A method and system for implementing a millimeter wave ring beam

Abstract

This invention provides a method and system for realizing millimeter-wave ring beams, belonging to the field of millimeter-wave transmission and near-field beamforming technology. It solves the problem in existing technologies that there is no research on the feasibility and implementation method of ring beams to improve the power capacity of the dielectric window. The method includes: S1, constructing a phase correction model for the ring beam realization system; S2, based on the phase correction model, performing a mirror design process for the two sets of reflectors in the ring beam realization system; S3, after completing the mirror design process, obtaining a first set of reflectors and a second set of reflectors; S4, arranging the first set of reflectors and the second set of reflectors in the system, placing the dielectric window between the first set of reflectors and the second set of reflectors, and realizing a millimeter-wave ring beam at the dielectric window by mode transformation of the electromagnetic wave beam through the reflector sets. This invention reduces the peak field strength and maximum temperature rise while maintaining existing hardware costs, significantly increasing the transmission power at the dielectric window.

Description

Technical Field

[0001] This invention belongs to the field of millimeter-wave transmission and near-field shaping technology, specifically a method and system for realizing millimeter-wave ring beams. Background Technology

[0002] In experimental research on magnetically confined thermonuclear fusion, high-power millimeter waves are required for electron cyclotron resonance heating. These high-power millimeter waves are generated by a millimeter-wave source, and must pass through a dielectric window to isolate the vacuum before entering the transmission line for efficient transmission. Due to dielectric losses during this process, the high-power millimeter waves continuously heat the dielectric window during transmission. Since the electromagnetic wave power output from the millimeter-wave source is typically close to the megawatt level, stringent requirements are placed on the dielectric window, making its management crucial in experiments.

[0003] In current high-power millimeter-wave transmission systems, a fundamental-mode Gaussian beam is typically formed at the dielectric window. The field distribution of this beam is Gaussian, with the maximum power density located at the center of the dielectric window, which hinders edge liquid cooling. This results in a maximum theoretical power capacity of only 2MW, even when diamond is used as the dielectric window material. To improve the power capacity of the dielectric window, researchers have studied several electromagnetic wave distribution methods. They believe that a ring beam can reduce the peak field strength and facilitate radial heat conduction, enabling edge liquid cooling and potentially significantly increasing the power capacity at the dielectric window.

[0004] However, current research only focuses on the temperature rise under different electromagnetic field distributions on the dielectric window, and has not yet studied the feasibility and implementation methods of ring beams. How to obtain ring beams on existing electron cyclotron resonance systems without increasing hardware costs and system complexity has become a core research focus for those skilled in the art. Summary of the Invention

[0005] In order to break through and solve the research problems mentioned in the background art, the present invention will achieve the effect of the ring distribution of electromagnetic field at the dielectric window without increasing the complexity and cost of the existing electron cyclotron resonance system. Therefore, it can greatly improve the power capacity in the weak dielectric window region of the whole system, while maintaining very low transmission loss.

[0006] The present invention employs the following technical solutions to achieve its objective:

[0007] A method for implementing millimeter-wave loop beams includes the following steps:

[0008] S1. Construct a phase correction model for the ring beam system;

[0009] S2. Based on the phase correction model, perform the mirror design process for the two sets of reflectors in the ring beam realization system.

[0010] S3. After completing the mirror design process, the first and second mirror groups are obtained.

[0011] S4. Arrange the first and second mirror groups in the ring beam realization system, and place the dielectric window between the first and second mirror groups. The millimeter-wave ring beam can be realized at the dielectric window.

[0012] In S3, after the mirror design process is completed, the first mirror group will enter the ring beam to realize the paraxial complex beam transformation of the system into a ring beam and output it to the dielectric window; after the mirror design process is completed, the second mirror group will transform the ring beam leaving the dielectric window into a fundamental mode Gaussian beam and couple it into the corrugated waveguide transmission line, completing the process of millimeter wave generation and entry into the transmission line.

