dimension for electromagnetic waves, and provides a new perspective for people to understand electromagnetic waves. It must have great application value in transmission and detection.

In short-distance communication, the receiving end must receive all the energy of the OAM electromagnetic wave in the entire airspace before it can distinguish different OAM electromagnetic waves. However, due to the energy singularity of the electromagnetic wave beam with orbital angular momentum, its beam presents a circular distribution, and the radius of the ring energy (energy ring) expands continuously with the increase of the transmission distance. In long-distance transmission, if the full-airspace reception method similar to the above-mentioned short-distance communication is adopted, the required antenna aperture will be very large. Therefore, at this time, the receiving end cannot receive all the electromagnetic wave energy, but can only receive part of the electromagnetic wave energy, which poses serious difficulties to the correct reception of different orbital angular momentum signals in long-distance OAM electromagnetic wave transmission.

Contents of the invention

The present invention aims at at least to a certain extent solving the problem of difficult reception in space caused by beam divergence in the free space electromagnetic wave orbital angular momentum transmission described in the background.

Therefore, the object of the present invention is to propose a wireless transmission system of rotational electromagnetic wave orbital angular momentum, which can realize long-distance, large-capacity, high-spectrum-efficient electromagnetic wave orbital angular momentum transmission.

In order to achieve the above object, the embodiment of the present invention proposes a rotating electromagnetic wave orbital angular momentum wireless transmission system, including: a signal generator subsystem, and the signal generator subsystem includes: a modulator for performing Intermediate frequency modulation; a radio frequency transmitting unit, used for up-converting the intermediate frequency signal into a radio frequency signal of a corresponding frequency point; a transmitting antenna subsystem, the transmitting antenna subsystem including: a transmitting antenna, used for converting the guided wave on the transmission line into Electromagnetic waves propagating in free space; lenses, through which the electromagnetic waves are collimated to reduce the divergence angle; spiral phase plates, used to change the incident electromagnetic waves into electromagnetic waves with orbital angular momentum; rotating devices, used to control The spiral phase plate rotates to generate rotating orbital angular momentum electromagnetic waves, and then sends them into free space for propagation; the signal receiver subsystem, the signal receiver subsystem includes: a receiving antenna for transmitting the electromagnetic waves propagated in free space The rotating orbital angular momentum electromagnetic wave is converted into a guided wave in the transmission line; the radio frequency receiving unit is used for down-converting the radio frequency signal received by the receiving antenna to an intermediate frequency; the demodulator adopts an orthogonal frequency division multiplexing (OFDM) signal The demodulation method completes the demodulation of the intermediate frequency signal.

In the rotating electromagnetic wave orbital angular momentum wireless transmission system of the embodiment of the present invention, the information data first passes through the signal transmitter, and the signal transmitter completes the modulation and up-conversion of the baseband data and sends it to the antenna unit, and the antenna generates a corresponding electromagnetic wave beam, and the electromagnetic beam passes through After the lens converges, it is incident on the rotating spiral phase plate. The rotation speed of the spiral phase plate is controlled by the rotating device to generate electromagnetic waves with rotating orbital angular momentum. Electromagnetic waves with different orbital angular momentum will generate different frequencies at the receiving end after rotation. The electromagnetic wave with different orbital angular momentum of the rotation reaches the receiving end after propagating in free space. The receiving end uses the antenna to receive part of the energy of the electromagnetic wave, and then sends it to the signal receiver. The signal receiver down-converts the radio frequency signal and sends it The demodulator uses the OFDM signal demodulation method to demodulate the baseband signal, so as to realize the large-capacity and long-distance transmission of electromagnetic waves in free space, simplify the reception difficulty, and greatly improve the spectral efficiency.

In addition, the rotating electromagnetic wave orbital angular momentum wireless transmission system according to the above-mentioned embodiments of the present invention may also have the following additional technical features:

Optionally, in an embodiment of the present invention, the electromagnetic waves may include one or more of light waves, microwaves, millimeter waves, and terahertz waves.

Further, in one embodiment of the present invention, the principle of rotating the electromagnetic wave with orbital angular momentum is to rotate the phase distribution on the aperture surface of the antenna.

