WO2014114265A1

WO2014114265A1 - Cavity filter

Info

Publication number: WO2014114265A1
Application number: PCT/CN2014/071469
Authority: WO
Inventors: 朱银虎; 袁进华; 朱其玉
Original assignee: 华为技术有限公司
Priority date: 2013-01-25
Filing date: 2014-01-26
Publication date: 2014-07-31
Also published as: CN103094649B; CN103094649A

Abstract

Disclosed is a cavity filter, relating to communication technologies, so as to achieve the purpose of improving a power capacity and a frequency regulation range of the filter in the case that the filter cavity depth is made small in size. The cavity filter comprises a cavity with an upper end opening, a cover plate, a tuning screw rod and a resonance rod. The resonance rod is fixed on a bottom plate of the cavity and is accommodated in the cavity. The cover plate is fixedly mounted at the opening of the cavity, and a screw hole is provided on the cover plate. The tuning screw rod matches the screw hole and one end thereof penetrates through the cover plate and extends into the cavity. The middle of the resonance rod is provided with a through hole, the tuning screw rod extends into the through hole, and the outer wall of the resonance rod is fixedly connected to the bottom plate of the cavity. The present invention improves a power capacity and a frequency regulation range of a filter in the case that the filter cavity depth is made small in size.

Description

CHAMBER FILTER This application claims priority to Chinese Application No. 2 01 31 002 8 27 1 . 3 , filed on January 25, 2003, the Chinese name of the invention entitled "cavity filter", all of which The content is incorporated herein by reference. Technical field

The present invention relates to communication technologies, and more particularly to a cavity filter. Background technique

A filter is a device that processes electromagnetic waves. Its main function is to let the useful signal pass through as much as possible without attenuation, and to reflect the unwanted signal as much as possible. At present, a cavity filter is commonly used in a base station system to perform frequency selection on a transmitted signal or a received signal. The cavity filter typically includes a cavity, a resonant rod, a tuning screw, and a cover plate. The cavity is provided with a plurality of cavities, the resonant rod is combined with the cavity, and is received in the cavity, the cover plate is installed at the opening of the cavity, and the cover plate is provided with a plurality of screw holes, the position and resonance of the screw holes The rod corresponds. The tuning screw mates with the screw and one end of the tuning rod extends into the resonant rod after passing through the cover. The frequency of the filter is adjusted at a specific power by adjusting the length of the tuning screw into the resonant rod. With the rapid development of microwave wireless communication and the popularity of wireless communication, operators are increasingly demanding miniaturization and weight reduction of cavity filters.

In the prior art, in order to reduce the volume of the cavity filter, the cavity depth of the cavity of the filter is usually made small, but as the cavity depth of the filter is made smaller, the power capacity and frequency of the filter are also adjusted. It will become smaller. Therefore, in the case where the filter cavity is deep, how to improve the power capacity and frequency adjustment range of the filter becomes the primary technical problem in the field of cavity filter. Invented content

The invention provides a cavity filter, in the case that the filter cavity is deep and small, The purpose of increasing the power capacity of the filter and the adjustment range of the frequency.

In order to achieve the above object, the present invention uses the following technical solutions:

In one aspect, a cavity filter is provided, including a cavity having an open upper end, a cover plate, a tuning screw, and a resonant rod, the resonant rod being fixed on a bottom plate of the cavity and housed in the cavity The cover plate is fixedly mounted at the opening of the cavity, and the cover plate is provided with a screw hole, the tuning screw is engaged with the screw hole and one end passes through the cover plate and extends into the cavity The through hole is disposed in the middle of the resonant rod, the tuning screw extends into the through hole, and an outer wall of the resonant rod is fixedly connected to a bottom plate of the cavity.

In a first possible implementation, the bottom plate of the cavity is provided with a boss having a circular cross section along a depth direction of the cavity, and an outer wall of the resonant rod is cooperatively coupled with an inner wall of the boss.

In conjunction with the first possible implementation, in a second possible implementation, the inner wall of the boss is provided with an internal thread, and the outer wall of the lower end of the resonant rod is provided with an external thread that cooperates with the internal thread. .

In a third possible implementation manner, the shape of the upper portion of the through hole along the depth direction of the cavity is a hexagon.

In a fourth possible implementation, the resonant rod is provided with at least two symmetrical mounting holes on the upper end surface in the depth direction of the cavity.

In conjunction with the first possible implementation, in a fifth possible implementation, the outer wall of the resonant rod is connected to the inner wall of the boss by an interference fit.

