KR20240034324A - Compact Ceramic Waveguide Filter - Google Patents

Abstract

The disclosed embodiment has a plurality of resonance cavities defined as partitions divided by a plurality of penetrating partitions formed by penetrating a single ceramic block, and each of the plurality of resonance cavities is formed by extending inward from one side of the ceramic block in the direction of the other side of the ceramic block. A plurality of resonance grooves, a metal layer formed on the outer surface of the ceramic block and the inner surface of each of the plurality of resonance grooves, and a plurality of resonance metal surfaces formed at the inner ends of each of the plurality of resonance grooves with an area larger than the area of the longitudinal section. Including, it provides a ceramic waveguide filter that can be manufactured in a small and lightweight manner.

Description

Compact Ceramic Waveguide Filter}

The disclosed embodiments relate to a ceramic waveguide filter, and to a small ceramic waveguide filter that can significantly reduce volume and weight.

As communication services evolve, data transmission speeds increase, and for this to happen, 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, we face a situation where the requirements 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 price compared to other resonant cavities such as dielectric resonant cavities, so they are mainly used to implement filters in mobile communication systems.

However, due to the low output and miniaturization of base station systems such as massive MIMO antennas, there are limitations in size even when using existing coaxial resonance cavities, and the need to implement ultra-small filters is emerging.

For this reason, research on ceramic waveguide filters is being actively conducted as a filter to replace existing filters using resonant cavities with cavities filled with air. A ceramic waveguide filter is a filter that fills the cavity with a ceramic material with low loss and high dielectric constant. It can significantly reduce the size compared to existing coaxial resonance cavity filters and also provide excellent loss and power dissipation characteristics.

A typical conventional ceramic waveguide filter requires a process of manufacturing each ceramic cavity independently, forming a partition, and then combining each cavity. The joining of cavities is accomplished through soldering, etc.

However, the cavity joining process has the problem that misalignment tolerances frequently occur during the joining process, which causes changes in characteristics and significantly lowers the yield of the product. Additionally, if the characteristics change due to processing errors, a tuning process is required by grinding one side of the ceramic. However, since ceramic is a very hard material, it requires advanced technology and fine tuning is difficult. In addition, when trying to provide transmission-zero to improve the attenuation characteristics of a ceramic waveguide filter, cross coupling is mainly used, but cross coupling between cavities that are not adjacent to each other is used. There was a problem that additional work was required to implement the ring.

To solve this problem, an integrated ceramic waveguide filter implemented as a single ceramic block was proposed.

Figure 1 shows an example of a conventional integrated ceramic waveguide filter, and Figure 2 shows a side cross-sectional view of the ceramic waveguide filter of Figure 1.

Referring to Figures 1 and 2, the integrated ceramic waveguide filter penetrates between one side and the other side of the single ceramic block 10 and includes a plurality of penetrating partitions 21 and 22 formed to partition the ceramic block according to a predetermined pattern. ) and includes a number of resonant cavities (11 to 16) defined by .

The plurality of penetrating partition walls 21 and 22 function as cavity walls that separate the plurality of resonance cavities 11 to 16, and a plurality of penetrating partition walls 21 and 22 are formed spaced apart from each other. The space between may function as a coupling window that forms a coupling surface between the plurality of resonance cavities 11 to 16.

In addition, resonance grooves 31 to 36 may be formed on one or the other side of the ceramic block 10 in each of the plurality of resonance cavities 11 to 16. Each of the plurality of resonance grooves (31 to 36) is formed at the center where the electric field is concentrated in the corresponding resonance cavity (11 to 16) region to increase the capacitive component of each of the plurality of resonance cavities (11 to 16) to increase the resonance frequency. It causes a downward effect. Therefore, it was possible to miniaturize the ceramic waveguide filter by reducing the size of each resonance cavity (11 to 16).

At this time, inductive coupling in which a magnetic field (H-field) acts predominantly may be formed between the resonance cavities 11 to 16 formed adjacent to each other. On the other hand, since the electric field (E-field) crosses the surface of the coupling window between the plurality of spaced apart penetrating partitions 21 and 22, capacitive coupling is not easily achieved. .

As shown in FIG. 2, the ceramic block 10 is formed so that capacitive coupling in which the electric field (E-field) acts predominantly is achieved between the resonance cavities 11 to 16 formed adjacent to each other. A coupling groove 40 that is deeper than the resonance grooves 31 to 36 may be further formed on one side or the other side.

