KR20220035662A - RF Cavity Filter Having a Cover Where Tuning Structure is Integrated - Google Patents

Abstract

An RF cavity filter having a cover with an integrated tuning structure is disclosed. The disclosed filter includes a housing in which at least one cavity is formed; a cover coupled to the upper part of the housing; Bolt grooves formed in the cover; A bolt support member inserted into the bolt groove and forming a bolt hole; and a pressure bolt coupled to the bolt support member through the bolt hole, wherein the bottom of the bolt groove is formed in a thin film shape to have elasticity, and the pressure bolt is inserted through the bolt hole of the bolt support member. Provides an external force to the bottom of the bolt groove, and tuning is performed as the shape of the bottom of the bolt groove changes due to the external force. According to the disclosed filter, by applying an elastic structure integrated with the cover to the filter cover, it is possible to prevent deterioration of characteristics due to PIMD during tuning, and to enable automatic fixation of bolts during tuning, reducing the cost and time required for fixing bolts. This has the advantage of reducing the installation space of the filter.

Description

RF Cavity Filter Having a Cover Where Tuning Structure is Integrated}

The present invention relates to an RF cavity filter, and more specifically, to an RF cavity filter having a cover with an integrated tuning structure.

A filter is a device that passes only signals in a desired frequency band among input signals and is implemented in various ways. The bandpass frequency of an RF filter is determined by the inductance and capacitance components of the filter. The filter is designed to have the desired band-pass characteristics by appropriately setting the cavity size, number of cavities, and resonator structure, but it may not have the desired band-pass characteristics due to processing errors or other factors, and these problems can be solved. To do this, a tuning process is required after manufacturing the filter.

Figure 1 is a cross-sectional view of one cavity in a conventional RF cavity filter.

Referring to Figure 1, tuning bolt 112 penetrates through cover 106. The tuning bolt 112 is made of a metal material, and threads are formed on the outer peripheral surface of the tuning bolt and the inner peripheral surface of the through hole of the cover, and the insertion depth of the tuning bolt is determined by rotation of the tuning bolt 112.

The distance from the resonator 110 can be adjusted depending on the insertion depth of the tuning bolt 112, and tuning is achieved through variation of the insertion depth. The tuning bolt 112 may be rotated manually, or a separate tuning machine may be used.

When tuning is completed, fix the tuning bolt and finally secure the tuning bolt using a nut.

In the conventional filter tuning structure using such tuning bolts, tuning is performed by moving the tuning bolt up and down, so plating or material fragments fall into the filter, deteriorating PIMD performance.

In addition, after tuning is completed, the tuning bolt is fixed through a nut, but there is a problem in that the task of having the worker fix the nut one by one consumes a considerable amount of time and cost.

Furthermore, the protruding tuning bolt increases the installation space of the filter, causes damage or malfunction due to the protruding structure during transportation or storage, and deteriorates the aesthetics of the filter.

The present invention proposes an RF cavity filter that can prevent characteristic degradation due to PIMD during tuning by applying an elastic structure integrated with the cover to the filter cover.

In addition, the present invention proposes an RF cavity filter that enables automatic fixation of the tuning bolt, thereby reducing the cost and time required for fixing the tuning bolt.

Furthermore, the present invention proposes an RF cavity filter that can reduce the installation space of the filter.

According to one aspect of the present invention for achieving the above object, a housing in which at least one cavity is formed; A cover coupled to the upper part of the housing; Bolt grooves formed in the cover; A bolt support member inserted into the bolt groove and forming a bolt hole; and a pressure bolt coupled to the bolt support member through the bolt hole, wherein the bottom of the bolt groove is formed in a thin film shape to have elasticity, and the pressure bolt is inserted through the bolt hole of the bolt support member. An RF cavity filter is provided in which tuning is performed by providing an external force to the bottom of the bolt groove, and changing the shape of the bottom of the bolt groove by the external force.

The RF cavity filter further includes at least one resonator accommodated in the at least one cavity.

The bolt hole is formed in the central area of the bolt support member.

Threads are formed on the inner peripheral surface of the bolt hole and the outer peripheral surface of the pressure bolt, and the pressure bolt is inserted by rotation to adjust the insertion depth.