[0013] Furthermore, the construction process of the phase correction model in S1 is as follows:

[0014] Based on the electromagnetic wave diffraction theory, the field distribution of the target region at the dielectric window is obtained through the source field distribution, as shown in the following equation:

[0015]

[0016] In the formula, It is a free-space Green's function; It is the source field distribution; This refers to the field distribution in the target region. When the incident electromagnetic wave is reflected by the mirror, the change in field distribution due to mirror deformation is as follows:

[0017] U m =U0exp(jkΔΦ)

[0018] In the formula, k is the wave number; U m It is the change in field distribution; U0 is the incident field distribution; ΔΦ is the change in phase distribution; the change in phase distribution ΔΦ due to the propagation distance of the electromagnetic wave is as follows:

[0019] ΔΦ=2kΔz cos(θ)

[0020] In the formula, Δ z θ is the change in electromagnetic wave propagation distance; θ is the incident electromagnetic wave angle; based on the above three equations, the final change in field distribution caused by the deformation of the reflecting surface is as follows:

[0021] U m =U0exp(j2kΔz cos(θ))

[0022] This formula is the expression for the phase correction model.

[0023] Furthermore, the first reflector group includes a first reflector and a second reflector, both of which are phase correction mirrors; the specific steps of the mirror design process for the first reflector group are as follows:

[0024] A1. Position the first and second reflectors so that the outgoing beam of the first reflector is the incoming beam of the second reflector.

[0025] A2. The electromagnetic wave input field is propagated to the first reflecting mirror, and the field distribution of the first reflecting mirror is A(x)exp(jΦ(x));

[0026] A3. The target beam is propagated to the second reflecting mirror, and the field distribution of the second reflecting mirror is as follows:

[0027] A4. Begin the iterative process, propagating the electromagnetic wave from the first reflecting mirror to the second reflecting mirror, and obtain... renew Parameter values;

[0028] A5. According to The phase difference on the second mirror is obtained. Using the phase distribution ΔΦ = 2kΔz cos(θ) in the phase correction model, ΔΦ is then... Update the mirror surface shape of the second reflecting mirror;

[0029] A6. Propagate the electromagnetic wave on the second mirror to the first mirror to obtain D(x)exp(jΦ′(x)); update the parameter value of Φ′(x);

[0030] A7. Based on ΔΦ=Φ(x)-Φ′(x), the phase difference on the second mirror is obtained again. Using the phase distribution ΔΦ=2kΔz cos(θ) in the phase correction model, the mirror surface shape of the first mirror is updated.

[0031] A8. When the output field distribution of the second reflector is consistent with the field distribution of the target area, exit the iterative loop process and complete the mirror design process of the first reflector group.

[0032] This invention also provides a millimeter-wave ring beam realization system, comprising a millimeter-wave source, a first mirror group, a dielectric window, a second mirror group, and a corrugated waveguide transmission line arranged sequentially on the millimeter-wave transmission path; the millimeter-wave source is used to generate a paraxial complex beam, the first mirror group is used to transform the incoming paraxial complex beam into a ring beam and then apply it to the dielectric window; the second mirror group is used to transform the ring beam entering after passing through the dielectric window into a fundamental mode Gaussian beam and couple it into the corrugated waveguide transmission line.

[0033] In summary, due to the adoption of this technical solution, the beneficial effects of this invention are as follows:

[0034] This invention achieves a ring-shaped electromagnetic field distribution at the dielectric window without increasing the complexity and cost of existing electron cyclotron resonance systems, significantly improving the transmission power capacity of the electron cyclotron resonance heating system while maintaining efficient transmission. The main advantages of this invention include: 1. Reducing the peak field strength at the dielectric window, minimizing secondary electron emission effects that may be caused by window defects; 2. For edge liquid-cooled windows, reducing the radial heat dissipation path of the dielectric window, thus reducing the maximum temperature rise at the dielectric window; 3. High conversion efficiency with very low transmission loss. Based on the research concept, system, and methodological approach proposed in this invention, it is relatively convenient to use equations such as scalar diffraction theory, vector diffraction theory, or electromagnetic field transmission equations to complete the process of this invention, demonstrating excellent operability. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the structural principle of the system of the present invention;

[0036] Figure 2 This is a schematic flowchart of the method of the present invention;

[0037] Figure 3 This is a schematic diagram of the phase correction model;

[0038] Figure 4 for Figure 3 A magnified illustration of region S in the diagram.

