KR20150118768A - Radio frequency filter with cavity structure - Google Patents

Abstract

The present invention provides a radio frequency filter with a cavity structure, comprising: a housing having a hollow inside and an opened side at one side for having a cavity; a cover sealing the opening side of the housing; and resonance elements positioned at the hollow inside of the housing, wherein the cover forms a penetrated hole at a portion corresponding to each of the resonance elements and has a metal plate for blocking the penetrated hole and tuning frequency and a specific gravity of the cover is less than that of the metal plate.

Description

[0001] RADIO FREQUENCY FILTER WITH CAVITY STRUCTURE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio signal processing apparatus used in a wireless communication system, and more particularly to a radio frequency filter having a cavity structure, such as a cavity filter.

A radio frequency filter having a cavity structure generally has a housing space such as a rectangular parallelepiped through a housing made of a metal material, that is, a plurality of cavities. Inside each cavity, a cavity resonator element (DR: Dielectric Resonance element) Each element is provided to generate a very high frequency resonance. Further, in the radio frequency filter having such a cavity structure, a cover for shielding the opening face of the cavity is usually provided on the upper part of the cavity structure, and a cover for tuning the filtering characteristic of the corresponding radio frequency filter And a nut for fixing the tuning screw may be installed. An example of a radio frequency filter having a cavity structure is disclosed in Korean Patent Laid-Open Publication No. 2004-100084 filed by the present applicant (entitled "Radio Frequency Filter ", published on December 2, 2004 , Inventor: Jong Kyu Park et al.).

A radio frequency filter having such a cavity structure is used for processing a transmission / reception radio signal in a wireless communication system, and is particularly applied to a base station or a repeater in a mobile communication system.

On the other hand, Korean Patent Laid-Open Publication No. 10-2014-0026235 (entitled "Radio Frequency Filter Having Cavity Structure ", published on Mar. 05, 2014, inventor: Park Nam-sun, et al. , A simple and simplified filter structure capable of frequency tuning without employing a fastening structure of a tuning screw and a fixing nut is proposed. The above-mentioned Japanese Patent Application Laid-Open No. 10-2014-0026235 discloses that when a cover is manufactured through press working, die casting, or the like using a base material in the form of a plate made of an aluminum or magnesium material (including alloys) Thereby forming one or a plurality of depression sites. In addition, a plurality of dot peen structures are formed at the depressed portions by embossing or pressing by the embossing pins of the external embossing machine. Such a depressed portion and a dot pin structure are intended to replace the fastening structure of the tuning screw and the fixing nut which are conventionally used for frequency tuning, and the distance between the depressed portion (and the dot pin structure) Make tuning work possible.

The technique disclosed in Japanese Patent Application Laid-Open No. 10-2014-0026235 does not employ a conventional tuning screw and fixing nut fastening structure, and is particularly suitable for a filter structure for small size and light weight. However, when the filter having a relatively large size is fabricated, the above-mentioned recessed structure should be formed through die casting on the cover, which may result in an increase in the processing cost. Further, since the cover of the filter having a relatively large size has a considerable weight as the separator, it is difficult to achieve a satisfactory lightening effect even when applying the technique of the above-mentioned Japanese Patent Application Laid-Open No. 10-2014-0026235. In addition, a filter having a relatively large size must have a comparatively large thickness of the cover for impact protection and should be made of an aluminum (alloy) or the like in order to satisfy the required strength. In this case, There may be difficulties in.

Therefore, it is an object of the present invention to provide a structure for enabling frequency tuning without employing a fastening structure of a tuning screw and a fixing nut, and also a simple manufacturing operation and a low cost manufacturing can be performed even when a filter having a relatively large size is manufactured, And a radio frequency filter having a cavity structure in which the frequency tuning operation can be made easier.

According to an aspect of the present invention, there is provided a radio frequency filter having a cavity structure, comprising: a housing having a hollow inside and an open side to have a cavity; A cover for sealing an opening face of the housing; A resonant element located in the hollow of the housing; A through hole is formed in the cover corresponding to each resonance element; And a metal plate for tuning the frequency by closing the through hole, wherein the cover has a specific gravity smaller than that of the metal plate.

As described above, the radio frequency filter having a cavity structure according to the present invention provides a structure that enables frequency tuning without employing a general tuning screw and a fixing nut fastening structure. In the case of manufacturing a filter having a relatively large size It is possible to make a simple manufacturing operation and manufacture at low cost, to have a lighter weight structure, and to perform a frequency tuning operation more easily.