Alternatively, in one embodiment of the present invention, the rotating device may be a motor or any other type of mechanical rotation.

Further, in an embodiment of the present invention, there is at least one transmitting antenna subsystem.

Further, in an embodiment of the present invention, the transmitting antenna and the receiving antenna are any one of antennas such as horn antennas, parabolic antennas, Cassegolian antennas, patch antennas, and array antennas.

Further, in an embodiment of the present invention, the material for making the spiral phase plate includes one or more of common electromagnetic wave materials such as high-density polyethylene, polypropylene, and TPX.

Further, in an embodiment of the present invention, the spiral phase plate can be fabricated by punching a Lauber lens or a printed circuit board (PCB).

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and easy to understand from the following description of the embodiments in conjunction with the accompanying drawings, wherein:

Fig. 1 is a structural schematic diagram of a wireless transmission system of rotating electromagnetic wave orbital angular momentum according to an embodiment of the present invention;

Fig. 2 is a structural schematic diagram of a wireless transmission system of rotating electromagnetic wave orbital angular momentum according to a specific embodiment of the present invention;

3 is a schematic structural diagram of a spiral phase plate according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of implementing rotational orbital angular momentum using a spiral phase plate according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of frequency shifts of signals at the receiving end corresponding to different rotation rates and different orbital angular momentums according to an embodiment of the present invention; and

FIG. 6 is a schematic diagram of multiplexing transmission of rotational electromagnetic wave orbital angular momentum according to an embodiment of the present invention.

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals designate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

The following describes the wireless transmission system of rotational electromagnetic wave orbital angular momentum according to the embodiments of the present invention with reference to the accompanying drawings.

Fig. 1 is a schematic structural diagram of a wireless transmission system for rotating electromagnetic wave orbital angular momentum according to an embodiment of the present invention.

As shown in FIG. 1 , the wireless transmission system 10 includes: a signal generator subsystem 100 , a transmitting antenna subsystem 200 and a signal receiver subsystem 300 . Wherein, the signal generator subsystem 100 includes: a modulator 101, a radio frequency transmitting unit 102; the transmitting antenna subsystem 200 includes: a transmitting antenna 201, a lens 202, a spiral phase plate 203, and a rotating device 204; the signal receiver subsystem 300 includes: receiving An antenna 301 , a radio frequency receiving unit 302 , and a demodulator 303 .

Specifically, the modulator 101 is used to perform intermediate frequency modulation on baseband data. The radio frequency transmitting unit 102 is used for up-converting the intermediate frequency signal into a radio frequency signal of a corresponding frequency point. The transmitting antenna 201 is used to convert the guided wave on the transmission line into electromagnetic wave propagating in free space. The divergence angle is reduced after the electromagnetic wave is collimated by the lens 202 . The spiral phase plate 203 is used to change the incident electromagnetic wave into an electromagnetic wave with orbital angular momentum. The rotating device 204 is used to control the rotation of the helical phase plate 203 to generate a rotating orbital angular momentum electromagnetic wave, which is sent into free space for propagation. The receiving antenna 301 is used to convert the rotating orbital angular momentum electromagnetic wave propagating in free space into a guided wave in the transmission line. The radio frequency receiving unit 302 is used for down-converting the radio frequency signal received by the receiving antenna to an intermediate frequency. The demodulator adopts the OFDM signal demodulation method to complete the demodulation of the received signal according to the different frequency deviations generated by the rotation of electromagnetic waves with different orbital angular momentum at the transmitting end, so as to restore the original baseband bit data.

In the embodiment of the present invention, the orbital angular momentum of the electromagnetic wave is rotated, thereby generating a corresponding frequency shift at the receiving end. In the case of the same rotation speed, electromagnetic waves with different orbital angular momentums have different frequency shifts at the receiving end, and the frequencies can be orthogonal to each other. By modulating the baseband data to different orbital angular momentums, the effect similar to OFDM signals can be achieved. , and theoretically the value of the orbital angular momentum can be infinite, which can greatly improve the spectral efficiency of transmission.