[0039] The meanings of the markings in the attached diagram are as follows:

[0040] 1-Millimeter wave source, 2-First reflector group, 21-First reflector, 22-Second reflector, 3-Dielectric window, 4-Second reflector group, 41-Third reflector, 42-Fourth reflector, 5-Corrugated waveguide transmission line. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0042] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0043] Example 1

[0044] A method for implementing millimeter-wave loop beams can be found here. Figure 2 The flowchart illustrates the process, including the following steps:

[0045] S1. Construct a phase correction model for the ring beam system;

[0046] S2. Based on the phase correction model, carry out the mirror design process for the two sets of reflectors in the ring beam realization system;

[0047] S3. After completing the mirror design process, the first and second mirror groups are obtained.

[0048] S4. Arrange the first and second reflector groups in the ring beam realization system, and place the medium window between the first and second reflector groups. The millimeter-wave ring beam can be realized at the medium window.

[0049] In step S3, after the mirror design process is completed, the first mirror group will enter the ring beam to realize the paraxial complex beam transformation of the system into a ring beam and output it to the dielectric window; after the mirror design process is completed, the second mirror group will transform the ring beam leaving the dielectric window into a fundamental mode Gaussian beam and couple it into the corrugated waveguide transmission line, completing the process of millimeter wave generation and entry into the transmission line.

[0050] In this embodiment, the paraxial complex beam is generated by a millimeter-wave source and then directly enters the ring beam realization system.

[0051] The following section focuses on the specific details of the phase correction model and mirror design process in this embodiment; please refer to [link / reference needed]. Figure 3 and Figure 4 The specific process of constructing the phase correction model in step S1 is as follows:

[0052] Based on the electromagnetic wave diffraction theory, the field distribution of the target region at the dielectric window is obtained through the source field distribution, as shown in the following equation:

[0053]

[0054] In the formula, It is a free-space Green's function; It is the source field distribution; This refers to the field distribution in the target region. When the incident electromagnetic wave is reflected by the mirror, the change in field distribution due to mirror deformation is as follows:

[0055] U m =U0exp(jkΔΦ)

[0056] In the formula, k is the wave number; U m It is the change in field distribution; U0 is the incident field distribution; ΔΦ is the change in phase distribution; the change in phase distribution ΔΦ due to the propagation distance of the electromagnetic wave is as follows:

[0057] ΔΦ=2kΔz cos(θ)

[0058] In the formula, Δ z θ is the change in electromagnetic wave propagation distance; θ is the incident electromagnetic wave angle; based on the above three equations, the final change in field distribution caused by the deformation of the reflecting surface is as follows:

[0059] U m =U0exp(j2kΔz cos(θ))

[0060] This formula is the expression for the phase correction model.

[0061] In this embodiment, the mirror design process is as follows: In the mirror design processes of S2 and S3, the design processes for the first and second mirror groups are the same. Therefore, this embodiment will take the first mirror group as an example for detailed explanation. In the mirror design process, the mirror surface shape of each mirror in the first and second mirror groups is continuously updated in an iterative manner until the output field distribution of the first mirror group and the input field distribution of the second mirror group are the same as the field distribution of the target area.