Therefore, it is possible to reduce the manufacturing cost, and it is possible to achieve satisfactory weight reduction even in a filter having a relatively large size, which is advantageous in that it can be easily installed in a station such as a base station.

1 is a partially exploded perspective view of a radio frequency filter having a cavity structure according to a first embodiment of the present invention;
Fig. 2 is a partial sectional view taken along the line A-A '
3 is an enlarged view of a portion B in Fig. 2
4 is a block diagram of a frequency tuning device of the radio frequency filter of FIG.
5 is a perspective view showing the bottom surface (inner surface of the filter) of the cover of Fig. 1; Fig.
6 is an enlarged view of a portion C in Fig. 5
Fig. 7 is a plan view of a modification of Figs. 5 and 6
8 is a perspective view of a cover of a radio frequency filter having a cavity structure according to a second embodiment of the present invention.
9 is a partially exploded perspective view of a radio frequency filter having a cavity structure according to a third embodiment of the present invention.
10 is a structural diagram of a radio frequency filter having a cavity structure according to a fourth embodiment of the present invention
11 is a structural diagram of a radio frequency filter having a cavity structure according to a fifth embodiment of the present invention
12 is a perspective view of a cover of a radio frequency filter having a cavity structure according to a sixth embodiment of the present invention.
Fig. 13 is a perspective view of a cover showing a modified example of Fig.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a partially cutaway perspective view of a radio frequency filter having a cavity structure according to a first embodiment of the present invention, FIG. 2 is a partial sectional view taken along line A-A 'of the cover of FIG. 1, . 1 to 3, a radio frequency filter having a cavity structure according to a first embodiment of the present invention includes an enclosure having at least one cavity which is hollow inside and which is shielded from the outside . The housing forms respective cavities and is formed to include a housing 20 with one side opened (e.g., upper side) and a cover 10 sealing the open side of the housing 20.

In the examples of FIGS. 1 to 3, six cavity structures, for example, are connected in multiple stages within the housing 20. That is, the six cavity structures are formed in two lines of three, and can be viewed as a circuit-sequentially connected structure. The cavities of the housing 20, that is, the respective cavities are usually provided with resonance elements 30 (30-1, 30-2, 30-3, 30-4, 30-4, 30-5, 30-5) do. Further, in order to make each cavity structure in the housing 20 have a sequential coupling structure, a coupling window 23 (23-1, 23-2 , 23-3, 23-4, and 23-5 are formed. The coupling window 23 may be formed in a shape corresponding to a partition wall of the cavity structure in which predetermined portions are removed in a predetermined size.

1, through a hole (not shown) which can be formed on one side of the housing 20 so that the input terminal 41 and the output terminal 42 of the corresponding RF filter are connected to the input and output cavity structures, respectively .

The structure of the resonator 30 and the cavity structure formed in the housing 20 and the housing 20 in the filter according to the embodiment of the present invention is similar to the conventional structure. However, the cover 10 of the present invention is manufactured using a printed circuit board (PCB) unlike the conventional case.

In more detail, the cover 10 can be manufactured using various types of PCBs such as FR4 (FR: Flame Retardant) type which is widely used. The PCB used to fabricate the cover 10 may be a substrate inner layer (for example, 102 in FIG. 3) manufactured by using glass, epoxy, resin or the like and an upper and lower surface copper layer For example, 101 and 103 in FIG. 3). As described above, the cover 10 of the present invention can be manufactured using conventional PCBs. In addition, the cover 10 of the present invention has a synthetic resin layer such as plastic formed on the inner layer of the substrate, It will be understood that the present invention may be embodied as a substrate of any material and structure having a metal layer formed thereon. Further, in some cases, the cover 10 may be formed with a metal layer only on a surface facing the housing 20. In the cover 10 manufactured using the PCB, portions corresponding to the respective resonance elements 30 in the respective cavities of the housing 20 have predetermined sizes and shapes (circles in the example of Figs. 1 to 3) At least one through hole (11: 11-1, 11-2, 11-3, 11-4, 11-5, 11-6) penetrating the PCB is formed. The cover 10 is installed on the lower surface of the PCB 10 in such a manner as to cover the area formed by the through hole 11 passing through the PCB 10 and has metal plates 12 (12-1, 12-2, 12-3, 12-4, 12-5, and 12-6 are attached by soldering or the like. The metal plate 12 may be formed of a copper material having a higher elongation than the aluminum material and may be silver plated for ease of soldering to the lower surface of the cover 10 (that is, the lower copper foil layer 103).

