WO2020111396A1

WO2020111396A1 - Ceramic waveguide filter and method for producing same

Info

Publication number: WO2020111396A1
Application number: PCT/KR2019/002983
Authority: WO
Inventors: 천동완
Original assignee: 주식회사 에이스테크놀로지
Priority date: 2018-11-26
Filing date: 2019-03-14
Publication date: 2020-06-04

Abstract

The present invention provides a ceramic waveguide filter and a method for producing same, the ceramic waveguide filter comprising: multiple resonant cavities defined by multiple penetrating partitions formed to divide a single ceramic block into sections according to a predetermined pattern in the ceramic block; a metal layer formed on the inner surface of each of the multiple penetrating partitions; and input/output interfaces for inputting and outputting signals, the input/output interfaces being formed at two resonant cavities among the multiple resonant cavities. Accordingly, the ceramic waveguide filter can be integrally produced with a single ceramic block so as to enable production thereof through a simplified production process and with a low cost, minimize processing errors, and be easily tunable even when a property change occurs during production. In addition, the present invention can easily generate a transmission zero.

Description

Ceramic waveguide filter and manufacturing method thereof

The present invention relates to a ceramic waveguide filter, and more particularly, to a ceramic waveguide filter used in a mobile communication system.

As the communication service evolves, the data transmission rate increases, and for this, the system bandwidth must also increase, and it is necessary to improve reception sensitivity and minimize interference caused by carriers of other communication systems.

To this end, demands for low insertion loss, high rejection, and filters are increasing day by day. Coaxial resonant cavities manufactured using metal materials have advantages in terms of loss, size, and cost compared to other resonant cavities such as dielectric resonant cavities, and are mainly used to implement filters in mobile communication systems.

However, due to the low power and miniaturization of a base station system such as a massive MIMO antenna, there is a limitation in terms of size even when using an existing coaxial resonant cavity, and there is a need for implementation of an ultra-small filter.

As a filter to replace a filter using a conventional coaxial resonant cavity, research on ceramic waveguide filters has been actively conducted. The ceramic waveguide filter is a filter that fills a cavity with a ceramic material having low loss and high dielectric constant, which can significantly reduce the size compared to a conventional coaxial resonant cavity filter and also provide excellent loss characteristics.

1 is a view showing the structure of a conventional ceramic waveguide filter.

Referring to Figure 1, the existing ceramic waveguide filter is a plurality of ceramic cavities (111, 112, 113, 114), a plurality of partition walls (121, 122, 123) located between each cavity, the input interface port 140 And an output interface port 150.

In the conventional ceramic waveguide filter as shown in FIG. 1, each

cavity

111, 112, 113, and 114 is independently made of individual ceramic blocks, and

partition walls

121, 122, and 123 are formed on one surface of each cavity. The

partition walls

121, 122, and 123 may be formed through metallization of one surface of the cavity.

Slots

131, 132, and 133 are formed in each partition for inter-cavity coupling. The signal of the first cavity 111 can be coupled to the second cavity 112 through the first slot 131 formed in the first partition 121.

The conventional general ceramic waveguide filter as shown in FIG. 1 requires a process of manufacturing each

ceramic cavity

111, 112, 113, 114 independently, forming a partition wall, and then combining each cavity. The cavities are joined by soldering or the like.

However, such a cavity bonding process frequently caused misalignment tolerances in the bonding process, and there was a problem in that a characteristic change occurred due to the misalignment tolerances. There was a problem in that the yield of the product was remarkably lowered due to a large error even by a slight misalignment.

In addition, if the characteristics change due to processing errors, a process of tuning them is required. However, the conventional ceramic waveguide filter performs tuning by grinding and removing one surface of the ceramic constituting the cavity. Since ceramic is a very hard material, this tuning method requires a high level of technology and has a problem in that fine tuning is difficult.

In addition, the conventional ceramic waveguide filter mainly uses cross coupling when it is desired to provide transmission-zero to improve attenuation characteristics. In order to implement cross coupling from the ceramic waveguide filter of FIG. 1 to

cavities

111, 112, 113, and 114 that are not adjacent to each other, a separate additional operation is required.

The present invention proposes an integrated ceramic waveguide filter that can be manufactured in a simplified manufacturing process and minimizes processing errors.

In addition, the present invention proposes a ceramic waveguide filter that can be easily tuned when characteristic changes occur.

In addition, the present invention proposes a ceramic waveguide filter that can easily implement the transmission zero point by cross coupling.

In order to achieve the above object, the ceramic waveguide filter according to an embodiment of the present invention is defined by a plurality of through partition walls formed to separate the sections of the ceramic block according to a predetermined pattern in a single ceramic block Resonant cavity; A metal layer formed on an inner surface of each of the plurality of through partition walls; And an input/output interface formed on two resonant cavities for inputting and outputting signals among the plurality of resonant cavities. It includes.

The plurality of through partition walls may be formed to penetrate through the ceramic blocks in a pattern that divides the sections of the ceramic blocks so that the plurality of resonant cavities are defined in correspondence to a predetermined frequency band, and to be spaced apart from each other.

