CN217086845U

CN217086845U - Cavity filter

Info

Publication number: CN217086845U
Application number: CN202220615360.2U
Authority: CN
Inventors: 杜江; 矣峻岭
Original assignee: Chengdu Meishu Technology Co ltd
Current assignee: Chengdu Meishu Technology Co ltd
Priority date: 2022-03-21
Filing date: 2022-03-21
Publication date: 2022-07-29
Anticipated expiration: 2032-03-21

Abstract

The utility model discloses a cavity filter, include: a main signal transmission layer and a topology layer; the main signal transmission layer and the topology layer comprise a plurality of resonance units, and the number of the resonance units of the main signal transmission layer and the topology layer is the same; the plurality of resonance units of the main signal transmission layer are divided into two rows, and adjacent resonance units in the same row are connected through a main signal transmission channel; the two resonance units respectively positioned at the two columns of tail ends are connected through a main signal transmission channel; the resonance unit at the head end of one row is connected with the input port through the probe, and the resonance unit at the head end of the other row is connected with the output port through the probe; the plurality of resonance units of the topology layer correspond to the plurality of resonance units of the main signal transmission layer one by one, and the resonance units of the topology layer are connected with the resonance units of the main signal transmission layer through interlayer signal transmission channels. The cavity filter can reduce the floor area of the cavity dual-passband filter and enables the structure of the cavity filter to be more compact.

Description

Cavity filter

Technical Field

The utility model relates to a digital signal processing technology field particularly, relates to a cavity filter.

Background

A microwave filter is a device that separates signals, allows useful signals to pass through as unattenuated as possible, and attenuates unnecessary signals as much as possible to prevent the unwanted signals from passing through. Microwave band-pass filters are indispensable devices for transmitting ends and receiving ends in modern communication systems, and the quality of the performance of the microwave band-pass filters often affects the quality of the whole communication system. The cavity filter has the advantages of high Q value, high power capacity, steep out-of-band attenuation, narrow bandwidth and the like, and is widely applied to wireless communication and satellite communication. The dielectric cavity filter has the advantages of simple structural design, flexible cavity arrangement, low production cost and the like, and is generally applied to production design.

With the development of wireless communication, frequency division is increasingly finer, and the requirement of a communication system on the technical index of a filter is also higher. Modern communication systems may operate in multiple frequency bands, requiring dual or even multi-band filters to select signals in different frequency bands. Currently, the research on the dual-band filter mainly includes: the band-pass filter is cascaded with the band-pass filter to form a dual-band filter, the dual-band filter obtained by the method comprises two different filters, and the floor area of the filters is increased; two cascaded band-pass filters are connected in parallel to form a dual-band-pass filter, and the occupied area of the filter is increased.

In view of this, the present application is specifically made.

SUMMERY OF THE UTILITY MODEL

The utility model discloses the technical problem that will solve is: a traditional cavity dual-passband filter adopts a linear structure, and for a multi-order filter, the size of a single dimension is large. The cavity filter is bent into a U-shaped structure, and a double-layer topological structure is adopted to realize the double-passband filtering function of the cavity filter, so that the structure of the traditional cavity double-passband filter is changed from a one-dimensional linear structure to a two-dimensional plane, and the two-dimensional plane is expanded into a three-dimensional structure, so that the occupied area of the filter is reduced.

The utility model discloses a following technical scheme realizes:

a cavity filter, comprising: a main signal transmission layer and a topology layer; the main signal transmission layer and the topology layer comprise a plurality of resonance units, and the number of the resonance units of the main signal transmission layer and the number of the resonance units of the topology layer are the same; the plurality of resonance units of the main signal transmission layer are divided into two rows, and adjacent resonance units in the same row are connected through a main signal transmission channel; the two resonance units respectively positioned at the two columns of tail ends are connected through a main signal transmission channel; the resonance unit at the head end of one row is connected with the input port through the probe, and the resonance unit at the head end of the other row is connected with the output port through the probe; the plurality of resonance units of the topological layer correspond to the plurality of resonance units of the main signal transmission layer one by one, and the resonance units of the topological layer are connected with the resonance units of the main signal transmission layer through interlayer signal transmission channels.

