阅读说明：本技术 带零点的波导低通滤波器 (Waveguide low-pass filter with zero point ) 是由 江顺喜 殷实 梁国春 项显 宋昕宇 于 2021-07-30 设计创作，主要内容包括：本发明公开了一种带零点的波导低通滤波器,涉及电子通讯技术领域,解决了现有波导低通滤波器对近端杂散不能很好抑制的技术问题,其技术方案要点是在输入波导或输出波导端增加矩形凹陷,该矩形凹陷可以产生一个横向谐振,从而可以实现传输零点。传输零点的存在使得在不增加滤波器阶数的情况下,能够大大增加滤波器对近端杂散的抑制度。矩形凹陷与输入波导或输出波导共同作用,在滤波器的传输通带内实现两个谐振,实现传输极点。中间谐振腔的谐振柱为向上突起的金属柱,该金属谐振柱的顶端距离盖板的间隙很小,相当在中间谐振腔的顶端加载了一个很大的电容,使得中间谐振腔的第二个寄生的谐振会距离滤波器的通带频率很远,实现对远端谐波的抑制。(The invention discloses a waveguide low-pass filter with a zero point, which relates to the technical field of electronic communication and solves the technical problem that the conventional waveguide low-pass filter cannot well inhibit near-end stray. The presence of the transmission null enables the degree of rejection of the near-end spurs by the filter to be greatly increased without increasing the filter order. The rectangular recess and the input waveguide or the output waveguide act together to realize two resonances in the transmission pass band of the filter and to realize the transmission pole. The resonant column of the middle resonant cavity is an upward-protruding metal column, the gap between the top end of the metal resonant column and the cover plate is small, and equivalently, a large capacitor is loaded at the top end of the middle resonant cavity, so that the second parasitic resonance of the middle resonant cavity can be far away from the passband frequency of the filter, and the suppression of far-end harmonic waves is realized.)

1. The waveguide low-pass filter with the zero point is characterized by comprising a cover plate (8) and a body which are connected with each other, wherein the body comprises an input waveguide (1), an output waveguide (2), a resonant cavity and a rectangular recess (4);

the resonant cavities comprise a first resonant cavity (3), a second resonant cavity (6) and an intermediate resonant cavity (7), the first resonant cavity (3) is connected with the input waveguide (1), and the second resonant cavity (6) is connected with the output waveguide (2); the intermediate resonant cavity (7) is arranged between the first resonant cavity (3) and the second resonant cavity (6), and the intermediate resonant cavity (7) comprises at least one resonant column (5);

one end of the rectangular recess (4) is connected with the first resonant cavity (3) and/or the second resonant cavity (6), and the other end is connected with the middle resonant cavity (7).

2. The waveguide low-pass filter with zero of claim 1, characterized in that said rectangular recesses (4) are 1 or 2, comprising:

when the number of the rectangular depressions (4) is 1, the rectangular depressions (4) are arranged between the first resonant cavity (3) and the middle resonant cavity (7); or the rectangular recess (4) is arranged between the second resonant cavity (6) and the intermediate resonant cavity (7);

when the number of the rectangular depressions (4) is 2, one rectangular depression (4) is arranged between the first resonant cavity (3) and the middle resonant cavity (7), and the other rectangular depression (4) is arranged between the second resonant cavity (6) and the middle resonant cavity (7).

3. A zero-equipped waveguide low pass filter according to claim 2, characterized in that the input waveguide, the output waveguide and the resonator are rectangular and the resonator cylinder (5) is a cuboid or a cube or a cylinder.

4. A zero-equipped waveguide low-pass filter according to claim 3, characterized in that said first resonator cavity (3) and said second resonator cavity (6) are both double film cavities, including TE201 mode and TM101 mode.

5. Waveguide low-pass filter with zero according to any of claims 1-4, characterized in that when there are 2 rectangular recesses (4), the length, width and depth of each of said rectangular recesses (4) are the same.

Technical Field

The present disclosure relates to the field of electronic communications technologies, and in particular, to a waveguide low-pass filter with a zero point.

