A large aperture high power pseudo-bessel beam generation method and generation device

Abstract

The application relates to a large-diameter high-power pseudo-Bessel beam generation method and a generation device, and belongs to the technical field of communication. The method comprises the following steps: S100, an electromagnetic beam output by a feed horn is propagated to a first reflecting surface, and a target pseudo-Bessel beam is reversely propagated to a second reflecting surface; S200, the electromagnetic beam is propagated to the second reflecting surface through the first reflecting surface, a phase difference on the second reflecting surface is obtained, and a deformation variable of the second reflecting surface is updated; S300, the target pseudo-Bessel beam is propagated to the first reflecting surface through the second reflecting surface, a phase difference on the first reflecting surface is obtained, and a deformation variable of the first reflecting surface is updated; and S400, steps S100 to S300 are repeated until the relative field distribution of the output electromagnetic beam and the target pseudo-Bessel beam reaches a stable state, and a large-diameter high-power pseudo-Bessel beam is obtained. The application can solve the technical problems of existing media loss and limited power capacity.

Description

Technical Field

[0001] This invention belongs to the field of communication technology, and specifically relates to a method and apparatus for generating a large-aperture, high-power pseudo-Bessel beam. Background Technology

[0002] With the rise of near-field antennas in microwave imaging, wireless power transmission, and other fields in recent years, diffraction-free beams have received extensive research attention due to their advantages such as large depth of field, no diffraction loss within a certain area during propagation, and beam self-healing. The ideal Bessel beam is the most famous type of diffraction-free beam; it is a particular solution of the wave equation in cylindrical coordinates, requiring an infinitely large antenna aperture. In practical applications, antenna apertures are finite; therefore, how to generate high-quality pseudo-Bessel beams with finite apertures has become one of the research hotspots in this field.

[0003] Currently, there are various methods to generate pseudo-Bessel beams, mainly including transmission prisms, metasurfaces, leaky antenna arrays, slot antenna arrays, reflective array antennas, and near-field reflectors. The following are the disadvantages of these technologies: they often have dielectric losses, which reduce transmission efficiency; the generated pseudo-Bessel beam has a limited aperture electrical size, resulting in a short non-diffraction region; and the power capacity of slot antenna arrays, leaky antenna arrays, or devices using phase shifting devices is limited, which cannot meet the application requirements of high-power transmission. Summary of the Invention

[0004] To address the shortcomings of existing technologies, a method and apparatus for generating large-aperture, high-power pseudo-Bessel beams are proposed to solve the technical problems of dielectric loss and limited power capacity in existing technologies.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] In a first aspect, the present invention provides a method for generating a large-aperture, high-power pseudo-Bessel beam, comprising the following steps:

[0007] S100, the electromagnetic beam output by the feed horn propagates to the first reflecting surface, and the target pseudo Bessel beam propagates in the opposite direction to the second reflecting surface;

[0008] S200. The electromagnetic beam propagates through the first reflecting surface to the second reflecting surface, obtaining the phase difference on the second reflecting surface and updating the deformation of the second reflecting surface.

[0009] S300, the target pseudo-Bessel beam propagates to the first reflecting surface through the second reflecting surface, obtains the phase difference on the first reflecting surface, and updates the deformation of the first reflecting surface;

[0010] S400, Repeat steps S100 to S300 until the relative field distribution between the output electromagnetic beam and the target pseudo-Bessel beam reaches a stable state, thus obtaining a large-aperture high-power pseudo-Bessel beam.

[0011] The technical solution is further configured such that both the first reflecting surface and the second reflecting surface are shaped reflecting surface antennas, and their surfaces are irregular curved surfaces.

[0012] This technical solution is further configured such that, in step S200, obtaining the phase difference on the second reflecting surface specifically involves:

[0013] The electromagnetic beam output from the feed horn propagates to the first reflecting surface, and the field distribution of the first reflecting surface is set as follows: The electromagnetic beam propagates from the first reflecting surface to the second reflecting surface, and the field distribution of the second reflecting surface is set as follows: Update the field phase distribution of the second reflecting surface. ;

[0014] The target pseudo-Bessel beam propagates in the back direction to the second reflecting surface, and the field distribution of the second reflecting surface is set as follows: ,use The phase difference of the second reflecting surface is obtained. .

[0015] This technical solution is further configured such that, in step S200, updating the deformation of the second reflecting surface specifically involves:

[0016] use The deformation of the second reflecting surface is obtained. And update, where k is the wave vector, The angle of incidence of the electromagnetic beam on the second reflecting surface is denoted as .