As a further description of the present invention, the resonance unit includes: a metal cavity and a dielectric resonator; the bottom surface of the metal cavity is a low dielectric constant base; the dielectric resonator is fixed on the low dielectric constant base and is positioned in the metal cavity.

As a further description of the present invention, the top surface of the metal cavity is a tuning cover plate, and the tuning cover plate is connected to the top of the dielectric resonator through a screw.

As a further description of the present invention, the metal cavity is a cubic structure; each side surface of the metal cavity is provided with a longitudinal coupling window for connecting a main signal transmission channel; the low dielectric constant base and the tuning cover plate are provided with transverse coupling windows for connecting interlayer signal transmission channels; in an unconnected state, the longitudinal coupling window and the lateral coupling window are closed.

As a further description of the present invention, in the overlooking angle, the angle formed by the intersection of each side surface of the metal cavity is a chamfer.

As a further description of the present invention, the metal cavity is a cylindrical structure; a plurality of longitudinal coupling windows used for connecting the main signal transmission channel are arranged on the side wall of the metal cavity at intervals; the low dielectric constant base and the tuning cover plate are provided with transverse coupling windows for connecting interlayer signal transmission channels; in the unconnected state, the longitudinal coupling window and the lateral coupling window are closed.

As a further description of the present invention, the main signal transmission channel or the interlayer signal transmission channel includes: a media channel and a coupling screw; the coupling screw is located in the middle of the medium channel.

As a further description of the present invention, the probe and the input port connected end are provided with a matching layer of PML material, and the probe and the output port connected end are provided with a matching layer of PML material.

As a further description of the present invention, the equivalent circuit of the cavity filter includes a plurality of dual-passband filter units, two adjacent dual-passband filter units are connected by a transmission element, and the plurality of dual-passband filter units are cascaded by a plurality of transmission elements to form a dual-passband filter circuit; one end of the dual-passband filter circuit is connected with a power supply through a transmission element, and the other end of the dual-passband filter circuit is connected with a load through the transmission element.

As a further description of the present invention, the dual-passband filter unit includes two cavity filter circuits, one end of one of the cavity filter circuits is grounded, and the other end is grounded after being connected in series with the other cavity filter circuit through the transmission element; the cavity filter circuit comprises an inductor and a capacitor which are connected in parallel.

Compared with the prior art, the utility model, following advantage and beneficial effect have:

1. the embodiment of the utility model provides a cavity filter, buckle traditional one-dimensional linear type cavity dual-passband filter into U-shaped structure, reduced the area of cavity dual-passband filter, adopt bilayer structure to make the structure of filter compacter simultaneously;

2. the embodiment of the utility model provides a cavity filter, adopt the metal sheet of low dielectric constant as the cavity base of resonance unit, and place the dielectric resonator on low dielectric constant base, can reduce cavity energy loss;

3. the embodiment of the utility model provides a cavity filter adopts the tuning cover plate as the cavity top cap of resonance unit, and is fixed on the dielectric resonator by the fixing screw, realizes changing the height of the tuning cover plate by adjusting the fixing screw, thereby tuning the function of frequency;

4. the embodiment of the utility model provides a pair of cavity filter, metal cavity's side, top surface and ground are provided with the coupling window that is used for connecting the coupling passageway, have increased the coupling face of resonant unit, realize the nimble expansion to the wave filter to and realize that the shape is diversified, satisfy different application scenes.

5. The embodiment of the utility model provides a cavity filter, set up the chamfer to the metal cavity of cube structure, the processing of being convenient for in kind;

6. the embodiment of the utility model provides a pair of cavity filter, the PML material layer that the probe tip increases has improved the matching degree of probe and input/output port.

Drawings

In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and that for those skilled in the art, other related drawings can be obtained from these drawings without inventive effort.

Fig. 1 is a schematic structural view of a cavity filter with a double-layer U-shaped structure according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a main signal transmission layer according to an embodiment of the present invention;

fig. 3 is a schematic view of an uplink two-side resonance unit and a connection mode thereof according to an embodiment of the present invention;

fig. 4 is a schematic diagram of a connection relationship between a resonant unit located at the end of a single row and an adjacent resonant unit according to an embodiment of the present invention;

fig. 5 is an equivalent circuit diagram corresponding to the cavity filter with a double-layer U-shaped structure provided in the embodiment of the present invention.

