CN111384525A - Dielectric filter, preparation method thereof and communication equipment - Google Patents

Abstract

The present application provides a dielectric filter, a preparation method thereof, and a communication device. The dielectric filter is formed by arranging at least two dielectric blocks side by side, which reduces the required length of the dielectric block when only one dielectric block is used to form the dielectric block, improves the application range of the dielectric filter, and reduces the Even the risk of bending and deformation of the dielectric block during the sintering process is eliminated, the yield is improved, and the structure is simple, easy to form, and suitable for mass production.

Description

Dielectric filter and preparation method thereof, and communication equipment

technical field

The present application relates to the field of communication technologies, and in particular, to a dielectric filter, a preparation method thereof, and a communication device.

Background technique

With the rapid development of communication technology, the application of 5G communication technology is becoming more and more extensive. As an important component in the 5G communication system, a highly integrated and low-cost filter is an inevitable requirement of 5G communication technology.

In the prior art, a high dielectric constant ceramic material is generally used to prepare a dielectric block forming a cuboid structure to form a filter that meets the above requirements. It is easy to bend and deform during the process.

SUMMARY OF THE INVENTION

The present application mainly provides a dielectric filter, a method for manufacturing the same, and a communication device, aiming at solving the problem of easy bending and deformation caused by excessively long dielectric blocks.

In order to solve the above technical problem, a technical solution adopted in the present application is: to provide a dielectric filter, the dielectric filter includes at least two dielectric blocks, each of the dielectric blocks includes first end faces arranged at intervals along the length direction and the second end face, the first side and the second side spaced along the width direction, and the third side face and the fourth side face spaced along the thickness direction, the size of the dielectric block along the length direction is larger than the size along the width direction and the thickness direction. size; each of the dielectric blocks is divided into at least two dielectric resonance units cascaded with each other along the length direction; the at least two dielectric blocks are arranged side by side and spaced apart from each other along the width direction or the thickness direction, the at least two dielectric blocks are A medium plate is disposed between the adjacent side surfaces of the two medium blocks, and the medium plate is integrally disposed with the at least two medium blocks, so as to realize the relative fixation between the at least two medium blocks; wherein, the Materials of the dielectric filter include at least zinc oxide, silicon dioxide and magnesium oxide.

In order to solve the above technical problem, another technical solution adopted in the present application is to provide a method for preparing a dielectric filter, wherein the method is used for preparing the above-mentioned dielectric filter, and the method includes: providing a corresponding zinc oxide , raw materials of silicon dioxide and magnesium oxide; add organic solvent and grinding balls and perform a ball milling; dry the slurry obtained by the first ball milling, and obtain a ceramic body by calcining; pulverize the ceramic body, add an organic solvent and Grinding balls and performing secondary ball milling; drying the slurry obtained by the secondary ball milling; mixing the obtained powder with a binder into a slurry for granulation; in a mold matching the shape of the dielectric filter medium dry pressing; and removing the binder and sintering again to obtain at least two integrally formed dielectric blocks and a dielectric plate between two adjacent said dielectric blocks; The outer surface of the dielectric plate is coated with an electromagnetic shielding layer to obtain the dielectric filter.

In order to solve the above technical problem, another technical solution adopted in the present application is to provide a communication device, where the communication device includes the above-mentioned dielectric filter.

The beneficial effects of the present application are: different from the situation in the prior art, the present application forms a dielectric filter by arranging at least two dielectric blocks side by side, which reduces the need for a dielectric block when a dielectric filter is formed by only one dielectric block. The length of the dielectric filter increases the application range of the dielectric filter, reduces or even eliminates the risk of bending deformation of the dielectric block during the sintering process, improves the yield, and has a simple structure, easy to form, and is suitable for mass production. The material includes at least zinc oxide, silicon dioxide and magnesium oxide, and the material of the dielectric filter has low dielectric constant, low loss and near-zero temperature coefficient, which can improve the dielectric properties of the dielectric filter.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present application more clearly, the following briefly introduces the drawings that are used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, under the premise of no creative work, other drawings can also be obtained from these drawings, wherein:

1 is a schematic diagram of an exploded structure of a first embodiment of a dielectric filter provided by the present application;

Fig. 2 is the connection schematic diagram of two adjacent dielectric resonance units in Fig. 1;

Fig. 3 is the assembly structure schematic diagram of the dielectric filter in Fig. 1;

4 is a schematic structural diagram of a second embodiment of a dielectric filter provided by the present application;

Fig. 5 is the exploded structure schematic diagram of two medium blocks in Fig. 4;

6 is a schematic structural diagram of a third embodiment of a dielectric filter provided by the present application;

Fig. 7 is the exploded structure schematic diagram of two medium blocks in Fig. 6;

8 is a schematic flowchart of an embodiment of a method for preparing a dielectric filter provided by the present application;

FIG. 9 exemplarily shows the test results of the microwave dielectric properties of the ceramics provided in the present application.

