Chebyshev multi-aperture coupler based on tapered height waveguide

Abstract

The application belongs to the technical field of wireless communication, and relates to a directional coupler, and particularly provides a Chebyshev multi-hole coupler based on a tapered height-reducing waveguide, which is used to solve the high-frequency resonance problem of a traditional Chebyshev multi-hole coupler. On the basis of the traditional Chebyshev multi-hole coupler, the main waveguide and the auxiliary waveguide adopting the standard waveguide are replaced by the tapered height-reducing waveguide structure, so that the waveguide height and the coupling hole size are inversely proportional to each other and matched, the high-frequency resonance point of the coupler is eliminated through the matching, the high-frequency resonance problem of the traditional Chebyshev coupler is solved, the working bandwidth of the coupler is widened, and the performance of the coupler is further improved.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication technology and relates to directional couplers, specifically providing a Chebyshev porous coupler based on a gradually decreasing waveguide. Background Technology

[0002] With the rapid development of wireless communication technology, low-frequency communication channels have become extremely congested, especially the radio frequency and microwave bands. The most direct solution to this problem is to further increase the communication frequency to the millimeter-wave band. Currently, millimeter-wave communication technology has wide-ranging applications in 5G communication, air-to-ground satellite communication, and other fields.

[0003] As a crucial component in millimeter-wave communication, directional couplers enable directional coupling of transmitted signals and control the magnitude of the coupled output. In the millimeter-wave band, compared to passive structures such as coaxial lines, microstrip lines, and striplines, waveguide couplers offer advantages such as high power capacity and low loss, thus enjoying widespread use. The coupling mechanisms of waveguide directional couplers are mainly categorized into branch coupling, aperture coupling, and matched double-T coupling. Among these, aperture couplers, with their small size and high directivity, are the most widely used. Regarding the arrangement of coupling holes in aperture couplers, they are further classified into uniform linear arrays, binomial arrays, and Chebyshev arrays. For example, the literature "Ma Chongyang. Research and Design of Novel Broadband High-Power Waveguide Directional Coupler Based on S-Band. Beijing Jiaotong University, 2016. DOI:CNKI:CDMD:2.1016.058499." discloses a uniform linear array structure. The performance of this type of coupler can be improved by adding more coupling holes to increase the bandwidth and directivity of the coupler, but this will significantly increase the size of the coupler. In comparison, Chebyshev aperture coupling structures have a greater advantage in directivity. For example, the literature "Luo Chunjie. Power of High-Power Microwave Directional Coupler" shows that... "Research on Capacity Improvement and Miniaturization. University of Electronic Science and Technology of China [2024-11-19]. DOI:10.7666 / d.D498921." However, Chebyshev coupling structures also have problems. Because Chebyshev coupling structures require the coupling aperture size to follow a pattern of increasing from left to right and then decreasing again, the maximum coupling aperture size will be significantly larger than that of uniform straight-aperture coupling structures. A larger coupling aperture size will significantly increase the risk of introducing resonant modes. In terms of performance, this manifests as resonance occurring in the high-frequency range. If the resonance point appears within the band, it will cause severe deterioration of the directivity at that point, thus limiting the further expansion of the coupler's bandwidth. Therefore, how to solve the high-frequency resonance problem when using a Chebyshev coupling structure has become the research focus of this invention. Summary of the Invention

[0004] The purpose of this invention is to provide a Chebyshev porous coupler based on a gradually decreasing waveguide, in order to solve the high-frequency resonance problem of traditional Chebyshev porous couplers.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A Chebyshev multi-aperture coupler based on a gradually decreasing waveguide includes: a main waveguide, a sub-waveguide, and a double row of Chebyshev coupling holes, wherein the double row of Chebyshev coupling holes are formed on the common waveguide wall of the main waveguide and the sub-waveguide.

[0007] A three-dimensional rectangular coordinate system is established with the center point of the Chebyshev porous coupler as the origin, the main waveguide signal propagation direction as the y-axis and the waveguide wall electric field direction as the z-axis. The Chebyshev porous coupler has a symmetrical structure along the xoy plane.

[0008] The main waveguide is formed by sequentially connecting the main waveguide input end 1-1, the gradually reducing main waveguide 1-2, and the main waveguide straight end 1-3. The sub-waveguide is formed by sequentially connecting the sub-waveguide isolation end 3-1, the gradually reducing sub-waveguide 3-2, and the sub-waveguide coupling end 3-3. The gradually reducing main waveguide 1-2 and the gradually reducing sub-waveguide 3-2 are coupled through double-row Chebyshev coupling holes 2-1.

