CN111384510A

CN111384510A - Dielectric filter, preparation method thereof and communication equipment

Info

Publication number: CN111384510A
Application number: CN201910217192.4A
Authority: CN
Inventors: 吴亚晖; 袁昕; 钟志波; 袁亮亮; 陆正武; 陈薛爱
Original assignee: Shenzhen Tatfook Technology Co Ltd
Current assignee: Shenzhen Tatfook Technology Co Ltd
Priority date: 2018-12-31
Filing date: 2019-03-21
Publication date: 2020-07-07

Abstract

The application provides a dielectric filter, a preparation method thereof and communication equipment. This dielectric filter sets up the mode in order to form dielectric filter side by side through at least two dielectric blocks, when having reduced only to form dielectric filter through a dielectric block, the required length of dielectric block has improved dielectric filter's range of application, has reduced or even eliminated the dielectric block and has appeared the risk of bending deformation in sintering process, improves the yields, and simple structure, easily shaping is fit for mass production.

Description

Dielectric filter, preparation method thereof and communication equipment

Technical Field

The present application relates to the field of communications technologies, and in particular, to a dielectric filter, a method for manufacturing the dielectric filter, and a communications device.

Background

With the rapid advance of communication technology, the application of 5G communication technology is more and more extensive, the filter is used as an important component in a 5G communication system, and a highly integrated and low-cost filter is inevitably required in the 5G communication technology.

In the prior art, a dielectric block with a cuboid structure is generally prepared by adopting a ceramic material with a high dielectric constant to form a filter meeting the requirements, but the dielectric block with the structure has a long length and a narrow application range, and is easy to bend and deform in a sintering process.

Disclosure of Invention

The application mainly provides a dielectric filter, a preparation method thereof and communication equipment, and aims to solve the problem that a dielectric block is too long and easy to bend and deform.

In order to solve the technical problem, the application adopts a technical scheme that: providing a dielectric filter, wherein the dielectric filter comprises at least two dielectric blocks, 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 magnesium oxide, calcium oxide, titanium dioxide and zinc oxide.

In order to solve the above technical problem, another technical solution adopted by the present application is: there is provided a method of manufacturing a dielectric filter, wherein the method is used for manufacturing a dielectric filter as described above, the method comprising: providing raw materials corresponding to magnesium oxide, calcium oxide, titanium dioxide and zinc 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; 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.

In order to solve the above technical problem, the present application adopts another technical solution: there is provided a communication device including the dielectric filter described above.

The beneficial effect of this application is: different from the condition of prior art, this application sets up the mode in order to form dielectric filter side by side through at least two dielectric blocks, when having reduced only to form dielectric filter through a dielectric block, the required length of dielectric block, dielectric filter's range of application has been improved, the risk that dielectric block bending deformation appears in the sintering process has been reduced or even eliminated, the yield is improved, and simple structure, easily shaping, be fit for mass production, in addition, dielectric filter's material includes magnesium oxide, calcium oxide, titanium dioxide and zinc oxide at least, dielectric filter's material has low dielectric constant, low loss and nearly zero temperature coefficient, dielectric filter's that can improve.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, it is obvious that the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without inventive efforts, wherein:

fig. 1 is an exploded schematic view of a first embodiment of a dielectric filter provided herein;

fig. 2 is a schematic connection diagram of two adjacent dielectric resonance units in fig. 1;

FIG. 3 is a schematic view of the assembled structure of the dielectric filter of FIG. 1;

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

FIG. 5 is an exploded view of two of the dielectric blocks of FIG. 4;

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

FIG. 7 is an exploded view of two of the dielectric blocks of FIG. 6;

fig. 8 is a schematic flow chart of an embodiment of a method for manufacturing a dielectric filter provided herein.

Detailed Description

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, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Referring to fig. 1, fig. 1 is an exploded schematic structural diagram of a first embodiment of a dielectric filter 10 provided in the present application, where the dielectric filter 10 in the present embodiment includes a dielectric block 11.