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

Referring to FIG. 1 , FIG. 1 is a schematic diagram of an exploded structure of a first embodiment of a dielectric filter 10 provided by the present application. The dielectric filter 10 in this embodiment includes a dielectric block 11 .

The dielectric block 11 includes a first end face 111 and a second end face 112 that are spaced along the length direction, that is, the X direction as shown in FIG. 1 , and the width direction, that is, the Y space interval shown in FIG. 1 . The first side surface 113 and the second side surface 114 are provided, and the third side surface 115 and the fourth side surface 116 are arranged along the thickness direction, that is, in the Z upward direction as shown in FIG. 1 .

Optionally, in this embodiment, the dielectric block 11 is provided in the shape of a rectangular parallelepiped, and the first end surface 111 , the second end surface 112 , the first side surface 113 , the second side surface 114 , the third side surface 115 , and the fourth side surface 116 are respectively the same. The six faces of the cuboid are arranged in the above-mentioned directions. Of course, in other embodiments, the medium blocks 11 may also be arranged in other regular or irregular shapes, which are not limited here.

Further, the size of the dielectric block 11 in the length direction is larger than the size in the width direction and the thickness direction.

Optionally, the size of the dielectric block 11 in the width direction is larger than the size in the thickness direction.

Optionally, the medium block 11 is symmetrically arranged with respect to a central axis plane disposed along the length direction and perpendicular to the width direction. It is understood that the central axis plane is a virtual plane provided for convenience of description.

Optionally, the material of the dielectric block 11 is a ceramic material. Since the dielectric constant of the ceramic material is high, the effective size of the dielectric resonance unit can be greatly compressed by the compression effect of the high dielectric constant ceramic material on the microwave wavelength. , to miniaturize the overall size of the dielectric filter, and at the same time, because the ceramic material is easy to mold, it can achieve lower-cost mass production, so the miniaturization and integration of ceramic filters and 5G micro base stations (SmallCells) with advantages . The technical requirements of the MIMO system are highly matched. Of course, in other embodiments, the material of the dielectric block 11 can also be other materials with a dielectric constant similar to that of ceramics.

Further, as shown by the dotted line in FIG. 1 , the dielectric block 11 is divided into at least two dielectric resonance units cascaded with each other along the length direction, and the at least two dielectric resonance units may be at least two dielectric resonance units as shown in FIG. 1 . The dielectric resonance unit 11a may also be at least two dielectric resonance units 11b. In this embodiment, the two dielectric resonance units located at both ends of the dielectric block 11 are the dielectric resonance units 11a, and the one located between the two dielectric resonance units 11a is the dielectric resonance unit 11a. Dielectric resonance unit 11b.

Referring to FIG. 1 and FIG. 2 together, FIG. 2 is a schematic diagram of the connection of two adjacent dielectric resonance units in FIG. 1 , wherein a hollow slot 101 is provided in the connection area of the two adjacent dielectric resonance units, and is perpendicular to the connection area. After the two adjacent dielectric resonant units are divided into two equal parts in the length direction, the geometric centers of the adjacent parts of the two adjacent dielectric resonant units are located in the hollow slot 101. For example, as shown in FIG. The adjacent dielectric resonance units are respectively the dielectric resonance unit 11a and the dielectric resonance unit 11b. The dielectric resonance unit 11a and the dielectric resonance unit 11b are divided into two equal parts 1111, 1112 and 1113, 1114 in the direction perpendicular to the length. The geometric centers A and B of the adjacent parts 1112 and 1113 of the unit 11a and the dielectric resonance unit 11b are located in the hollow slot 101, so as to improve the ratio of the secondary resonance frequency to the fundamental mode resonance frequency of the two adjacent dielectric resonance units, and further The out-of-band harmonic characteristics of the dielectric filter 10 are improved, and a plurality of dielectric resonators are integrally formed without splicing and secondary sintering, the structure and process are simple, the stability and consistency of the structure size are improved, and the product quality is improved. rate to achieve mass production.

It can be understood that in this implementation, since both ends of the dielectric resonance unit 11b need to be cascaded with other dielectric resonance units, after the dielectric resonance unit 11b is divided into two parts 1113 and 1114 perpendicular to the length direction, the dielectric resonance unit 11b is divided into two parts. The geometric center C of the other part 1114 of the unit 11b is also located in the other hollow slot 101 .

Optionally, the hollow slot 101 is set so that the ratio of the secondary resonance frequency to the fundamental mode resonance frequency of two adjacent dielectric resonance units is not less than 1.5.

Optionally, the hollow groove 101 communicates with the first side 113 and the second side 114 , or communicates with the third side 115 and the fourth side 116 . In this embodiment, the hollow groove 101 communicates with the third side 115 and the fourth side 116 .

Optionally, the hollow slot 101 is exposed to the air.

Optionally, the hollow grooves 101 are symmetrically arranged with respect to the central axis plane arranged in the length direction and perpendicular to the width direction.