[0009] The main waveguide input terminal 1-1, the main waveguide through terminal 1-3, the secondary waveguide isolation terminal 3-1, and the secondary waveguide coupling terminal 3-3 all adopt standard rectangular waveguides.

[0010] The gradually reducing height main waveguide 1-2 and the gradually reducing height secondary waveguide 3-2 adopt the same gradually reducing height waveguide structure. The x-axis dimension is defined as the width, the y-axis dimension as the length, and the z-axis dimension as the height. The gradually reducing height waveguide structure is symmetrical along the xoz plane. Its width is consistent with that of the standard waveguide, and its height decreases linearly from both ends to the middle.

[0011] Furthermore, the height of a standard rectangular waveguide is denoted as b, and the height of the lowest point of a gradually decreasing waveguide structure is denoted as h. The range of h is: 0.8b ≤ h ≤ 0.9b.

[0012] Furthermore, the total length of the double-row Chebyshev coupling aperture is denoted as t, and the total length of the gradually decreasing waveguide structure is denoted as 2l. Then, the range of l is: 0.5t≤l≤0.6t.

[0013] Furthermore, the standard rectangular waveguide adopts the standard WR-10 waveguide.

[0014] Furthermore, the double-row Chebyshev coupling holes adopt a double-row staggered Chebyshev coupling hole structure.

[0015] Based on the above technical solution, the beneficial effects of the present invention are as follows:

[0016] This invention proposes a Chebyshev multi-aperture coupler based on a tapered reduced-height waveguide. Building upon the traditional Chebyshev multi-aperture coupler, the main and secondary waveguides, which are typically standard waveguides, are replaced with tapered reduced-height waveguide structures. This allows the waveguide height to be inversely matched to the coupling aperture size, eliminating the coupler's high-frequency resonant point and solving the high-frequency resonance problem inherent in traditional Chebyshev couplers. Furthermore, it broadens the coupler's operating bandwidth and further improves its performance. Simultaneously, the waveguide height in the tapered reduced-height waveguide structure increases linearly from the middle to both ends, achieving a low-reflection transition between the tapered reduced-height waveguide structure and the standard waveguide while matching the Chebyshev coupling aperture. This simplifies the design of the coupler's structural parameters and facilitates actual fabrication. Attached Figure Description

[0017] Figure 1 This is a three-dimensional structural schematic diagram of the Chebyshev porous coupler based on a gradually decreasing waveguide in this invention.

[0018] Figure 2 This is a side view of the Chebyshev porous coupler based on a gradually decreasing waveguide in this invention.

[0019] Figure 3 This is a dimensioned diagram of the Chebyshev porous coupler based on a gradually decreasing waveguide in this invention.

[0020] Figure 4 This is a schematic diagram of the double-row Chebyshev coupling holes of the Chebyshev multi-hole coupler based on the gradually decreasing height waveguide in this invention.

[0021] Figure 5 The figure shows the S-parameter simulation results of the Chebyshev porous coupler based on the gradually decreasing height waveguide in this invention.

[0022] Figure 6 The figure shows the S-parameter simulation results of the traditional Chebyshev porous coupler in the comparative example. Detailed Implementation

[0023] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0024] This embodiment provides a Chebyshev porous coupler based on a gradually decreasing waveguide, the structure of which is as follows: Figure 1 and Figure 2 As shown, it specifically includes: a main waveguide, a secondary waveguide, and a double row of Chebyshev coupling holes, wherein the double row of Chebyshev coupling holes are opened on the common waveguide wall of the main waveguide and the secondary waveguide; a three-dimensional rectangular coordinate system is established with the center point of the coupler as the origin, the signal propagation direction of the main waveguide as the y-axis, and the electric field direction of the waveguide wall as the z-axis; the coupler has a symmetrical structure (vertically symmetrical) along the xoy plane.

[0025] The main waveguide is formed by sequentially connecting the main waveguide input end 1-1, the gradually reducing main waveguide 1-2, and the main waveguide straight end 1-3. The sub-waveguide is formed by sequentially connecting the sub-waveguide isolation end 3-1, the gradually reducing sub-waveguide 3-2, and the sub-waveguide coupling end 3-3. The gradually reducing main waveguide 1-2 and the gradually reducing sub-waveguide 3-2 are coupled through double-row Chebyshev coupling holes 2-1.