[0062] The first mirror assembly includes a first mirror and a second mirror, both of which are phase-correcting mirrors. The specific steps in the mirror design process for the first mirror assembly are as follows:

[0063] A1. Position the first and second reflectors so that the outgoing beam of the first reflector is the incoming beam of the second reflector; the placement of the first and second reflectors in this embodiment is as follows: Figure 1 The diagram illustrates that the two are positioned similarly to a periscope.

[0064] A2. The electromagnetic wave input field is propagated to the first reflecting mirror, and the field distribution of the first reflecting mirror is A(x)exp(jΦ(x));

[0065] A3. The target beam is propagated to the second reflecting mirror, and the field distribution of the second reflecting mirror is as follows:

[0066] A4. Begin the iterative process, propagating the electromagnetic wave from the first reflecting mirror to the second reflecting mirror, and obtain... renew Parameter values;

[0067] A5. According to The phase difference on the second mirror is obtained. Using the phase distribution ΔΦ = 2kΔz cos(θ) in the phase correction model, ΔΦ is then... Update the mirror surface shape of the second reflecting mirror;

[0068] A6. Propagate the electromagnetic wave on the second mirror to the first mirror to obtain D(x)exp(jΦ′(x)); update the parameter value of Φ′(x);

[0069] A7. Based on ΔΦ=Φ(x)-Φ′(x), the phase difference on the second mirror is obtained again. Using the phase distribution ΔΦ=2kΔz cos(θ) in the phase correction model, the mirror surface shape of the first mirror is updated.

[0070] A8. When the output field distribution of the second reflector is consistent with the field distribution of the target area, exit the iterative loop process and complete the mirror design process of the first reflector group.

[0071] In the method of this embodiment, specifically, the first reflector group includes a first reflector and a second reflector, and the second reflector group includes a third reflector and a fourth reflector; the first reflector, the second reflector, the third reflector and the fourth reflector are all phase correction mirrors with irregular curved surfaces.

[0072] Example 2

[0073] Based on Example 1, this example introduces a millimeter-wave ring beam implementation system, which can be found in the following document. Figure 1 The system includes a millimeter-wave source 1, a first reflector group 2, a dielectric window 3, a second reflector group 4, and a corrugated waveguide transmission line 5, which are sequentially arranged on the millimeter-wave transmission path. The millimeter-wave source 1 is used to generate a paraxial complex beam. The first reflector group 2 is used to transform the incoming paraxial complex beam into a ring beam and then apply it to the dielectric window 3. The second reflector group 4 is used to transform the ring beam that enters after passing through the dielectric window 3 into a fundamental mode Gaussian beam and couple it into the corrugated waveguide transmission line 5.

[0074] In this embodiment, the first reflector group 2 includes a first reflector 21 and a second reflector 22; the outgoing beam of the first reflector 21 is the incoming beam of the second reflector 22; the first reflector 21 is used to receive the input of the paraxial complex beam, and the second reflector 22 is used to output a ring beam to the dielectric window 3.

[0075] In this embodiment, the second reflector group 4 includes a third reflector 41 and a fourth reflector 42; the output beam of the third reflector 41 is the incident beam of the fourth reflector 42; the third reflector 41 is used to receive the input of the ring beam at the dielectric window, and the fourth reflector 42 is used to couple the output fundamental mode Gaussian beam to the corrugated waveguide transmission line 5.