Background

In electronic communication equipment in the microwave frequency band, a waveguide filter is often needed to filter out harmonics and spurs, because these harmonics and spurs interfere with the normal operation of the electronic equipment after being amplified by an amplifier. In addition, modern radar and communication equipment increase the peak power and average power output in pursuit of longer range, but high power transmitters inevitably bring about excessively high harmonic power, and the harmonic and stray energy of the high power transmitters can seriously interfere with and even burn electronic equipment. In addition, electronic devices that fail to output harmonics and spurs cannot obtain factory licenses from the radio regulatory committee. The harmonics and spurious spectral energy output by the electronics must be filtered out at the rf front end.

The common waveguide low-pass filter adopts a ridge waveguide form, is simple in structure, adopts Chebyshev and other ripple responses, has good inhibition on far-end harmonic waves, but has no good inhibition on near-end stray waves.

Disclosure of Invention

The present disclosure provides a waveguide low-pass filter with a zero point, which aims to improve the suppression effect of the low-pass filter on near-end stray.

The technical purpose of the present disclosure is achieved by the following technical solutions:

a waveguide low-pass filter with a zero point comprises a cover plate and a body which are connected with each other, wherein the body comprises an input waveguide, an output waveguide, a resonant cavity and a rectangular recess;

the resonant cavities comprise a first resonant cavity, a second resonant cavity and an intermediate resonant cavity, the first resonant cavity is connected with the input waveguide, and the second resonant cavity is connected with the output waveguide; the intermediate resonant cavity is arranged between the first resonant cavity and the second resonant cavity and comprises at least one resonant column;

one end of the rectangular recess is connected with the first resonant cavity and/or the second resonant cavity, and the other end of the rectangular recess is connected with the middle resonant cavity.

The beneficial effect of this disclosure lies in: according to the waveguide low-pass filter with the zero point, the rectangular recess is additionally arranged at the input waveguide end or the output waveguide end, and the rectangular recess can generate transverse resonance, so that the transmission zero point can be realized. The presence of the transmission null enables the degree of rejection of the near-end spurs by the filter to be greatly increased without increasing the filter order. In addition, the rectangular depression and the input waveguide or the output waveguide act together to realize two resonances in the transmission passband of the filter, thereby realizing a transmission pole. The resonant column of the middle resonant cavity is an upward-protruding metal column, and the gap between the top end of the metal resonant column and the cover plate is small, so that a large capacitor is loaded at the top end of the middle resonant cavity, and the second parasitic resonance of the middle resonant cavity can be far away from the passband frequency of the filter, thereby realizing the suppression of far-end harmonic waves.

The low-pass filter has the advantages of small volume, light weight, easy processing and low cost, and the response curve can obtain good out-of-band rejection performance by using fewer orders.

Drawings

FIG. 1 is a schematic diagram of a filter according to an embodiment of the present application;

FIG. 2 is a magnetic field distribution diagram for the TE201 mode;

FIG. 3 is a diagram of a TM101 mode resonant magnetic field distribution;

FIG. 4 is a magnetic field distribution plot of the resonance frequency of the stop band transmission zero;

FIG. 5 is a frequency response curve of a filter according to the present application;

FIG. 6 is a dimensional schematic of an embodiment of the filter operating at 38 Ghz;

in the figure: 1-an input waveguide; 2-an output waveguide; 3-a first resonant cavity; 4-rectangular recess; 5-a resonant column; 6-a second resonant cavity; 7-intermediate resonant cavity; 8-cover plate.

Detailed Description

The technical scheme of the disclosure will be described in detail with reference to the accompanying drawings. In the description of the present application, it is to be understood that the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated, but merely as distinguishing between different components.

Further, the terms "intermediate," "between," "top," "up," "left-to-right," and the like, indicate an orientation or positional relationship based on that shown in the drawings, merely for convenience in describing the application and for simplicity in description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed in a particular orientation, and be operated, and therefore should not be construed as limiting the application.

Fig. 1 is a schematic structural diagram of an embodiment of the filter according to the present application, and as shown in fig. 1, the filter includes a cover plate 8 and a body connected to each other, and the body includes an input waveguide 1, an output waveguide 2, a resonant cavity and a rectangular recess 4.

The resonant cavity comprises a first resonant cavity 3, a second resonant cavity 6 and a middle resonant cavity 7, the first resonant cavity 3 is connected with the input waveguide 1, the second resonant cavity 6 is connected with the output waveguide 2, and the first resonant cavity 3 and the second resonant cavity 6 are realized by waveguides smaller than standard narrow sides.