The dielectric block 11 includes a first end surface 111 and a second end surface 112 spaced apart from each other in a length direction, i.e., in an X direction as shown in fig. 1, a first side surface 113 and a second side surface 114 spaced apart from each other in a width direction, i.e., in a Y direction as shown in fig. 1, and a third side surface 115 and a fourth side surface 116 spaced apart from each other in a thickness direction, i.e., in a Z direction as shown in fig. 1.

Optionally, in this embodiment, the dielectric block 11 is disposed in 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 disposed on six sides of the rectangular parallelepiped in the above direction, which is not limited herein, of course, in other embodiments, the dielectric block 11 may also be disposed in other regular or irregular shapes.

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

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

Optionally, the dielectric blocks 11 are symmetrically disposed with respect to a central axis disposed along the length direction and perpendicular to the width direction, and it can be understood that the central axis is a virtual plane disposed for convenience of description.

Optionally, the dielectric block 11 is made of a ceramic material, and the dielectric constant of the ceramic material is high, so that the effective size of the dielectric resonance unit can be greatly compressed by the compression effect of the ceramic material with high dielectric constant on the microwave wavelength, so that the overall dimension of the dielectric filter is miniaturized, and meanwhile, the ceramic material is easy to mold, so that batch production with low cost can be realized, and therefore the ceramic filter with advantages in miniaturization and integration application is highly matched with the technical requirements of 5G micro base stations (SmallCells) and MIMO systems, and certainly, in other embodiments, the dielectric block 11 can also be made of a material with other dielectric constant close to that of the ceramic.

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

Referring to fig. 1 and fig. 2 together, fig. 2 is a schematic connection diagram of two adjacent dielectric resonance units in fig. 1, wherein a hollow-out groove 101 is disposed in a connection region of the two adjacent dielectric resonance units, and after the two adjacent dielectric resonance units are respectively equally divided into two parts perpendicular to a length direction, geometric centers of the parts of the two adjacent dielectric resonance units adjacent to each other are located in the hollow-out groove 101, for example, as shown in fig. 2, the two adjacent dielectric resonance units are respectively a dielectric resonance unit 11a and a dielectric resonance unit 11B, the dielectric resonance unit 11a and the dielectric resonance unit 11B are respectively equally divided into two

parts

1111, 1112 and 1113, 1114 perpendicular to the length direction, geometric centers a and B of the

parts

1112 and 1113 of the dielectric resonance unit 11a and the dielectric resonance unit 11B are located in the hollow-out groove 101, so as to increase a ratio of a secondary resonance frequency of the two adjacent dielectric resonance units to a fundamental mode resonance frequency, and then improve the outband harmonic characteristic of dielectric filter 10, and a plurality of dielectric resonators do not need concatenation, secondary sintering through integrated into one piece's mode, and structure and simple process improve the stability and the uniformity of structure size, improve the product yield, realize mass production.

It can be understood that, in this embodiment, 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 equally divided into two

parts

1113 and 1114 perpendicular to the length direction, the geometric center C of the other part 1114 of the dielectric resonance unit 11b is also located in the other hollowed-out groove 101.

Optionally, the hollowed-out groove 101 is configured to enable a ratio of a secondary resonance frequency to a fundamental mode resonance frequency of two adjacent dielectric resonance units to be 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, and in this embodiment, the hollow groove 101 communicates with the third side 115 and the fourth side 116.

Optionally, the hollow-out groove 101 is exposed to the air.

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

Optionally, the hollow groove 101 is disposed in a rectangular parallelepiped, and it can be understood that in other embodiments, the hollow groove 101 may also have other shapes.

Referring to fig. 1 and fig. 3 together, fig. 3 is a schematic view of an 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, the output terminal 12 and the input terminal 11 are respectively disposed 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.

Alternatively, the output terminal 12 and the input terminal 13 are in the form of probes, and in other embodiments, the output terminal may 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 implement a shielding function.

