CN106169637A - Coaxial cavity filter - Google Patents

Abstract

The invention discloses a coaxial cavity filter, comprising: the filter comprises a modular single cavity, a resonance rod, a cover plate, a tuning screw, a coupling screw and a filter joint; a groove is formed in the cover plate and used for mounting the modular single cavity, and the upper end of the modular single cavity is fixed in the cover plate groove and is sealed with the cover plate to form a resonant cavity; the modular single cavities are spliced together to form a connected resonant cavity so as to form a filter cavity; the resonance rod is arranged at the bottom in the modular single cavity; the tuning screw and the coupling screw are both arranged on the cover plate, and part of the tuning screw and part of the coupling screw extend into the resonant cavity; the filter joint is fixed on the modularized single cavity at the head end and the tail end of the coaxial cavity filter. The filter-free shell has the advantages of simple processing and assembling process, good interchangeability and reusability.

Description

A coaxial cavity filter

【Technical field】

The invention relates to the technical field of communication equipment, in particular to a coaxial cavity filter.

【Background technique】

A filter is a frequency filtering device, which selects signals in the required frequency band and suppresses signals in the unnecessary frequency band. Filters are widely used in communication fields such as radio frequency and microwave. At present, the most widely used filter in the radio frequency and microwave frequency band is the coaxial cavity filter. The coaxial cavity filter has good electromagnetic shielding, compact structure, and low passband insertion loss. In the case of capacitive loading, the coaxial cavity filter can be made very small, and has a high square coefficient and high power Advantages of high capacity. Fig. 1 is a three-dimensional exploded view of a typical structure of a coaxial cavity filter in the prior art, and Fig. 2 is a cross-sectional view of a filter in the prior art after assembly, and it can be seen from the figure that the structure of the coaxial cavity filter in the prior art mainly includes a filter Housing 101 , cover plate 102 , cover plate fastening screw 103 , resonant rod 104 , resonant rod fixing screw 105 , tuning screw 106 , coupling screw 107 , set nut 108 , filter joint 109 and joint fastening screw 110 . Wherein, the resonant rod 104 is installed on the bottom of the inner cavity of the filter housing 101 through the resonant rod fixing screw 105, and the cover plate fastening screw seals the cover plate to the filter housing to form a resonant cavity. There are screw holes on the cover plate for installing tuning screws and coupling screws. Screw the tuning screws into or out of the resonant cavity to adjust the resonant frequency, and screw the coupling screws into or out of the resonant cavity to adjust the frequency of the adjacent cavity. The coupling strength of the electromagnetic field. A thin wall is provided in the inner cavity of the filter housing, and the thin wall divides the inner cavity of the filter housing into several same or similar small single cavities. The thin walls between adjacent single cavities are provided with windows for the coupling of electromagnetic fields of adjacent single cavities. Figure 3 is a structural diagram of the filter housing. In the prior art, the weight of the coaxial cavity filter is mainly the filter housing, and the larger the filter, the greater the proportion of the weight of the housing, which seriously restricts the cost control of the filter. Moreover, the cavity structure inside the filter is integrated with the filter housing, and a defect in a certain cavity may easily cause the entire product to be scrapped, and the scrapped product cannot be reused. Moreover, the cover plate and the filter housing are fastened by a large number of screws, resulting in dense screw holes in the housing, complex processing and assembly processes, and high screw material costs. The assembly of a large number of screws will also increase assembly time and reduce production efficiency.

Therefore, it is necessary to propose a new technical solution to solve the above technical problems.

【Content of invention】

The object of the present invention is to provide a reusable coaxial cavity filter without a filter housing, simple in processing and assembly process, good in interchangeability.