Optionally, the hollow slot 101 is provided in the shape of a rectangular parallelepiped. It can be understood that in other embodiments, the hollow slot 101 may also take other shapes.

Referring to FIG. 1 and FIG. 3 together, FIG. 3 is a schematic diagram of the assembly structure of the dielectric filter 10 in FIG. 1 . The dielectric filter 10 in this embodiment further includes an output terminal 12 and an input terminal 13 , and the output terminal 12 and the input terminal 11 are respectively Adjacent to the first end surface 111 and the second end surface 112 , that is, the output terminal 12 and the input terminal 13 may be disposed on any one of the first side surface 113 , the second side surface 114 , the third side surface 115 and the fourth side surface 116 .

Optionally, the output terminal 12 and the input terminal 13 are in the form of probes, and in other embodiments, they can also be in the form of a printed circuit board, a microstrip line, or the like.

Further, the dielectric filter 10 in this embodiment further includes an electromagnetic shielding layer 14, and the electromagnetic shielding layer 14 covers the outer surface of the dielectric block 11 to achieve a shielding function.

Optionally, the electromagnetic shielding layer 14 includes a shielding cover plate 141 covering at least the hollow slot 101 . In this embodiment, two shielding cover plates 141 are used on the third side 115 and the fourth side 116 of the dielectric block 11 . Covering the hollow groove 101 and other outer surfaces of the dielectric block 11 without the shielding cover plate 141 can be formed by coating metals including but not limited to copper, silver, tin or aluminum to form a metal coating, the metal coating and the shielding cover. The plates 141 together form the electromagnetic shielding layer 14 in this embodiment.

The shielding cover plate 141 is provided with a tuning screw 15 extending into the hollow slot 101 to adjust the resonance frequency of the dielectric filter 10 through the tuning screw 15. By setting the tuning screw 15 in this way, it is not necessary to install the tuning screw 11 on the dielectric block 11 . Tuning holes are reserved on the top of the dielectric block 11 to avoid technological difficulties caused by setting tuning holes on the dielectric block 11 .

Optionally, the number of tuning screws 15 is at least two, and the at least two tuning screws 15 are arranged at intervals along the length direction.

Referring to FIG. 4 , FIG. 4 is a schematic structural diagram of a second embodiment of a dielectric filter 20 provided by the present application. The dielectric filter 20 in this embodiment includes at least two dielectric blocks 21 , two of which are used in the illustration in this embodiment. example.

Referring to FIG. 5 , FIG. 5 is a schematic diagram of the exploded structure of the two dielectric blocks 21 in FIG. 4 , wherein each dielectric block 21 includes first end faces 211 spaced along the length direction, that is, the X-direction as shown in FIG. 5 . and the second end face 212, along the width direction, that is, the first side surface 213 and the second side surface 214 spaced in the Y upward direction as shown in FIG. 5, along the thickness direction, that is, the Z upward interval as shown in FIG. The third side 215 and the fourth side 216 are provided.

Optionally, in this embodiment, each medium block 21 is provided in the shape of a cuboid, and the above-mentioned first end surface 211 , second end surface 212 , first side surface 213 , second side surface 214 , third side surface 215 and fourth side surface 216 The six faces of the cuboid are respectively arranged in the above-mentioned directions. Of course, in other embodiments, the medium blocks 21 may also be arranged in other regular or irregular shapes, which are not limited here.

Further, the size of the dielectric block 21 in the length direction is larger than the size in the width direction and the thickness direction.

Optionally, the size of the dielectric block 21 in the width direction is larger than the size in the thickness direction.

Optionally, the medium block 21 is symmetrically arranged with respect to a central axis plane disposed along the length direction and perpendicular to the width direction. It is understood that the central axis plane is a virtual plane provided for convenience of description.

Optionally, the material of the dielectric block 21 is a ceramic material. Since the dielectric constant of the ceramic material is high, the effective size of the dielectric resonance unit can be greatly compressed by the compression effect of the high dielectric constant ceramic material on the microwave wavelength. , to miniaturize the overall size of the dielectric filter, and at the same time, because the ceramic material is easy to mold, it can achieve lower-cost mass production, so the miniaturization and integration of ceramic filters and 5G micro base stations (SmallCells) with advantages . The technical requirements of the MIMO system are highly matched. Of course, in other embodiments, the material of the dielectric block 21 can also be other materials with a dielectric constant similar to that of ceramics.

Further, as shown by the dotted line in FIG. 5 , each dielectric block 21 is divided into at least two cascaded dielectric resonance units along the length direction, and the at least two dielectric resonance units may be at least two dielectric resonance units as shown in FIG. 5 . Each dielectric resonance unit 21a can also be at least two dielectric resonance units 21b. In this embodiment, the two dielectric resonance units located at both ends of the dielectric block 21 are the dielectric resonance units 21a, and the two dielectric resonance units located between the two dielectric resonance units 21a are the dielectric resonance units 21a. It is the dielectric resonance unit 21b.

