A waveguide filter with high near-end suppression

Abstract

This invention discloses a high near-end suppression waveguide filter, comprising a waveguide resonator, a waveguide cavity, and a coupling window. Several waveguide resonators are arranged, with adjacent waveguide resonators connected by the coupling window. The filter also includes a frequency adjustment screw and a zero-point adjustment screw. The frequency adjustment screw is correspondingly disposed in each waveguide resonator near the centerline of the high near-end suppression waveguide filter; the zero-point adjustment screw is also correspondingly disposed in each waveguide resonator but away from the centerline of the high near-end suppression waveguide filter. A coupling adjustment screw for adjusting the coupling amount is also provided on the coupling window. The high near-end suppression waveguide filter of this invention allows each independent waveguide resonator to form an independent high-suppression transmission zero, improving the near-end suppression effect. This not only achieves small size and high suppression but also further reduces loss and in-band group delay.

Description

Technical Field

[0001] This invention relates to the field of filter technology, and in particular to a waveguide filter with high near-end suppression. Background Technology

[0002] Filters are an important component in modern communication systems. Their main function is to allow useful signals to pass through the filter without attenuation, while maximizing the attenuation of unwanted signals. Waveguide filters are a common type of filter, characterized by their simple structure, excellent performance, and ease of adjustment, and are widely used in communication systems.

[0003] Chinese Patent Publication No. CN110911791B discloses a high rectangular coefficient waveguide bandpass filter and its design method, including a diaphragm, waveguide resonant cavities, cylindrical pins, and waveguide cavities. The waveguide cavities are disposed at both ends of the high rectangular coefficient waveguide bandpass filter, and the waveguide resonant cavities are disposed between the waveguide cavities. Several waveguide resonant cavities are provided, and the cylindrical pins are correspondingly disposed within each of the waveguide resonant cavities. While this design can improve the rectangular coefficient of the filter without increasing the number of filter stages and reduce the filter size to some extent, it can only achieve the effect of two transmission zeros by setting two zero-point cavities at each end. Furthermore, the zero-point cavities are connected in series with the waveguide resonant cavities, still resulting in a large number of filter cavities, large size, high loss, and the need for timely extension. Summary of the Invention

[0004] To address the aforementioned deficiencies in the prior art, this invention proposes a waveguide filter that can independently generate high-suppression transmission zeros in a single resonant cavity, thereby improving near-end suppression. Furthermore, the zeros and the main channel resonant cavity are connected in parallel, which does not increase passband loss or group delay. This results in a small-sized waveguide filter with high suppression, low loss, and low delay, achieving high near-end suppression.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A high near-end suppression waveguide filter includes waveguide resonant cavities, waveguide cavities, and coupling windows. Several waveguide resonant cavities are provided, and adjacent waveguide resonant cavities are connected through the coupling windows. The waveguide resonant cavities are arranged between each waveguide cavity. The filter also includes a frequency adjustment screw and a zero-point adjustment screw. The frequency adjustment screw is correspondingly disposed in each waveguide resonant cavity, located near the centerline of the high near-end suppression waveguide filter. The zero-point adjustment screw is also correspondingly disposed in each waveguide resonant cavity, but located away from the centerline of the high near-end suppression waveguide filter. A coupling adjustment screw for adjusting the coupling amount is also provided on the coupling window.

[0006] As described above, in the high near-end suppression waveguide filter, each of the waveguide resonant cavities is provided with mounting holes adapted to the frequency adjustment screw and the zero-point adjustment screw. The frequency adjustment screw and the zero-point adjustment screw extend into the waveguide resonant cavity through the mounting holes, and the depth is adjustable.

[0007] As described above, in the high near-end suppression waveguide filter, the upper part of the coupling window is provided with a mounting hole adapted to the coupling adjustment screw. The coupling adjustment screw extends into the coupling window through the mounting hole, and the depth is adjustable.

[0008] As described above, in the high near-end suppression waveguide filter, the coupling window is a trapezoidal window that is wider at the top and narrower at the bottom. The upper and lower parts of the trapezoidal window are two rectangles, with the length of the upper rectangle being greater than the length of the lower rectangle.

[0009] As described above, the high near-end suppression waveguide filter includes a first waveguide resonator, a second waveguide resonator, and a third waveguide resonator. Each waveguide resonator includes an input waveguide and an output waveguide. One end of the first waveguide resonator is connected to the input waveguide, and the other end is connected to the second waveguide resonator. One end of the third waveguide resonator is connected to the second waveguide resonator, and the other end is connected to the output waveguide. A coupling window is provided between the first and second waveguide resonators, and between the third and second waveguide resonators.