A wrinkle structure that partially protrudes downward or upward is formed at the bottom of the bolt groove.

According to another aspect of the invention, a housing in which at least one cavity is formed; a cover coupled to the upper part of the housing; Bolt grooves formed in the cover; A bolt support member inserted into the bolt groove and forming a bolt hole; and a pressure bolt coupled to the bolt support member through the bolt hole, wherein the bottom of the bolt groove is formed in a thin film shape to have elasticity, and the bolt hole is formed in the central area of the bolt support member. A cavity filter is provided.

The RF cavity filter of the present invention has the advantage of preventing characteristic degradation due to PIMD during tuning by applying an elastic structure integrated with the cover to the filter cover.

In addition, the RF cavity filter of the present invention enables automatic fixation of bolts during tuning, thereby reducing the cost and time required for fixing bolts, and has the advantage of reducing the installation space of the filter.

1 is a cross-sectional view of one cavity in a conventional RF cavity filter.
Figure 2 is an exploded perspective view of an RF cavity filter having a cover with an integrated tuning structure according to an embodiment of the present invention.
Figure 3 is a cross-sectional view of a bolt groove formed in a cover according to an embodiment of the present invention.
Figure 4 is a cross-sectional view of a bolt support member according to an embodiment of the present invention.
Figure 5 is a view showing a state in which a bolt support member is inserted into a bolt groove according to an embodiment of the present invention.
Figure 6 is a view showing a state in which a pressurizing bolt is coupled to a bolt support member according to an embodiment of the present invention.
Figure 7 is a diagram showing a process in which the shape of the bottom of the bolt groove changes according to a change in the pressurizing bolt according to an embodiment of the present invention.
Figure 8 is a cross-sectional view of a bolt groove according to another embodiment of the present invention.
Figure 9 is a diagram showing the structure of an RF cavity filter according to another embodiment of the present invention.
Figure 10 is a plan view of bolt support members according to another embodiment of the present invention.

In order to fully understand the present invention, its operational advantages, and the objectives achieved by practicing the present invention, reference should be made to the accompanying drawings illustrating preferred embodiments of the present invention and the contents described in the accompanying drawings.

Hereinafter, the present invention will be described in detail by explaining preferred embodiments of the present invention with reference to the accompanying drawings. However, the present invention may be implemented in many different forms and is not limited to the described embodiments. In order to clearly explain the present invention, parts not relevant to the description are omitted, and like reference numerals in the drawings indicate like members.

Throughout the specification, when a part is said to “include” a certain element, this does not mean excluding other elements, unless specifically stated to the contrary, but rather means that it may further include other elements. In addition, terms such as “… unit”, “… unit”, “module”, and “block” used in the specification refer to a unit that processes at least one function or operation, which is hardware, software, or hardware. and software.

Figure 2 is an exploded perspective view of an RF cavity filter having a cover with an integrated tuning structure according to an embodiment of the present invention.

Referring to FIG. 2, the RF cavity filter according to an embodiment of the present invention includes a cover 200, a housing 210, a plurality of bolt support members 300, and a plurality of pressurizing bolts 400.

A plurality of cavities 220 are defined in the housing 210 through a plurality of partition walls. A resonator 250 is accommodated in each cavity 220. For example, in Figure 2, six cavities are formed, and a resonator 250 is installed in each cavity.

Independent resonance occurs in each of the plurality of cavities 220 formed in the housing 210, and filtering is performed by resonance in the cavities 220.

The resonator 250 accommodated in each of the plurality of cavities has a pillar shape that protrudes upward from the bottom of the cavity. The resonator 250 is an element commonly used in cavity filters, and various known types of resonators 250 may also be used in the RF cavity filter of the present invention.

Each cavity formed in the housing functions as the LC module of the filter, where L stands for inductance and C stands for capacitance. The resonance frequency in each cavity is determined by the shape and size of the resonator 250, and in particular, the capacitance (C) is determined by the distance between the resonator 250 and the cover 200.