The structure of the through hole 10 of the cover 10 and the metal plate 12 attached thereto is intended to replace the conventional fastening screw and fastening nut fastening structure. In one embodiment of the present invention, the filtering characteristic is optimized while monitoring the filtering characteristics at the time of frequency tuning, or the upper end of the resonant element 30 of the housing 20 and the metal plate 12, At least one (usually a plurality of) dots (not shown) are formed on the metal plate 12 through the through hole 10 by means of external embossing equipment (5 in Fig. 4) To form a dot peen structure (a). In Fig. 2, a state in which the dot pin structure (a) is formed by embossing or pressing by a embossing pin (502 in Fig. 2) of the external embossing machine is shown as an example.

4, a radio frequency filter 1 according to the first embodiment of the present invention, which is an object of frequency tuning, comprises a steering gear 5 having an embossing pin 502, It is placed on the shelf. The embossing equipment 5 can be constituted by a conventional dot pin marking machine. The operating characteristics of the radio frequency filter 1 are measured by the measuring instrument 2. To this end, the measuring instrument 2 provides an input signal of a preset frequency to the radio frequency filter 1, Is connected to the filter (1). The operating characteristics of the radiofrequency filter 1 measured by the measuring instrument 2 are provided to the control equipment 3 which can be implemented by a PC or the like. The control equipment 3 monitors the operation characteristics of the radio frequency filter 1 and controls the operation of the steering equipment 5 until the filtering characteristic is optimized or the reference value is satisfied so that the steering equipment 5 The dot pin structure (a) having the appropriate number and shape is formed on the metal plate 12 through the through hole 11 of the cover 10 of the radio frequency filter 1. [

A plurality of the dot fin structures (a) may be formed so as to be distributed in the circular shape in the same manner along the portions of the circular through-holes 11. The material, thickness, and size of the metal plate 12 are appropriately set so that undesired deformation does not occur in the stress due to the frequency tuning operation in which the dot pin structure (a) is formed. In this case, the metal plate 12 is made of a copper material having a higher elongation than aluminum, for example, so that the dot pin structure a is more easily formed and the metal plate 12 12). A dot pin structure (a) showing different variable amounts can be formed even when working with the same embossing machine 5 depending on the width, thickness, or shape of the depression of the metal plate 12. A more detailed detailed structure of the concave-convex structure 302 can be appropriately designed according to the characteristics and conditions required for the radiofrequency filter 1 to be designed.

As described above, according to the embodiment of the present invention, the cover 10, which is manufactured using a PCB and to which the metal plate 12 is attached to the through hole 11, can be soldered using a high frequency induction heating method, And a predetermined portion of the lower copper foil layer 103 is bonded to the housing 10 through the through holes. At this time, some joint points between the cover 10 and the housing 20 may further strengthen the mutual engagement state by the screw coupling method. That is, a via hole is formed at an appropriate junction point (s) of the PCB forming the cover 10, a screw groove is formed at a corresponding junction point (s) in the housing 20, A fixing screw can be coupled to the screw groove formed in the housing 20. [

The via hole formed in the PCB may be formed by a hole forming and plating operation by a drilling operation at the time of manufacturing a typical PCB. Likewise, the through holes 11 of the cover 10 may be formed by a drilling operation, a plating operation, or the like in the same manner as the via holes when a PCB is manufactured. FIG. 3 shows a state in which the upper surface copper foil layer 102 and the lower surface copper foil layer are electrically connected by the plating layer by the through-holes 11 formed as described above. In addition, a thin bypass film may be further adhered to the upper portion of the upper surface copper foil layer 102 as in the case of a typical PCB.

The cover 10 is provided with a coupling tuning screw hole (not shown) for providing a coupling tuning screw (not shown) at a position corresponding to the coupling window 23, which is a connecting passage structure of the respective cavity structures in the housing 20, (13: 13-1, 13-2, 13-3, 13-4, 13-5) may be formed. The coupling tuning screw hole 13 can be formed in the same manner as a usual via hole in the PCB manufacturing process and a coupling tuning screw (not shown) for coupling tuning is inserted into the coupling tuning screw hole 13 at an appropriate depth So that coupling tuning can be performed. At this time, fixing the coupling tuning screw to the proper position can be fixed by using a separate adhesive such as epoxy resin.