Optionally, the electromagnetic shielding layer 14 includes shielding cover plates 141 at least covering the hollow groove 101, in this embodiment, the hollow groove 101 is covered on the third side 115 and the fourth side 116 of the dielectric block 11 by two shielding cover plates 141, and other outer surfaces of the dielectric block 11, on which the shielding cover plates 141 are not disposed, may be coated with a metal including, but not limited to, copper, silver, tin, or aluminum to form a metal coating, and the metal coating and the shielding cover plates 141 together form the electromagnetic shielding layer 14 in this embodiment.

The tuning screw 15 extending into the hollow groove 101 is arranged on the shielding cover plate 141, so that the resonant frequency of the dielectric filter 10 can be adjusted through the tuning screw 15, and by means of the mode of arranging the tuning screw 15, tuning holes do not need to be reserved on the dielectric block 11, and the process difficulty caused by the fact that the tuning holes are arranged on the dielectric block 11 is avoided.

Optionally, the number of the tuning screws 15 is at least two, and 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 the dielectric filter 20 provided in the present application, where the dielectric filter 20 in the present embodiment includes at least two dielectric blocks 21, and two are taken as an example in the illustration of the present embodiment.

Referring to fig. 5, fig. 5 is an exploded schematic view of two dielectric blocks 21 in fig. 4, wherein each dielectric block 21 includes a first end surface 211 and a second end surface 212 spaced apart from each other in a length direction, i.e., in an X direction shown in fig. 5, a first side surface 213 and a second side surface 214 spaced apart from each other in a width direction, i.e., in a Y direction shown in fig. 5, and a third side surface 215 and a fourth side surface 216 spaced apart from each other in a thickness direction, i.e., in a Z direction shown in fig. 5.

Optionally, in this embodiment, each dielectric block 21 is disposed in a rectangular parallelepiped, and the first end surface 211, the second end surface 212, the first side surface 213, the second side surface 214, the third side surface 215, and the fourth side surface 216 are respectively disposed on six surfaces of the rectangular parallelepiped in the above direction, but in other embodiments, the dielectric blocks 21 may be disposed in other regular or irregular shapes, which is not limited herein.

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

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

Alternatively, the dielectric blocks 21 are symmetrically disposed with respect to a central axis plane disposed along the length direction and perpendicular to the width direction, and it is understood that the central axis plane is a virtual plane disposed for convenience of description.

Optionally, the dielectric block 21 is made of a ceramic material, and the dielectric constant of the ceramic material is high, so that the effective size of the dielectric resonance unit can be greatly compressed by the compression effect of the ceramic material with high dielectric constant on the microwave wavelength, so that the overall dimension of the dielectric filter is miniaturized, and meanwhile, the ceramic material is easy to mold, so that batch production with low cost can be realized, and therefore the ceramic filter with advantages in miniaturization and integration application is highly matched with the technical requirements of 5G micro base stations (SmallCells) and MIMO systems, and certainly, in other embodiments, the dielectric block 21 can also be made of a material with other dielectric constant close to that of the ceramic.

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

The connection region of two adjacent dielectric resonance units of the same dielectric block 21 is provided with a hollow groove 201, and after the two adjacent dielectric resonance units are respectively equally divided into two parts in a direction perpendicular to the length direction, the geometric centers of the parts adjacent to each other of the two adjacent dielectric resonance units are located in the hollow groove 201, 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 improve the out-of-band harmonic characteristic of the dielectric filter 20.

Optionally, the hollow-out groove 201 is configured such 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 201 communicates with the first side 213 and the second side 214, or communicates with the third side 215 and the fourth side 216, and in this embodiment, the hollow 201 communicates with the third side 215 and the fourth side 216.

Optionally, the hollow-out groove 201 is exposed to the air.

Optionally, the hollow-out grooves 201 are symmetrically arranged with respect to a central axis which is arranged in the length direction and perpendicular to the width direction.