In order to solve the above problems, the technical solution of the present invention is as follows:

The present invention provides a coaxial cavity filter. The coaxial cavity filter includes: a modular single cavity, a resonant rod, a cover plate, a tuning screw, a coupling screw, and a filter connector;

Wherein, a groove is opened on the cover plate, and the groove is used to install the modular single cavity, and the upper end of the modular single cavity is fixed in the cover plate groove, and is closed with the cover plate to form a resonant cavity; A plurality of the modular single cavities are spliced together to form a connected resonant cavity to form a filter cavity; the resonant rod is arranged at the bottom of the modular single cavity; the tuning screw and the coupling screw are both arranged at the bottom of the modular single cavity the cover plate, and partly extend into the resonant cavity; the filter connector is fixed on the modular single cavity at both ends of the coaxial cavity filter.

Preferably, the resonant rod and the bottom of the modular single cavity are provided with through holes, and the resonant rod is installed on the modular single cavity through the fastening pin of the resonant rod through the through holes of the resonant rod and the modular single cavity. cavity bottom.

Preferably, a spring washer is provided between the resonant rod fastening pin and the resonant rod.

Preferably, one end of the resonant rod fastening pin is tapered, the other end is flat, and the middle is cylindrical with a smaller diameter than the two ends.

Preferably, a slot is provided at the tapered end of the fastening pin of the resonant rod.

Preferably, windows are provided on adjacent thin walls of adjacent modular single chambers, and the windows are used for electromagnetic field coupling.

Preferably, a metal layer is provided on the surface of the modular single cavity, the inner surface of the cover plate covering the modular single cavity, the surface of the resonant rod, the surface of the tuning screw and the surface of the coupling screw.

Preferably, a locking hoop is provided around the bottom periphery of the filter cavity.

Preferably, the locking band is a fixed or adjustable locking band.

Preferably, the modular single chamber and the window are integrally formed.

Compared with the prior art, the coaxial cavity filter provided by the present invention forms a filter cavity by making the filter housing into a thin-walled modular single cavity, splicing and fixing multiple modular single cavities on the cover plate , the resonant rod is fastened to the bottom of the cavity by a new type of pin. Compared with the prior art where the filter cavity is directly made from the filter shell and the resonant rod is fastened to the bottom of the cavity by screws, the present invention decomposes the filter shell into a single thin-walled cavity, which improves production Efficiency saves the heavy shell, saves materials and reduces weight; the modular single cavity can be replaced flexibly, avoiding the risk of scrapping the entire filter due to a single cavity structure defect; the modular single cavity can be replaced in advance Preparation, assembly immediately when needed, greatly shortening the production cycle; the modular single cavity in the old filter can be recycled, and the modular single cavity of the same type of filter can also be interchangeable, which greatly improves the material utilization rate and saves resources , to facilitate future equipment maintenance; the installation and disassembly of the new pins are simple, the fixation is reliable, and the production process is simplified.

In order to make the above content of the present invention more comprehensible, preferred embodiments are specifically cited below, together with the accompanying drawings, and described in detail as follows.

【Description of drawings】

FIG. 1 is a three-dimensional exploded schematic diagram of a cavity filter provided by the prior art;

FIG. 2 is a schematic cross-sectional view of a cavity filter provided by the prior art;

FIG. 3 is a schematic structural diagram of a cavity filter provided by the prior art;

FIG. 4 is a three-dimensional exploded schematic view of the coaxial cavity filter provided by Embodiment 1 of the present invention;

FIG. 5 is a schematic diagram of an assembly and a longitudinal section of the coaxial cavity filter provided by Embodiment 1 of the present invention;

FIG. 6 is a schematic structural diagram of a coaxial cavity filter cover plate provided by Embodiment 1 of the present invention;

Fig. 7 is a schematic structural diagram of the fastening pin of the resonator rod of the coaxial cavity filter provided by Embodiment 1 of the present invention;

8 is a schematic structural view of a thin-walled single cavity in the middle of the coaxial cavity filter provided by Embodiment 1 of the present invention;

9 is a schematic diagram of a thin-walled single cavity at the joint of the coaxial cavity filter provided by Embodiment 1 of the present invention;

Fig. 10 is a schematic diagram of a fixed cavity locking hoop provided by Embodiment 2 of the present invention;

Fig. 11 is a schematic diagram of the adjustable cavity locking hoop provided by the second embodiment of the present invention;

Fig. 12 is a schematic diagram of an assembly and a longitudinal section of the coaxial cavity filter provided by Embodiment 2 of the present invention.