Wherein, a hollow slot 201 is provided in the connection area of two adjacent dielectric resonance units of the same dielectric block 21, and after the two adjacent dielectric resonance units are divided into two equal parts perpendicular to the length direction, the adjacent dielectric resonance units are divided into two parts. The geometric center of the adjacent parts of the two dielectric resonant units is located in the hollow slot 201, so as to improve the ratio of the secondary resonance frequency to the fundamental mode resonance frequency of the two adjacent dielectric resonant units, thereby improving the dielectric filter 20. The out-of-band harmonic characteristics, the dielectric resonance unit 21a and the dielectric resonance unit 21b in this embodiment are the same as the dielectric resonance unit 11a and the dielectric resonance unit 11b in the above-mentioned first embodiment, and will not be repeated here.

Optionally, the hollow slot 201 is set so that the ratio of the secondary resonance frequency of the two adjacent dielectric resonance units to the fundamental mode resonance frequency is not less than 1.5.

Optionally, the hollow groove 201 communicates with the first side 213 and the second side 214 , or communicates with the third side 215 and the fourth side 216 . In this embodiment, the hollow groove 201 communicates with the third side 215 and the fourth side 216 .

Optionally, the hollow slot 201 is exposed to the air.

Optionally, the hollow grooves 201 are symmetrically arranged with respect to the central axis plane arranged in the length direction and perpendicular to the width direction.

Optionally, the hollow slot 201 is provided in the shape of a rectangular parallelepiped. It can be understood that, in other embodiments, the hollow slot 201 can also be set in other shapes.

Further, at least two dielectric blocks 21 are arranged side by side along the width direction or thickness direction, and adjacent sides of the at least two dielectric blocks 21 are provided with metal shielding layers 22, in this embodiment, as shown in FIG. 5 The first side surface 213 of one of the dielectric blocks 21 and the second side surface 212 of the other dielectric block 21 are provided with a metal shielding layer 22 .

Wherein, the metal shielding layers 22 on the adjacent sides of the at least two dielectric blocks 21 are bonded to each other, so that the at least two dielectric blocks 21 are relatively fixed.

Specifically, after the adjacent sides of the at least two dielectric blocks 21 are coated with metal coatings, pre-baking may be performed first, then a clamp is used to fix and splicing, and finally the metal coatings are bonded by means of high temperature sintering.

Further, the metal shielding layers 22 of the at least two dielectric blocks 21 are respectively provided with coupling windows 221 which are bonded to each other at least partially overlapped on the adjacent side metal shielding layers 22, so as to realize the dielectric resonance unit on the at least two dielectric blocks 21. In the process of applying the metal coating as described above, shielding can be performed at the position of the coupling window 221 to prevent the metal coating from penetrating into the coupling window 221, resulting in the coupling of the dielectric resonance units on different dielectric blocks 21. invalid.

Wherein, when at least two dielectric blocks 21 are arranged side by side, at least two cascaded dielectric resonance units on the dielectric block 21 can be directly coupled or cross-coupled, for example, at least two cascaded dielectric resonance units on the same dielectric block 21 The dielectric resonance units may be directly coupled, at least two cascaded dielectric resonance units on different dielectric blocks 21 may be cross-coupled, or at least two cascaded dielectric resonance units on different dielectric blocks 21 may be directly coupled, and on the same dielectric block 21 The at least two cascaded dielectric resonance units are cross-coupled, which improves the frequency selection characteristic of the dielectric filter 20 .

Further, the dielectric filter 20 in this embodiment further includes an output terminal 23 and an input terminal 24 respectively disposed on the at least two dielectric blocks 21 .

Optionally, the output terminal 23 and the input terminal 24 are in the form of probes, and in other embodiments, they can also be in the form of a printed circuit board, a microstrip line, or the like.

Further, the dielectric filter 20 in this embodiment further includes a shielding cover plate 25, and the shielding cover plate 25 covers at least the hollow groove 201. In this embodiment, each dielectric block 21 is provided with two covering the hollow groove 201. Shield cover 25 of slot 201 .

Wherein, the shielding cover plate 25 is provided with a tuning screw 26 extending to the hollow slot 201 to adjust the resonance frequency of the dielectric filter 20 through the tuning screw 26. By setting the tuning screw 26 in this way, it is not necessary to install the tuning screw 21 on the dielectric block 21. Tuning holes are reserved to avoid technological difficulties caused by setting tuning holes on the dielectric block 21 .

Optionally, the number of tuning screws 26 is at least two, and the at least two tuning screws 26 are arranged at intervals along the length direction.

Referring to FIG. 6, FIG. 6 is a schematic structural diagram of a third embodiment of a dielectric filter 30 provided by the present application. The dielectric filter 30 in this embodiment has at least two dielectric blocks 31. In this embodiment, two dielectric blocks 31 are used as example.