Figure 1 shows, as an example, an integrated ceramic waveguide filter in which six resonance cavities (11 to 16) are formed. However, recent massive MIMO devices generally require 32 or 64 ceramic waveguide filters to be mounted, so even when using an integrated ceramic waveguide filter as shown in Figure 1, there is still a need to reduce size and weight.

Korean Patent Publication No. 10-2021-0073902 (published on June 21, 2021)

The disclosed embodiments are aimed at providing a ceramic waveguide filter that can be manufactured in a small and lightweight manner.

A ceramic waveguide filter according to an embodiment includes a plurality of resonance cavities defined as partitions divided by a plurality of penetrating partitions formed through a single ceramic block; a plurality of resonance grooves extending inward from one side of the ceramic block to the other side of the ceramic block within each section of the plurality of resonance cavities; a metal layer formed on an outer surface of the ceramic block and an inner surface of each of the plurality of resonance grooves; and a plurality of resonance metal surfaces formed at inner ends of each of the plurality of resonance grooves and having an area larger than the area of the longitudinal cross-section.

Each of the plurality of resonance grooves may be formed in the shape of a cylinder having a first diameter from one surface side of the ceramic block, and each of the plurality of resonance metal surfaces may be formed in the shape of a disk having a second diameter larger than the first diameter. there is.

The ceramic waveguide filter includes at least one coupling groove extending inward from one side of the ceramic block to the other side between adjacent resonance cavities among the plurality of resonance cavities; And it may further include at least one coupling metal surface having an area larger than the area of the longitudinal section at the inner end of the coupling groove.

The at least one coupling groove is formed in a cylindrical shape extending from one surface side of the ceramic block to a predetermined third diameter, and the at least one coupling metal surface has a disk shape having a fourth diameter larger than the third diameter. can be formed.

The at least one coupling metal surface may be formed to have an area larger than that of the plurality of resonant metal surfaces.

The at least one coupling groove may be formed to have the same depth as the plurality of resonance grooves in the ceramic block.

The at least one coupling groove may be formed in a cylindrical shape having the same diameter as the plurality of resonance grooves.

The ceramic waveguide filter is formed by penetrating the ceramic block between adjacent resonance cavities among the plurality of resonance cavities, and the diameter of the through hole penetrating the ceramic block is smaller than the diameter of the inlet area on one side of the ceramic block. is formed, and the inner surface may further include at least one coupling hole in which the metal layer is formed.

The at least one coupling hole may further have an intermediate region formed between the through hole and the inlet region having a diameter between the diameter of the through hole and the diameter of the inlet region.

The at least one coupling hole may include a slot in which the metal layer is removed into a ring shape with a predetermined thickness at a predetermined location in the inlet area.

Therefore, the small ceramic waveguide filter according to the embodiment has a resonance groove on one side of the inner side of the resonance groove formed in the inner direction from one surface of the ceramic block in each of a plurality of resonance cavities defined by a plurality of through partitions in a single ceramic block. It can be made compact and lightweight by placing a metal plate larger than its diameter to increase capacitance. Additionally, a coupling groove having a structure similar to the resonance groove can be formed between the resonance grooves and used as a capacitive reactance for capacitive coupling, making it possible to manufacture it more compactly.

Figure 1 shows an example of a conventional integrated ceramic waveguide filter.
Figure 2 shows a side cross-sectional view of the ceramic waveguide filter of Figure 1.
Figure 3 shows a side cross-sectional view of a ceramic waveguide filter according to one embodiment.
Figure 4 shows a side cross-sectional view of a ceramic waveguide filter according to another embodiment.
Figure 5 shows a side cross-sectional view of a ceramic waveguide filter according to another embodiment.

Hereinafter, specific embodiments of one embodiment will be described with reference to the drawings. The detailed description below is provided to provide a comprehensive understanding of the methods, devices and/or systems described herein. However, this is only an example and the present invention is not limited thereto.

In describing one embodiment, if it is determined that a detailed description of the known technology related to the present invention may unnecessarily obscure the gist of an embodiment, the detailed description will be omitted. In addition, the terms described below are terms defined in consideration of functions in the present invention, and may vary depending on the intention or custom of the user or operator. Therefore, the definition should be made based on the contents throughout this specification. The terminology used in the detailed description is intended to describe only one embodiment and should in no way be limiting. Unless explicitly stated otherwise, singular forms include plural meanings. In this description, expressions such as “comprising” or “comprising” are intended to indicate certain features, numbers, steps, operations, elements, parts or combinations thereof, and one or more than those described. It should not be construed to exclude the existence or possibility of any other characteristic, number, step, operation, element, or part or combination thereof. 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 3 shows a side cross-sectional view of a ceramic waveguide filter according to one embodiment.

