Feed system based on incoherent microwave power synthesis

Abstract

The invention provides a feed system based on incoherent microwave power synthesis. The feed system comprises a rectangular resonant cavity, a dielectric waveguide, a microwave reaction cavity and two rectangular waveguides, the bottom of the rectangular resonant cavity is sealed, the side length difference between two adjacent sides of the bottom of the rectangular resonant cavity meets a preset condition, the top of the rectangular resonant cavity is provided with an opening, and the dielectric waveguide is arranged in the opening; the microwave reaction cavity is arranged above the rectangular resonant cavity; the two rectangular waveguides are respectively connected with two adjacent side surfaces, except the top and the bottom, of the rectangular resonant cavity, and the bottoms of the two rectangular waveguides are parallel to the bottom of the rectangular resonant cavity; the two rectangular waveguides are respectively used for feeding one path of received microwaves into the rectangular resonant cavity, and after incoherent microwave power synthesis of the two paths of microwaves is carried out in the rectangular resonant cavity, the two paths of microwaves are fed into the microwave reaction cavity through the dielectric waveguide; the feed system provided by the invention has the advantages of high feed efficiency, small mutual coupling between microwave sources, low possibility of load interference, low cost and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of physics, in particular to the field of microwave heating technology, and more particularly to a microwave reactor, and most particularly to a feeding system based on non-coherent microwave power synthesis. BACKGROUND

[0002] In the field of microwave heating, in order to increase the target temperature of the reaction medium in the microwave reactor, it is necessary to increase the microwave power in the microwave reactor. The following three methods are commonly used to increase the microwave power in the microwave reactor: (1) increasing the power of a single microwave source; (2) directly feeding multiple microwave sources into the microwave reactor; and (3) feeding the microwave reactor after power synthesis of multiple microwave sources.

[0003] The existing three methods have the following disadvantages: method (1) uses a single high-power microwave source, which has the problem of high cost. When the power of a single microwave source is increased, the cost of the single microwave source device and the matching power supply system will significantly increase. Taking a 2-kilowatt magnetron as an example, when the power of the magnetron is increased from 1 kilowatt to 2 kilowatts, the cost of the power supply system will increase several times; method (2) directly feeds multiple microwave sources into the microwave reactor, and the feeding efficiency will decrease sharply with the change of the temperature of the reaction medium. During the heating process of the microwave reactor, the temperature of the medium changes constantly, and the dielectric properties also change accordingly, causing the mode in the reaction chamber to change constantly, making it difficult for the microwave to be efficiently fed in; method (3) feeds the microwave reactor after power synthesis of multiple microwave sources, which can improve the shortcomings of method (2) to some extent, but during the heating process, there is a serious coupling problem between different microwave sources, causing mutual interference between the microwave sources. SUMMARY

[0004] The present application aims to provide a feeding system based on non-coherent microwave power synthesis to solve the problems identified in the background.

[0005] The application provides a feeding system based on non-coherent microwave power synthesis, which comprises a rectangular resonant cavity, a dielectric waveguide, a microwave reaction cavity and two rectangular waveguides; wherein the bottom of the rectangular resonant cavity is sealed, and the length difference of two adjacent sides of the bottom of the rectangular resonant cavity meets a preset condition; the top of the rectangular resonant cavity is provided with an opening, and the dielectric waveguide is arranged in the opening; the microwave reaction cavity is arranged above the rectangular resonant cavity; two rectangular waveguides are connected with two adjacent sides of the rectangular resonant cavity except the top and the bottom, and the bottom of the two rectangular waveguides is parallel to the bottom of the rectangular resonant cavity; the two rectangular waveguides are used for feeding one received microwave into the rectangular resonant cavity; after non-coherent microwave power synthesis of two microwaves in the rectangular resonant cavity, the microwave is fed into the microwave reaction cavity through the dielectric waveguide.

[0006] In the application, the feeding system based on two-way non-coherent microwave power synthesis of rectangular cavity degenerate mode has the advantages of high feeding efficiency, small mutual coupling between microwave sources, difficult load interference and low cost.

[0007] In an implementation manner of the application, the feeding system based on non-coherent microwave power synthesis further comprises two independent microwave sources; one microwave source is connected with one rectangular waveguide, and one microwave source is used for emitting one microwave, and two microwaves emitted by two microwave sources are non-coherent.