【detailed description】

The word "embodiment" as used in this specification means serving as an example, instance or illustration. Furthermore, the article "a" as used in this specification and the appended claims may generally be construed to mean "one or more" unless specified otherwise or clear from context to refer to a singular form.

In order to illustrate the technical solutions of the present invention, specific examples are used below to illustrate.

Embodiment one

Please refer to FIG. 4 to FIG. 9 together, which are schematic structural diagrams of the coaxial cavity filter provided by the embodiment of the present invention. For ease of description, only parts related to the embodiments of the present invention are shown.

The coaxial cavity filter includes: a modular single cavity 200, a resonant rod 201, a resonant rod fastening pin 202, a spring washer 203, a cover plate 204, a tuning screw 205, a coupling screw 206, a fastening nut 207 and a filter connector 208.

Wherein, a slot is opened on the cover plate 204 for installing the modular single chamber 200 , and screw holes for installing the tuning screw 205 and the coupling screw 206 are also provided on the cover plate 204 , as shown in FIG. 6 . The upper end of the modular single chamber 200 is fixed in the groove of the cover plate by welding or conductive glue bonding or pressing, so as to be closed with the cover plate 204 to form a resonant cavity.

Both the resonant rod 201 and the bottom of the modular single cavity 200 are provided with through holes, and the resonant rod 201 is installed on the modular single cavity 200 through the resonant rod fastening pin 202 passing through the through holes of the resonant rod 201 and the modular single cavity 200 inner bottom. For example, one end of the resonant rod fastening pin 202 can be tapered with a groove, as shown in FIG. The tapered head passes through the through hole. A spring washer 203 is provided between the resonant rod fastening pin 202 and the resonant rod 201 to apply a pre-tightening force to the resonant rod fastening pin 202 to keep the resonant rod fastening pin 202 to press the resonant rod 201 on the modular single cavity 200 bottom.

The tuning screw 205 and the coupling screw 206 are installed on the cover plate 204 through screw holes. Screw the tuning screw 205 into or out of the resonant cavity to adjust the resonant frequency, screw the coupling screw 206 into or out of the resonant cavity to adjust the coupling strength of the electromagnetic field of the adjacent cavity, and lock it with the fastening nut 207 after adjustment .

One end of the resonance rod fastening pin 202 is tapered, the other end is flat, and the middle is cylindrical with a smaller diameter than the two ends, as shown in FIG. 7 . A groove is provided at the conical end so that when the conical surface is under pressure, the conical head can elastically deform towards the center to reduce the diameter of the conical head to pass through a smaller hole. through the smaller hole.

The modular single chamber 200 is a hollow cuboid, and its cross section can be circular, quadrangular, pentagonal, hexagonal, etc. The modular single chamber 200 is formed by stamping a thin copper or aluminum sheet. A window 209 is opened by machining on the adjacent thin wall of the adjacent modular single cavity, and the window 209 is used for coupling of electromagnetic field. 8 and 9 show the modular single chamber 200 in the middle and near the filter connector 208, respectively. The upper end of the modularized single cavity 200 is fixed in the groove of the cover plate 204 by press-fitting, thereby sealing with the cover plate 204 to form a resonant cavity. The bottom of the modular single cavity 200 is provided with a through hole for installing the resonant rod 201 . The through hole is slightly larger or equal to the diameter of the center column of the fastening pin of the resonant rod, and 1-3 mm smaller than the diameter of the cone head of the fastening pin of the resonant rod.