[0017] This technical solution is further configured such that, in step S300, obtaining the phase difference on the first reflecting surface specifically involves:

[0018] The target pseudo-Bessel beam propagates in the back direction to the second reflecting surface, and the field distribution of the second reflecting surface is set as follows: The target pseudo-Bessel beam propagates from the second reflecting surface to the first reflecting surface, and the field distribution of the first reflecting surface is set as follows: Update the field phase distribution of the first reflecting surface. ;

[0019] The electromagnetic beam output from the feed horn propagates to the first reflecting surface, and the field distribution of the first reflecting surface is set as follows: ,use The phase difference of the first reflecting surface is obtained. .

[0020] This technical solution is further configured such that, in step S300, updating the deformation of the first reflecting surface specifically involves:

[0021] use The deformation of the first reflecting surface is obtained. And update, where k is the wave vector, The angle of incidence of the electromagnetic beam on the first reflecting surface is denoted as .

[0022] This technical solution is further configured such that, in step S400, the relative field distribution between the output electromagnetic beam and the target pseudo-Bessel beam reaches a stable state, specifically:

[0023] The vector correlation coefficient between the electromagnetic beam field distribution reflected by the second reflecting surface and the target pseudo-Bessel beam field distribution reaches the set threshold.

[0024] This technical solution is further configured such that the deformation of the first and second reflecting surfaces causes a change in the electromagnetic beam field distribution, then: Where U0 is the incident electromagnetic beam field distribution, U m The electromagnetic beam field distribution after deformation, where k is the wave vector. The deformation of the first reflecting surface and the second reflecting surface. The incident angles of the electromagnetic beam at the first and second reflecting surfaces.

[0025] Secondly, the present invention provides a large-aperture, high-power pseudo-Bessel beam generating device, comprising:

[0026] A feed horn, used to output an electromagnetic beam;

[0027] Shaped reflector, which is used to reflect the electromagnetic beam output from the feed horn multiple times and convert it into a pseudo Bessel beam;

[0028] The aperture surface is used to output the electromagnetic beam after it has been deformed by the shaped reflector. The electromagnetic field amplitude distribution at the aperture surface is a Bessel function, and its phase distribution is a conical wavefront.

[0029] The technical solution is further configured such that the shaped reflective surface includes a first reflective surface and a second reflective surface, and the electromagnetic beam propagates sequentially to the first reflective surface, the second reflective surface and the aperture surface. The first reflective surface and the second reflective surface are both shaped reflective surface antennas, and their surfaces are both irregular curved surfaces.

[0030] The beneficial effects of this invention are:

[0031] Constructing a multi-reflector system allows electromagnetic waves to propagate in free space, with only ohmic losses from the reflectors, eliminating the need for dielectric materials and phase-shifting devices. This results in high transmission efficiency and high power capacity. It also enables large-aperture systems, reducing aperture cutoff and significantly increasing the diffraction-free region of pseudo-Bessel beams. Furthermore, it offers strong versatility, with quasi-optical transmission-based techniques covering frequencies from microwave to terahertz. Attached Figure Description

[0032] Figure 1 This is a flowchart of the method for generating large-aperture high-power pseudo-Bessel beams in an embodiment of the present invention.

[0033] Figure 2 This is a schematic diagram illustrating the propagation direction of the electromagnetic beam and the target pseudo-Bessel beam in an embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of the phase correction model of the reflecting surface in an embodiment of the present invention;

[0035] Figure 4(a) is a schematic diagram comparing the actual aperture distribution of the pseudo Bessel beam generated by the embodiment of the present invention with the amplitude distribution of the target pseudo Bessel beam;

[0036] Figure 4(b) is a schematic diagram comparing the actual aperture distribution of the pseudo Bessel beam generated by the embodiment of the present invention with the phase distribution of the target pseudo Bessel beam;

[0037] Figure 5 This is a schematic diagram of a large-aperture, high-power pseudo-Bessel beam generating device in an embodiment of the present invention;

[0038] Figure 6(a) is a one-dimensional amplitude distribution curve (radial schematic diagram) of the target pseudo Bessel beam in an embodiment of the present invention.

[0039] Figure 6(b) is a one-dimensional phase distribution curve (radial schematic diagram) of the target pseudo-Bessel beam in an embodiment of the present invention. Detailed Implementation

[0040] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Based on the embodiments in this application, other similar embodiments obtained by those skilled in the art without creative effort should all fall within the scope of protection of this application. Furthermore, directional terms mentioned in the following embodiments, such as "up," "down," "left," and "right," are only for reference to the directions in the accompanying drawings; therefore, the directional terms used are for illustrative purposes and not for limiting the invention.