The plurality of through barrier ribs are sequentially coupled to adjacent resonant cavities through a coupling window, which is a spaced apart region between the plurality of through barrier ribs, in response to the signals through which the plurality of resonant cavities are input through the input/output interface. A pattern may be formed to filter the frequency band.

The plurality of through partition walls may be formed in a pattern in which at least one resonant cavity among the plurality of resonant cavities is disposed adjacent to the plurality of resonant cavities, so that cross coupling can occur.

The ceramic waveguide filter includes a coupling groove spaced from a through partition wall on one surface of the ceramic block between resonant cavities where the cross coupling is generated on one surface of the ceramic block; This is further formed, the metal layer may be further formed on the inner surface of the coupling groove.

The ceramic waveguide filter may include a coupling hole spaced apart from a through partition wall between the resonant cavities where the cross coupling occurs, and penetrates the ceramic block; This is further formed, the metal layer may be further formed on the inner surface of the coupling hole.

The metal layer may be formed in an area other than the slot area defined on the inner surface of the coupling hole.

The coupling hole may be formed in a stepped structure on the inside, and the metal layer may be formed in an area of the stepped structure except for a predetermined slot area facing the one surface of the ceramic block.

The ceramic waveguide filter may include a conductive sticker attached to an area where the coupling hole is formed on one surface of the ceramic block; It may further include.

The thickness of the metal layer may be adjusted according to a predetermined frequency band.

In order to achieve the above object, a method of manufacturing a ceramic waveguide filter according to another embodiment of the present invention divides a section of the ceramic block according to a predetermined pattern in order to define a plurality of resonant cavities in a single ceramic block Forming a plurality of through partition walls; Forming a metal layer on each inner surface of each of the plurality of through partition walls; And forming an input/output interface for inputting and outputting signals to two of the plurality of resonant cavities; It includes.

According to an embodiment of the present invention, it is possible to manufacture at a low cost with a simplified manufacturing process. In addition, processing errors can be minimized, and tuning can be easily performed even when characteristics change during manufacturing.

1 is a view showing the structure of a conventional ceramic waveguide filter.

2 is a view showing the structure of a ceramic waveguide filter according to an embodiment of the present invention.

3 shows a result of simulating filter characteristics of the ceramic waveguide filter of FIG. 2.

4 is a view showing the structure of a ceramic waveguide filter according to another embodiment of the present invention.

5 to 8 show various examples of the capacitive coupling structure of FIG. 4.

9 shows a result of simulating filter characteristics of the ceramic waveguide filter of FIG. 4.

10 and 11 respectively show a top view and a perspective projection view of a ceramic waveguide filter according to another embodiment of the present invention.

12 shows a result of simulating filter characteristics of the ceramic waveguide filters of FIGS. 10 and 11.

13 shows a method of manufacturing a ceramic waveguide filter according to an embodiment of the present invention.

Hereinafter, the present invention will be described with reference to the accompanying drawings. However, the present invention may be implemented in various different forms, and thus is not limited to the embodiments described herein.

In addition, in order to clearly describe the present invention in the drawings, parts irrelevant to the description are omitted, and like reference numerals are assigned to similar parts throughout the specification.

Throughout the specification, when a part is "connected" to another part, this includes not only "directly connected" but also "indirectly connected" with another member in between. .

Also, when a part “includes” a certain component, this means that other components may be further provided, not excluding other components, unless otherwise specified.

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

2 is a view showing the structure of a ceramic waveguide filter according to an embodiment of the present invention (a) is a top view, (b) is a perspective projection view.

Referring to FIG. 2, the ceramic waveguide filter according to the present embodiment includes a plurality of resonant cavities defined by a plurality of through

partition walls

221, 222, and 223 penetrating between one surface and the other surface of a single ceramic block 200 ( 211, 212, 213).

The plurality of through

partition walls

221, 222, and 223 are formed to penetrate the ceramic block 200 according to a predetermined pattern to define a plurality of

resonant cavities

211, 212, and 213 by dividing the sections of the ceramic block 200. do. In FIG. 2, as an example, a plurality of through

partition walls

221, 222, and 223 are illustrated as being formed in a pattern extending in a straight line in the lateral direction from the ceramic block 200, but this embodiment is not limited thereto. In this embodiment, the plurality of through

partition walls

221, 222, and 223 may be formed in various forms capable of easily distinguishing the sections of the ceramic block 200, and in some cases, such as T-shape or Y-shape. It may also be formed in the form of a branch pattern.

However, in this embodiment, the plurality of through

partition walls

221, 222, and 223 are formed spaced apart from each other. At this time, at least one of the plurality of through

partition walls

221, 222, and 223 may be formed to extend to a side boundary of the ceramic block 200. Since a plurality of through

partition walls

221, 222, and 223 are formed to be spaced apart from each other, even if all through

partition walls

221, 222, and 223 are formed to extend to a side boundary of the ceramic block 200, the ceramic block 200 is It can maintain the shape of a single structure without being cut.