Optionally, the hollow groove 201 is disposed in a rectangular parallelepiped, and it can be understood that in other embodiments, the hollow groove 201 may also be disposed in other shapes.

Further, at least two dielectric blocks 21 are arranged side by side along the width direction or the thickness direction, and adjacent sides of at least two dielectric blocks 21 are provided with the metal shielding layer 22, in this embodiment, that is, the first side 213 of one of the dielectric blocks 21 and the second side 212 of another one of the dielectric blocks 21 are provided with the metal shielding layer 22 as shown in fig. 5.

Wherein the metal shielding layers 22 of adjacent sides of 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 metal coatings are coated on the adjacent side surfaces of at least two dielectric blocks 21, pre-baking can be performed, then the metal coatings are fixedly spliced by using a clamp, and finally the metal coatings are bonded by means of high-temperature sintering.

Further, the metal shielding layers 22 of at least two dielectric blocks 21 are respectively provided with coupling windows 221 which are bonded with the adjacent side metal shielding layers 22 and at least partially overlapped with each other, so as to realize the coupling between the dielectric resonance units on at least two dielectric blocks 21, and in the process of coating the metal coating, the positions of the coupling windows 221 can be shielded firstly, so as to prevent the metal coating from penetrating into the coupling windows 221, and causing the coupling failure of the dielectric resonance units on different dielectric blocks 21.

After the at least two dielectric blocks 21 are arranged side by side, the at least two cascaded dielectric resonance units on the dielectric blocks 21 may be directly coupled or cross-coupled, for example, the at least two cascaded dielectric resonance units on the same dielectric block 21 may be directly coupled, the at least two cascaded dielectric resonance units on different dielectric blocks 21 may be cross-coupled, or the at least two cascaded dielectric resonance units on different dielectric blocks 21 may be directly coupled, and the at least two cascaded dielectric resonance units on the same dielectric block 21 are cross-coupled, so that the frequency selection characteristic of the dielectric filter 20 is improved.

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.

Alternatively, the output terminal 23 and the input terminal 24 are in the form of probes, and in other embodiments, the output terminal may 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 25, the shielding cover 25 at least covers the hollow groove 201, and in this embodiment, each dielectric block 21 is provided with two shielding covers 25 covering the hollow groove 201.

The tuning screw 26 extending to the hollow groove 201 is arranged on the shielding cover plate 25, so that the resonant frequency of the dielectric filter 20 can be adjusted through the tuning screw 26, and by means of the tuning screw 26, a tuning hole does not need to be reserved on the dielectric block 21, and the process difficulty caused by the tuning hole arranged on the dielectric block 21 is avoided.

Optionally, the number of the tuning screws 26 is at least two, and 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 in the present application, in which the dielectric filter 30 in the present embodiment includes at least two dielectric blocks 31, and in the present embodiment, two dielectric blocks 31 are taken as an example.

Referring to fig. 7, fig. 7 is an exploded schematic view of two dielectric blocks 31 in fig. 6, wherein each dielectric block 31 includes a first end surface 311 and a second end surface 312 spaced apart from each other in a length direction, i.e., in an X direction shown in fig. 7, a first side surface 313 and a second side surface 314 spaced apart from each other in a width direction, i.e., in a Y direction shown in fig. 7, and a third side surface 315 and a fourth side surface 316 spaced apart from each other in a thickness direction, i.e., in a Z direction shown in fig. 7.

Optionally, in this embodiment, each dielectric block 31 is disposed in a rectangular parallelepiped, and the first end surface 311, the second end surface 312, the first side surface 313, the second side surface 314, the third side surface 315, and the fourth side surface 316 are respectively disposed on six surfaces of the rectangular parallelepiped in the above direction, but in other embodiments, the dielectric blocks 31 may also be disposed in other regular or irregular shapes, which is not limited herein.

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

Alternatively, the dielectric block 31 may have a dimension in the width direction larger than a dimension in the thickness direction.