Claims

1. A method for realizing millimeter-wave loop beams, characterized in that, The method comprises the following steps: S1, constructing a phase correction model of a ring beam implementation system; S2, performing a mirror surface design process of two groups of mirrors in the ring beam implementation system according to the phase correction model; S3, obtaining a first mirror group and a second mirror group after the mirror surface design process is completed; S4, arranging the first mirror group and the second mirror group in the ring beam implementation system, and arranging a medium window between the first mirror group and the second mirror group, so that a millimeter wave ring beam can be realized at the medium window. In S3, the first mirror group after the mirror surface design process is completed converts a near-axis complex beam into a ring beam and outputs the ring beam to the medium window; the second mirror group after the mirror surface design process is completed converts the ring beam that exits the medium window into a fundamental mode Gaussian beam and couples the fundamental mode Gaussian beam into a corrugated waveguide transmission line, thereby completing the process of generating the millimeter wave and entering the transmission line. The first mirror group comprises a first mirror and a second mirror, and the first mirror and the second mirror are both phase correction mirrors; the specific steps of the mirror surface design process of the first mirror group are as follows: A1, placing the first mirror and the second mirror so that the outgoing beam of the first mirror is the incoming beam of the second mirror; A2, the electromagnetic wave input field is propagated to the first mirror, and the field distribution of the first mirror is ; A3, propagating the target beam to a second mirror, the field distribution of the second mirror being ; A4. Start an iteration process, propagate the electromagnetic wave on the first mirror to the second mirror, obtain ; update parameter values; A5、According to , the phase difference on the second mirror is obtained, and the phase distribution in the phase correction model is updated , is the phase distribution change amount, is the wave number, is the electromagnetic wave propagation distance change amount, is the incident electromagnetic wave angle, and at this time is the phase difference on the second mirror , the mirror surface profile of the second mirror is updated; A6. The electromagnetic wave on the second reflecting mirror is propagated to the first reflecting mirror to obtain... ;renew Parameter values; A7. According to Again, the phase difference on the second mirror is obtained, and the phase distribution in the phase correction model is used to update the mirror surface profile of the first mirror. Again, the phase difference on the second mirror is obtained, and the phase distribution in the phase correction model is used to update the mirror surface profile of the first mirror. A8, when the output field distribution of the second mirror is consistent with the target region field distribution, exiting the iteration loop process and completing the mirror surface design process of the first mirror group.

2. The method of claim 1, wherein: The near-axis complex beam is directly input into the ring beam implementation system after being generated by a millimeter wave source.

3. The method of claim 1, wherein, The construction process of the phase correction model in S1 is as follows: According to electromagnetic wave diffraction theory, the target region field distribution at the medium window is obtained through a source field distribution, as follows: wherein is the free space Green function; is the source field distribution; is the target region field distribution; when the incident electromagnetic wave is reflected by the mirror surface, the field distribution change due to the mirror surface deformation is as follows: In the formula, is a field distribution change; is an incident field distribution; a phase distribution change amount due to an electromagnetic wave propagation distance the following formula: According to the above three formulas, the change of the field distribution caused by the final change of the reflection surface shape is as follows: This formula is the expression of the phase correction model.

4. The method of claim 3, wherein: In the mirror surface design process of S2 and S3, the design process of the first mirror group and the second mirror group is the same; In the mirror surface design process, the mirror surface shape of each mirror in the first mirror group and the second mirror group is continuously updated in an iterative manner until the output field distribution of the first mirror group and the input field distribution of the second mirror group are both the same as the target region field distribution.

5. The method of claim 1, wherein: The first mirror group comprises a first mirror and a second mirror, and the second mirror group comprises a third mirror and a fourth mirror; the first mirror, the second mirror, the third mirror and the fourth mirror are all phase correction mirrors with irregular curved mirror surfaces.

6. A millimeter wave ring beam implementation system implementing the method of claim 1, characterized by: The method comprises the following steps: The method comprises the following steps:

7. The millimeter wave ring beam implementation system of claim 6, wherein: The first mirror group comprises a first mirror and a second mirror; the outgoing beam of the first mirror is the incident beam of the second mirror; the first mirror is used for receiving the input of the near-axis complex beam, and the second mirror is used for outputting the annular beam to the medium window.

8. The millimeter wave ring beam implementation system of claim 7, wherein: The second mirror group comprises a third mirror and a fourth mirror; the outgoing beam of the third mirror is the incident beam of the fourth mirror; the third mirror is used for receiving the input of the annular beam at the medium window, and the fourth mirror is used for outputting the fundamental mode Gaussian beam to the corrugated waveguide transmission line coupling.

Images