[0026] The main waveguide input terminal 1-1, the main waveguide through terminal 1-3, the secondary waveguide isolation terminal 3-1, and the secondary waveguide coupling terminal 3-3 all adopt standard rectangular waveguides. The gradient-height reduced main waveguide 1-2 and the gradient-height reduced secondary waveguide 3-2 adopt the same gradient-height reduced waveguide structure, defining the x-axis dimension as width, the y-axis dimension as length, and the z-axis dimension as height. The width of the gradient-height reduced waveguide structure is consistent with that of the standard waveguide. The height of the gradient-height reduced waveguide structure decreases linearly and then increases linearly, and the lowest point appears at the center of the gradient-height reduced waveguide structure, that is, the gradient-height reduced waveguide structure is symmetrical along the xoz plane.

[0027] Furthermore, such as Figure 3 As shown, if the height of the standard rectangular waveguide is represented as b, then the maximum height of the gradient-reduced waveguide structure is b, the minimum height (lowest point) of the gradient-reduced waveguide structure is represented as h, and the gradient length (linear or decreasing height) of the gradient-reduced waveguide structure is represented as l. Then the total length of the gradient-reduced waveguide structure is 2l; the total length of the Chebyshev coupling aperture structure is represented as t. In this embodiment, the lowest point of the gradient-height reduction waveguide structure and the center point of the double-row Chebyshev coupling aperture are both located on the xoz plane. Since the size of the Chebyshev coupling aperture is characterized by being larger in the middle and smaller on both sides, this embodiment adopts a gradient-height reduction waveguide structure design so that its height is inversely proportional to the size of the coupling aperture. That is, the lowest point of the gradient-height reduction waveguide structure matches the largest coupling aperture of the Chebyshev coupling aperture structure. This matching eliminates the high-frequency resonant points of the coupler, thereby achieving the purpose of widening the operating bandwidth of the coupler. Furthermore, the waveguide height in the gradient-height reduction waveguide structure increases linearly from the center to both sides, achieving a low-reflection transition between the gradient-height reduction waveguide structure and the standard waveguide while matching the Chebyshev coupling aperture structure.

[0028] Furthermore, based on the aforementioned gradually decreasing waveguide structure, the reduction is defined as ∆h, where ∆h = bh. As ∆h increases, the high-frequency resonant point of the coupler shifts to higher frequencies, and the theoretical operating bandwidth of the coupler also increases, but the reflection coefficient and directivity deteriorate accordingly. Therefore, in this embodiment, the optimal range of h is given as: 0.8b ≤ h ≤ 0.9b. Similarly, as l increases, the reflection coefficient and directivity will improve to some extent, while l will be limited by the total length of the device. In this embodiment, the optimal range of l is given as: 0.5t ≤ l ≤ 0.6t.

[0029] The beneficial effects of the present invention will be explained in detail below with reference to simulation tests.

[0030] In this embodiment, the main waveguide input terminal 1-1, the main waveguide through terminal 1-3, the secondary waveguide isolation terminal 3-1, and the secondary waveguide coupling terminal 3-3 all adopt standard WR-10 waveguides with a width of 2.54 mm and a height of 1.27 mm. The thickness of the shared waveguide wall between the main waveguide and the secondary waveguide is 0.2 mm. The total length of the gradient height-reducing waveguide structure is 16.7 mm, and the height of the lowest point is 1.07 mm, a reduction of 0.2 mm. The double-row Chebyshev coupling holes adopt a double-row staggered Chebyshev coupling hole structure, such as... Figure 4 As shown, the coupling holes, from left to right, are the first coupling hole, the second coupling hole, the third coupling hole, the fourth coupling hole, the fifth coupling hole, the sixth coupling hole, the seventh coupling hole, the eighth coupling hole, the ninth coupling hole, and the tenth coupling hole. Each coupling hole adopts a rectangular structure. The width of the first coupling hole is 0.4 mm and the length is 0.4 mm; the width of the second coupling hole is 0.48 mm and the length is 0.49 mm; the width of the third coupling hole is 0.52 mm and the length is 0.67 mm; the width of the fourth coupling hole is 0.67 mm and the length is 0.88 mm; and the width of the fifth coupling hole is 0.76 mm and the length is 1.02 mm. The single row of coupling holes is completely symmetrical from left to right, and the misalignment distance of the double row of coupling holes is 1.22 mm. In addition, a radius of 0.2 mm fillet is added to the simulation model due to the high-precision CNC milling process.