The ceramic waveguide filter according to the embodiment shown in FIG. 3 is also implemented as an integrated ceramic waveguide filter. In addition, the ceramic waveguide filter of one embodiment, like the ceramic waveguide filter of FIG. 1, is defined by a plurality of penetrating partition walls (not shown) formed in a predetermined pattern through between one side and the other side of the single ceramic block 100. It is assumed that it is implemented in an integrated form including a resonance cavity. Each of the resonant cavities divided by a plurality of penetrating partition walls can be viewed as a configuration corresponding to an individual resonator in a conventional ceramic waveguide filter.

And Figure 3 shows a side cross-sectional view of the ceramic wave guide filter along the line A - A' in the integrated ceramic wave guide filter, as in Figure 2. Accordingly, FIG. 3 shows two resonance cavities 113 and 114 defined by a plurality of through partitions (not shown) as in FIG. 2 in the ceramic wave guide filter, and the two resonance cavities 113 and 114 are shown in FIG. In the region, two resonance grooves 133 and 134 formed inward from one surface of the single ceramic block 100 are shown, respectively. Each resonance groove (133, 134) is preferably formed at the center where the electric field is concentrated in the region of the resonance cavity (113, 114).

As shown in Figures 1 and 2, the existing resonance grooves 31 to 36 are formed in a cylindrical shape with a uniform diameter or a gradually decreasing diameter as it progresses from one side of the ceramic block 10 to the inside. . Additionally, the plurality of resonance grooves 133 and 134 according to this embodiment are also formed in a cylindrical shape extending inward from one surface of the ceramic block 100. That is, as shown in FIG. 3, each of the plurality of resonance grooves 133 and 134 may be formed in a cylindrical shape having a first diameter D1 on one surface of the ceramic block 100 and extending to a predetermined depth. .

And a metal layer 190 is formed on the outer surface of the ceramic block 100. The metal layer 190 may be formed by applying a metallization process such as plating, deposition, or sputtering. Typically, silver (Ag), which has excellent electrical conductivity among conductive materials, is used in RF equipment such as filters and waveguides to minimize losses, but conductive materials other than silver can also be used to improve properties such as corrosion resistance. The metal layer 190 is not only formed on the inner surface of each of the plurality of penetrating partitions, but also on the inner surface of each of the plurality of resonance grooves 133 and 134, as shown in FIG. 3, and is formed on the coupling groove (described later) It is also formed on the inner surface of 140).

Since the resonance grooves 133 and 134 are formed in a cylindrical shape extending inward from one surface of the ceramic block 100 and the metal layer 190 is formed inside, each resonance groove 133 and 134 has a corresponding resonance cavity ( 113, 114), the resonance frequency can be lowered by increasing the capacitive component.

However, in the ceramic waveguide filter of the embodiment, a second diameter larger than the diameter D1 of the resonance grooves 133 and 134 is formed at the inner end of the plurality of resonance grooves 133 and 134, that is, at the top of the resonance grooves 133 and 134. Resonant metal surfaces 163 and 164 having (D2) are formed and disposed. Here, the resonant metal surfaces 163 and 164 may be implemented in various flat shapes. At this time, the resonance metal surfaces 163 and 164 may be formed in a polygonal flat structure such as a square or hexagon, but here, it is assumed that they are formed in a circular shape. And the resonant metal surfaces 163 and 164 formed in a circular plate structure are formed to have a second diameter D2 larger than the first diameter D1 of the resonant grooves 133 and 134. That is, the resonant metal surfaces 163 and 164 have an area larger than the inner longitudinal section of the resonant grooves 133 and 134.

As the resonant metal surfaces 163 and 164 are formed to have a larger area with a second diameter (D2, D2 > D1) larger than the diameter D1 of the resonant grooves 133 and 134, the resonant cavities 113 and 114 have It has a larger capacitive component compared to the case where only the resonance grooves 133 and 134 are formed. That is, the resonance frequency can be lowered further compared to the case where the resonance metal surfaces 163 and 164 are not formed.

Therefore, the ceramic waveguide filter of the embodiment can be implemented in a smaller size than the existing ceramic waveguide filter shown in FIG. 1 because each resonator can have the same capacitance even if the size is smaller.