[0008] In an implementation manner of the application, the microwave source comprises a magnetron or a solid-state source; one magnetron or one solid-state source is connected with one rectangular waveguide, and the magnetron or the solid-state source is used for emitting the microwave.

[0009] In an implementation manner of the application, the shape of the opening at least comprises any one of the following: a circle, a rectangle, a parallelogram, a rhombus and a triangle; and / or the shape of the dielectric waveguide at least comprises any one of the following: a cylinder, a cone, a tetrahedron or a multi-face column.

[0010] In an implementation manner of the application, the opening is located at the center position of the top of the rectangular resonant cavity.

[0011] In an implementation manner of the application, the rectangular resonant cavity is made of a metal material.

[0012] In an implementation manner of the application, the preset condition is that the length difference is less than or equal to a preset value.

[0013] In an implementation manner of the application, the preset condition is that the length difference is equal to 0.

[0014] In the present implementation, since the side length difference is equal to 0, i.e. the bottom of the rectangular resonant cavity is a square, for any working frequency, a group of degenerate modes must exist at the same time, so that the coupling between the two rectangular waveguides is very small, and good isolation is achieved.

[0015] In an implementation of the present application, the bottom of the rectangular waveguide is at a preset distance from the bottom of the rectangular resonant cavity.

[0016] In an implementation of the present application, the material of the dielectric waveguide is a wave-transparent material; wherein the wave-transparent material at least includes quartz and / or corundum.

[0017] As described above, the feeding system based on non-coherent microwave power synthesis according to the present application has the following beneficial effects:

[0018] (1) Compared with the prior art, the present application provides a feeding system based on two-way non-coherent microwave power synthesis of rectangular cavity degenerate modes, since the rectangular resonant cavity with a bottom close to a square has the working characteristics of degenerate modes, the mutual coupling of two-way non-coherent microwaves is very small, avoiding interference between microwave sources, and achieving good isolation.

[0019] (2) The present application uses a rectangular resonant cavity, which has the advantages of easy processing and installation, and can maintain high feeding efficiency when the dielectric properties of the reaction medium in the microwave reaction cavity change greatly.

[0020] (3) Compared with using a high-power microwave source and a power source, the two-way microwave power synthesis provided by the present application has the advantage of low cost. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 A principle block diagram of the feeding system based on non-coherent microwave power synthesis according to the embodiments of the present application is shown.

[0022] Figure 2 A structure schematic diagram of the feeding system based on non-coherent microwave power synthesis according to the embodiments of the present application is shown.

[0023] Figure 3 A size schematic diagram of the rectangular resonant cavity according to the embodiments of the present application is shown. DETAILED DESCRIPTION

[0024] Following make the specific concrete example explain the embodiment of the present application, the person skilled in the art can be easily understood from the disclosure of the present application other advantages and efficacy.The present application can also be implemented or applied by another different embodiment, the details in the specification can be based on different views and applications, without departing from the spirit of the present application, various modifications or changes are made.The need to explain, in the following examples and the features in the examples can be combined with each other without conflict.

[0025] Need to explain, the drawings provided in the following examples only illustrate the basic concept of the present application in a schematic way, only show the components related to the present application in the drawing, not according to the actual implementation of the number of components, shape and size drawing, the actual implementation of each component type, quantity and proportion can be a kind of arbitrary change, and its component layout type may be more complex.

[0026] Reference Figures 1 to 3 The following examples of the present application provide a feed system based on incoherent microwave power synthesis, compared with the prior art, the present application provides a two-way incoherent microwave power synthesis feed system based on rectangular cavity (i.e. rectangular resonant cavity) degenerate mode, due to the use of the bottom surface is close to square rectangular resonant cavity has the working characteristics of degenerate mode, so that the mutual coupling of two-way incoherent microwave is small, avoid the interference between microwave sources, realize the good isolation;The present application adopts rectangular resonant cavity, has the advantages of easy processing, installation, and can maintain high feeding efficiency when the dielectric properties of the reaction medium in the microwave reaction cavity change greatly;Compared with the use of high-power microwave source and power source, the two-way microwave power synthesis provided by the present application has the advantage of low cost.

[0027] Need to explain, degenerate mode refers to several modes in waveguide or resonant cavity, which have the same cutoff wavelength or resonant wavelength, but have different electromagnetic field distribution.

[0028] The technical solutions in the embodiments of the present application will be described in detail below with reference to the drawings of the embodiments of the present application.