In addition, the inner surfaces of the plurality of through

partition walls

221, 222, and 223 are formed with

metal layers

231, 232, and 233. The metal layers 231, 232, and 233 may be formed by applying a metallization process such as plating, vapor deposition, and sputtering. Typically, in RF equipment such as filters and waveguides, silver (Ag) having excellent electrical conductivity is used among conductive materials to minimize loss, but conductive materials other than silver may be used to improve properties such as corrosion resistance.

In this embodiment, the plurality of

resonant cavities

211, 212, and 213 divided by the plurality of through

partition walls

221, 222, and 223 may include a plurality of ceramic cavities 111, in the conventional ceramic wave guide filter shown in FIG. 112, 113, 114).

Since the plurality of

resonant cavities

211, 212, and 213 are defined separately by the plurality of through

partition walls

221, 222, and 223, the plurality of through

partition walls

221, 222, and 223 function as a cavity wall In addition, the space between the plurality of through

partition walls

221, 222, and 223 may be viewed as a coupling window forming a coupling surface between the plurality of

resonant cavities

211, 212, and 213.

As the plurality of through

partition walls

221, 222, and 223 are formed to be spaced apart from each other, the resonant cavities adjacent to each other among the plurality of

resonant cavities

211, 212, and 213 are formed in the ceramic block 200 through the through

partition walls

221, 222, 223 ) May be resonated through a coupling window, which is an area where no formation is made, and coupling may be performed. To this end, the patterns of the plurality of through

partition walls

221, 222, and 223 may be formed in such a manner that the plurality of

resonant cavities

211, 212, and 213 can be easily coupled. In addition, the pattern of the plurality of through

partition walls

221, 222, 223 may be adjusted such that the plurality of

resonant cavities

211, 212, 213 resonate in a designated frequency band, that is, the size of the resonant cavity is determined. In FIG. 2, for example, the pattern of the plurality of through

partition walls

221, 222, and 223 is formed when the plurality of

resonant cavities

211, 212, and 213 are resonated in the TE101 mode.

In this embodiment, the input/

output interfaces

240 and 250 are provided to the two

resonant cavities

211 and 213 of the initial stage and the last stage according to a specified coupling order among the plurality of

resonant cavities

211, 212, and 213 of the ceramic waveguide filter. ) Is formed. In addition, input/output interface ports for inputting and outputting signals through a ceramic waveguide filter may be inserted into the formed input/

output interfaces

240 and 250. Here, the input/

output interfaces

240 and 250 may be formed, for example, as through holes penetrating between one surface and the other surface of the ceramic block 200.

In FIG. 2, for example, the input/

output interfaces

240 and 250 are illustrated as being formed in the first resonant cavity 211 and the third resonant cavity 213. In addition, it is assumed here that the input interface port is inserted into the input/output interface 240 formed in the first resonant cavity 211. In this case, the first resonant cavity 211 receives a signal from an input interface inserted in the input/output interface 240 and is adjacent to the first resonant cavity 211 through a coupling window that is a space between the first through partition walls 221. ) And the second resonant cavity 212. In addition, coupling is made between the adjacent second resonant cavity 212 and the third resonant cavity 213 through a coupling window that is a space between the second through partition walls 222, and the third resonant cavity 213 is input/output. The signal is output to the output interface port passing through the interface 250.

At this time, each of the plurality of

resonant cavities

211, 212, and 213 may be resonated in a designated frequency band according to the size and shape defined by the plurality of through

partition walls

221, 222, and 223. Therefore, in the ceramic waveguide filter according to the present embodiment, a plurality of

resonant cavities

211, 212, and 213 defined by a plurality of through

partition walls

221, 222, and 223 filter the signal transmitted through the input interface port in multiple stages. You can output through the output interface port. That is, in the ceramic waveguide filter according to the present embodiment, the first to third

resonant cavities

211, 212, and 213 sequentially filter signals input from the input interface, similar to the conventional ceramic waveguide filter of FIG. It can be output through the output interface.

On the other hand, when a plurality of

resonant cavities

211, 212, and 213 are sequentially coupled in the same way as the ceramic waveguide filter of FIG. 1, the plurality of through

partitions

221, 222, and 223 are lateral to the ceramic block 200. It may be formed in a pattern extending parallel to each other. However, in this case, cross coupling between the plurality of

resonant cavities

211, 212, and 213 is difficult to implement.

On the other hand, in the ceramic waveguide filter according to the present embodiment shown in FIG. 2, the plurality of through partition walls 221 so that the first resonant cavity 211 is also adjacent to the second resonant cavity 212 and the third

resonant cavity

213, 222 and 223 are formed in a pattern extending in different directions from the center of the ceramic block 200 to the side. This is to facilitate cross-coupling in the ceramic waveguide filter according to this embodiment.