Here, as an example, the diameters D1 of each resonance groove 133 and 134 are shown to be the same, and the diameter D2 of each resonance metal surface 163 and 164 is shown to be the same. However, in some cases, the diameter D1 of each resonance groove 133 and 134 is the same. , 134) may be implemented differently, and the diameters D2 of the resonant metal surfaces 163 and 164 may also be implemented differently.

Meanwhile, in the ceramic waveguide filter according to this embodiment, like the ceramic waveguide filter of FIGS. 1 and 2, the electric field (E-field) is dominant between the third resonance cavity 113 and the fourth resonance cavity 114. A coupling groove 140 may be further formed to enable capacitive coupling.

Like the resonance grooves 133 and 134, the coupling groove 140 may be formed in a cylindrical shape extending inward from one surface of the ceramic block 100. Additionally, a coupling metal surface 170 similar to the resonance metal surfaces 163 and 164 is formed at the inner end of the coupling groove 140, that is, at the top of the coupling groove 140. The coupling metal surface 170 may also be formed in a polygonal or circular plate structure. Here, it is assumed to be formed in a circular plate structure.

In the ceramic waveguide filter shown in FIGS. 1 and 2, the coupling groove 40 is formed deeper than the resonance grooves 31 to 36. This is to enable stronger capacitive coupling in the coupling groove 40 than in the resonance grooves 31 to 36. However, if the coupling groove 40 is formed deeper to achieve strong capacitive coupling, the inner end of the coupling groove 40, that is, the top of the coupling groove 40 and the ceramic block 10 The gap between the riding surfaces narrows. Therefore, the thickness of the ceramic block 10 becomes very thin at the location where the coupling groove 40 is formed, which increases the possibility that the ceramic block 10 will be damaged. In order to prevent such damage, the thickness of the ceramic block 10 must be maintained above a certain level at the location where the coupling groove 40 is formed. That is, the coupling groove 40, together with the resonance grooves 31 to 36, becomes an obstacle that makes it difficult to miniaturize the ceramic waveguide filter.

On the other hand, in the ceramic waveguide filter of the embodiment, the coupling groove 140 may be formed to the same depth as the resonance grooves 133 and 134. That is, the length from the entrance to the inner end of the coupling groove 140, which has an entrance at one end of the ceramic block 10 and extends in the inner direction, is the same as the length from the entrance to the inner end of the resonance grooves 133 and 134. It can be implemented as follows.

However, if the coupling groove 140 is formed to the same depth as the resonance grooves 133 and 134, an increase in the thickness of the ceramic block 100 can be suppressed, but capacitive coupling is not achieved at the required strength. It won't happen. Accordingly, in the embodiment, the coupling metal surface 170 is formed to have a fourth diameter (D4, D4 > D2) that is larger than the diameter (D2) of the resonant metal surfaces 163 and 164. That is, the coupling metal surface 170 has a larger area and a larger capacitance than the resonant metal surfaces 163 and 164. Therefore, the coupling groove 140 can be capacitively coupled more strongly than the resonance grooves 133 and 134 even at the same depth.

In an embodiment, the diameter D3 of the coupling groove 140 may be implemented to be the same as the diameter D1 of the resonance grooves 133 and 134 (D1 = D3), but may be implemented differently from each other.

The coupling groove 140 operates as a capacitive reactance in the pass band of the ceramic waveguide filter. Also, a metal layer 190 is formed on the inner surface of the coupling groove 140, as in the resonance grooves 133 and 134.

In the above, as an example, a case where the coupling groove 140 is formed between the third and fourth resonance cavities 113 and 114 is shown, but the coupling groove 140 is formed between other resonance cavities located adjacent to each other. It could be.

As a result, in the ceramic waveguide filter of the embodiment, the resonance grooves 133 and 134 and the coupling groove 140 are formed at the inner ends by the resonance metal surfaces 163 and 164 and the coupling metal surfaces 170. By (163, 164), it is possible to have the same capacitance in a smaller size compared to the existing resonance grooves (31 to 36) and the coupling groove (40), allowing the ceramic waveguide filter to be manufactured in a small size. In particular, the coupling metal surface 170 is formed with a larger area than the resonant metal surfaces 163 and 164 to form a larger capacitance, thereby enabling stronger capacitive coupling, so that the coupling groove 140 It may be formed to have a depth similar to that of the resonance grooves 133 and 134. Therefore, not only can the size of the ceramic waveguide filter be further reduced, but the risk of damage can be greatly reduced.