The first resonant cavity 3 and the second resonant cavity 6 are both double-film cavities, and include a TE201 mode and a TM101 mode, fig. 2 is a magnetic field distribution diagram of the TE201 mode, and fig. 3 is a TM101 mode resonant magnetic field distribution diagram.

The intermediate resonant cavity 7 is arranged between the first resonant cavity 3 and the second resonant cavity 6, and the intermediate resonant cavity 7 comprises four resonant columns 5.

One end of the rectangular recess 4 is connected with the first resonant cavity 3 and/or the second resonant cavity 6, and the other end is connected with the resonant column 5. The number of the rectangular recesses 4 is 1 or 2.

When the number of the rectangular depressions 4 is 1, the rectangular depression 4 is arranged between the first resonant cavity 3 and the intermediate resonant cavity 7; or the rectangular depression 4 is arranged between the second resonant cavity 6 and the intermediate resonant cavity 7;

when the number of the rectangular depressions 4 is 2, one rectangular depression 4 is provided between the first resonant cavity 3 and the resonant column 5, and the other rectangular depression 4 is provided between the second resonant cavity 6 and the resonant column 5.

When rectangular depressions are added to both the input end and the output end of the filter, two transmission zeros can be realized, and due to the existence of the transmission zeros, the suppression degree of the filter on the near-end stray can be greatly increased under the condition that the order of the filter is not increased, and fig. 4 is a magnetic field distribution diagram of the resonance frequency of the stop band transmission zeros. Meanwhile, the rectangular recess and the rectangular input waveguide and the rectangular output waveguide of the filter act together to realize two resonances in the transmission passband of the filter, thereby realizing two transmission poles. Fig. 5 is a frequency response curve of the filter, and it can be seen from fig. 5 that two transmission zeros formed by two rectangular recesses of the filter greatly increase the degree of near-end spurious suppression of the filter.

Input waveguide, output waveguide and resonant cavity all are the rectangle, and the resonance post is the cuboid (also can be square or cylinder), and the resonance post is the metal resonance post, and the top of these metal resonance posts is very little apart from the clearance of apron, consequently has loaded a very big electric capacity on the top of this syntonizer, because the existence of this electric capacity, can make the spurious resonance of second of middle resonant cavity can be very far away from the passband frequency of wave filter to the realization is to the suppression of distal end harmonic.

The number of the rectangular depressions can be 1 or 2, and when only one depression is provided, a transmission zero point is generated; when the number of the rectangular depressions 4 is 2, two transmission zeros are generated; the rectangular depressions 4 are different in length, width, and depth, and the generated transmission zero points are different in position. The length, the width and the depth of each resonant column 5 are the same, and the distance between the adjacent resonant columns is different according to different coupling coefficients. The actual simulated dimensions may differ slightly depending on the effect.

As a specific embodiment, when the center frequency of the filter is 38GHz, the dimensions of each component of the filter are as shown in fig. 6, fig. 6 is a dimension labeled according to a simulation diagram of the filter, the first resonator to the second resonator are from left to right, the resonant columns are respectively labeled as a resonant column a, a resonant column b, a resonant column c, and a resonant column d from left to right, and the rectangular recesses are respectively a rectangular recess a and a rectangular recess b from left to right, then the dimensions (mm) of each component are respectively: the first resonant cavity length is 3.75, the rectangular depression a is 1.03, the distance from the rectangular depression a to the resonant column a is 3.01, the length of the resonant column a is 0.8, the distance from the resonant column a to the resonant column b is 1.96, the length of the resonant column b is 0.88, the distance from the resonant column b to the resonant column c is 1.9, the length of the resonant column c is 0.89, the distance from the resonant column c to the resonant column d is 1.93, the length of the resonant column d is 0.82, the distance from the resonant column d to the rectangular depression b is 3, the length of the rectangular depression b is 1.03, and the length of the second resonant cavity is 3.76.

The rectangular depressions a and b each had a depth of 2.35 and a width of 4.96.

The depth of each of the resonant pillars a to d is 1.04, and the width thereof is 0.7.

The first cavity and the second cavity both had a depth of 1.46 and a width of 4.96.

The input and output waveguides have a width of 7.

When the filter is at different central frequencies, the sizes corresponding to all the components of the filter can be calculated according to simulation software, so that the suppression of the filter on near-end stray is improved.

The foregoing is an exemplary embodiment of the present application, and the scope of the present application is defined by the claims and their equivalents.