Referring to FIG. 7 , FIG. 7 is a schematic diagram of the exploded structure of the two dielectric blocks 31 in FIG. 6 , wherein each dielectric block 31 includes first end faces 311 spaced along the length direction, that is, the X-direction as shown in FIG. 7 . and the second end face 312, along the width direction, that is, the first side surface 313 and the second side surface 314, which are spaced in the Y upward direction as shown in FIG. The third side 315 and the fourth side 316 are provided.

Optionally, in this embodiment, each medium block 31 is provided in the shape of a rectangular parallelepiped. The six faces of the cuboid are respectively arranged in the above-mentioned directions. Of course, in other embodiments, the medium blocks 31 may also be arranged in other regular or irregular shapes, which are not limited herein.

Further, the size of the dielectric block 31 in the length direction is larger than the size in the width direction and the thickness direction.

Optionally, the size of the dielectric block 31 in the width direction is larger than the size in the thickness direction.

Optionally, the medium block 31 is symmetrically arranged with respect to a central axis plane disposed along the length direction and perpendicular to the width direction. It is understood that the central axis plane is a virtual plane provided for convenience of description.

Optionally, the material of the dielectric block 31 is a ceramic material. Since the dielectric constant of the ceramic material is high, the effective size of the dielectric resonance unit can be greatly compressed by the compression effect of the high dielectric constant ceramic material on the microwave wavelength. , to miniaturize the overall size of the dielectric filter, and at the same time, because the ceramic material is easy to mold, it can achieve lower-cost mass production, so the miniaturization and integration of ceramic filters and 3G micro base stations (SmallCells) with advantages . The technical requirements of the MIMO system are highly matched. Of course, in other embodiments, the material of the dielectric block 31 can also be other materials with a dielectric constant similar to that of ceramics.

Further, as shown by the dotted line in FIG. 7 , each dielectric block 31 is divided into at least two cascaded dielectric resonance units along the length direction, and the at least two dielectric resonance units may be at least two dielectric resonance units as shown in FIG. 7 . Each dielectric resonance unit 31a may also be at least two dielectric resonance units 31b. In this embodiment, the two dielectric resonance units located at both ends of the dielectric block 31 are the dielectric resonance units 31a, and the two dielectric resonance units located between the two dielectric resonance units 31a are the dielectric resonance units 31a. is the dielectric resonance unit 31b.

Wherein, a hollow slot 301 is provided in the connection area of two adjacent dielectric resonance units of the same dielectric block 31, and after the two adjacent dielectric resonance units are divided into two equal parts perpendicular to the length direction, the adjacent two dielectric resonance units are divided into two parts. The geometric centers of the adjacent parts of the two dielectric resonant units are located in the hollow slot 301, so as to improve the ratio of the secondary resonance frequency to the fundamental mode resonance frequency of the two adjacent dielectric resonant units, thereby improving the performance of the dielectric filter 30. The out-of-band harmonic characteristics, the dielectric resonance unit 31a and the dielectric resonance unit 31b in this embodiment are the same as the dielectric resonance unit 11a and the dielectric resonance unit 11b in the above-mentioned first embodiment, and will not be repeated here.

Optionally, the hollow slot 301 is set so that the ratio of the secondary resonance frequency to the fundamental mode resonance frequency of two adjacent dielectric resonance units is not less than 1.5.

Optionally, the hollow groove 301 communicates with the first side 313 and the second side 314 , or communicates with the third side 315 and the fourth side 316 . In this embodiment, the hollow groove 301 communicates with the third side 315 and the fourth side 316 .

Optionally, the hollow slot 301 is exposed to the air.

Optionally, the hollow grooves 301 are symmetrically arranged with respect to the central axis plane arranged in the length direction and perpendicular to the width direction.

Optionally, the hollow slot 301 is provided in the shape of a rectangular parallelepiped. It can be understood that, in other embodiments, the hollow slot 301 can also be set in other shapes.

Further, at least two dielectric blocks 31 are arranged side by side in the width direction or thickness direction and spaced apart from each other, and a dielectric plate 32 is provided between the adjacent side surfaces of the at least two dielectric blocks 31 , and the dielectric plate 32 is respectively connected to the two dielectric blocks 31 . The integrated arrangement can realize the relative fixation between the at least two medium blocks 31, reduce the precision of the fixture required when the at least two medium blocks 31 are spliced, and improve the success rate of splicing.

Further, the dielectric plate 32 also serves as a coupling window for mutual coupling between the dielectric resonant units on the at least two dielectric blocks 31 , which reduces or even eliminates the loss of metal during the sintering process compared to the method of re-bonding through metal coating. Risk of penetration into the coupling window.

Wherein, when at least two dielectric blocks 31 are arranged side by side, at least two cascaded dielectric resonance units on the dielectric block 31 can be directly coupled or cross-coupled to improve the frequency selection characteristics of the dielectric filter 30. For details, please refer to The corresponding description in the second embodiment of the dielectric filter 20 described above.

Further, the dielectric filter 30 in this embodiment further includes an output terminal 33 and an input terminal 34 respectively disposed on the at least two dielectric blocks 31 .