In a sixth possible implementation, the resonant rod has a step extending radially outward near a position connected to the boss, the step overlapping the top plane of the boss.

In a seventh possible implementation, the resonant rod is provided with a flange on a radially outward direction. According to the embodiment of the present invention, since the through hole is provided in the middle of the resonance rod, the tuning screw protrudes into the through hole and the outer wall of the resonance rod is fixedly connected with the bottom plate of the cavity, so that the tuning screw can extend into the vicinity in the cavity depth direction. The position of the bottom plate of the cavity, such that the through hole in the resonant rod can be fully utilized to achieve an increase in the adjustment margin of the tuning screw, thereby achieving the purpose of increasing the adjustment range of the filter frequency. Therefore, the cavity filter of the present invention can achieve the purpose of improving the adjustment range of the filter power capacity and frequency by increasing the adjustment margin of the tuning screw when the cavity depth is small. Attachment

In order to more clearly illustrate the technical solution of the embodiment of the present invention, the following will be an embodiment. BRIEF DESCRIPTION OF THE DRAWINGS The drawings used in the description are briefly described. It is obvious that the drawings in the following description are only some embodiments of the present invention, and those skilled in the art, without any creative work, Other drawings can be obtained from these figures.

1 is a cross-sectional view showing the structure of a cavity filter according to an embodiment of the present invention; FIG. 2 is a partial schematic view of FIG.

Figure 3 is a cross-sectional view of the resonant rod of Figure 1;

4 is a schematic perspective view of a cavity filter according to an embodiment of the present invention; FIG. 5 is another schematic perspective view of a cavity filter according to an embodiment of the present invention; Figure 7 is a cross-sectional view of the resonator rod of Figure 6;

Figure 8 is a partial schematic view of Figure 6. detailed description

The technical solutions in the embodiments of the present invention will be clearly described in conjunction with the drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

As shown in FIG. 1 and FIG. 6, a specific embodiment of the cavity filter provided by the present invention is a single-cavity filter including a cavity 11 with an open upper end, a cover 12, and a tuning screw 13 The oscillating rod 14 is fixed on the bottom plate 16 of the cavity 11 and received in the cavity 11. The cover plate 12 can be fixedly mounted on the opening of the cavity 11 by screwing or welding, and the cover plate 12 is mounted on the cover plate 12 a screw hole is provided, and the tuning screw 13 is engaged with the screw hole and one end passes through the cover plate 12 and protrudes into the cavity 11. The resonant rod 14 is provided with a through hole 15 therebetween, and the tuning screw 13 extends into the through hole 15, and The outer wall of the resonant rod 14 is fixedly connected to the bottom plate 16 of the cavity 11.

In the cavity filter provided by the embodiment of the present invention, since the through hole 15 is disposed in the middle of the resonant rod 14, the tuning screw 13 extends into the through hole 15 and the outer wall of the resonant rod 14 is fixedly connected with the bottom plate 16 of the cavity 11, so The tuning screw 13 can extend into the position close to the bottom plate 16 of the cavity 11 in the cavity depth direction, so that the through hole 15 in the resonant rod 14 can be fully utilized to achieve an increase in the adjustment margin of the tuning screw 13, thereby improving the filter. The purpose of the frequency adjustment range. Therefore, the cavity filter of the present invention can still improve tuning by making the cavity depth small. The adjustment margin of the screw achieves the purpose of increasing the adjustment range of the filter power capacity and frequency. As shown in FIG. 1 , FIG. 2 , FIG. 6 and FIG. 8 , as a further improvement of the above embodiment, the bottom plate 16 of the cavity 11 is provided with a boss 17 having a circular cross section along the depth direction of the cavity, and the resonant rod 14 is The outer wall is mated with the inner wall of the boss 17. This connection method is relatively simple and easy to implement, and at the same time, the thickness of the cavity bottom plate can be reduced to a certain extent, and the weight of the cavity filter can be reduced. The boss 17 may be integrally molded with the cavity 11, and the bottom plate 16 of the cavity 11 and the boss 17 may be fixed together by post-welding or other connection.