As described above, when the order of the first resonant cavity 211, the second resonant cavity 212, and the third resonant cavity 213 is a coupling path, the first resonant cavity 211 and the second resonant cavity 211 are arranged according to a specified order. A coupling is made between the two resonant cavities 212. In addition, cross coupling may be performed between the first resonant cavity 211 and the third resonant cavity 213. That is, as the plurality of through

partition walls

221, 222, and 223 are formed so that the first resonant cavity 211 is disposed adjacent to the third resonant cavity 213 as well as the second resonant cavity 212, the first resonant cavity is formed. Cross coupling between the 211 and the third resonant cavity 213 may be easily performed.

The cross-coupling between the first resonant cavity 211 and the third resonant cavity 213 generates a transmission-zero, thereby improving the attenuation characteristics of the ceramic waveguide filter. That is, the ceramic waveguide filter according to the present embodiment easily implements cross-coupling without additional work according to the formation pattern of the plurality of through

partition walls

221, 222, and 223, thereby easily generating transmission-zero. I can do it.

In some cases, in order to suppress cross coupling between the first resonant cavity 211 and the third resonant cavity 213, the third through partition wall 223 may be formed to extend to the side surface of the ceramic block 200. have.

As described above, in the case of the conventional ceramic waveguide filter, a plurality of

cavities

111, 112, 113, and 114 made of ceramic blocks are joined and manufactured, whereas the ceramic waveguide filter according to the present embodiment is single. A plurality of

resonant cavities

211, 212, and 213 are formed in the ceramic block 200 by a plurality of through

partition walls

221, 222, and 223 to be integrally manufactured. Therefore, the process of joining the cavities for joining the plurality of

cavities

111, 112, 113, and 114 is omitted. Accordingly, the manufacturing process can be simplified to facilitate manufacturing, and it is possible to prevent the occurrence of characteristic variations due to misalignment tolerances.

Meanwhile, a ceramic waveguide filter made of a ceramic material is sensitive to mechanical tolerances. Therefore, tuning is essential to ensure that the ceramic waveguide filter performs accurate filtering.

As shown in FIG. 1, in order to accurately tune an existing ceramic waveguide filter to which a plurality of

cavities

111, 112, 113, and 114 are bonded, characteristics in a state where a plurality of

cavities

111, 112, 113, and 114 are combined Should be checked. Then, the tuning is performed so that the identified characteristics are adjusted to the required characteristics. At this time, the existing ceramic waveguide filter has a plurality of cavities (111, 112, 113, 114) already joined, so that the surfaces of the cavities (111, 112, 113, 114) made of ceramic material are grinded. It is done in a way that modulates the properties. However, there is a problem that the ceramic material is very hard and is not easy to process.

In contrast, in the ceramic waveguide filter according to the present embodiment, since a metal layer of a material softer than the ceramic material is formed on the inner surfaces of the plurality of through

partition walls

221, 222, and 223, the metal layer can be grinded to easily adjust the thickness. . That is, the tuning operation for adjusting the characteristics of the ceramic waveguide filter can be easily performed.

In the above, as an example, it has been described that the tuning operation is performed by grinding the metal layer, but the tuning operation may use various methods for adjusting the thickness of the metal layer.

In addition, although the ceramic block 200 is shown as an example of a rectangular parallelepiped in FIG. 2, it is not limited thereto and may be implemented in various forms to improve the performance of the ceramic waveguide filter. In addition, the size of the ceramic block 200 may also be variously changed according to the frequency band of the signal to be filtered.

In addition, in FIG. 2, the metal layers 231, 232, and 233 are formed only on the inner surfaces of the plurality of through

partition walls

221, 222, and 223, but the metal layers are wrapped to cover the outer surfaces of the ceramic block 200. Can be formed.

Referring to FIG. 3, the ceramic waveguide filter including the three

resonant cavities

211, 212, and 213 shown in FIG. 2 performs an operation with a band pass filter (BPF). In particular, the first resonant cavity 211 and the third resonant cavity 213 are inductively cross-coupled, so it can be confirmed that the ceramic waveguide filter can generate a transmission zero point at a frequency of 3.6 GHz, which is higher than the transmission band. .

The ceramic waveguide filter shown in FIG. 4 basically has the same configuration as the ceramic waveguide filter of FIG. 2. Therefore, in the ceramic waveguide filter of FIG. 4, the same identification number is assigned to the same configuration as the ceramic waveguide filter of FIG.

In the ceramic waveguide filter of FIG. 2, inductive cross coupling in which a plurality of

resonant cavities

211, 212, and 213 predominately act on a magnetic field (H-field) may be achieved. On the other hand, in the ceramic waveguide filter of FIG. 4, capacitive cross coupling in which an electric field (E-field) predominates between the first resonant cavity 211 and the third resonant cavity 213 is provided. A capacitive coupling structure 360 is further formed between the first resonant cavity 211 and the third resonant cavity 213 to be made.

That is, the ceramic waveguide filter of FIG. 4 includes the third through partition wall 223 between the first resonant cavity 211 and the third resonant cavity 213 in the ceramic block 200, as well as a capacitive coupling structure 360 ) Is further formed.