Optionally, the output terminal 33 and the input terminal 34 are in the form of probes, and in other embodiments, they can also be in the form of a printed circuit board, a microstrip line, or the like.

Further, the dielectric filter 30 in this embodiment further includes a shielding cover plate 35 , and the shielding cover plate 35 covers at least the hollow slot 301 .

The shielding cover 35 is provided with a tuning screw 36 extending to the hollow slot 301 to adjust the resonant frequency of the dielectric filter 30 through the tuning screw 36. By setting the tuning screw 36 in this way, it is not necessary to install the tuning screw 31 on the dielectric block 31. Tuning holes are reserved to avoid the technical difficulty caused by arranging tuning holes on the dielectric block 31 .

Optionally, the number of tuning screws 36 is at least two, and the at least two tuning screws 36 are arranged at intervals along the length direction.

The material of the dielectric filter disclosed in the above embodiments may be ceramic, and the ceramic material includes zinc oxide, silicon dioxide and magnesium oxide. That is, the ceramic material is mainly composed of the above-mentioned components, and it can be understood that the ceramic may also contain a small or trace amount of other substances.

In some embodiments, the mole percentage of zinc oxide therein ranges from 20% to 70%.

In some embodiments, the molar percentage of silica therein ranges from 20% to 60%.

In some embodiments, the molar percentage of magnesium oxide therein ranges from 10% to 20%.

Wherein, mole percent refers to the percentage of the amount of substance. For example, after mixing 1 mol of substance A with 4 mol of substance B, the mole percentage of substance A is equal to 1/(1+4)=20%, and the mole percentage of substance B is equal to 4/(1+4)=80%.

In some embodiments, the ceramic may also include modifying additives, ie, additives capable of improving the properties of the ceramic. It should be understood that the modification additive is not necessarily in a liquid state, but may also be in a solid state or the like. Specifically, the modifying additive may be a combination of one or more of CoO, NiO or MnO ₂ , that is, the modifying additive may only include one of CoO, NiO or MnO ₂ , or may include one of them of two or three. Optionally, the proportion of the modification additive may be 0-2 mol%. That is to say, the molar percentage of the modification additive in the whole material is not more than 2%.

The chemical composition of the ceramic can be expressed as xZnO-ySiO-zMgO ₂ -dMO, wherein the ratio of x, y, z and d is 0.2～0.7:0.2～0.6:0.1～0.2:0～0.02, and MO represents the aforementioned modification additive . For example, if the values of x, y, z and d are taken as 0.5, 0.3, 0.18 and 0.02 respectively, and CoO is selected as the modification additive, the chemical composition of the ceramic can be expressed as 0.5ZnO-0.3SiO-0.18MgO ₂ -0.02CoO. Of course, the values of x, y, z and d can also take other values within this range. By changing the ratio between the chemical components of the ceramic, the microwave dielectric properties of the ceramic can be further adjusted.

According to the test results, the dielectric constant of the ceramic is 7~8, and the Q*f value is 9000~105000GHz. For example, using a network analyzer (Agilent5071C) to test the microwave dielectric properties of the ceramic at a test frequency of 12GHz, the test results shown in the table in FIG. 9 are obtained.

The ceramics provided by the present application are mainly composed of zinc oxide, silicon dioxide and magnesium oxide, which have low dielectric constant, low loss and near-zero temperature coefficient. Accordingly, the ceramics provided by the practice of the present application have improved microwave dielectric properties.

The present application further provides a method for manufacturing a dielectric filter according to an embodiment. The dielectric filters disclosed in the above embodiments are all manufactured by the method for manufacturing a dielectric filter. As shown in FIG. 8 , the method includes the following steps:

S110: Provide raw materials corresponding to zinc oxide, silicon dioxide and magnesium oxide.

In some embodiments, the raw materials corresponding to zinc oxide, silica and magnesium oxide may be oxides or carbonates of corresponding metal elements. Among them, the oxides of metal elements directly correspond to the components of the dielectric filter to be prepared, and the carbonates of some metal elements can be converted into oxides of the metal elements under conditions such as heating, so they can also be used as raw materials. In other embodiments, the starting material can also be an alcoholate of the corresponding metal element, in which case the metal alcoholate can be converted to the desired oxide using appropriate chemical treatment methods. The specific method is a known technology in the field, and details are not repeated here.

In this embodiment, the molar percentage of the raw material corresponding to zinc oxide is 20-70%, the molar percentage of the raw material corresponding to silicon dioxide is 20%-60%, and the molar percentage of the raw material corresponding to magnesium oxide is 10%-20%. It should be understood that the above molar percentage refers to the molar percentage after removing impurities in the raw materials.

In this embodiment, the raw materials can be prepared according to the proportion of each component of the dielectric filter. When the mole percentage of each component is known, the required mass of the raw material can be calculated according to the molecular weight of each component, the purity of the raw material and other parameters. Calculate the required mass of each component according to the required number of moles and molecular weight of each component, and then calculate the required mass of raw material according to the required mass of each component and the purity of the above-mentioned raw materials. In this way, the corresponding weight of raw materials can be prepared according to the calculated results.