The resonant rod is a hollow cylinder with a through hole at the bottom. The diameter of the through hole is slightly larger or equal to that of the middle column of the fastening pin of the resonant rod, and 1-3mm smaller than the diameter of the cone head of the fastening pin of the resonant rod. The conical head of the fastening pin of the resonant rod passes through the through hole of the resonant rod and the through hole at the bottom of the modular single cavity to fasten the resonant rod to the bottom of the modular single cavity. A spring washer is also provided between the fastening pin of the resonant rod and the resonant rod to apply a pre-tightening force to the fastening pin of the resonant rod to keep the resonant rod and the modular single cavity tightly fitted.

Since the wall thickness of the modularized single cavity is relatively thin, the volume of the cavity can be increased and the Q value of the single cavity can be improved. The filter connector 208 is fixed on the modular single cavity at both ends of the coaxial cavity filter by welding. A plurality of modular single cavities are spliced together to form a connected filter resonant cavity to form a filter cavity.

In this embodiment, the surface of the modular single cavity, the inner surface of the cover plate covering the modular single cavity, the surface of the resonant rod, the tuning screw and the coupling screw are all silver-plated as required to form a conductive structure on the above-mentioned surface. metal layer.

In this embodiment, the modular single cavity is a hollow cube with a quadrilateral cross section. A plurality of modular single cavities are combined and fixed on the cover plate to form a resonant cavity. The elastic resonant rod fastening pin fixes the resonant rod to the bottom of the modular single cavity. Compared with the prior art scheme in which the resonant cavity and the filter housing are integrated, the filter in this embodiment removes the thick and heavy housing, and decomposes the integrated cavity into individual cavities, effectively reducing the volume and quality of the filter. The cost is reduced; the modular single cavity can be prepared in advance, and can be assembled immediately when needed, shortening the production cycle; the modular single cavity can be replaced, avoiding the risk of scrapping the entire filter due to a defect in a resonant cavity; using The fastening pin of the elastic resonant rod fixes the resonant rod, the process is simple and reliable, and the production efficiency is improved.

Embodiment two

Please refer to FIG. 10 to FIG. 12 together, which are schematic structural diagrams of the coaxial cavity filter provided by Embodiment 2 of the present invention. For ease of description, only parts related to the embodiments of the present invention are shown.

The coaxial cavity filter includes: a modular single cavity 300 , a locking collar 301 , a resonant rod 302 , a cover plate 303 , a tuning screw 304 , a coupling screw 305 , a fastening nut 306 and a filter connector 307 .

Wherein, a slot is opened on the cover plate 303 for installing the modular single chamber 300 , and screw holes for installing the tuning screw 304 and the coupling screw 305 are also provided on the cover plate 303 . The upper end of the modular single cavity 300 is fixed in the groove of the cover plate by welding or conductive glue bonding or pressing, so as to be closed with the cover plate 303 to form a resonant cavity. At the same time, a locking hoop 301 is provided on the periphery of the bottom of the modular single chamber 300 to lock the modular single chamber 300 . The resonant rod 302 is bonded to the bottom of the modular single cavity 300 by welding or conductive silver glue. The filter joint 307 is fixed on the modularized single cavity at both ends of the coaxial cavity filter by welding.

The tuning screw 304 and the coupling screw 305 are installed on the cover plate 303 through screw holes. Screw the tuning screw 304 into or out of the resonant cavity to adjust the resonant frequency, screw the coupling screw 305 into or out of the resonant cavity to adjust the coupling strength of the electromagnetic field of the adjacent cavity, and lock it with the fastening nut 306 after adjustment .

The modular single chamber 300 is a hollow cuboid with a quadrilateral cross section. The windows on the modular single cavity and the thin wall of the adjacent single cavity are integrally formed by aluminum alloy die-casting or powder metallurgy. The upper end of the modular single chamber is pressed into the groove of the cover plate and fastened to the cover plate by welding or conductive silver glue.