The size and shape of the cavity 220 and the resonator 250 are predetermined based on the required passband of the filter. However, due to processing errors during the manufacturing process of the filter, the cavity 220 and the resonator 250 may not be manufactured in the desired shape and size, and in this case, the intended pass band of the filter is not formed.

In this way, tuning work is performed on the manufactured filter to respond to changes in the pass band that occur due to processing errors and other factors. As explained in the background art, conventional filter tuning was accomplished by inserting a tuning bolt into the cavity and adjusting the insertion depth of the tuning bolt.

By adjusting the insertion depth of the tuning bolt, the distance between the resonator and the end of the tuning bolt changes. As the distance changes, the capacitance value changes and the resonance frequency of the cavity changes, thereby tuning the filter.

However, this conventional tuning structure had a problem in that metal fragments fell into the filter when the tuning bolt was rotated, and the fallen metal fragments deteriorated the PIMD performance of the filter. In addition, once tuning is completed, the tuning bolts must be fixed, and fixing these tuning bolts also takes a significant amount of time and cost.

In order to solve the above problems, the present invention proposes a filter structure in which an elastic part is formed in a structure integrated with the cover, and tuning is achieved through changes in the formation of the integrated elastic part.

The cover 200 is made of a metal material and is combined with the housing to form a shielding structure of the RF cavity filter. The cover 200 and housing 210 are manufactured independently and then combined. Various joining methods may be used to connect the cover 200 and the housing 220, such as bolting or soldering.

A plurality of bolt grooves 500 are formed in the cover 200. The bolt groove 500 is formed based on the positions of each resonator 250 and cavity 220. As shown in FIG. 2, when six cavities exist, six bolt grooves 500 can be formed.

The bolt groove 500 is set to have a lower thickness than other areas of the cover 200, and the bolt groove 500 may be formed in various ways. The bolt groove 500 may be formed when manufacturing the cover 200, and the bolt groove 500 may be formed using a separate machine after manufacturing the cover with a flat structure.

A bolt support member 300 is inserted and coupled to each bolt groove 500. The bolt support member 300 may be inserted and coupled into the bolt groove 500 in various ways. For example, the bolt support member 300 may be coupled to the bolt groove 500 by a soldering method or may be coupled to the bolt groove 500 by an interference fitting method.

A hole is formed in the bolt support member 300, and a thread is formed on the inner peripheral surface of the hole. The pressure bolt 400 is inserted through the hole formed in the bolt support member, and the pressure bolt 400 inserted into the hole presses the bottom of the bolt groove 500.

Since the bottom of the bolt groove 500 has a thin film structure, it has elasticity that changes shape due to external force, and tuning of the filter is achieved through shape change due to this elastic structure.

Figure 3 is a cross-sectional view of a bolt groove formed in a cover according to an embodiment of the present invention.

Referring to FIG. 3, the bolt groove 500 is a structure in which a portion of the cover 200 of a planar structure is cut, and the bottom of the bolt groove 500 has a thin film structure. As described above, the thickness of the bottom of the bolt groove 500 is set to have an elastic structure with elastic force and restoring force, and thus the bottom of the bolt groove 500 functions as an elastic portion.

2 and 3 illustrate the case where the bolt groove is circular, but it will be obvious to those skilled in the art that the shape of the bolt groove is not limited to this and can have various shapes.

Meanwhile, Figures 2 and 3 show a case where the bolt groove is rectangular in terms of cross-sectional structure, but the shape of the cross-section may also change as needed.

Figure 4 is a cross-sectional view of a bolt support member according to an embodiment of the present invention.

Referring to FIG. 4, the bolt support member 300 according to an embodiment of the present invention includes a support portion 310 and a bolt hole 320 formed on both sides.

The support portion 310 functions to support the main body of the bolt support member 300 on the bottom of the bolt groove 500. The support portion 310 may be coupled to the bottom of the bolt groove 500 using a preset coupling method.

The bolt hole 320 is a hole into which the pressurizing bolt 400 is inserted, and as described above, a screw thread is formed on the inner peripheral surface of the bolt hole 320. Meanwhile, a thread is also formed on the outer peripheral surface of the pressure bolt 400, so that the insertion depth of the pressure bolt 400 can be adjusted by rotating the pressure bolt 400.