Here, the capacitive coupling structure 360 may not be formed to overlap the third through partition wall 223. Therefore, when the capacitive coupling structure 360 is formed, the length of the third through partition wall 223 is such that the corresponding third through partition wall 223 does not overlap with the position of the capacitive coupling structure 360. Can be adjusted. For example, the length of the third through partition wall 223 of FIG. 4 is shorter than that of the third through partition wall 223 of FIG. 2.

In addition, a metal layer may be formed on the inner surface of the capacitive coupling structure 360, and the metal layer may also be formed on the outer surface of the ceramic block 200.

As illustrated in FIG. 4, a capacitive coupling structure 360 is further formed between the first resonant cavity 211 and the third resonant cavity 213 to form the first resonant cavity 211 and the third resonant cavity. When the capacitive cross-coupling is mainly performed between 213, the frequency at which the transmission zero point occurs is variable, and thus the filter characteristics of the ceramic waveguide filter may be varied.

5 to 8 show various examples of the capacitive coupling structure of FIG. 4.

In FIG. 5, a capacitive cross coupling in which the electric field predominates between the plurality of

resonant cavities

211, 212, and 213 in the ceramic waveguide filter is capacitive in one direction from the other side of the ceramic block 400. The case where the coupling groove 461 is formed by the coupling structure 460 is illustrated.

The coupling groove 461 may be formed to not overlap the third through partition wall 223 between the first resonant cavity 211 and the third resonant cavity 213 on one surface of the ceramic block 400. In addition, a metal layer 462 is formed on the inner surface of the coupling groove 461 like the plurality of through

partition walls

221, 222, and 223.

Here, the depth of the coupling groove 461 may be adjusted according to the frequency at which the capacitive cross coupling is performed. Therefore, depending on the frequency at which the capacitive cross coupling is to be performed, the depth of the coupling groove 461 may be deep, and the thickness of the ceramic block 400 may be very thin at the position where the coupling groove 461 is formed. In this case, damage may occur in a region where the coupling groove 461 is formed during manufacture and handling of the ceramic waveguide filter.

6 illustrates a case where the capacitive coupling structure 560 is implemented as a coupling hole 561 penetrating one surface and the other surface of the ceramic block 500. In addition, a metal layer 562 is formed on the inner surface of the coupling hole 561. In FIG. 6, as the capacitive coupling structure 560 is formed in a hole shape penetrating the ceramic block 500, it is possible to prevent damage caused by the capacitive coupling structure to the ceramic block 500. have.

Here, the metal layer 562 may be removed from a portion of the inner surface of the coupling hole 561 to further form a slot (not shown).

Meanwhile, in FIG. 7, the capacitive coupling structure 660 is implemented as a coupling hole 661 penetrating one surface and the other surface of the ceramic block 600 as in FIG. 6, but the coupling hole 661 is shown in FIG. 6. Unlike the coupling hole 561 of the, it is formed in a stepped structure. And the metal layer 662 is formed on the inner surface of the coupling hole 661. At this time, in FIG. 7, the metal layer 662 may be removed from a portion of the inner surface of the stepped structure coupling hole 661 to further form a slot 663. The slot 663 may be formed in a portion of a surface parallel to one surface of the ceramic block 600 on the inner surface of the coupling hole 661.

When the slot 663 is formed, the size of the slot 663 is adjusted with a grinder or the like to perform tuning for the frequency at which the capacitive cross coupling is performed, so that the coupling groove 461 or the coupling hole ( The thickness of the metal layers 462 and 562 or slots (not shown) formed on the inner surface of the 561) may be adjusted by a method such as grinding to facilitate tuning.

In FIG. 8, the capacitive coupling structure 760 may have a stepped structure coupling hole 761, a metal layer 762, and a slot 763 similar to that of FIG. 7. In addition, in FIG. 8, a conductive sticker 765 for preventing signal leakage by the slot 763 is further attached to one surface of the ceramic block 700. The conductive sticker 765 may be attached to the entire surface of the ceramic block 700, but may be attached only to an area corresponding to the coupling hole 761.

The

capacitive coupling structures

560, 660, and 760 of FIGS. 6 to 8 prevent damage caused by the coupling groove 461 shown in FIG. 5 during manufacture and handling of the ceramic waveguide filter. It is a structure for.

When the simulation result of FIG. 9 is compared with FIG. 3, in the simulation result illustrated in FIG. 9, a capacitive couple together with a third through partition wall 223 between the first resonant cavity 211 and the third resonant cavity 213 The ring structure 360 is formed to perform a capacitive cross coupling between the first resonant cavity 211 and the third resonant cavity 213, so that the ceramic waveguide filter is at a frequency of 3.3 GHz, which is lower than the pass band. It can be confirmed that the transmission zero point can be generated.

That is, in the ceramic waveguide filter according to the present embodiment, the frequency at which the transmission zero point occurs can be varied depending on whether a coupling groove is additionally formed between two resonant cavities where cross coupling occurs.

2 and 4, for convenience of explanation, a ceramic wave guide in which three

resonant cavities

211, 212, and 213 are formed by three through

partition walls

221, 222, and 223 on a ceramic block 200 as a simple example Although a filter is shown, the present invention is not limited to this.