The bottom periphery of the modular single cavity is locked by a locking hoop. Locking bands can be fixed or adjustable. The locking collar can be made of plastic material, such as Teflon PT FE, or light metal material, such as aluminum alloy. As shown in Figure 10, it is a fixed locking hoop. The inner perimeter of the locking hoop is slightly smaller than the outer perimeter of the entire cavity of the filter, and is nested on the bottom periphery of the entire cavity of the filter by pressing. Figure 11 is an adjustable locking hoop that can be adjusted by screws. The inner circumference of the locking hoop is equal to the outer circumference of the entire cavity of the filter. Put the locking hoop around the periphery of the filter cavity and tighten it with screws. The head is locked.

The resonant rod 302 is a hollow cylinder, which is bonded to the bottom of the modular single cavity by welding or conductive silver glue.

Since the wall thickness of the modular single cavity is relatively thin, the filter joint 307 is fixed on the modular single cavity at both ends of the filter by welding or conductive adhesive bonding.

In this embodiment, the surface of the modularized single cavity, the inner surface of the single cavity covered by the cover plate, the surface of the resonant rod, the surface of the tuning screw and the coupling screw are all copper-plated and then silver-plated as required to form an excellent Conductive metal layer.

The second embodiment is basically the same as the first embodiment, except that:

In Embodiment 1, the bottom of the modular single cavity and the bottom of the resonant rod are provided with through holes, and the fastening pin of the resonant rod fixes the resonant rod on the bottom of the modular single cavity through these two through holes, and the modular single cavity is tightened by pressing. fixed on the cover. However, there is no through hole in the bottom of the modular single cavity and the resonant rod in the second embodiment, the resonant rod is bonded to the bottom of the modular single cavity by welding or conductive silver glue, and the modular single cavity is also bonded by welding or conductive silver glue It is fastened on the cover plate, and at the same time, a locking hoop is installed on the periphery of the bottom of the modular single chamber to lock the modular single chamber. Cavity locking hoops can be fixed or adjustable. As shown in Figure 10, it is a fixed locking hoop. The inner perimeter of the locking hoop is slightly smaller than the outer perimeter of the filter cavity, and it is nested on the periphery of the filter cavity by pressing. Figure 11 is an adjustable locking hoop that can be adjusted by screws. The inner circumference of the locking hoop is equal to the outer circumference of the filter cavity. The locking hoop is placed on the periphery of the filter cavity, and the locking head is tightened by screws. lock tight.

In the first embodiment, the modular single cavity is formed by punching a thin copper plate or thin aluminum plate, and the bottom and the through hole at the bottom of the resonance rod and the window on the thin wall are produced by machining. In the second embodiment, the modular single cavity is formed by aluminum alloy die-casting or powder metallurgy, and there is no through hole at the bottom, and the window on the thin wall is integrally formed in the process of modular single-cavity die-casting or powder metallurgy.

There is no through hole at the bottom of the modular single cavity and the resonant rod in the second embodiment, the resonant rod and the modular single cavity, the modular single cavity and the cover plate are fastened by welding or conductive adhesive bonding, the single cavity cavity and the window One-piece molding by die-casting or powder metallurgy. In this way, the processing technology of the filter housing and the modular single cavity can be further simplified, and the processing cost can be reduced. At the same time, the process of installing the resonant rod in the modular single cavity is omitted, which improves the production efficiency. Finally, a locking hoop is used to lock the bottom periphery of the combined modular single cavity, which strengthens the structural strength of the filter and ensures reliability.