[0029] As Figure 1 And Figure 2 As shown in an embodiment, the present application provides a feed system based on incoherent microwave power synthesis, the feed system based on incoherent microwave power synthesis includes: rectangular resonant cavity 1, dielectric waveguide 2, microwave reaction cavity 3 and two rectangular waveguides 4.

[0030] Specifically, the bottom of the rectangular resonant cavity 1 is sealed, and the length difference of two adjacent sides of the bottom of the rectangular resonant cavity 1 meets a preset condition; the top of the rectangular resonant cavity 1 is provided with an opening (not shown in the figure), and the dielectric waveguide 2 is arranged in the opening; the microwave reaction cavity 3 is arranged above the rectangular resonant cavity 1; two rectangular waveguides 4 are connected with two adjacent sides of the rectangular resonant cavity 1 except the top and the bottom, and the bottoms of the two rectangular waveguides 4 are parallel to the bottom of the rectangular resonant cavity 1; the two rectangular waveguides 4 are respectively used for feeding one-way microwave received into the rectangular resonant cavity 1; after the non-coherent microwave power synthesis of two ways of the microwave in the rectangular resonant cavity 1, the microwave is fed into the microwave reaction cavity 3 through the dielectric waveguide 2 (between the microwave reaction cavity 3 and the microwave source, the rectangular waveguide 4 and the rectangular resonant cavity 1 are combined to feed power, so that the feeding efficiency is ensured).

[0031] It should be noted that when the phase difference of each synthesized signal cannot meet the constant (in many cases, the phase difference is required to be zero) within a certain time, it is called "non-coherent microwave power synthesis"; the non-coherent microwave power synthesis does not require strict and accurate control of the parameters of each microwave source, can get rid of the strict requirement of the traditional coherent microwave power synthesis on the consistency of the frequency, phase and amplitude of each microwave source, saves the phase shifter, phase-locked loop and other related phase control devices, realizes the simplification of the synthesis system, and thus reduces the cost.

[0032] In the application, two rectangular waveguides 4 feed into the adjacent surfaces of the rectangular resonant cavity 1, each rectangular waveguide 4 independently excites different modes in the same group of degenerate modes to perform non-coherent power synthesis, and interference between two ways of microwave is avoided.

[0033] As shown in Figure 1 In an embodiment, the non-coherent microwave power synthesis based feeding system further comprises two independent microwave sources 5; one microwave source 5 is connected with one rectangular waveguide 4, and one microwave source 5 is used for emitting one-way microwave, and two microwave sources 5 emit two-way non-coherent microwave.

[0034] Specifically, two independent microwave sources 5 emit two-way non-coherent microwave signals, which enter two rectangular waveguides 4 respectively; the microwave passes through the rectangular waveguide 4, is fed into the rectangular resonant cavity 1, performs non-coherent power synthesis, and then enters the microwave reaction cavity 3 through the dielectric waveguide 2.

[0035] In an embodiment, the microwave source 5 comprises a magnetron or a solid-state source; one magnetron or one solid-state source is connected with one rectangular waveguide 4, and the magnetron or the solid-state source is used for emitting the microwave.

[0036] In an embodiment, the rectangular waveguide 4 transmits TE10 mode.

[0037] In an embodiment, the rectangular waveguide 4 is a standard rectangular waveguide.

[0038] It should be noted that the standard rectangular waveguide is a common waveguide type, which is widely used in the field of microwave and millimeter wave, and has simple structure and good transmission performance, so it has been widely used in the field of communication, radar, radio, etc.; the standard rectangular waveguide is composed of a metal rectangular tube and a metal cover plate.

[0039] In an embodiment, the rectangular waveguide 4 is a non-standard rectangular waveguide.

[0040] In an embodiment, the shape of the opening at least includes but is not limited to any one of the following: circular, rectangular, parallelogram, diamond, triangle.

[0041] In an embodiment, the shape of the dielectric waveguide 2 at least includes but is not limited to any one of the following: cylinder, cone, tetrahedron or multi-faced column.

[0042] In an embodiment, the opening is located at the center of the top of the rectangular resonant cavity 1.

[0043] In an embodiment, the rectangular resonant cavity 1 is made of a metal material.

[0044] In an embodiment, the preset condition is that the side length difference is less than or equal to a preset value.

[0045] It should be noted that the purpose of setting the preset value is to ensure that the length and width of the bottom of the rectangular resonant cavity 1 are as close as possible, that is, the bottom of the rectangular resonant cavity 1 is close to a square, so the preset value is small, but the specific value of the preset value is not as a condition for limiting the present application, and in actual application, it can be set according to the specific application scene.