As described above, the ceramic waveguide filter shown in FIG. 3 has resonance metal surfaces 163 and 164 and coupling metal surfaces 170 on the inner longitudinal surfaces of the resonance grooves 133 and 134 and the coupling groove 140. It can be miniaturized by forming and increasing the capacitive component. However, with the existing manufacturing method of cutting in an internal direction from one side of the ceramic block 100, the resonance metal surfaces 163 and 164 and the coupling metal surfaces are formed on the inner longitudinal surfaces of the resonance grooves 133 and 134 and the coupling groove 140. It is very difficult to form (170).

Accordingly, in order to improve manufacturing convenience, in the ceramic waveguide filter of the embodiment, the ceramic block 100 is formed with resonance metal surfaces 163 and 164 and coupling metal surfaces 170 shown as lines B - B' in FIG. 3. It can be manufactured by dividing into an upper ceramic block (100a) and a lower ceramic block (100b) based on the plane. In this way, when manufactured separately into the upper ceramic block 100a and the lower ceramic block 100b, the resonance grooves 133 and 134 and the coupling groove 140 are first formed in the lower ceramic block 100b, and the upper ceramic block 100b The resonance metal surfaces 163 and 164 and the coupling metal surfaces 170 may first be formed at the positions where the resonance grooves 133 and 134 and the coupling groove 140 are formed on the lower surface of the ceramic block 100a. . And a lower ceramic block (100b) on which resonance grooves (133, 134) and coupling grooves (140) are formed, and an upper ceramic block (100a) on which resonance metal surfaces (163, 164) and coupling metal surfaces (170) are formed, are stacked. By combining and additionally forming the metal layer 190, a ceramic waveguide filter can be easily manufactured. Here, the method of laminating and combining the upper ceramic block 100a and the lower ceramic block 100b may be performed using, for example, a multilayer ceramic (MLC) method.

Figure 4 shows a side cross-sectional view of a ceramic waveguide filter according to another embodiment.

In the integrated ceramic waveguide filter of FIG. 4, a plurality of resonance cavities 213 and 214 are defined by a plurality of penetrating partition walls (not shown) formed in a predetermined pattern through between one side and the other side of the single ceramic block 200. It is implemented in an integrated form that includes Additionally, the plurality of through barrier ribs and input/output interfaces 251 and 252 have the same structure as the through barrier ribs 21 and 22 and the input and output interfaces 51 and 52 of the ceramic waveguide filter of FIG. 1 . Additionally, the plurality of resonance grooves 233 and 234 and the resonance metal surfaces 263 and 264 have the same structure as the resonance grooves 133 and 134 and the resonance metal surfaces 163 and 164 of FIG. 3 . That is, the plurality of resonance grooves 233 and 234 are formed in a cylindrical shape on one side of the ceramic block 200 and have a first diameter D1 and extend to a predetermined depth, and the resonance metal surfaces 263 and 264 have a resonance The inner ends of the grooves 233 and 234 may be formed to have a second diameter D2 larger than that of the resonant grooves 233 and 234.

However, in the ceramic waveguide filter shown in FIG. 4, unlike the ceramic waveguide filter in FIG. 3, the coupling groove 140 and the coupling metal surface 170 are not formed. Instead, the ceramic waveguide filter shown in FIG. 4 is formed with a coupling hole 240 penetrating from one side of the ceramic block 200 to the other side. Unlike the coupling groove 140, the coupling hole 240 is formed by penetrating from one side of the ceramic block 200 to the other side, thereby further reducing the risk of damage to the ceramic waveguide filter. Additionally, the coupling hole 240 can be formed in a smaller size than the coupling groove 140 of FIG. 3, which is advantageous for miniaturizing the ceramic waveguide filter.

Here, the coupling hole 240 has a smaller diameter (D5) of the through hole (241) penetrating the ceramic block (200) than the diameter (D6) of the entrance area (242) on one side of the ceramic block (200). It can be formed in a step structure. Additionally, a metal layer 290 is formed on the inner surface of the coupling hole 240 as well as the outer surface of the ceramic block 200 and the inner surface of the through partition and the resonance grooves 233 and 234. However, if the metal layer 290 is formed on the entire inner surface of the coupling hole 240, capacitive coupling is not easily achieved. Accordingly, as shown in FIG. 4, in the ceramic waveguide filter, the metal layer 290 is formed by excluding the ring-shaped predetermined slot area 243 from the inner surface of the coupling hole 240, thereby providing capacitive coupling. Let this happen.

Here, the ring-shaped slot area 243 may be formed at a predetermined position in the entrance area 242 of the coupling hole 240, and in particular, as shown in FIG. 4, the ceramic block 200 may be formed in the entrance area 242. It can be formed parallel to one side.