To sum up, in the coaxial cavity filter provided by the embodiment of the present invention, the filter housing is made into a thin-walled modular single cavity, and multiple modular single cavities are spliced and fixed on the cover to form a filter Cavity, the resonant rod is fastened to the bottom of the cavity by a new type of pin. Compared with the prior art where the filter cavity is directly made from the filter shell and the resonant rod is fastened to the bottom of the cavity by screws, the present invention decomposes the filter shell into a single thin-walled cavity, which improves production Efficiency saves the heavy shell, saves materials and reduces weight; the modular single cavity can be replaced flexibly, avoiding the risk of scrapping the entire filter due to a single cavity structure defect; the modular single cavity can be replaced in advance Preparation, assembly immediately when needed, greatly shortening the production cycle; the modular single cavity in the old filter can be recycled, and the modular single cavity of the same type of filter can also be interchangeable, which greatly improves the material utilization rate and saves resources , to facilitate future equipment maintenance; the installation and disassembly of the new pins are simple, the fixation is reliable, and the production process is simplified.

While the invention has been shown and described with respect to one or more implementations, equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. The present invention includes all such modifications and variations and is limited only by the scope of the appended claims. With particular reference to the various functions performed by the components described above, terminology used to describe such components is intended to correspond to any component that performs the specified function (eg, which is functionally equivalent) of the described component (unless otherwise indicated). , even if not structurally equivalent to the disclosed structures that perform the functions shown herein in the exemplary implementations of the specification. Furthermore, although a particular feature of this specification has been disclosed with respect to only one of several implementations, such feature may be combined with one or more other implementations as may be desirable and advantageous for a given or particular application. other feature combinations. Moreover, to the extent the terms "comprises", "has", "comprising" or variations thereof are used in the detailed description or the claims, such terms are intended to be encompassed in a manner similar to the term "comprising".

In summary, although the present invention has been disclosed above with preferred embodiments, the above preferred embodiments are not intended to limit the present invention, and those of ordinary skill in the art can make various modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope defined in the claims.

Claims (10)

1. A coaxial cavity filter, characterized in that, the coaxial cavity filter comprises: a modular single cavity, a resonant rod, a cover plate, a tuning screw, a coupling screw, and a filter connector; Wherein, a groove is opened on the cover plate, and the groove is used to install the modular single cavity, and the upper end of the modular single cavity is fixed in the cover plate groove, and is closed with the cover plate to form a resonant cavity; A plurality of the modular single cavities are spliced together to form a connected resonant cavity to form a filter cavity; the resonant rod is arranged at the bottom of the modular single cavity; the tuning screw and the coupling screw are both arranged at the bottom of the modular single cavity the cover plate, and partly extend into the resonant cavity; the filter connector is fixed on the modular single cavity at both ends of the coaxial cavity filter. 2. The coaxial cavity filter according to claim 1, wherein the resonant rod and the bottom of the modularized single cavity are provided with through holes, through which the fastening pin of the resonant rod passes through the resonant rod and the through hole of the modular single cavity, the resonant rod is installed at the bottom of the modular single cavity. 3. The coaxial cavity filter according to claim 2, wherein a spring washer is provided between the fastening pin of the resonant rod and the resonant rod. 4 . The coaxial cavity filter according to claim 2 , wherein one end of the resonant rod fastening pin is tapered, the other end is flat, and the middle is cylindrical with a diameter smaller than that of the two ends. 5 . The coaxial cavity filter according to claim 4 , wherein a slot is opened on the tapered end of the fastening pin of the resonant rod. 6 . 6. The coaxial cavity filter according to claim 1, characterized in that windows are opened on adjacent thin walls of adjacent modularized single cavities, and the windows are used for electromagnetic field coupling. 7. The coaxial cavity filter according to claim 1, characterized in that, on the surface of the modular single cavity, the inner surface of the modular single cavity covered by the cover plate, the surface of the resonant rod, the surface of the tuning screw and the coupling The surfaces of the screws are all provided with a metal layer. 8 . The coaxial cavity filter according to claim 1 , wherein a locking band is arranged around the bottom periphery of the filter cavity. 9 . The coaxial cavity filter according to claim 8 , wherein the locking band is a fixed or adjustable locking band. 10. The coaxial cavity filter according to claim 6, wherein the modular single cavity and the window are integrally formed.