[0046] In an embodiment, the preset condition is that the side length difference is equal to 0.

[0047] That is, the preset value is 0 corresponding to the above.

[0048] It should be noted that in this embodiment, the side length difference of the two adjacent sides of the bottom of the rectangular resonant cavity 1 is 0, which means that the bottom of the rectangular resonant cavity 1 is a square, so that degenerate modes are generated in the rectangular resonant cavity 1 (the degenerate modes are used for the above-mentioned non-coherent microwave power synthesis).

[0049] In an embodiment, the bottom of the rectangular waveguide 4 is apart from the bottom of the rectangular resonant cavity 1 by a preset distance.

[0050] It should be noted that the preset distance is not limited to the application, and the value of the preset distance can be determined by simulation method in actual application, so that the rectangular resonant cavity 1 works in low mode or lower mode.

[0051] In an embodiment, the material of the dielectric waveguide 2 is a wave-transparent material, which at least includes but is not limited to quartz and / or corundum.

[0052] The working principle of the feeding system based on non-coherent microwave power synthesis will be further explained by specific embodiments.

[0053] As shown in Figure 3 , in an embodiment, the size of the rectangular resonant cavity 1 is x×y×z (wherein x represents the length of the rectangular resonant cavity 1; y represents the width of the rectangular resonant cavity 1; and z represents the height of the rectangular resonant cavity 1), two adjacent sides of the rectangular resonant cavity 1 are connected to two rectangular waveguides 4 (for example, in Figure 3 , the front side and the right side of the rectangular resonant cavity 1 are connected to two rectangular waveguides 4), the bottom of the rectangular waveguide 4 is h away from the bottom of the rectangular resonant cavity 1, the top of the rectangular resonant cavity 1 is closed with metal, but a small opening is formed in the center, which is circular in shape and has an inner diameter of d, the dielectric waveguide 2 is embedded in the small opening, so that the microwave energy is coupled from the rectangular resonant cavity 1 to the microwave reaction cavity 3; the shape of the dielectric waveguide 2 is a circular cone, the height of the bottom is s, and the height of the extension into the rectangular resonant cavity 1 is t; the working frequency of the rectangular resonant cavity 1 is:

[0054]

[0055] wherein f mnl is the working frequency; c is the speed of light in vacuum; ε r and μ r are the relative permittivity and relative permeability of the medium filled in the rectangular resonant cavity 1, respectively; m, n, l are the number of half-wavelengths on the length, width and height of the rectangular resonant cavity, respectively.

[0056] It should be noted that m, n, l can be any natural number in 0, 1, 2, 3, ….

[0057] In an embodiment, m, n, l are all ≤10.

[0058] It should be noted that when m, n, l are all ≤10, the rectangular resonant cavity 1 works in a lower resonant mode, i.e. low mode or lower mode.

[0059] In order to reduce the mutual coupling of the two energies entering the rectangular resonant cavity 1 from the rectangular waveguides 4, the size of the rectangular resonant cavity 1 needs to meet the following conditions:

[0060] x ≈ y;

[0061] That is, the length and width of the bottom of the rectangular resonant cavity 1 are as close as possible, so that the bottom of the rectangular resonant cavity 1 is as close to a square as possible.

[0062] The reason is that for the rectangular resonant cavity 1 with a square bottom, that is, x = y, the operating frequency is:

[0063]

[0064] Since the bottom of the rectangular resonant cavity 1 is a square, for any operating frequency, there is a group of degenerate modes that must exist at the same time.

[0065] For convenience of description, the degenerate modes are denoted as mode A1 and mode A2, respectively, so that one rectangular waveguide 4 connected to the rectangular resonant cavity 1 excites a mode A1 in the rectangular resonant cavity 1, and another rectangular waveguide 4 adjacent to the rectangular resonant cavity 1 must excite another corresponding degenerate mode A2. Due to the orthogonality of the modes, that is, the inner product of any two degenerate modes is 0, which means that the mode A1 is difficult to enter the rectangular waveguide 4 that excites the mode A2, and similarly, the mode A2 is also difficult to enter the rectangular waveguide 4 that exits the mode A1, that is, the coupling between the two rectangular waveguides 4 is small, thereby achieving good isolation.