Reference numbers and corresponding part names in the drawings:

1-main signal transmission layer, 2-topological layer, 3-resonance unit, 4-main signal transmission channel, 5-probe, 8-interlayer signal transmission channel, 9-dual-passband filter unit, 10-transmission element, 31-metal cavity, 32-dielectric resonator, 33-low dielectric constant base, 34-tuning cover plate, 51-matching layer, 81-dielectric channel, 82-coupling screw, 91-cavity filter circuit, 311-longitudinal coupling window and 312-transverse coupling window.

Detailed Description

To make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the following examples and drawings, and the exemplary embodiments and descriptions thereof of the present invention are only used for explaining the present invention, and are not intended as limitations of the present invention.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those of ordinary skill in the art that: it is not necessary to employ these specific details to practice the invention. In other instances, well-known structures, circuits, materials, or methods have not been described in detail so as not to obscure the present invention.

Throughout the specification, reference to "one embodiment," "an embodiment," "one example," or "an example" means: the particular features, structures, or characteristics described in connection with the embodiment or example are included in at least one embodiment of the present invention. Thus, the appearances of the phrases "one embodiment," "an embodiment," "one example" or "an example" in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, or characteristics may be combined in any suitable combination and/or sub-combination in one or more embodiments or examples. Further, those of ordinary skill in the art will appreciate that the illustrations provided herein are for illustrative purposes and are not necessarily drawn to scale. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In the description of the present invention, the terms "front", "back", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inner", "outer", etc. indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the scope of the present invention.

Examples

For reducing the floor area of dual-passband cavity filter, this embodiment provides a cavity filter of double-deck U-shaped structure, improves traditional cascaded dual-passband filter, extends the linear filter of one-dimensional to the two-dimensional plane, adopts superimposed layer structure to extend the filter from the two-dimensional plane to three-dimensional spatial structure simultaneously to solve traditional cavity dual-passband filter and adopt linear type structure, to multistage filter, the big problem of size of its single dimension.

Specifically, the cavity filter with the double-layer U-shaped structure provided in this embodiment is shown in fig. 1, and includes: a main signaling layer 1 and a topology layer 2. Wherein, the main signal transmission layer 1 and the topology layer 2 both comprise 8 resonance units 3 with the same structure. The 8 resonance units 3 of the main signal transmission layer 1 are equally divided into two columns, and each column is composed of 4 resonance units 3 which are arranged in a word at intervals. In the main signal transmission layer 1, adjacent resonance units 3 located in the same column are connected by a main signal transmission channel 4; the two resonance units 3 respectively positioned at the two columns of tail ends are connected through a main signal transmission channel 4; the resonance unit 3 at the head end of one row is connected with the input port through the probe 5, and the resonance unit 3 at the head end of the other row is connected with the output port through the probe 5; since the main signal transmission layer 1 has a bilaterally symmetric structure, the input terminal and the output terminal are determined as the case may be. 8 resonance units 3 of

topology layer

2 and 8 resonance units 3 of main signal transmission layer 1 one-to-one, in this embodiment, the resonance units 3 of topology layer 2 all set up directly over the resonance unit 3 of main transmission layer, the resonance unit 3 of topology layer 2 with the resonance unit 3 of main signal transmission layer 1 passes through interlayer signal transmission channel 8 and connects.

Fig. 2 shows an arrangement and connection of 8 resonant units 3 of the main signal transmission layer 1, and fig. 3 shows an arrangement and connection of 8 resonant units 3 of the topology layer 2. Therefore, the cavity filter with the double-layer U-shaped structure is in a vertically and horizontally symmetrical structure in the overall structure.