[0041] According to an embodiment of the present invention, a method for generating a large-aperture, high-power pseudo-Bessel beam is provided. Please refer to [link to relevant documentation]. Figures 1 to 2 This includes the following steps:

[0042] S100, the electromagnetic beam output by the feed horn propagates to the first reflecting surface, and the target pseudo Bessel beam propagates in the opposite direction to the second reflecting surface;

[0043] S200. The electromagnetic beam propagates through the first reflecting surface to the second reflecting surface, obtaining the phase difference on the second reflecting surface and updating the deformation of the second reflecting surface.

[0044] S300, the target pseudo-Bessel beam propagates to the first reflecting surface through the second reflecting surface, obtains the phase difference on the first reflecting surface, and updates the deformation of the first reflecting surface;

[0045] S400, Repeat steps S100 to S300 until the relative field distribution between the output electromagnetic beam and the target pseudo-Bessel beam reaches a stable state, thus obtaining a large-aperture high-power pseudo-Bessel beam.

[0046] For the large-aperture, high-power pseudo-Bessel beam generation method described in this embodiment, please refer to [link to relevant documentation]. Figures 1 to 3 Both the first and second reflecting surfaces are shaped reflector antennas, with irregular curved surfaces on their surfaces. Specifically, the first and second reflecting surfaces are collectively referred to as reflecting surfaces, and the phase correction model for the reflecting surfaces is as follows: Figure 3 As shown.

[0047] According to diffraction theory, the field distribution of the target region can be obtained from the source field distribution, as shown in equation (1):

[0048] (1)

[0049] in, For free space Green's function, For the source field distribution, For the field distribution of the target region, The coordinates of the source point, Let be the field point coordinates, and s represent the surface of the reflecting surface.

[0050] Meanwhile, when the incident electromagnetic beam is reflected by the reflecting surface, the field distribution changes due to the deformation of the reflecting surface, as shown in equation (2):

[0051] (2)

[0052] in, The imaginary unit, This represents the phase difference.

[0053] The phase distribution resulting from the propagation distance of electromagnetic waves can be obtained from equation (3):

[0054] (3)

[0055] in, The angle of incidence of the electromagnetic beam on the reflecting surface. It is the wave vector.

[0056] Therefore, the change in field distribution caused by the deformation of the reflecting surface can be obtained from equation (4):

[0057] (4)

[0058] Where U0 is the incident electromagnetic beam field distribution, U m The electromagnetic beam field distribution after deformation, where k is the wave vector. This represents the deformation of the reflecting surface.

[0059] For the large-aperture, high-power pseudo-Bessel beam generation method described in this embodiment, please refer to [link to relevant documentation]. Figures 1 to 2 In step S200, obtaining the phase difference on the second reflecting surface specifically involves:

[0060] The electromagnetic beam output from the feed horn propagates to the first reflecting surface, and the field distribution of the first reflecting surface is set as follows: The electromagnetic beam propagates from the first reflecting surface to the second reflecting surface, and the field distribution of the second reflecting surface is set as follows: Update the field phase distribution of the second reflecting surface. ;

[0061] The target pseudo-Bessel beam propagates in the back direction to the second reflecting surface, and the field distribution of the second reflecting surface is set as follows: ,use The phase difference of the second reflecting surface is obtained. .

[0062] For the large-aperture, high-power pseudo-Bessel beam generation method described in this embodiment, please refer to [link to relevant documentation]. Figures 1 to 2 In step S200, updating the deformation of the second reflecting surface specifically involves:

[0063] Formula for phase distribution caused by electromagnetic wave propagation distance The deformation of the second reflecting surface is obtained. Where k is the wave vector, The angle of incidence of the electromagnetic beam on the second reflecting surface is denoted as .

[0064] For the large-aperture, high-power pseudo-Bessel beam generation method described in this embodiment, please refer to [link to relevant documentation]. Figures 1 to 2 In step S300, obtaining the phase difference on the first reflecting surface specifically involves:

[0065] The target pseudo-Bessel beam propagates in the back direction to the second reflecting surface, and the field distribution of the second reflecting surface is set as follows: The target pseudo-Bessel beam propagates from the second reflecting surface to the first reflecting surface, and the field distribution of the first reflecting surface is set as follows: Update the field phase distribution of the first reflecting surface. ;

[0066] The electromagnetic beam output from the feed horn propagates to the first reflecting surface, and the field distribution of the first reflecting surface is set as follows: ,use The phase difference of the first reflecting surface is obtained. .