In an embodiment of the present invention, the electromagnetic waves may include one or more of light waves, microwaves, millimeter waves, and terahertz waves. Furthermore, the wireless transmission system based on the orbital angular momentum of rotating electromagnetic waves in the embodiment of the present invention can be widely used in wireless transmission systems in the light wave, microwave, millimeter wave, and terahertz bands, and transmits electromagnetic waves with different orbital angular momentum at the transmitting end through rotation. It is converted into electromagnetic waves with different frequency offsets at the receiving end, so as to realize the transition from full-space reception of orbital angular momentum electromagnetic waves to single-point orthogonal reception in the time domain, making long-distance transmission possible, and has the characteristics of large transmission capacity, flexibility and convenience.

Further, in one embodiment of the present invention, in the transmitting antenna subsystem 200, the principle of rotating electromagnetic waves with orbital angular momentum is to rotate the phase distribution on the antenna aperture plane, that is, by rotating the helical phase plate 203, the antenna aperture is dynamically changed Phase distribution on the surface.

Further, in an embodiment of the present invention, there is at least one transmitting antenna subsystem 200 . The received signal can be a single signal transmitted by one antenna system, or a multiple signal transmitted by multiple antenna systems. If the transmitting end transmits signals with electromagnetic waves of different orbital angular momentum, what the receiving end receives will be a group of electromagnetic wave signals with different frequency shifts. Specifically, in the signal receiver subsystem 300, the antenna receives a partial energy signal on the ring energy, and the signal processor down-converts the signal to an intermediate frequency, and the demodulator recovers the baseband data by using the OFDM signal demodulation method.

In one embodiment of the present invention, the transmitting antenna and the receiving antenna are any antennas such as horn antennas, parabolic antennas, Cassegolian antennas, patch antennas, and array antennas.

Further, in one embodiment of the present invention, the material of the spiral phase plate includes one or more of electromagnetic wave materials such as high-density polyethylene, polypropylene, and TPX, and can be punched through a Lauber lens, PCB, Spiral phase plates can be made in any way such as spiral lenses to convert spherical waves or plane waves into electromagnetic waves with orbital angular momentum.

In the embodiment of the present invention, firstly, the baseband signal is modulated and then up-converted to obtain a radio frequency signal, and secondly, the principle of rotating electromagnetic waves with orbital angular momentum is the phase distribution on the aperture surface of the rotating antenna, which can be realized in various ways, such as: A helical phase plate 203 is placed at the aperture of the antenna, and a motor or other mechanical rotating device 204 is used to drive the helical phase plate 203 to rotate. The transmitting antenna subsystem 200 may be a single antenna that generates one orbital angular momentum signal, or multiple antennas that simultaneously generate multiple orbital angular momentum signals. The rotation rate of the phase plane of a single antenna can be kept constant or can be changed at any time; the rotation rate of the phase plane of different antennas can be the same or different, and finally the antenna will receive part of the energy signal on the ring energy, and the signal processor will The signal is first down-converted to an intermediate frequency signal, and then the baseband data is recovered by using the demodulation method of the OFDM signal.

To sum up, the transmission system needs more and more long-distance and high-capacity transmission, and the transmission method based on electromagnetic wave orbital angular momentum can greatly improve the transmission capacity. However, due to the existence of an energy singularity in an electromagnetic wave beam with orbital angular momentum, its energy is distributed on a circular ring. During long-distance transmission, the radius of its energy ring will become larger and larger, and the receiving end cannot receive all the electromagnetic wave energy, but can only receive part of the electromagnetic wave energy. Detection is very difficult. The wireless transmission system of rotating electromagnetic wave orbital angular momentum proposed by the embodiment of the present invention rotates the orbital angular momentum of electromagnetic waves by rotating the phase distribution of the antenna aperture at the transmitting end, and then produces different frequency shifts at the receiving end. The method of momentum is to convert different orbital angular momentum into different receiving frequencies by rotating the orbital angular momentum of electromagnetic waves, which reduces the difficulty of receiving and makes large-capacity long-distance transmission based on electromagnetic wave orbital angular momentum possible.