Figure 5 is a diagram showing a state in which a bolt support member is inserted into a bolt groove according to an embodiment of the present invention.

Referring to FIG. 5 , the width of the bolt support member 300 is determined based on the width of the bolt groove 500. The width of the bolt support member 300 is preferably set to have a small margin difference compared to the width of the bolt groove 500. In particular, when the bolt support member 300 is inserted and coupled to the bolt groove 500 by the interference fitting method, the width of the bolt support member 300 is set to have only a slight difference from the width of the bolt groove 500. There is a need.

The pressure bolt 400 is coupled through the bolt hole 320 after the bolt support member 300 is inserted into and coupled to the bolt groove 500.

Figure 6 is a diagram showing a state in which a pressure bolt according to an embodiment of the present invention is coupled to a bolt support member.

Referring to FIG. 6, the pressure bolt 400 is inserted while penetrating the bolt hole 320 of the bolt support member 300. As described above, it can be inserted using a screw coupling method using threads, but it will be obvious to those skilled in the art that this is only an example and that changes in the insertion method do not affect the technical scope of the present invention.

When the pressure bolt 400 continues to rotate, the pressure bolt 400 moves downward and comes into contact with the bottom of the bolt groove 500.

Figure 7 is a diagram showing a process in which the shape of the bottom of the bolt groove changes according to a change in the pressurizing bolt according to an embodiment of the present invention.

Referring to FIG. 7, when the pressure bolt 400 continues to descend even in contact with the bottom of the bolt groove 500, the bottom of the bolt groove 500 has elasticity, so the pressure bolt 400 Its shape changes depending on the pressure.

Since the pressure bolt 400 moves downward and pressurizes the bottom of the bolt groove 500, the bottom of the bolt groove 500 extends in the downward direction according to the pressure of the pressure bolt 400. As the depth at which the pressure bolt 400 is inserted increases, the degree of elongation of the bottom of the bolt groove 500 also increases.

When the bottom of the bolt groove 500 extends in the downward direction, the distance between the bottom of the bolt groove and the resonator changes, and the filter can be tuned through this change in distance.

Since the bottom of the bolt groove 500 has elastic force, when stretched in the downward direction, it continuously provides a restoring force to the press bolt 400 to restore it in the upward direction, and due to this restoring force, the press bolt 400 automatically It is fixed, and therefore no separate fixing means is required.

Meanwhile, it is preferable that the bolt hole 320 is formed in the central area of the bolt support member 300. Since the width of the bolt hole 320 and the pressure bolt 400 is narrower than the bottom of the bolt groove 500, which functions as an elastic portion, the pressure bolt 400 can appropriately pressurize the center of the bolt groove 500. Therefore, it is possible to maximize the shape change caused by the pressure of the pressurized bolt 400.

Figure 8 is a cross-sectional view of a bolt groove according to another embodiment of the present invention.

Referring to FIG. 8, the embodiment shown in FIG. 8 has a different shape of the bottom of the bolt groove that functions as an elastic portion compared to the embodiment shown in FIG. 3.

The degree of change in shape of the bottom of the elastic bolt groove 500 is inevitably relatively small compared to the insertion depth of the tuning bolt inserted into the existing cavity, which means that tuning is performed using the bottom of the bolt groove 500. This means that the tuning range is inevitably smaller.

In order to overcome this limitation of the tuning range, the bottom of the bolt groove 500 has a corrugated structure. In addition, in order to achieve a relatively large shape change in the central area of the bottom of the bolt groove 500, it is desirable for the bottom of the bolt groove 500 to have a wrinkled structure that partially protrudes downward.

When a wrinkle structure that partially protrudes downward is applied to the bottom of the bolt groove 500, a wider tuning range can be secured compared to the case where the bottom of the bolt groove 500 is a flat plate, which means that the wrinkle structure partially protrudes downward. This is because the structure makes it possible to have higher elasticity, and the distance to the resonator is varied by the downwardly protruding wrinkle structure.