Figure 5 shows a side cross-sectional view of a ceramic waveguide filter according to another embodiment.

In the ceramic waveguide filter of FIG. 5 , as in FIG. 4 , a coupling hole 340 penetrating one side and the other side of the ceramic block 300 is formed instead of the coupling groove 140 . However, in the ceramic waveguide filter of FIG. 4, the coupling hole 240 is formed as a one-stage step structure divided into a through hole 241 and an entrance area 242 having different diameters, whereas the ceramic waveguide filter shown in FIG. 5 In the waveguide filter, the coupling hole 340 is located between the through hole 341 and the inlet area 342, as well as the through hole 341 and the inlet area 342 having different diameters, and the through hole 341 It has a two-stage step structure in which an intermediate region 344 having a diameter between the and inlet region 342 is further formed. In this way, when the coupling hole 340 has a two-stage step structure in which the middle region 344 is further formed, the resonance frequency can be further lowered, and the ceramic waveguide filter can be miniaturized.

And the ceramic waveguide filter shown in FIGS. 4 and 5 is also similar to FIG. 3, with respect to the plane where the resonant metal surfaces 163 and 164 and the coupling metal surface 170 are formed, the upper ceramic block 100a and the lower It can be manufactured separately into ceramic blocks 100b and implemented by stacking and combining them according to the MLC method.

Although the present invention has been described in detail through representative embodiments above, 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.

100, 200, 300: Ceramic block
113, 114, 213, 214, 313, 314: Resonant cavity
133, 134, 233, 234, 333, 334: Resonant groove
140: Coupling groove
163, 164, 263, 264, 363, 364: Resonant metal surface
170: Coupling metal side
190, 290, 390: metal layer
240, 340: Coupling hole

Claims (10)

A plurality of resonant cavities defined as compartments separated by a plurality of penetrating partitions formed through a single ceramic block;
a plurality of resonance grooves extending inward from one side of the ceramic block to the other side of the ceramic block within each section of the plurality of resonance cavities;
a metal layer formed on an outer surface of the ceramic block and an inner surface of each of the plurality of resonance grooves; and
A ceramic waveguide filter comprising a plurality of resonant metal surfaces formed at inner ends of each of the plurality of resonant grooves and having an area larger than the area of the longitudinal cross-section. The method of claim 1, wherein each of the plurality of resonant grooves is
It is formed in a cylindrical shape with a first diameter from one side of the ceramic block,
Each of the plurality of resonant metal surfaces is
A ceramic waveguide filter formed in a disk shape having a second diameter larger than the first diameter. The method of claim 1, wherein the ceramic waveguide filter
At least one coupling groove extending inward from one side of the ceramic block to the other side of the ceramic block between adjacent resonance cavities among the plurality of resonance cavities; and
A ceramic waveguide filter further comprising at least one coupling metal surface having an area larger than the area of the longitudinal section at the inner end of the coupling groove. The method of claim 3, wherein the at least one coupling groove is
It is formed in a cylindrical shape extending from one side of the ceramic block to a predetermined third diameter,
At least one coupling metal surface is
A ceramic waveguide filter formed in a disk shape having a fourth diameter larger than the third diameter. The method of claim 3, wherein the at least one coupling metal surface is
A ceramic waveguide filter formed to have an area larger than the area of the plurality of resonant metal surfaces. The method of claim 3, wherein the at least one coupling groove is
A ceramic waveguide filter formed in the ceramic block to the same depth as the plurality of resonance grooves. The method of claim 3, wherein the at least one coupling groove is
A ceramic waveguide filter formed in a cylindrical shape with the same diameter as the plurality of resonance grooves. The method of claim 1, wherein the ceramic waveguide filter
It is formed to penetrate the ceramic block between adjacent resonance cavities among the plurality of resonance cavities, and the diameter of the through hole penetrating the ceramic block is smaller than the diameter of the inlet area on one side of the ceramic block, and is formed on the inner side. A ceramic waveguide filter further comprising at least one coupling hole in which the metal layer is formed. The method of claim 8, wherein the at least one coupling hole is
A ceramic waveguide filter further formed between the through hole and the inlet region and an intermediate region having a diameter between the diameter of the through hole and the diameter of the inlet region. The method of claim 8, wherein the at least one coupling hole is
A ceramic waveguide filter including a slot in which the metal layer is removed in a ring shape with a predetermined thickness at a predetermined position in the inlet area.