[0066] In addition, in order to achieve good isolation between the groups of degenerate modes in the rectangular resonant cavity 1, the values of x and h need to be adjusted so that the resonant modes of the rectangular resonant cavity 1 are as dispersed as possible. Since the mode density is proportional to the volume, the values of x and h should be as small as possible, so that the rectangular resonant cavity 1 operates at a lower resonant mode (that is, corresponding to m, n, l ≤ 10).

[0067] In an embodiment, the values of x and h are determined by simulation.

[0068] Specifically, first, the above-mentioned feeding system based on incoherent microwave power synthesis is simulated; then, the values of x and h are adjusted to improve the feeding efficiency and make the rectangular resonant cavity 1 operate at a lower resonant mode.

[0069] In an embodiment, the reflected wave energy of the rectangular resonant cavity 1 reflected into the two rectangular waveguides 4 is obtained to adjust x and h according to the reflected wave energy.

[0070] It should be noted that the lower the reflected wave energy, the higher the feeding efficiency; therefore, in this embodiment, x and h are adjusted to make the reflected wave energy as low as possible, and finally x and h are determined.

[0071] It should be noted that, through the implementation of the above method, since the rectangular resonant cavity operates in a lower resonance mode, the mode of the rectangular resonant cavity becomes relatively stable and is less affected by disturbances from the dielectric waveguide and the microwave reaction cavity, making the feeding efficiency less susceptible to the influence of the reaction medium in the microwave reaction cavity; since the rectangular resonant cavity operates in a degenerate mode, the coupling between the two feed waveguides is very small, achieving good isolation.

[0072] The descriptions of the processes or structures corresponding to the above figures each have their own emphasis. For parts of a process or structure that are not described in detail, please refer to the relevant descriptions of other processes or structures.

[0073] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A feed system based on non-coherent microwave power combining, characterized in that, The feeding system based on non-coherent microwave power synthesis comprises a rectangular resonant cavity, a dielectric waveguide, a microwave reaction cavity and two rectangular waveguides. The bottom of the rectangular resonant cavity is sealed, and the length difference of two adjacent sides of the bottom of the rectangular resonant cavity satisfies a preset condition, and the top of the rectangular resonant cavity is provided with an opening, and the dielectric waveguide is arranged in the opening. The microwave reaction cavity is arranged above the rectangular resonant cavity. Two rectangular waveguides are connected with two adjacent sides of the rectangular resonant cavity except the top and the bottom, and the bottom of the two rectangular waveguides is parallel to the bottom of the rectangular resonant cavity. The two rectangular waveguides are respectively used for feeding one received microwave into the rectangular resonant cavity, and after non-coherent microwave power synthesis of two microwaves in the rectangular resonant cavity, the microwave is fed into the microwave reaction cavity through the dielectric waveguide.

2. The non-coherent microwave power combining based feed system of claim 1, wherein, The feeding system based on non-coherent microwave power synthesis further comprises two independent microwave sources, one microwave source is connected with one rectangular waveguide, and one microwave source is used for emitting one microwave, and two microwaves emitted by two microwave sources are non-coherent.

3. A non-coherent microwave power combining based feed system according to claim 2, characterized in that, The microwave source comprises a magnetron or a solid-state source, one magnetron or one solid-state source is connected with one rectangular waveguide, and the magnetron or the solid-state source is used for emitting the microwave.

4. The non-coherent microwave power combining based feed system of claim 1, wherein, The shape of the opening at least comprises any one of the following: circular, rectangular, parallelogram, diamond, triangle; and / or The shape of the dielectric waveguide at least comprises any one of the following: cylinder, cone, tetrahedron or multi-faced column.

5. The non-coherent microwave power combining based feed system of claim 1, wherein, The opening is located at the center of the top of the rectangular resonant cavity.

6. The non-coherent microwave power combining based feed system of claim 1, wherein, The rectangular resonant cavity is made of metal material.

7. The non-coherent microwave power combining based feed system of claim 1, wherein, The preset condition is that the length difference is less than or equal to a preset value.

8. The non-coherent microwave power combining based feed system of claim 1, wherein, The preset condition is that the length difference is equal to 0.

9. The non-coherent microwave power combining based feed system of claim 1, wherein, The bottom of the rectangular waveguide is away from the bottom of the rectangular resonant cavity by a preset distance.

10. The non-coherent microwave power combining based feed system of claim 1, wherein, The material of the dielectric waveguide is a wave-transparent material, and the wave-transparent material at least comprises quartz and / or corundum.

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