In some embodiments, modifying additives may also be added to the raw materials. The modifying additive may be one or more of CoO, NiO or MnO ₂ . The proportion of modifying additives to the total moles of all raw materials should generally not exceed 2%.

S120: Add organic solvent and grinding ball and perform ball milling once.

In step S120, deionized water, alcohol, acetone, etc. may be selected as organic solvents, zirconium balls, agate balls, etc. may be selected as grinding balls, and grinding jars made of ceramic, polyurethane or nylon materials are selected, and planetary grinding, stirring grinding, Ball milling is carried out by means of roller grinding, vibration grinding, etc. Among them, in order to improve the effect of ball milling, an appropriate dispersant can also be added or the pH value of the slurry can be adjusted.

In some embodiments, deionized water can be used as the organic solvent, and grinding balls made of ZrO ₂ material can be used. In step S120, each accurately weighed raw material is poured into the ball mill jar, deionized water and ZrO grinding balls are added, the weight ratio of raw materials, deionized water and grinding balls is 1:1.5: ₄ , and the ball is milled for 4 Hour.

S130: drying the slurry obtained by one ball milling, and calcining to obtain a ceramic body.

The ball-milled materials are mixed uniformly, then discharged and dried. For example, the materials can be dried at 100-120°C.

The mixture obtained after ball milling and drying needs to be calcined at a certain temperature to synthesize a ceramic body, and the calcination temperature and holding time depend on the corresponding formula. For example, in this embodiment, the ball-milled and dried slurry can be calcined at 900-1050° C. for 2-8 hours to synthesize a ceramic body.

S140: Pulverize the ceramic body, add an organic solvent and grinding balls, and perform secondary ball milling.

The synthesized ceramic body is pulverized. The present application does not limit the method of pulverization, for example, it can be pulverized using a grinder. In some embodiments, the comminuted ceramic body can also be screened (eg, passed through a 40 mesh screen).

The pulverized ceramic body is poured into the ball-milling tank again for secondary ball-milling, and the process of secondary ball-milling can be similar to that of primary ball-milling. For example, the ratio of material, grinding balls and deionized water can be kept unchanged, and the pulverized ceramic body can be ball-milled for a second time for 24 hours. It should be understood that the process of the secondary ball milling may also be different from that of the primary ball milling, for example, the time of the secondary ball milling may be shorter (or greater than) the time of the primary ball milling, which is not limited herein.

S150: Dry the slurry obtained by the secondary ball milling.

Similarly, the ball-milled materials can be mixed uniformly and then discharged and dried. In some embodiments, the dried slurry can also be screened (eg, passed through a 40 mesh screen).

S160: Mix the obtained powder with a binder to form a slurry for granulation.

In some embodiments, a 5wt% polyvinyl alcohol solution can be selected as the binder (ie, the mass percentage of polyvinyl alcohol in the binder is 5%). The binder may constitute 15% of the total mass of the mixed slurry.

In some embodiments, the granulated powder may also be screened (eg, passed through a 40 mesh screen).

S170: Dry pressing in a mold matching the shape of the dielectric filter.

Specifically, the granulated powder is put into a mold matching the shape of the dielectric filter, and dry-pressed under appropriate pressure, for example, the powder can be dry-pressed under a pressure of 100-150 MPa.

的圆片，以方便测试。如需要使用该陶瓷粉料来制备介质陶瓷块，则可以使用与该介质陶瓷块的形状匹配的模具来进行干压成型。应当理解，该模具的形状和尺寸可根据需要任意选取，在此不做限定。In this step, the shape of the mold can be selected as required. For example, if testing is required, a special mold for testing can be selected to dry-press the powder into

wafers to facilitate testing. If the ceramic powder needs to be used to prepare a dielectric ceramic block, a mold matching the shape of the dielectric ceramic block can be used for dry pressing. It should be understood that the shape and size of the mold can be arbitrarily selected as required, which is not limited herein.

S180: Remove the binder and sinter again to obtain at least two integrated dielectric blocks and a dielectric plate between two adjacent dielectric blocks.

Appropriate temperature can be selected for heat preservation treatment, so as to remove the binder introduced in step S160, and then sintered again to finally obtain the desired dielectric block and dielectric plate. Specifically, in this embodiment, the formed material may be kept at 400-700°C (eg, 500-600°C) for 2-10 hours, and then sintered at 1100-1250°C for 2-10 hours (eg, 1150°C) sintered for 2 hours). In this way, the binder added to the material in step S160 can be removed, and the required shape of the dielectric block and the dielectric plate can be obtained. S190: Coat an electromagnetic shielding layer on the outer surfaces of the at least two dielectric blocks and the dielectric plate.