[0067] For the large-aperture, high-power pseudo-Bessel beam generation method described in this embodiment, please refer to [link to relevant documentation]. Figures 1 to 2 In step S300, updating the deformation of the first reflecting surface specifically involves:

[0068] Formula for phase distribution caused by electromagnetic wave propagation distance The deformation of the first reflecting surface is obtained. Where k is the wave vector, The angle of incidence of the electromagnetic beam on the first reflecting surface is denoted as .

[0069] For the large-aperture, high-power pseudo-Bessel beam generation method described in this embodiment, please refer to [link to relevant documentation]. Figures 1 to 2 In step S400, the relative field distribution between the output electromagnetic beam and the target pseudo-Bessel beam reaches a stable state, specifically as follows:

[0070] The vector correlation coefficient between the electromagnetic beam field distribution reflected by the second reflecting surface and the target pseudo-Bessel beam field distribution reaches the set threshold.

[0071] Specifically, the vector correlation coefficient C cs The expression is:

[0072] , where A x For the output electromagnetic field amplitude distribution, B x For the target pseudo-Bessel beam amplitude distribution, The phase distribution of the output electromagnetic field. The target pseudo-Bessel beam phase distribution;

[0073] The principle for setting the threshold is greater than or equal to 99%.

[0074] For the large-aperture, high-power pseudo-Bessel beam generation method described in this embodiment, please refer to [link to relevant documentation]. Figures 1 to 2 The deformation of the first and second reflecting surfaces causes a change in the electromagnetic beam field distribution, therefore: Where U0 is the incident electromagnetic beam field distribution, U m The electromagnetic beam field distribution after deformation, where k is the wave vector. The deformation of the first reflecting surface and the second reflecting surface. The incident angles of the electromagnetic beam at the first and second reflecting surfaces.

[0075] Without using dielectric materials or phase-shifting devices that affect power capacity, it boasts advantages such as high transmission efficiency and high power capacity. Employing reflector shaping synthesis technology, a multi-reflector system is constructed, allowing electromagnetic waves to propagate in free space with only ohmic losses at the reflectors. It enables large-aperture antennas (aperture greater than 100 times the wavelength), reducing aperture truncation and significantly increasing the diffraction-free region of the pseudo-Bessel beam. It is highly versatile, with quasi-optical transmission-based techniques covering frequencies from microwave to terahertz. Using these methods, a large-aperture, high-power pseudo-Bessel beam is obtained, with a vector correlation coefficient exceeding 99% between its aperture distribution and the target pseudo-Bessel beam field distribution, as shown in Figures 4(a), 4(b), 6(a), and 6(b). It should be noted that the antenna aperture is 100 times the free-space wavelength, classifying it as a large-aperture antenna. Currently, no antennas with similar large apertures generating Bessel beams have been observed in the microwave and millimeter-wave bands.

[0076] According to an embodiment of the present invention, a large-aperture, high-power pseudo-Bessel beam generator is provided. (See also...) Figure 5 ,include:

[0077] A feed horn, used to output an electromagnetic beam;

[0078] Shaped reflector, which is used to reflect the electromagnetic beam output from the feed horn multiple times and convert it into a pseudo Bessel beam;

[0079] The aperture surface is used to output the electromagnetic beam after it has been deformed by the shaped reflector. The electromagnetic field amplitude distribution at the aperture surface is a Bessel function, and its phase distribution is a conical wavefront.

[0080] It should be noted that the electromagnetic beam after transmission transformation through the shaped reflector will form a pseudo-Bessel beam at the aperture surface. The Bessel function of the aperture surface is the pseudo-Bessel beam distribution, thereby obtaining the non-diffraction region of the focused beam.

[0081] For the large-aperture, high-power pseudo-Bessel beam generator in this embodiment, please refer to [link / reference needed]. Figure 5 The shaped reflector includes a first reflector and a second reflector. The electromagnetic beam propagates sequentially to the first reflector, the second reflector, and the aperture surface. Both the first reflector and the second reflector are shaped reflector antennas, and their surfaces are irregular curved surfaces.

[0082] The present invention has been described in detail above. The above description is only a preferred embodiment of the present invention and should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made in accordance with the scope of this application should still fall within the scope of the present invention.