In the ceramic waveguide filter according to the present invention, a plurality of resonant cavities may be defined by a plurality of through partition walls formed through the ceramic block according to a predetermined pattern. Accordingly, in FIGS. 10 and 11, six through partition walls 821 to 826 penetrating between one surface and the other surface of the ceramic block 800 are formed according to a predetermined pattern, thereby dividing the ceramic block 800 into six sections, Six resonant cavities 811 to 816 are defined.

The six through partition walls 821 to 826 are formed in a pattern for dividing the ceramic block 800 into six sections, and the shapes of the six through partition walls 821 to 826 may be formed differently. In addition, as shown in FIGS. 10 and 11, the six through partition walls 821 to 826 may be formed in different patterns from each other, and some may be formed in the form of branch patterns such as T-shape or Y-shape. have.

Metal layers 831 to 836 are formed on the inner surfaces of each of the six through partition walls 821 to 826.

In addition, input/

output interfaces

840 and 850 in which input/output interface ports are inserted are formed in the first resonance cavity 811 and the sixth resonance cavity 816 among the six resonance cavities 811 to 816. The first resonant cavity 811 receives a signal from an input interface port inserted in the input/output interface 840, is sequentially coupled in the second to sixth resonant cavities 812 to 816, and the sixth resonant cavity 816 outputs a signal to the output interface port inserted in the input/output interface 850.

The first to sixth resonant cavities 811 to 816 may be sequentially coupled through a coupling window between six through partitions 821 to 826 formed spaced apart. That is, coupling is made between the first resonant cavity 811 and the second resonant cavity 812 through a coupling window corresponding to the first and second through

partition walls

821 and 822, and the second and third through holes are formed. Coupling is performed between the second resonant cavity 812 and the third resonant cavity 813 through a coupling window corresponding to the

partition walls

822 and 823, and the third and fourth through

partition walls

823 and 824 Coupling may be performed between the third resonant cavity 813 and the fourth resonant cavity 814 through a corresponding coupling window. Then, coupling is made between the fourth and fifth resonant cavities 814 through the coupling windows corresponding to the fourth and fifth through

partitions

824 and 825, and the fifth and sixth penetrating Coupling may be performed between the fifth resonant cavity 815 and the sixth resonant cavity 816 through a coupling window corresponding to the

partition walls

825 and 826.

At this time, the first to sixth resonant cavities 811 to 816 are resonated in the designated frequency band to filter signals in the designated frequency band. Therefore, the ceramic waveguide filter shown in FIGS. 10 and 11 functions as a multi-stage filter performing 6-stage filtering.

Meanwhile, in the ceramic waveguide filter illustrated in FIGS. 10 and 11, cross coupling between the first resonant cavity 811 and the third resonant cavity 813 through a coupling window corresponding to the second through partition wall 822. This can be easily done. In addition, cross-coupling may be performed between the second resonant cavity 812 and the adjacent fourth resonant cavity 814, and cross-coupling may also occur between the third resonant cavity 813 and the fifth resonant cavity 815. Cross coupling may be performed between the fourth resonant cavity 814 and the sixth resonant cavity 816. That is, in the ceramic waveguide filter illustrated in FIGS. 10 and 11, cross coupling may occur between a plurality of resonant cavities.

However, at least one through partition wall of the six through partition walls 821 to 826 may be formed to extend to a side boundary of the ceramic block 800 so that cross coupling between resonant cavities is suppressed. For example, in the ceramic waveguide filter of FIGS. 10 and 11, cross coupling between the second resonant cavity 812 and the fourth resonant cavity 814, the fourth resonant cavity 814 and the sixth resonant cavity 816. Each of the third through partition wall 823 and the fifth through partition wall 825 may be formed to extend to a side boundary of the ceramic block 800 so as to be suppressed.

10 and 11, the first and third resonant cavities are further formed by forming a capacitive coupling structure 860 together with the second through partitions 822 between the first and third

resonant cavities

811 and 813. A capacitive cross coupling can be made between (811, 813). At this time, the capacitive coupling structure 860 may be formed in the form of a coupling groove 461 or in the form of coupling holes 561, 661, 761, as shown in FIGS. . Further, the coupling hole may be formed in a step shape, and

metal layers

462, 562, 662, and 762 may be formed on the inner surface of the coupling groove 461 or the coupling holes 561, 661, and 761. In addition, the metal layers 562, 662, and 762 are not removed or formed in some regions to form

slots

663 and 763, and correspond to

coupling holes

561, 661, and 761 on one surface of the ceramic block. The position conductive sticker 765 may be further attached.

At this time, the pattern of the second through partition wall 822 may be adjusted so as not to overlap with the region where the capacitive coupling structure 860 is formed.

As a result, referring to FIGS. 10 and 11, in the ceramic waveguide filter according to the present embodiment, a plurality of through partitions 821 to 826 are formed in a single ceramic block to easily implement multiple resonance cavities.