Alternatively, the dielectric blocks 31 are symmetrically disposed with respect to a central axis plane disposed along the length direction and perpendicular to the width direction, and it is understood that the central axis plane is a virtual plane disposed for convenience of description.

Optionally, the dielectric block 31 is made of a ceramic material, and the dielectric constant of the ceramic material is high, so that the effective size of the dielectric resonance unit can be greatly compressed by the compression effect of the ceramic material with high dielectric constant on the microwave wavelength, so that the overall dimension of the dielectric filter is miniaturized, and meanwhile, the ceramic material is easy to mold, so that batch production with low cost can be realized, and therefore the ceramic filter with advantages in miniaturization and integration application is highly matched with the technical requirements of 3G micro base stations (SmallCells) and MIMO systems, and certainly, in other embodiments, the dielectric block 31 can also be made of a material with other dielectric constant close to that of the ceramic.

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

The connection region of two adjacent dielectric resonance units of the same dielectric block 31 is provided with a hollow groove 301, and after the two adjacent dielectric resonance units are respectively equally divided into two parts in a direction perpendicular to the length direction, the geometric centers of the parts adjacent to each other of the two adjacent dielectric resonance units are located in the hollow groove 301 to improve the ratio of the secondary resonance frequency to the fundamental mode resonance frequency of the two adjacent dielectric resonance units, so as to improve the out-of-band harmonic characteristic of the dielectric filter 30.

Optionally, the hollowed-out groove 301 is configured to enable a ratio of a secondary resonance frequency to a fundamental mode resonance frequency of two adjacent dielectric resonance units to be not less than 1.5.

Optionally, the hollow-out groove 301 connects the first side 313 and the second side 314, or connects the third side 315 and the fourth side 316, and in this embodiment, the hollow-out groove 301 connects the third side 315 and the fourth side 316.

Optionally, the hollow-out groove 301 is exposed to the air.

Optionally, the hollow-out grooves 301 are symmetrically arranged with respect to a central axis which is arranged in the length direction and perpendicular to the width direction.

Optionally, the hollow groove 301 is disposed in a rectangular parallelepiped, and it can be understood that in other embodiments, the hollow groove 301 may also be disposed in other shapes.

Further, at least two dielectric blocks 31 are arranged side by side along the width direction or the thickness direction and are arranged at intervals, a dielectric plate 32 is arranged between the adjacent side faces of the at least two dielectric blocks 31, the dielectric plate 32 is integrally arranged with the two dielectric blocks 31 respectively, relative fixation between the at least two dielectric blocks 31 is achieved, the precision of a required clamp when the at least two dielectric blocks 31 are jointed is reduced, and the jointing success rate is improved.

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, and compared with a mode of metal coating and bonding, the risk of metal penetrating into the coupling window in the sintering process is reduced or even eliminated.

When at least two dielectric blocks 31 are arranged side by side, at least two cascaded dielectric resonant units on the dielectric blocks 31 may be directly coupled or cross-coupled to improve the frequency-selective characteristic of the dielectric filter 30, which may be referred to the corresponding description in the second embodiment of the dielectric filter 20.

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.

Alternatively, the output terminal 33 and the input terminal 34 are in the form of probes, and in other embodiments, the output terminal may 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 35, and the shielding cover 35 covers at least the hollow groove 301.

The tuning screw 36 extending to the hollow groove 301 is arranged on the shielding cover plate 35 to adjust the resonant frequency of the dielectric filter 30 through the tuning screw 36, and by the way of arranging the tuning screw 36, a tuning hole does not need to be reserved on the dielectric block 31, thereby avoiding the process difficulty caused by arranging the tuning hole on the dielectric block 31.

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

The material of the dielectric filter disclosed in the above embodiment may be ceramic, which includes magnesium oxide, calcium oxide, titanium dioxide, and zinc oxide. I.e., the ceramic consists essentially of the above-described components, it is understood that the ceramic may also contain small or trace amounts of other substances.

In some embodiments, the magnesium oxide is present in a molar percentage of 20% to 30%.