[0031] The S-parameters of the Chebyshev porous coupler based on the tapered waveguide with reduced height were simulated, and the results are as follows: Figure 5 As shown, S 11 S 21 S 31 S 41The figures represent the reflection coefficient, the through-end transmission coefficient, the coupling degree, and the isolation degree, respectively. As can be seen from the figure, the coupler has an operating bandwidth of 66GHz~114GHz and an in-band coupling degree of -12dB, which meets the power distribution requirements. At the same time, the in-band return loss is better than -30dB, the isolation degree is better than 45dB, and the in-band directivity is better than -33dB. It can be seen that the Chebyshev porous coupler based on a tapered waveguide proposed in this invention has superior performance such as high isolation, low loss, and high directivity.

[0032] To further demonstrate that the Chebyshev porous coupler based on a gradually decreasing waveguide proposed in this embodiment can eliminate high-frequency resonance points, this invention proposes a comparative example. The only difference between this example and the one in which the main and secondary waveguides both use standard WR-10 waveguides, and their S-parameters are simulated. The results are as follows: Figure 6 As shown in the figure, the Chebyshev porous coupler in the comparative example exhibits significant resonance phenomena near 104 GHz and 110 GHz, leading to a severe deterioration in coupler performance.

[0033] In summary, this invention provides a Chebyshev porous coupler based on a gradient-height reduced waveguide. Building upon the traditional Chebyshev porous coupler, the main and secondary waveguides, which are typically standard waveguides, are replaced with a gradient-height reduced waveguide structure. This effectively eliminates the resonant points of the coupler in the high-frequency range, thereby widening the coupler's operating bandwidth and significantly improving its performance.

[0034] The above description is merely a specific embodiment of the present invention. Any feature disclosed in this specification may be replaced by other equivalent or similar features unless otherwise specified. All disclosed features, or steps in all methods or processes, may be combined in any way except for mutually exclusive features and / or steps.

Claims

1. A Chebyshev porous coupler based on a gradient-height waveguide, comprising: A main waveguide, a secondary waveguide, and a double row of Chebyshev coupling holes, wherein the double row of Chebyshev coupling holes are formed on the common waveguide wall of the main waveguide and the secondary waveguide; characterized in that: A three-dimensional rectangular coordinate system is established with the center point of the Chebyshev porous coupler as the origin, the main waveguide signal propagation direction as the y-axis and the waveguide wall electric field direction as the z-axis. The Chebyshev porous coupler has a symmetrical structure along the xoy plane. The main waveguide is composed of a main waveguide input end (1-1), a gradually reducing main waveguide (1-2), and a main waveguide through end (1-3) connected in sequence. The sub-waveguide is composed of a sub-waveguide isolation end (3-1), a gradually reducing sub-waveguide (3-2), and a sub-waveguide coupling end (3-3) connected in sequence. The gradually reducing main waveguide (1-2) and the gradually reducing sub-waveguide (3-2) are coupled through a double row of Chebyshev coupling holes (2-1). The main waveguide input terminal (1-1), the main waveguide through terminal (1-3), the secondary waveguide isolation terminal (3-1), and the secondary waveguide coupling terminal (3-3) all adopt standard rectangular waveguides; The gradient height reduction main waveguide (1-2) and the gradient height reduction sub-waveguide (3-2) adopt the same gradient height reduction waveguide structure. The x-axis dimension is defined as the width, the y-axis dimension as the length, and the z-axis dimension as the height. The gradient height reduction waveguide structure is symmetrical along the xoz plane. Its width is consistent with that of the standard waveguide, and its height decreases linearly from both ends to the middle.

2. The Chebyshev porous coupler based on a gradient-height reduction waveguide according to claim 1, characterized in that, The height of a standard rectangular waveguide is denoted as b, and the height of the lowest point of a gradually decreasing waveguide structure is denoted as h. The range of h is: 0.8b ≤ h ≤ 0.9b.

3. The Chebyshev porous coupler based on a gradient-height reduction waveguide according to claim 1, characterized in that, The total length of the double-row Chebyshev coupling aperture is denoted as t, and the total length of the gradually decreasing waveguide structure is denoted as 2l. Then the range of l is: 0.5t≤l≤0.6t.

4. The Chebyshev porous coupler based on a gradient-height reduction waveguide according to claim 1, characterized in that, The standard rectangular waveguide uses the standard WR-10 waveguide.

5. The Chebyshev porous coupler based on a gradient-height reduction waveguide according to claim 1, characterized in that, The double-row Chebyshev coupling holes adopt a double-row staggered Chebyshev coupling hole structure.

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