Claims

1. A method for generating a large-aperture, high-power pseudo-Bessel beam, characterized in that, Includes the following steps: S100, the electromagnetic beam output by the feed horn propagates to the first reflecting surface, and the target pseudo Bessel beam propagates in the opposite direction to the second reflecting surface; S200. The electromagnetic beam propagates through the first reflecting surface to the second reflecting surface, obtaining the phase difference on the second reflecting surface and updating the deformation of the second reflecting surface. Calculate the phase distribution of the electromagnetic beam on the second reflecting surface. Phase distribution of the target pseudo-Bessel beam on the second reflecting surface phase difference between ,in k is the wave number. The deformation of the second reflecting surface, The angle of incidence of the electromagnetic beam on the second reflecting surface; S300, the target pseudo-Bessel beam propagates to the first reflecting surface through the second reflecting surface, obtains the phase difference on the first reflecting surface, and updates the deformation of the first reflecting surface; Calculate the phase distribution of the electromagnetic beam on the first reflecting surface. Phase distribution of the target pseudo-Bessel beam on the first reflecting surface phase difference between ,in k is the wave number. The deformation of the first reflecting surface, The angle of incidence of the electromagnetic beam at the first reflecting surface; S400, Repeat steps S100 to S300 until the relative field distribution between the output electromagnetic beam and the target pseudo-Bessel beam reaches a stable state, thus obtaining a large-aperture high-power pseudo-Bessel beam, which has a Bessel function magnetic field amplitude distribution and a conical wavefront phase distribution. Specifically: The vector correlation coefficient between the electromagnetic beam field distribution reflected by the second reflecting surface and the target pseudo-Bessel beam field distribution reaches a set threshold, with the threshold set according to the principle of being greater than or equal to 99%. Vector correlation coefficient C cs The expression is: , where A x For the output electromagnetic field amplitude distribution, B x For the target pseudo-Bessel beam amplitude distribution, The phase distribution of the output electromagnetic field. The phase distribution of the target pseudo-Bessel beam.

2. The method for generating a large-aperture, high-power pseudo-Bessel beam according to claim 1, characterized in that, Both the first and second reflective surfaces are shaped reflective antennas, and their surfaces are irregular curved surfaces.

3. The method for generating a large-aperture, high-power pseudo-Bessel beam according to claim 1, characterized in that, In step S200, obtaining the phase difference on the second reflecting surface specifically involves: The electromagnetic beam output from the feed horn propagates to the first reflecting surface, and the field distribution of the first reflecting surface is set as follows: The electromagnetic beam propagates from the first reflecting surface to the second reflecting surface, and the field distribution of the second reflecting surface is set as follows: Update the field phase distribution of the second reflecting surface. ; The target pseudo-Bessel beam propagates in the back direction to the second reflecting surface, and the field distribution of the second reflecting surface is set as follows: ,use The phase difference of the second reflecting surface is obtained. .

4. The method for generating a large-aperture, high-power pseudo-Bessel beam according to claim 3, characterized in that, In step S300, obtaining the phase difference on the first reflecting surface specifically involves: The target pseudo-Bessel beam propagates in the back direction to the second reflecting surface, and the field distribution of the second reflecting surface is set as follows: The target pseudo-Bessel beam propagates from the second reflecting surface to the first reflecting surface, and the field distribution of the first reflecting surface is set as follows: Update the field phase distribution of the first reflecting surface. ; The electromagnetic beam output from the feed horn propagates to the first reflecting surface, and the field distribution of the first reflecting surface is set as follows: ,use The phase difference of the first reflecting surface is obtained. .

5. The method for generating a large-aperture, high-power pseudo-Bessel beam according to claim 4, characterized in that, The deformation of the first and second reflecting surfaces causes a change in the electromagnetic beam field distribution, therefore: Where U0 is the incident electromagnetic beam field distribution, U m The electromagnetic beam field distribution after deformation, where k is the wave vector. The deformation of the first reflecting surface and the second reflecting surface. The incident angles of the electromagnetic beam at the first and second reflecting surfaces.

6. An apparatus for implementing the large-aperture high-power pseudo-Bessel beam generation method according to any one of claims 1-5, characterized in that, include: A feed horn, used to output an electromagnetic beam; Shaped reflector, which is used to reflect the electromagnetic beam output from the feed horn multiple times and convert it into a pseudo Bessel beam; The aperture surface is used to output the electromagnetic beam after it has been deformed by the shaped reflector. The electromagnetic field amplitude distribution at the aperture surface is a Bessel function, and its phase distribution is a conical wavefront.

7. The apparatus according to claim 6, characterized in that, The shaped reflector includes a first reflector and a second reflector. The electromagnetic beam propagates sequentially to the first reflector, the second reflector, and the aperture surface. Both the first reflector and the second reflector are shaped reflector antennas, and their surfaces are irregular curved surfaces.

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