[0010] The beneficial effects of this invention are as follows: 1. By setting a frequency adjustment screw for adjusting the main frequency and a zero adjustment screw for controlling the transmission zero in each waveguide resonant cavity, the TM102 mode achieves dual frequency in a single cavity. One single cavity realizes two resonant frequencies, and each single cavity can independently generate a transmission zero, thereby improving the near-end suppression effect. Moreover, the zero and the main channel resonant cavity are connected in parallel, which will not increase the passband loss and group delay.

[0011] 2. A frequency adjustment screw and a zero-point adjustment screw are installed in the waveguide resonant cavity, and the coupling window is designed as a trapezoidal window or other shape that matches the waveguide resonant cavity. The coupling window also features a coupling adjustment screw to adjust the coupling amount. Firstly, this design enables the formation of independent transmission zeros without cross-coupling, eliminating the structural space required for cross-coupling zeros and redundant resonant cavities, significantly reducing the overall product size and adapting to space-constrained applications. Secondly, it avoids increased signal loss and group delay due to excessive number of cavities or complex structures, ensuring low-loss and low-latency data transmission in the system. Thirdly, it provides a feasible technical solution with lower cost and better performance for waveguide filter product development, enhancing product competitiveness. Attached Figure Description

[0012] Figure 1 This is a three-dimensional structural schematic diagram of the high near-end suppression waveguide filter of the present invention; Figure 2 This is a schematic diagram of the internal structure of the high near-end suppression waveguide filter of the present invention; Figure 3 This is a top view of the high near-end suppression waveguide filter of the present invention; Figure 4 This is a cross-sectional view of the trapezoidal structure of the coupling window of the present invention; Figure 5 This is a simulation diagram showing the formation of the capacitive zero point in this invention; Figure 6 This is a simulation diagram for forming the inductive zero point of this invention.

[0013] In the figure: 1. Waveguide resonant cavity, 2. Waveguide cavity, 3. Coupling window, 4. Frequency adjustment screw, 5. Zero-point adjustment screw, 6. Coupling adjustment screw, 110. First waveguide resonant cavity, 120. Second waveguide resonant cavity, 130. Third waveguide resonant cavity, 210. Input waveguide, 220. Output waveguide. Detailed Implementation

[0014] The technical solution of the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0015] like Figure 1 As shown in Figure 4, a high near-end suppression waveguide filter includes a waveguide resonant cavity 1, a waveguide cavity 2, and a coupling window 3. Several waveguide resonant cavities 1 are provided, and adjacent waveguide resonant cavities 1 are connected through the coupling window 3. Several waveguide resonant cavities 1 are disposed between waveguide cavities 2. The filter also includes a frequency adjustment screw 4 and a zero-point adjustment screw 5. The frequency adjustment screw 4 is correspondingly disposed in each waveguide resonant cavity 1, located near the centerline of the high near-end suppression waveguide filter. The zero-point adjustment screw 5 is also correspondingly disposed in each waveguide resonant cavity 1, but located away from the centerline of the high near-end suppression waveguide filter. A coupling adjustment screw 6 for adjusting the coupling amount is also provided on the coupling window 3.

[0016] In this application, each of the waveguide resonant cavities 1 is provided with mounting holes adapted to the frequency adjustment screw 4 and the zero-point adjustment screw 5. The frequency adjustment screw 4 and the zero-point adjustment screw 5 extend into the waveguide resonant cavity 1 through the mounting holes, and the depth is adjustable.

[0017] The mounting hole engages with the frequency adjustment screw 4 and the zero-point adjustment screw 5. By adjusting the depth of the frequency adjustment screw 4 into the waveguide resonant cavity 1, the main frequency of the high near-end suppression waveguide filter is adjusted. By adjusting the depth of the zero-point adjustment screw 5 into the waveguide resonant cavity 1, the strength of the transmission zero is controlled, thereby realizing the TM102 mode, single cavity dual frequency, that is, one single cavity realizes two resonant frequencies, and each waveguide resonant cavity 1 can generate a transmission zero independently.

[0018] In this application, the upper part of the coupling window 3 is provided with a mounting hole adapted to the coupling adjustment screw 6. The coupling adjustment screw 6 extends into the coupling window 3 through the mounting hole, and the depth is adjustable.

[0019] In this application, the coupling window 3 is a trapezoidal window that is wider at the top and narrower at the bottom. The upper and lower parts of the trapezoidal window are two rectangles, and the length of the upper rectangle is greater than the length of the lower rectangle.

[0020] like Figure 3 As shown, the coupling window 3 is designed as a trapezoidal window with two rectangular structures, the upper rectangle being longer than the lower rectangle. It works in conjunction with the frequency adjustment screw 4 and the zero-point adjustment screw 5, which are provided in each waveguide resonant cavity 1, to adjust the main frequency and the strength of the zero point.

[0021] The upper height of coupling window 3 is set to H1, and the lower height is set to H2, where H1 is less than H2. By changing the shape of the trapezoid, the coupling strength can be effectively changed and the second resonant frequency can be used to form a transmission zero.