It can be seen from the structure of the cavity filter provided in this embodiment that the cavity filter bends the traditional cascaded linear pass-band filter, and expands the one-dimensional linear structure to the two-dimensional planar structure on the premise of not changing the main signal transmission line and transmission function of the filter, thereby reducing the size occupied by the filter in a single dimension. It should be noted that, in order to explain the improved principle of the cavity filter described in the present application, the linear cavity filter is bent only once in this embodiment, so as to obtain a simpler U-shaped structure as shown in fig. 2. Of course, according to the practical situation, when the order of the filter is larger, the number of the resonant units 3 is larger, and the application scenario of the cavity filter is combined, the linear cavity filter may also be bent for multiple times to obtain other two-dimensional structures with different shapes, such as S-shaped structures, zigzag structures, etc., but the connection mode between the adjacent resonant units 3 in the same column and between the two resonant units 3 at the intersection of different columns is the same as the connection mode between the resonant units 3 in the U-shaped structure provided in this embodiment, please refer to fig. 4. The U-shaped structure of main signal transmission layer 1 has realized single passband filtering function, on this basis, 8 resonance unit 3 of

topological layer

2 and 8 resonance unit 3 one-to-one of main signal transmission layer 1, and connect through the transverse coupling passageway, dual passband filtering function has been realized, the three-dimensional structure has been extended to the cavity filter structure with two-dimentional simultaneously, the area occupied by the wave filter on the two-dimensional plane has further been reduced, and this three-dimensional structure makes the structure of wave filter compacter, more be favorable to realizing the miniaturization.

Further, referring to any one of fig. 1 to 4, the resonance unit 3 includes: a metal cavity 31 and a dielectric resonator 32; the bottom surface of the metal cavity 31 is a low dielectric constant base 33. The dielectric resonator 32 is fixed on the low-permittivity base 33, and the dielectric resonator 32 is located inside the metal cavity 31. The purpose of using a low dielectric constant pedestal 33 is to reduce the energy loss of the cavity. And, the top surface of the metal cavity 31 is a tuning cover plate 34, and the tuning cover plate 34 is connected with the top of the dielectric resonator 32 by a screw. The purpose of using the tuning cover plate 34 and screwing is to achieve the function of changing the height of the tuning cover plate 34 by adjusting the fixing screws, thereby tuning the frequency.

In this embodiment, two metal cavity 31 structures are provided. One is a cubic structure and the other is a cylindrical structure. For the metal cavity 31 with a cubic structure, a longitudinal coupling window 311 for connecting the main signal transmission channel 4 is arranged on each side surface of the metal cavity 31; the low dielectric constant base 33 and the tuning cover plate 34 are provided with transverse coupling windows 312 for connecting the interlayer signal transmission channels 8; in the unconnected state, the longitudinal coupling window 311 and the lateral coupling window 312 are closed. For the metal cavity 31 with a cylindrical structure, a plurality of longitudinal coupling windows 311 for connecting the main signal transmission channel 4 are arranged on the cylindrical side surface of the metal cavity 31, and the number of the coupling windows is determined according to the number of the resonance units 3 which need to be cascaded actually; the low dielectric constant base 33 and the tuning cover plate 34 are provided with transverse coupling windows 312 for connecting the interlayer signal transmission channels 8; in the unconnected state, the longitudinal coupling window 311 and the lateral coupling window 312 are closed. The purpose of arranging a plurality of coupling windows on the side wall of the metal cavity 31 (cube structure, cylindrical structure or other regular polygonal structures) is to increase the coupling surface of the resonant unit 3, realize the flexible expansion of the filter, realize the shape diversification, and meet different application scenarios. It should be noted that the corners formed at the intersection of the side surfaces of the metal cavity 31 are chamfers, which facilitates the physical processing.

Further, a medium passage 81 and a coupling screw 82; the coupling screw 82 is located at the middle of the medium passage 81.

In order to improve the matching degree between the probe 5 and the input/output port, a matching layer 51 made of PML material is disposed at one end of the probe 5 connected to the input port or the output port in this embodiment.

In addition, as shown in fig. 5, the equivalent circuit corresponding to the 16-port cavity filter includes 16 dual-passband filter units 9, two adjacent dual-passband filter units 9 are connected by a transmission element 10, and the multiple dual-passband filter units 9 are cascaded by multiple transmission elements 10 to form a dual-passband filter circuit; one end of the dual-passband filter circuit is connected to a power source through a transmission element 10, and the other end is connected to a load through the transmission element 10. The dual-passband filter unit 9 comprises two cavity filter circuits 91, wherein one end of one cavity filter circuit 91 is grounded, and the other end of the one cavity filter circuit 91 is grounded after being connected in series with the other cavity filter circuit 91 through a transmission element 10; the cavity filter circuit 91 includes an inductor and a capacitor connected in parallel.