In the above embodiment, the resonant rod 14 and the boss 17 can be coupled by a screw connection (see Fig. 1) or an interference fit connection (see Fig. 6). When the threaded connection is used, as shown in Figs. 2 and 3, the internal thread 22 can be machined on the inner wall of the boss 17, and the external thread 31 fitted to the internal thread 22 can be machined on the outer wall of the lower end of the resonance rod 14. During installation, the portion of the resonant rod 14 having the external thread 31 needs to be screwed into the inner bore 21 of the boss 17 to be mated with the internal thread 22 of the boss 17. In order to facilitate the installation of the resonant rod 14, as shown in FIG. 4, we can design the shape of the upper portion of the through hole 15 in the resonant rod 14 to be hexagonal, so that we can use the mounting tool 41 having a hexagonal cross section. The resonant rod 14 is mounted, and one end of the mounting tool 41 is inserted into the hexagonal hole of the resonant rod 14 during specific mounting, and then the other end of the rotating mounting tool 41 is screwed into the inner hole of the boss 17 having the internal thread 22 21 in. Alternatively, as shown in FIG. 5, at least two symmetrical mounting holes 512 are provided on the upper end surface of the resonant rod 14, so that the resonant rod 14 can be mounted by means of the mounting tool 51, and the two pin bodies at the lower end of the tool 51 are mounted during installation. The 511 is inserted into the mounting hole 512, and the upper portion of the mounting tool 51 is manually rotated to realize the mounting of the resonant rod 14.

When the interference is connected by the interference fit as shown in FIG. 6, the outer diameter of the lower end portion of the resonance rod 14 can be designed to be slightly larger than the outer diameter of the boss 17, and by crimping or riveting during installation. The lower end of the resonant rod 14 is pressed into the inner hole 21 of the boss 17, and the interference fit connection between the resonant rod 14 and the boss 17 is achieved.

As shown in FIG. 3 and FIG. 7, in order to realize the mounting limit of the resonant rod 14 and the boss 17 when the resonant rod 14 is mounted, the resonant rod 14 can be extended radially outward near the position connected to the boss 17. A step 32 is provided which overlaps the top plane of the boss 17. Thus, when the resonant rod 14 is screwed or pressed into the inner hole 21 of the boss 17, when the step 32 is overlapped on the top plane of the boss 17, it is proved that it has been installed in place, so as to avoid the installation being too shallow, resulting in insufficient firmness or too deep installation. Affect the accuracy of the frequency. The step 32 is preferably integrally formed with the resonant rod 14.

Since the filter cavity is deeper, the frequency will increase, in order to reduce the frequency to the required The desired frequency band, as shown in Figures 3 and 7, is provided with a flange 18 radially outward of the resonant rod 14. The flange 18 is preferably integrally formed with the resonant rod 14.

As shown in FIG. 1 and FIG. 6, the nut 19 is fitted to the tuning screw 13, so that when the tuning screw 13 is adjusted, the nut 19 is first loosened, and when the position is adjusted to the required position, the nut 19 is tightened and the adjusting screw 13 is adjusted. The cover plates 12 are fixedly coupled together.

The above is only the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any change or replacement that can be easily conceived by those skilled in the art within the technical scope of the present invention is All should be covered by the scope of the present invention. Accordingly, the scope of the invention should be determined by the scope of the appended claims.

Claims

claims

1. A cavity filter, including a cavity with an upper end open, a cover plate, a tuning screw and a resonant rod. The resonant rod is fixed on the bottom plate of the cavity and accommodated in the cavity. The cover plate It is fixedly installed at the opening of the cavity, and the cover plate is provided with a screw hole. The tuning screw cooperates with the screw hole and has one end passing through the cover plate and extending into the cavity. Its characteristics Preferably, a through hole is provided in the middle of the resonant rod, the tuning screw extends into the through hole, and the outer wall of the resonant rod is fixedly connected to the bottom plate of the cavity.

2. The cavity filter according to claim 1, wherein a boss with a circular cross-section is provided on the bottom plate of the cavity along the depth direction of the cavity, and the outer wall of the resonance rod is connected to the boss. The inner wall of the table is matched and connected.

3. The cavity filter according to claim 2, wherein the inner wall of the boss is provided with internal threads, and the outer wall of the lower end of the resonant rod is provided with external threads that cooperate with the internal threads.

4. The cavity filter according to any one of claims 1 to 3, characterized in that the shape of the upper part of the through hole along the cavity depth direction is hexagonal.

5. The cavity filter according to any one of claims 1 to 4, characterized in that, the resonance

6. The cavity filter according to any one of claims 2-5, characterized in that the resonant rod is connected to the boss with an interference fit.

7. The cavity filter according to any one of claims 2 to 6, characterized in that, the resonant rod has a step extending radially outward near the position connected to the boss, and the step is Connected to the top plane of the boss.

8. The cavity filter according to any one of claims 1 to 7, characterized in that the resonant rod is provided with a flange radially outward.