In FIG. 12, capacitive coupling structures 860 are formed between the first and third

resonant cavities

811 and 813 in the ceramic waveguide filters of FIGS. 10 and 11, and the third and fifth through

partition walls

823 , 825 extends to the lateral boundary of the ceramic block 800 to cross couple between the second resonant cavity 812 and the fourth resonant cavity 814 and the fourth resonant cavity 814 and the sixth resonant cavity 816. It is assumed that the ring is suppressed.

As the capacitive coupling structure 860 is formed between the first and third

resonant cavities

811 and 813, the capacitive cross coupling is provided between the first and third

resonant cavities

811 and 813. On the other hand, an inductive cross coupling is performed between the third resonant cavity 813 and the fifth resonant cavity 815.

3 and 5, inductive cross coupling generates a transmission zero at frequencies higher than the transmission band, whereas capacitive cross coupling generates a transmission zero at frequencies lower than the transmission band.

Accordingly, the ceramic waveguide filters of FIGS. 10 and 11 in which both inductive cross coupling and capacitive cross coupling are generated, as illustrated in FIG. 12, can be confirmed that transmission zeros are generated at both ends of the transmission band frequency. . And these results indicate that the ceramic waveguide filter according to this embodiment can function as a band pass filter with very good performance.

A method of manufacturing the ceramic waveguide filter of FIG. 13 will be described with reference to FIGS. 2 to 12.

Prior to manufacturing the ceramic waveguide filter, the frequency band and filtering characteristics that the ceramic waveguide filter should filter are predetermined. Then, a ceramic block is manufactured according to the determined frequency band (S10). Here, the ceramic block may be manufactured by determining the size and shape according to the determined frequency band.

In addition, a plurality of resonant cavities are implemented by forming a plurality of through partition walls penetrating one surface and the other surface of the ceramic block in a predetermined pattern according to a frequency band to be filtered, and dividing the ceramic block sections into a plurality (S20). At this time, a plurality of through partition walls are formed spaced apart from each other. Since a plurality of through partition walls are formed spaced apart from each other, a plurality of resonant cavities can be coupled through a spaced apart coupling window between the plurality of through partition walls.

When a plurality of through partition walls are formed, if a capacitive cross coupling is required according to a predetermined filtering characteristic, that is, if a transmission zero point needs to be generated at a frequency lower than the pass band, a cap for generating a capacitive cross coupling The sieve coupling structure is further formed (S30). The capacitive coupling structure may be formed so as not to overlap with a through partition wall corresponding between two resonant cavities of the plurality of resonant cavities. In addition, the capacitive coupling structure may be formed in the form of coupling grooves 461 or

coupling holes

561, 661, and 761, as shown in FIGS. In addition, the coupling hole may be formed in a step shape.

Here, the step of forming the capacitive coupling structure may be omitted when capacitive cross coupling is not required.

Thereafter, a metal layer is formed by applying a metallization process such as plating, deposition, sputtering, etc. to a conductive material such as silver on each inner surface of the plurality of through partition walls (S30). At this time, the metal layer is formed not only on the inner surface of each of the plurality of through partition walls, but also on the inner surface of the capacitive coupling structure. And it can also be formed on the outer surface of the ceramic block. When the capacitive coupling structure is formed of stepped

coupling holes

661 and 761, a metal layer may not be formed to form

slots

663 and 763 on some surfaces of the coupling hole. Alternatively, the metal layer is formed irrespective of the

slots

663 and 763, and may be adjusted in a tuning step (S60) described later with a metal layer formed on the inner surface of the through partition wall, such as grinding.

In addition, an input/output interface is formed in two resonant cavities among the plurality of resonant cavities (S50). Here, the input/output interface is both ends in a sequence in which a plurality of resonant cavities of a ceramic waveguide filter are sequentially coupled to receive a signal from an input interface port and output a filtered signal to an output interface port. It can be formed in the resonance cavity.

Meanwhile, the characteristics of the ceramic waveguide filter are tuned by fine-adjusting the coupling values between the plurality of resonant cavities in such a way that the thickness of the metal layer formed on each inner surface of each of the plurality of through partitions is adjusted (S60). At this time, when the capacitive coupling structure is formed, the thickness of the inner surface of the capacitive coupling structure can be adjusted together. Then, the metal layers formed on the inner surfaces of the coupling holes 661 and 761 are formed to form the

slots

663 and 763, or the size of the formed

slots

663 and 763 is adjusted to control the frequency at which the capacitive cross coupling is performed. I can tune it.

In the manufacturing method of the ceramic waveguide filter of FIG. 13, the step of forming a capacitive coupling structure (S30), the step of forming a metal layer (S40), and the step of forming an input/output interface (S50) are to improve process efficiency. The order can be adjusted.

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 defined by the technical spirit of the appended claims.