The above-mentioned embodiments, further detailed description of the objects, technical solutions and advantages of the present invention, it should be understood that the above description is only the embodiments of the present invention, and is not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A cavity filter, comprising: a main signal transmission layer (1) and a topology layer (2); the main signal transmission layer (1) and the topology layer (2) comprise a plurality of resonance units (3), and the number of the resonance units (3) of the main signal transmission layer (1) and the topology layer (2) is the same; the plurality of resonance units (3) of the main signal transmission layer (1) are divided into two rows, and adjacent resonance units (3) in the same row are connected through a main signal transmission channel (4); the two resonance units (3) respectively positioned at the two columns of tail ends are connected through a main signal transmission channel (4); the resonance unit (3) at the head end of one row is connected with the input port through the probe (5), and the resonance unit (3) at the head end of the other row is connected with the output port through the probe (5); the plurality of resonance units (3) of the topology layer (2) correspond to the plurality of resonance units (3) of the main signal transmission layer (1) one by one, and the resonance units (3) of the topology layer (2) are connected with the resonance units (3) of the main signal transmission layer (1) through interlayer signal transmission channels (8).

2. A cavity filter according to claim 1, wherein the resonator unit (3) comprises: a metal cavity (31) and a dielectric resonator (32); the bottom surface of the metal cavity (31) is a low-dielectric-constant base (33); the dielectric resonator (32) is fixed on the low dielectric constant base (33), and the dielectric resonator (32) is positioned inside the metal cavity (31).

3. A cavity filter according to claim 2, wherein the top surface of the metal cavity (31) is a tuning cover plate (34), and the tuning cover plate (34) is connected to the top of the dielectric resonator (32) by screws.

4. A cavity filter according to claim 3, wherein the metal cavity (31) is of a cubic structure; each side surface of the metal cavity (31) is provided with a longitudinal coupling window (311) used for connecting a main signal transmission channel (4); the low dielectric constant base (33) and the tuning cover plate (34) are provided with transverse coupling windows (312) for connecting interlayer signal transmission channels (8); in the unconnected state, the longitudinal coupling window (311) and the transverse coupling window (312) are closed.

5. A cavity filter according to claim 4, wherein the corners formed by the intersections of the side surfaces of the metal cavity (31) are chamfered in top view.

6. A cavity filter according to claim 3, wherein the metal cavity (31) is a cylindrical structure; a plurality of longitudinal coupling windows (311) used for connecting the main signal transmission channel (4) are arranged on the side wall of the metal cavity (31) at intervals; the low dielectric constant base (33) and the tuning cover plate (34) are provided with transverse coupling windows (312) for connecting interlayer signal transmission channels (8); in the unconnected state, the longitudinal coupling window (311) and the transverse coupling window (312) are closed.

7. A cavity filter according to any of claims 1-5, wherein the main signal transmission channel (4) or the interlayer signal transmission channel (8) comprises: a media channel (81) and a coupling screw (82); the coupling screw (82) is located in the middle of the medium channel (81).

8. A cavity filter according to claim 1, wherein the end of the probe (5) connected to the input port is provided with a matching layer (51) of PML material, and the end of the probe (5) connected to the output port is provided with a matching layer (51) of PML material.

9. The cavity filter according to claim 1, wherein the equivalent circuit of the cavity filter comprises a plurality of dual-passband filter units (9), two adjacent dual-passband filter units (9) are connected through a transmission element (10), and the plurality of dual-passband filter units (9) are cascaded into a dual-passband filter circuit through a plurality of transmission elements (10); one end of the dual-passband filter circuit is connected with a power supply through a transmission element (10), and the other end of the dual-passband filter circuit is connected with a load through the transmission element (10).

10. A cavity filter according to claim 9, wherein the dual-passband filter unit (9) comprises two cavity filter circuits (91), one end of one cavity filter circuit (91) is grounded, and the other end is grounded after being connected in series with the other cavity filter circuit (91) through the transmission element (10); the cavity filter circuit (91) comprises an inductor and a capacitor which are connected in parallel.