An electromagnetic shielding layer is covered on the surfaces of the at least two dielectric blocks and the dielectric plate to confine the electromagnetic field in the dielectric block and prevent the leakage of electromagnetic signals. The material of the electromagnetic shielding layer can be metal materials such as silver, copper, aluminum, titanium, tin or gold, and the electromagnetic shielding layer can be covered on the surface of the dielectric block by means of electroplating, spraying or welding.

The present application also provides a communication device, where the communication device includes the dielectric filter in any of the foregoing embodiments.

Different from the situation in the prior art, in the present application, by arranging at least two dielectric blocks side by side to form a dielectric filter, the required length of the dielectric block is reduced when only one dielectric block is used to form a dielectric filter, and the dielectric filter is improved. The application range of the device reduces or even eliminates the risk of bending deformation of the dielectric block during the sintering process, improves the yield, and has a simple structure, easy to form, and is suitable for mass production.

The above are only the embodiments of the present application, and are not intended to limit the scope of the patent of the present application. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present application, or directly or indirectly applied to other related technologies Fields are similarly included within the scope of patent protection of this application.

Claims (10)

1. A dielectric filter is characterized by comprising at least two dielectric blocks, wherein each dielectric block comprises a first end face and a second end face which are arranged at intervals along the length direction, a first side face and a second side face which are arranged at intervals along the width direction, and a third side face and a fourth side face which are arranged at intervals along the thickness direction, and the size of the dielectric block along the length direction is larger than the size of the dielectric block along the width direction and the thickness direction;

each dielectric block is divided into at least two dielectric resonance units which are cascaded with each other along the length direction;

the at least two dielectric blocks are arranged side by side along the width direction or the thickness direction at intervals, a dielectric plate is arranged between the adjacent side surfaces of the at least two dielectric blocks, and the dielectric plates are respectively arranged integrally with the at least two dielectric blocks, so that the at least two dielectric blocks are relatively fixed;

wherein the material of the dielectric filter at least comprises zinc oxide, silicon dioxide and magnesium oxide.

2. The dielectric filter of claim 1, wherein the zinc oxide accounts for 20-70% of the mole percentage; the mole percentage of the silicon dioxide is 20-60%; the magnesium oxide accounts for 10 to 20 percent of the molar percentage.

3. The dielectric filter of claim 1, wherein the dielectric plate further serves as a coupling window for realizing mutual coupling between dielectric resonance units on the at least two dielectric blocks.

4. The dielectric filter according to claim 1, wherein a hollow groove is formed in a connection region between two adjacent dielectric resonance units of the same dielectric block, wherein after the two adjacent dielectric resonance units are respectively equally divided into two parts perpendicular to the length direction, geometric centers of the parts adjacent to each other of the two adjacent dielectric resonance units are located in the hollow groove, the hollow groove communicates with the first side surface and the second side surface, or communicates with the third side surface and the fourth side surface, a dimension of the dielectric block in the width direction is larger than a dimension in the thickness direction, the hollow groove communicates with the third side surface and the fourth side surface, the dielectric block and the hollow groove are symmetrically arranged with respect to a central axis arranged in the length direction and perpendicular to the width direction, and the hollow groove is rectangular, the inner surface of the hollow-out groove is exposed out of the air.

5. The dielectric filter according to claim 4, further comprising a shielding cover plate covering at least the hollow groove, wherein the shielding cover plate is provided with a tuning screw extending into the hollow groove.

6. The dielectric filter of claim 5, wherein the tuning screws are at least two and spaced apart along the length.

7. The dielectric filter according to claim 4, wherein the hollowed-out groove is provided so that a ratio of a secondary resonance frequency to a fundamental mode resonance frequency of the two adjacent dielectric resonance units is not less than 1.5.

8. The dielectric filter according to any one of claims 1 to 7, wherein the chemical composition of the material of the dielectric filter is xZnO-ySiO-zMgO₂dMO, wherein the ratio of x, y, z and d is 0.2-0.7: 0.2-0.6: 0.1-0.2: 0-0.02, MO represents a modifying additive.

9. A method for producing a dielectric filter, the method being used for producing a dielectric filter according to any one of claims 1 to 8, the method comprising:

providing raw materials corresponding to zinc oxide, silicon dioxide and magnesium oxide;

adding an organic solvent and grinding balls and carrying out primary ball milling;

drying the slurry obtained by the primary ball milling, and calcining to obtain a ceramic body;

crushing the ceramic body, adding an organic solvent and grinding balls, and performing secondary ball milling;

drying the slurry obtained by the secondary ball milling;

mixing the obtained powder with a binder to form slurry, and granulating;

dry-pressing and molding in a mold matched with the shape of the dielectric filter; and

removing the binder and sintering again to obtain at least two integrally formed dielectric blocks and a dielectric plate between two adjacent dielectric blocks;

and coating electromagnetic shielding layers on the outer surfaces of the at least two dielectric blocks and the dielectric plate to obtain the dielectric filter.

10. A communication device, characterized in that it comprises a dielectric filter according to any one of claims 1 to 8.

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