Fig. 2 is a schematic structural diagram of a wireless transmission system for rotational electromagnetic wave orbital angular momentum according to a specific embodiment of the present invention.

As shown in Figure 2, taking the millimeter wave band as an example, the system mainly consists of a signal generator subsystem, a transmitting antenna subsystem, and a signal receiver subsystem. In the embodiment of the present invention, the baseband data is modulated to an intermediate frequency in the signal generator subsystem, and then the intermediate frequency signal is up-converted to a radio frequency signal of a corresponding frequency point through a radio frequency unit. The radio frequency signal is fed into the transmitting antenna subsystem by the transmission line. The transmitting antenna subsystem first converts the guided wave in the transmission line into an electromagnetic wave in free space by a conventional antenna and emits it. The radiated electromagnetic wave is collimated by a lens and then transmitted by The helical phase plate located at the aperture of the antenna is transformed into electromagnetic waves with orbital angular momentum, and then the helical phase plate is rotated by the rotating device to generate electromagnetic waves with rotational orbital angular momentum. The electromagnetic wave is received by the signal receiver subsystem after propagating in free space. In the signal receiving subsystem, the conventional antenna first receives part of the energy on the energy ring formed by the electromagnetic wave with orbital angular momentum, and then sends it to the signal processor to complete the down-conversion of the radio frequency signal and the demodulation and recovery of the intermediate frequency signal Out of the baseband data, so as to achieve the purpose of transmission. In the present invention, except that the spiral phase plate needs to be aligned with the aperture center of the transmitting antenna and the center of the lens, other components do not need to be aligned accurately, which greatly reduces the difficulty of system implementation. The various parts of the system are described below:

1. Signal generator subsystem

(1) Modulator: According to the encoded baseband data, to control the parameters of the carrier signal, such as amplitude, frequency, phase or pulse width, etc., so that it changes according to the baseband signal. The modulation method can adopt any analog or digital modulation method.

(2) Radio frequency transmitting unit: Up-convert the baseband modulated intermediate frequency signal to the radio frequency signal of the required frequency point.

2. Transmitting Antenna Subsystem

(1) Transmitting antenna: The transmitting antenna converts the guided wave in the transmission line into electromagnetic wave in free space. Its form can be various types, such as: horn antenna, parabolic antenna, Cassecolumn antenna, patch antenna, array antenna, etc.

(2) Lens: collimate the incident electromagnetic wave, expand its beam width, and reduce the beam divergence angle.

(3) Helical phase plate: The helical phase plate mainly converts spherical waves or plane waves into electromagnetic waves with orbital angular momentum. Its production materials can be various materials suitable for electromagnetic waves, such as: high-density polyethylene, polypropylene, TPX, etc., and its production methods can also adopt various methods, such as Lauber lens, PCB drilling, spiral lens, etc.

(4) Rotation device: used to realize the rotation of the helical phase plate. A motor or any other type of mechanical rotation can be used.

3. Signal processor subsystem

(1) Receiving antenna: converts electromagnetic waves in free space into guided waves in transmission lines. Its form can be various types, such as: horn antenna, parabolic antenna, Cassecolumn antenna, patch antenna, array antenna, etc.

(2) RF receiving unit: Down-convert the RF signal received by the antenna to an intermediate frequency.

(3) Demodulator: Strip the carrier signal and restore the baseband signal.

In the embodiment of the present invention, the system of the embodiment of the present invention converts different orbital angular momentums into different receiving frequencies by rotating the orbital angular momentums of electromagnetic waves. This reduces the difficulty of receiving and makes it possible to transmit large-capacity and long-distance based on the orbital angular momentum of electromagnetic waves.

The working principle of the wireless transmission system in the embodiment of the present invention will be described in detail below.

As shown in Figure 3, if the spiral phase plate method is used to generate electromagnetic wave orbital angular momentum, then for an electromagnetic wave with a wavelength of λ and a frequency of f, using a medium with a refractive index n to generate an electromagnetic wave with an orbital angular momentum of l, the required The spiral height of is:

Among them, Δh is the height of the spiral, and c is the speed of light.