Meanwhile, the wrinkle structure can be a downwardly protruding structure as well as an upwardly protruding structure, and the wrinkles of the upwardly protruding structure and the wrinkles of the downwardly protruding structure may be selectively used based on the required elastic coefficient and the deformation form of the elastic portion.

Of course, both the upwardly protruding pleated structure and the downward protruding pleated structure may be used.

Figure 9 is a diagram showing the structure of an RF cavity filter according to another embodiment of the present invention.

Referring to FIG. 9, the RF cavity filter according to another embodiment of the present invention is different from the embodiment shown in FIG. 2 only in the shape of the bolt support member 900. The bolt support member 900 shown in FIG. 8 has a cylindrical shape and has a structure in which a bolt hole 910 is formed in the cylindrical body.

Screw threads are also formed on the inner peripheral surface of the bolt hole 910 of the bolt support member 900 of the embodiment shown in FIG. 9 to have a structure that allows insertion of a pressure bolt.

Of course, it will be apparent to those skilled in the art that not only the exemplary structures shown in FIGS. 2 and 8 but also various shapes of bolt support members for supporting the pressurizing bolt can be used.

Figure 10 is a plan view of bolt support members according to another embodiment of the present invention.

As shown in Figures 10 (a) and (b), the bolt support member may have various shapes other than those shown in Figures 2 and 9.

As described above, in the RF cavity filter of the present invention, even if metal fragments are generated during tuning using a pressurized bolt, they accumulate at the bottom of the bolt groove and cannot penetrate into the filter, thereby preventing degradation of characteristics due to PIMD.

In addition, the RF cavity filter of the present invention does not require a separate fixing means due to the restoring force of the bottom of the bolt groove, and has a structure in which the pressurized bolt does not protrude significantly from the top of the cover, so it has the advantage of creating an installation space for the filter. There is.

The present invention has been described with reference to the embodiments shown in the drawings, but these are merely exemplary, and those skilled in the art will understand that various modifications and other equivalent embodiments are possible therefrom.

Therefore, the true technical protection scope of the present invention should be determined by the technical spirit of the attached claims.

Claims (9)

a housing in which at least one cavity is formed;
a cover coupled to the upper part of the housing;
Bolt grooves formed in the cover;
A bolt support member inserted into the bolt groove and forming a bolt hole;
and
Including a pressurized bolt coupled to the bolt support member through the bolt hole,
The bottom of the bolt groove is formed in a thin film shape to have elasticity, and the pressurizing bolt inserted through the bolt hole of the bolt support member provides an external force to the bottom of the bolt groove, and the external force causes the bolt to An RF cavity filter in which tuning is achieved by changing the shape of the bottom of the groove.
According to paragraph 1,
RF cavity filter further comprising at least one resonator accommodated in the at least one cavity.
According to paragraph 1,
RF cavity filter, characterized in that the bolt hole is formed in the central area of the bolt support member.
According to paragraph 3,
An RF cavity filter, wherein threads are formed on the inner peripheral surface of the bolt hole and the outer peripheral surface of the pressure bolt, and the pressure bolt is inserted by rotation to adjust the insertion depth.
According to paragraph 3,
An RF cavity filter in which a wrinkle structure that partially protrudes downward or upward is formed at the bottom of the bolt groove.
a housing in which at least one cavity is formed;
a cover coupled to the upper part of the housing;
Bolt grooves formed in the cover;
A bolt support member inserted into the bolt groove and forming a bolt hole;
and
Including a pressurized bolt coupled to the bolt support member through the bolt hole,
The bottom of the bolt groove is formed in a thin film shape to have elasticity, and the bolt hole is formed in a central area of the bolt support member.
According to clause 6,
The pressing bolt inserted through the bolt hole of the bolt support member provides an external force to the bottom of the bolt groove, and the external force changes the shape of the bottom of the bolt groove to perform tuning.
According to clause 6,
RF cavity filter further comprising at least one resonator accommodated in the at least one cavity.
According to clause 6,
An RF cavity filter, wherein threads are formed on the inner peripheral surface of the bolt hole and the outer peripheral surface of the pressure bolt, and the pressure bolt is inserted by rotation to adjust the insertion depth.