Claims

A plurality of resonant cavities defined by a plurality of through partition walls formed to separate the sections of the ceramic block according to a predetermined pattern in a single ceramic block;

A metal layer formed on an inner surface of each of the plurality of through partition walls; And

An input/output interface formed in two resonance cavities for inputting and outputting signals among the plurality of resonance cavities; Ceramic waveguide filter, characterized in that it comprises a.
The method of claim 1, wherein the plurality of through partition walls

A ceramic waveguide filter formed through the ceramic block and spaced apart from each other in a pattern that divides the compartments of the ceramic block so that the plurality of resonant cavities are defined in correspondence to a predetermined frequency band.
The method of claim 2, wherein the plurality of through partition walls

Filtering the frequency band while the plurality of resonant cavities are sequentially coupled with adjacent resonant cavities through a coupling window that is a spaced apart area between the plurality of through partitions in response to a signal input through the input/output interface. A ceramic waveguide filter with a pattern.
The method of claim 3, wherein the plurality of through partition walls

A ceramic waveguide filter that is formed in a pattern in which at least one resonant cavity among the plurality of resonant cavities is disposed adjacent to the plurality of resonant cavities, so that cross coupling occurs.
The method of claim 4, wherein the ceramic waveguide filter

A coupling groove spaced from the through partition wall on one surface of the ceramic block between the resonance cavities where the cross coupling is generated on one surface of the ceramic block; Is formed more,

The metal layer

A ceramic waveguide filter further formed on the inner surface of the coupling groove.
The method of claim 4, wherein the ceramic waveguide filter

A coupling hole spaced apart from the through partition wall between the resonant cavities where the cross coupling occurs, and penetrates the ceramic block; Is formed more,

The metal layer

Ceramic waveguide filter is further formed on the inner surface of the coupling hole.
The method of claim 6, wherein the coupling hole

The inside is formed in a stepped structure,

The metal layer

A ceramic waveguide filter formed in an area except for a predetermined slot area facing the one surface of the ceramic block on the inner surface of the coupling hole having a stepped structure.
The method of claim 6, wherein the ceramic waveguide filter

A conductive sticker attached to an area where the coupling hole is formed on one surface of the ceramic block; Ceramic waveguide filter further comprising a.
The method of claim 1, wherein the metal layer

Ceramic waveguide filter whose thickness is adjusted according to a predetermined frequency band.
Forming a plurality of through partition walls separating the sections of the ceramic block according to a predetermined pattern to define a plurality of resonant cavities in a single ceramic block;

Forming a metal layer on each inner surface of each of the plurality of through partition walls; And

Forming an input/output interface for inputting and outputting signals to two of the plurality of resonant cavities; Method of manufacturing a ceramic waveguide filter comprising a.
11. The method of claim 10, The step of forming the plurality of through partition walls

A method of manufacturing a ceramic waveguide filter that divides the sections of the ceramic block so as to define the plurality of resonant cavities corresponding to a predetermined frequency band and penetrates the ceramic block in a pattern spaced apart from each other to form the plurality of through partition walls.
The method of claim 11, wherein the step of forming the plurality of through partition walls

The plurality of resonant cavities are sequentially coupled with adjacent resonant cavities through a coupling window that is a spaced apart area between the plurality of through partitions in response to a signal input through the input/output interface, and the frequency band is filtered. A method of manufacturing a ceramic waveguide filter in which a pattern is formed.
The method of claim 12, wherein the step of forming the plurality of through partition walls

A method of manufacturing a ceramic waveguide filter, wherein at least one resonant cavity among the plurality of resonant cavities is formed in a pattern disposed adjacent to the plurality of resonant cavities, so that cross coupling occurs.
The method of claim 13, wherein the method of manufacturing the ceramic waveguide filter

Forming a coupling groove spaced from the through partition wall between the resonant cavities where the cross coupling occurs on one surface of the ceramic block; And

Forming the metal layer on an inner surface of the coupling groove; Method of manufacturing a ceramic waveguide filter further comprising.
The method of claim 13, wherein the method of manufacturing the ceramic waveguide filter

Forming a coupling hole spaced apart from the through partition wall between the resonant cavities where the cross coupling occurs, and penetrates the ceramic block; And

Forming the metal layer on the inner surface of the coupling hole; Method of manufacturing a ceramic waveguide filter further comprising.
The method of claim 15, wherein the step of forming the coupling hole

The inside of the coupling hole is formed in a stepped structure,

The step of forming on the inner surface of the coupling hole

A method of manufacturing a ceramic waveguide filter, wherein the metal layer is formed in an area except for a predetermined slot area facing the one surface of the ceramic block on the inner surface of the coupling hole having a stepped structure.
The method of claim 16, wherein the manufacturing method of the ceramic waveguide filter

Attaching a conductive sticker to an area where the coupling hole is formed on one surface of the ceramic block; Method of manufacturing a ceramic waveguide filter further comprising.
The method of claim 10, wherein the method of manufacturing the ceramic waveguide filter

Adjusting the thickness of the metal layer according to a predetermined frequency band; Method of manufacturing a ceramic waveguide filter further comprising.
The method of claim 6, wherein the ceramic waveguide filter

A conductive sticker attached to an area where the coupling hole is formed on one surface of the ceramic block; Ceramic waveguide filter further comprising a.