In order to rotate the orbital angular momentum of electromagnetic waves, a rotating device is needed to rotate the helical phase plate. The principle is shown in Figure 4: the motor 3 drives the helical phase plate 1 to rotate through the belt or gear 2 .

As shown in Figure 5, it is the frequency shift of the signal generated under different rotation speeds and different orbital angular momentums. Among them, in the case of low speed, the speed and orbital angular momentum mode number have the following relationship with the frequency shift of the generated signal:

Δf=l n, (2)

Among them, Δf is the corresponding frequency shift, l is the orbital angular momentum mode number, and n is the rotational speed.

Specifically, as shown in FIG. 2 , it is a schematic diagram of a wireless transmission system based on orbital angular momentum of rotating electromagnetic waves (taking the millimeter wave band as an example). The bit information of the baseband data source 1 is sent to the modulator 4 after being compressed by the source encoder 2 and adding error correction information by the channel encoder 3, and the modulator changes the amplitude, frequency or phase information of the carrier according to the encoded baseband data, Afterwards, the radio frequency unit 5 up-converts the intermediate frequency signal to a desired radio frequency point. The radio frequency signal is fed into the transmitting antenna 6 through the transmission line, and the transmitting antenna converts the guided wave in the transmission line into an electromagnetic wave in free space and radiates it out. The electromagnetic wave beam is converged by the lens 7 to reduce the divergence angle, and then enters the spiral phase plate 8. The helical height of the helical phase plate is calculated by formula (1), and the helical phase plate is rotated by a motor or any other mechanical rotating device 9 to generate orbital angular momentum of rotation. After the electromagnetic wave is transmitted through free space, part of its energy is received by the antenna 10 at the receiving end and sent to the radio frequency unit 11. The radio frequency unit down-converts it to an intermediate frequency and then sends it to the demodulator 12. The demodulator strips the intermediate frequency carrier. The OFDM signal demodulation method restores the encoded baseband data, and then the channel decoder 13 completes the error correction and error detection of the source data, and then the source decoder 14 completes the source decoding, thereby restoring the original baseband signal 15 , to complete a transmission process.

As shown in Figure 6, it is a schematic diagram of a multiplexing transmission system based on orbital angular momentum of rotating electromagnetic waves (taking the millimeter wave band as an example). The signal generator module 1 generates multiple transmission signals at the same time, and each transmission signal passes through a corresponding antenna transmission sub-module 2 to generate a corresponding rotating electromagnetic wave orbital angular momentum signal. The OAM transmitted by each sub-module 2 is different, and the multi-channel signals pass through A plurality of combiner modules 3 combine signals and finally transmit them through the same caliber; after propagation in free space, at the receiving end, the antenna 4 simultaneously receives the multi-channel signals, and then sends them to the signal receiver module 5 to combine the multiple signals. Separate, demodulate, decode and restore the original baseband signal.

In the rotating electromagnetic wave orbital angular momentum wireless transmission system of the embodiment of the present invention, the information data first passes through the signal transmitter, and the signal transmitter completes the encoding and modulation of the baseband data, and then sends the radio frequency signal to the antenna unit through the data line, and the antenna generates a corresponding Electromagnetic wave beam, the electromagnetic beam is incident on the rotating helical phase plate after being converged by the lens, the rotation speed of the helical phase plate is controlled by the rotating device to generate electromagnetic waves with rotational orbital angular momentum, and the electromagnetic waves propagate through free space and then reach the receiving end , the receiving end uses the antenna to receive part of the energy of the electromagnetic wave, and then sends it to the signal receiver. The signal receiver completes the down-conversion, demodulation and decoding of the radio frequency signal, and finally restores the baseband signal, so that the electromagnetic wave can be transmitted in free space. The large capacity and long-distance transmission in the medium reduce the difficulty of reception and greatly improve the spectral efficiency of transmission.

In describing the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " Back", "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inner", "Outer", "Clockwise", "Counterclockwise", "Axial", The orientation or positional relationship indicated by "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying the referred device or element Must be in a particular orientation, be constructed in a particular orientation, and operate in a particular orientation, and therefore should not be construed as limiting the invention.