The metal plate 12 may be provided with a hole for injecting a finer conductive fin respectively so that the resonance element 30 of the housing 20 and the metal plate 12 are short- Is used for conductive pin implantation. In more detail, a frequency tuning operation may be sequentially and individually performed for each resonance element of each cavity according to a frequency tuning method. In this case, in addition to the cavity currently undergoing tuning operation, It is necessary to be electrically short-circuited. In this case, the conductive pin is injected through the conductive fin injection hole formed in the metal plate 12, so that the resonance element 20 of the cavity can be short-circuited.

1 to 3, a radio frequency filter having a cavity structure according to the first embodiment of the present invention forms an entire shape of a cover 10 using a general PCB substrate, The frequency tuning structure is realized by using the through hole 11 and the metal plate 12 attached to the through hole 11 so that the structure having a simpler structure and lower cost than the structure using the conventional tuning screw and fixing nut fastening structure It is possible to make a quick production, and it becomes possible to make it smaller and lighter. In addition, compared with the technique disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 10-2014-0026235, even a relatively large-sized filter can be manufactured with a simple manufacturing operation and a low cost, and a lighter structure can be obtained.

Fig. 5 is a perspective view showing a bottom surface (inner surface of the filter) of the cover of Fig. 1, and Fig. 6 is an enlarged view of a portion C of Fig. 5 and 6, the cover 10 shown in FIG. 1 is turned upside down. A plurality of metal plates 12 (12-1, 12-2, 12- 3, 12-4, 12-5, 12-6) are more clearly shown. 5 and 6, a notch 15 is formed on the lower surface of the cover 10 as an example. The notch 15 shown in Figs. 5 and 6 is formed, for example, to electrically connect the cavity of the second stage to the cavity of the fifth stage.

The notches 15 shown in FIGS. 5 and 6 may be made of a conductive material having protrusions that respectively extend into the two cavities connected to each other. The notches 15 may be attached to the appropriate portions of the lower surface of the cover 10 by soldering or the like have. The protrusions of the notch 15 serve to couple the signal to the resonant element of the cavity. At this time, the lower surface copper foil layer of the corresponding portion is removed in advance (by etching or the like) so that the corresponding portion of the lower surface copper foil layer of the cover 10 to which the notch 15 is attached is divided in a circuit with the notch 15. [ Also, a plurality of fine via-holes 16 are formed at closely spaced intervals around the periphery of the area where the lower surface copper foil layer is removed. The plurality of via holes 16 electrically connect the upper copper foil layer and the lower copper foil layer, thereby satisfying the grounding property.

Fig. 7 is a plan view of a modification of Figs. 5 and 6, showing a notch 15 'other than the notch 15 shown in Figs. 5 and 6 above. The notches 15 'shown in FIG. 7 can be formed in a circuit pattern having predetermined coupling areas inside both cavities that connect to each other, and the coupling areas are connected to each other. The notch 15 'can be formed by etching the bottom copper layer of the cover 10 as in the case of a typical PCB. At this time, as shown in FIGS. 5 and 6, a plurality of minute via holes 16 'having a minute size are formed at closely spaced intervals around the periphery of the notch 15' in the form of a circuit pattern.

FIG. 8 is a perspective view of a cover of a radio frequency filter having a cavity structure according to a second embodiment of the present invention. In the second embodiment shown in FIG. 8, the illustration of the housing is omitted for convenience of explanation. In the second embodiment shown in FIG. 8, as in the first embodiment shown in FIGS. 1 to 6, six cavity structures are sequentially connected in two lines, for example, three, The cover 10 'shown in Fig. In this case, the housing (not shown) may have the same structure as that of the first embodiment shown in FIGS. 1 to 6.

Referring to FIG. 8, in the radio frequency filter according to the second embodiment of the present invention, the cover 10 'has a plurality of through holes 11' passing through the PCB at positions corresponding to the respective cavities (and their resonant elements) : 11-1 ', 11-2', 11-3 ', 11-4', 11-5 ', and 11-6' are formed. In other words, in the first embodiment shown in FIGS. 1 to 6, one through hole 10 is formed in correspondence with one cavity structure, whereas in the second embodiment shown in FIG. 8, (For example, four) through holes 11 'corresponding to one relatively small size.

The metal plate 12 (12-6) is mounted on the lower surface of the cover 10 'in the same manner as in the first embodiment in such a manner as to cover areas formed by the plurality of through holes 11' do. In the frequency tuning for each cavity, a dot pin structure is formed in the metal plate 12 through the plurality of through holes 10 '.