[0022] In this application, the waveguide resonant cavity 1 includes a first waveguide resonant cavity 110, a second waveguide resonant cavity 120, and a third waveguide resonant cavity 130. The waveguide cavity includes an input waveguide 210 and an output waveguide 220. One end of the first waveguide resonant cavity 110 is connected to the input waveguide 210, and the other end is connected to the second waveguide resonant cavity 120. One end of the third waveguide resonant cavity 130 is connected to the second waveguide resonant cavity 120, and the other end is connected to the output waveguide 220. The coupling window 3 is provided between the first waveguide resonant cavity 110 and the second waveguide resonant cavity 120, and the coupling window 3 is provided between the third waveguide resonant cavity 130 and the second waveguide resonant cavity 120.

[0023] Example 1 like Figure 4 As shown, the shapes of the first waveguide resonant cavity 110, the second waveguide resonant cavity 120 and the third waveguide resonant cavity 130 of the waveguide filter of this application are not limited to square. The coupling windows 3 between the waveguide resonant cavities 1 are all trapezoidal windows. In this case, the left zero point of the straight cavity can be realized, the three cavities realize three transmission zero points, and a single cavity can realize two resonant frequencies at the same time, and the phases are opposite, forming three transmission zero points on the left, that is, forming capacitive zero points on the left.

[0024] Example 2 like Figure 5 As shown, the shapes of the first waveguide resonant cavity 110, the second waveguide resonant cavity 120, and the third waveguide resonant cavity 130 of the waveguide filter of this application are not limited to square. The coupling windows 3 between the waveguide resonant cavities 1 are all window shapes that cooperate to realize the inductive zero. At this time, the right zero of the straight cavity can be realized, and the three cavities realize three transmission zeros. One waveguide resonant cavity 1 can realize two resonant frequencies at the same time, that is, an inductive zero is formed on the right side.

[0025] Example 3 By changing the size and shape of the first waveguide resonator 110, the second waveguide resonator 120, and the third waveguide resonator 130 (not limited to square shapes), and by combining the changes in the shape of the coupling window between the waveguide resonators 1, it is also possible to achieve a state with two capacitive zeros and one inductive zero, or a state with one capacitive zero and two inductive zeros.

[0026] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high near-end suppression waveguide filter, comprising a waveguide resonant cavity (1), a waveguide cavity (2), and a coupling window (3), wherein a plurality of waveguide resonant cavities (1) are provided, and adjacent two waveguide resonant cavities (1) are connected through the coupling window (3), and the plurality of waveguide resonant cavities (1) are disposed between the waveguide cavities (2). Its features are, It also includes a frequency adjustment screw (4) and a zero-point adjustment screw (5). The frequency adjustment screw (4) is correspondingly disposed in each of the waveguide resonant cavities (1) and located near the center line of the high near-end suppression waveguide filter. The zero-point adjustment screw (5) is also correspondingly disposed in each of the waveguide resonant cavities (1) and is far away from the center line of the high near-end suppression waveguide filter. The coupling window (3) is also provided with a coupling adjustment screw (6) for adjusting the coupling amount of the window.

2. The high near-end suppression waveguide filter according to claim 1, characterized in that, Each of the waveguide resonant cavities (1) is provided with mounting holes adapted to the frequency adjustment screw (4) and the zero-point adjustment screw (5). The frequency adjustment screw (4) and the zero-point adjustment screw (5) extend into the waveguide resonant cavity (1) through the mounting holes, and the depth is adjustable.

3. The high near-end suppression waveguide filter according to claim 1, characterized in that, The upper part of the coupling window (3) is provided with a mounting hole adapted to the coupling adjustment screw (6). The coupling adjustment screw (6) extends into the coupling window (3) through the mounting hole, and the depth is adjustable.

4. The high near-end suppression waveguide filter according to claim 3, characterized in that, The coupling window (3) is a trapezoidal window that is wider at the top and narrower at the bottom. The upper and lower parts of the trapezoidal window are two rectangles, and the length of the upper rectangle is greater than the length of the lower rectangle.

5. The high near-end suppression waveguide filter according to claim 1, 2, or 3, characterized in that, The waveguide resonant cavity includes a first waveguide resonant cavity (110), a second waveguide resonant cavity (120), and a third waveguide resonant cavity (130). The waveguide cavity (2) includes an input waveguide (210) and an output waveguide (220). One end of the first waveguide resonant cavity (110) is connected to the input waveguide (210), and the other end is connected to the second waveguide resonant cavity (120). One end of the third waveguide resonant cavity (130) is connected to the second waveguide resonant cavity (120), and the other end is connected to the output waveguide (220). The coupling window (3) is provided between the first waveguide resonant cavity (110) and the second waveguide resonant cavity (120), and the coupling window (3) is provided between the third waveguide resonant cavity and the second waveguide resonant cavity.

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