In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

In the present invention, unless otherwise clearly specified and limited, terms such as "installation", "connection", "connection" and "fixation" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection , or integrated; it may be mechanically connected or electrically connected; it may be directly connected or indirectly connected through an intermediary, and it may be the internal communication of two components or the interaction relationship between two components, unless otherwise specified limit. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

In the present invention, unless otherwise clearly specified and limited, the first feature may be in direct contact with the first feature or the first and second feature may be in direct contact with the second feature through an intermediary. touch. Moreover, "above", "above" and "above" the first feature on the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. "Below", "beneath" and "beneath" the first feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is less horizontally than the second feature.

In the description of this specification, descriptions with reference to the terms "one embodiment", "some embodiments", "example", "specific examples", or "some examples" mean that specific features described in connection with the embodiment or example , structure, material or characteristic is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the described specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without conflicting with each other.

Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention, those skilled in the art can make the above-mentioned The embodiments are subject to changes, modifications, substitutions and variations.

Claims (8)

1. A wireless transmission system for rotating electromagnetic wave orbital angular momentum, characterized in that it comprises: A signal generator subsystem, wherein the signal generator subsystem includes: a modulator, used for performing intermediate frequency modulation on baseband data; a radio frequency transmitting unit, used for up-converting the intermediate frequency signal into a radio frequency signal of a corresponding frequency point; A transmitting antenna subsystem, the transmitting antenna subsystem comprising: a transmitting antenna, used to convert the guided wave on the transmission line into an electromagnetic wave propagated in free space; a lens, the electromagnetic wave is collimated by the lens to reduce the divergence angle; The spiral phase plate is used to change the incident electromagnetic wave into an electromagnetic wave with orbital angular momentum; the rotating device is used to control the rotation of the spiral phase plate to generate a rotating orbital angular momentum electromagnetic wave, and then send it into free space for propagation ;as well as The signal receiver subsystem, the signal receiver subsystem includes: a receiving antenna for converting the rotating orbital angular momentum electromagnetic wave propagating in free space into a guided wave in a transmission line; a radio frequency receiving unit for converting the The radio frequency signal received by the receiving antenna is down-converted to an intermediate frequency; the demodulator, the transmitting antenna subsystem simultaneously generates multiple electromagnetic waves with orbital angular momentum, which generate different frequency offsets at the receiving end after rotation, and the demodulator uses The demodulation method of Orthogonal Frequency Division Multiplexing (OFDM) signal completes the demodulation of the signal. 2. The wireless transmission system of rotational electromagnetic wave orbital angular momentum according to claim 1, wherein the electromagnetic wave includes one or more of light waves, microwaves, millimeter waves and terahertz waves. 3. The wireless transmission system of rotating electromagnetic wave orbital angular momentum as claimed in claim 1, wherein the principle of rotating the electromagnetic wave with orbital angular momentum is to rotate the phase distribution on the aperture surface of the antenna. 4. The wireless transmission system of rotating electromagnetic wave orbital angular momentum according to claim 3, wherein the rotating device can be a motor or any other type of mechanical rotating device. 5. The rotating electromagnetic wave orbital angular momentum wireless transmission system according to claim 1, characterized in that there is at least one transmitting antenna subsystem. 6. The rotating electromagnetic wave orbital angular momentum wireless transmission system as claimed in claim 1, wherein said transmitting antenna and said receiving antenna are horn antennas, parabolic antennas, Cassegolian antennas, patch antennas, and array antennas any kind of antenna. 7. The wireless transmission system of rotating electromagnetic wave orbital angular momentum as claimed in claim 1, wherein the manufacturing materials of the spiral phase plate include high-density polyethylene, polypropylene, polymethylpentene (TPX) and other materials one or more of. 8. The wireless transmission system of rotational electromagnetic wave orbital angular momentum as claimed in claim 7, wherein the spiral phase plate can adopt any shape and material to generate electromagnetic waves with orbital angular momentum.