The structure of the second embodiment shown in FIG. 8 is a structure capable of further reducing the possibility of deformation of the metal plate 12 at the time of forming the dot pins. Such a structure may be more advantageous in manufacturing a larger size filter.

9 is a partially exploded perspective view of a radio frequency filter having a cavity structure according to a third embodiment of the present invention. 9, the RF filter according to the third embodiment of the present invention includes a substrate 10 made of a PCB, similar to the structure of the first embodiment shown in FIGS. 1 to 6, In the structure of. In the third embodiment shown in Fig. 9, the lower side (i.e., lower surface) 22 corresponding to the upper side coupled with the cover 10 in the housing 21 is formed using a PCB do. That is, the lower side surface 22 can also be manufactured by using commonly used various types of PCBs having a copper foil layer on the upper and lower surfaces. In the lower side surface 22 manufactured by using the PCB, 30-2, 30-3, 30-4, 30-5, and 30-6 are attached to the resonance elements 30: 30-1, 30-2, 30-3, and 30-4. In this manner, the manufactured lower side 22 can be coupled to the lower end of the housing 21 by soldering and screw connection thereto.

It can be seen that the structure of the third embodiment shown in FIG. 9 is more advantageous in weight reduction.

FIG. 10 is a structural view of a radio frequency filter having a cavity structure according to a fourth embodiment of the present invention. In FIG. 10, a filter having one cavity is shown. In the fourth embodiment shown in FIG. 10, the cover 10 'can be manufactured using a PCB material similar to the cover structures shown in the first to third embodiments. However, in the structure of the metal plate 12' Which is different from other embodiments. The metal plate 12 'according to the fourth embodiment shown in FIG. 10 has a cap shape in which the most peripheral portion extends into the cavity. This structure is more advantageous for temperature compensation of the filter.

More specifically, the cavity filter can expand or contract the inner resonance element 30, the housing 23, etc. according to the ambient temperature rise in the use environment. In this case, the cavity filter and the resonance element 30 ), The distance between the housing 23 and the cover 10 ', and the like. When the resonance element 30 is fabricated to compensate for the change in the characteristic according to the temperature change, the lower portion is formed of aluminum material, which is the same material as the housing 23, and the upper portion of the resonance element 30 is formed of Bs, Sum, Cu , And a method of using the lower and other dissimilar metals is applied.

In contrast, the structure of the cap-shaped metal plate 12 'shown in FIG. 10 may be formed of the same material, and the distance between the cap 12 and the resonance element 30 and the coupling characteristics thereof may be compensated In the direction in which it is to be expanded or contracted. In this case, the resonance element 30 can be simply fabricated using an aluminum material as a whole (without need for a dissimilar metal bonding operation).

11 is a structural view of a radio frequency filter having a cavity structure according to a fifth embodiment of the present invention. In the fifth embodiment shown in FIG. 11, the cover 10 'can be manufactured using a PCB material similar to the cover structure shown in the first to third embodiments, except that the installation structure of the metal plate 12 " The metal plate 12 "according to the fifth embodiment shown in Fig. 11 is attached to the upper surface (that is, the upper surface copper layer) of the cover 10 '. This structure is more advantageous in reducing the size (height) of the filter.

12 is a perspective view of a cover of a radio frequency filter having a cavity structure according to a sixth embodiment of the present invention. Referring to Fig. 12, in the radio frequency filter according to the sixth embodiment of the present invention, the cover 10 "includes a filter region m configured similarly to the cover structure of the other embodiments, A component mounting region n in which the additional component (s) for mounting the additional component (s) for mounting the SMD (Surface Mount Technology) Various integrated circuits and electrical and electronic components of a mounting type or a lead type can be mounted and a circuit pattern connecting them can be formed. As shown in FIG.

Thus, the structure having the cover 10 "shown in Fig. 12 can be realized without additional additional PCB substrate in the case where the additional body, which can be constituted by including the additional components in addition to the filter, For example, when the present filter is applied to a base station, a repeater, and the like in a mobile communication system, various additional devices such as an LNA (Low Noise Amplifier) for transmitting / receiving signal processing are additionally provided The substrate mounting components for the additional equipment can be easily mounted on the component mounting area n of the cover 10 "through the configuration shown in Fig.

13 is a perspective view of a cover showing a modified example of Fig. In the radio frequency filter shown in Fig. 13, a modified example of the cover 10 " is shown in which the component mounting region n is formed by partially sharing the filter region m, which is slightly different from the example of Fig. In this case, for example, a SMD (Surface Mounting Device) type component to be installed in the SMT system is provided in the component mounting region n, and a circuit pattern connecting them can be formed. It is possible that various integrated circuits of the lead type and electric and electronic parts are mounted in the component mounting region n when a slight change in characteristics is taken into consideration, And a circuit pattern connecting them may be formed.

As described above, a radio frequency filter having a cavity structure according to the embodiments of the present invention can be configured, while various other embodiments and modifications can be made in the invention. For example, in the above description, the number and shape of the through holes formed for each cavity in the cover may have various numbers and shapes in addition to the numbers and shapes shown in the above embodiments. In addition, it is also possible to form through holes of different shapes and numbers for each cavity.

In addition, in the above-described embodiments, the cover of the present invention is constructed using a synthetic resin or the like such as a PCB. In addition, the cover of the present invention may be formed of, for example, a housing made of aluminum And a relatively lightweight metal material as compared with a cover made of a metal sheet.

When the cover is made of a metal material and the overall structure is compared with the structure of the above-mentioned Japanese Patent Application Laid-Open No. 10-2014-0026235, in the case of manufacturing a filter of a relatively large size in the above-mentioned Patent Document 10-2014-0026235 In order to form a structure corresponding to the through hole of the present invention and the metal plate attached to the metal cover, it is necessary to cut a corresponding portion of the cover through a lathe operation to form a groove of an appropriate size. This task is relatively complex and time-consuming. In contrast to this, in the present invention, the through hole is formed in the cover, and the operation of attaching the metal plate to the cover is relatively simple and quick.

In addition, in the method of the above-mentioned Japanese Unexamined Patent Application Publication No. 10-2014-0026235, the thickness of the cover itself must be relatively large in order to prevent the deformation during the work process when the shelf is formed for forming the groove on the cover. On the other hand, according to the present invention, the process of forming the holes in the cover can be formed to have a thinner thickness since no strain is applied during the working process. In addition, in the method of the above-mentioned Japanese Unexamined Patent Application Publication No. 10-2014-0026235, a cover can be formed through one base material (i.e., only one material), but in the present invention, So as to have a different metal material. Of course, in some cases, it can be made of a metal material of the same material.

As another example, in the above description, a structure in which a separate resonant element is attached to the inside of the housing has been described as an example, but as in the technique disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 10-2014-0026235 , And a structure in which the housing and the internal resonance element are integrally formed by a press working method as a whole.

Thus, various modifications and variations of the present invention can be made without departing from the spirit and scope of the present invention as defined by the appended claims and their equivalents.

Claims (13)

In a radio frequency filter having a cavity structure,
A housing having an interior hollow and an open side to provide a cavity;
A cover for sealing an opening face of the housing;
A resonant element located in the hollow of the housing;
A through hole is formed in the cover corresponding to each resonance element;
A metal plate for covering the through hole and tuning the frequency,
Wherein the cover has a specific gravity smaller than that of the metal plate.
The radio frequency filter according to claim 1, wherein a plurality of dot peen structures are formed on the metal plate by external steering equipment.
The radio frequency filter according to claim 1, wherein the metal plate is made of a copper material.
2. The filter according to claim 1, wherein when the filter has a plurality of cavities,
And a coupling tuning screw hole for providing a coupling tuning screw is formed on the cover.
The filter according to claim 1, wherein when the filter has a plurality of cavity structures,
Wherein a surface of the cover facing the housing is provided with a notch for signal coupling between two predetermined cavities.
The radio frequency filter according to claim 5, wherein the notch is made of a conductive material having protrusions that respectively extend into the two cavities.
The method according to claim 1,
The cover is made of synthetic resin,
Wherein a metal layer is provided on a surface of the cover facing the housing.
2. The apparatus of claim 1, wherein the cover comprises:
And a printed circuit board (PCB) having a face opposite to the housing and a copper foil layer on the other face.
The radio frequency filter according to claim 8, wherein the notch is formed in a circuit pattern having predetermined coupling areas inside the two cavity structures, the coupling areas being connected to each other.
The radio frequency filter according to claim 1, wherein the housing has a bottom surface formed using a printed circuit board.
The radio frequency filter according to claim 1, wherein the metal plate has a cap shape in which a peripheral edge portion extends into the cavity.
9. The PCB according to claim 8,
Wherein a circuit pattern is further formed for installing separate electrical and electronic components in a SMT (surface mounted technology) system.
2. The semiconductor device according to claim 1, wherein the through-
Wherein the at least two cavities are divided into at least two cavities corresponding to one cavity.

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