In some embodiments, the calcium oxide is present in a molar percentage of 2% to 10%.

In some embodiments, the titanium dioxide comprises 50 to 75 mole percent thereof.

In some embodiments, the zinc oxide is present in an amount of 0.1 to 5 mole percent.

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

The chemical composition of the ceramic can be expressed as aMgO-bCaO-cTiO₂-dZnO, wherein the ratio of a, b, c and d is 0.2-0.3: 0.02-0.1: 0.5-0.7: 0.001-0.05. For example, if the values of a, b, c and d are taken as 0.2, 0.1, 0.65 and 0.05, respectively, the chemical composition of the ceramic may be expressed as 0.2MgO-0.1CaO-0.65TiO₂-0.05 ZnO. Of course, the values of a, b, c and d may take other values within this range. The microwave dielectric property of the ceramic can be further adjusted by changing the proportion of the chemical components of the ceramic.

In some embodiments, the ceramic may further include a modifying additive, i.e., an additive capable of improving the properties of the ceramic. It should be understood that the modifying additive need not be in a liquid form, but may be in a solid form, etc. Specifically, the modifying additive may be a combination of one or more of oxides of Si, Cu, or Ni, that is, the modifying additive may include only one of the oxides of Si, Cu, or Ni, or may include two or three thereof. Optionally, the proportion of the modifying additive can be 0-2 wt%. That is, the modifying additive is present in an amount of no more than 2% by weight of the total material.

According to the test result, the dielectric constant of the ceramic is 18-22, and the Q f value is larger than 80000 GHz. For example, the microwave dielectric property of the ceramic is tested by a network analyzer (Agilent 5071C) at a test frequency of 4.7GHz, and the microwave dielectric property of the ceramic is obtained as follows: dielectric constant ε_r20.6, dielectric loss Q ═ 83000GHz, temperature coefficient τ_f＝-2ppm/℃。

The ceramic provided by the application mainly comprises magnesium oxide, calcium oxide, titanium dioxide and zinc oxide, and has low dielectric constant, low loss and near-zero temperature coefficient. Thus, the ceramics provided by the practice of the present application have improved dielectric properties of dielectric filters.

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

s110: raw materials corresponding to magnesium oxide, calcium oxide, titanium dioxide and zinc oxide are provided.

In some embodiments, the raw materials corresponding to magnesium oxide, calcium oxide, titanium dioxide, and zinc oxide may be oxides or carbonates of the corresponding metal elements. Wherein the oxide of the metal element directly corresponds to the component of the dielectric filter to be prepared, and some carbonates of the metal element can be converted into the oxide of the metal element under the condition of heating and the like, so that the carbonate can also be used as a raw material. In other embodiments, the starting material may also be an alcoholate of the corresponding metal element, in which case the alcoholate of the metal may be converted to the desired oxide using a suitable chemical treatment. The specific method is well known in the art and will not be described herein.

In this embodiment, the molar percentage of the raw material corresponding to magnesium oxide is 20 to 30%, the molar percentage of the raw material corresponding to calcium oxide is 2 to 10%, the molar percentage of the raw material corresponding to titanium dioxide is 50 to 75%, and the molar percentage of the raw material corresponding to zinc oxide is 0.1 to 5%. It should be understood that the above mole percentages refer to mole percentages after removal of impurities in the raw materials.

In this embodiment, raw materials can be prepared in accordance with the proportions of the components 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 parameters such as the molecular weight of each component, the purity of the raw material and the like. For example, 97 wt% of MgO and 99.8 wt% of CaCO can be used₃And TiO₂And 99.5 wt% of ZnO, calculating the mass required by each component according to the required mole number and molecular weight of each component, and calculating the mass of the required raw material according to the mass required by each component and the purity of the raw material. This makes it possible to prepare raw materials of corresponding weights based on the results of the calculation.

In some embodiments, modifying additives may also be added to the raw materials. The modifying additive may be one or more of oxides of Si, Cu or Ni. The modifying additive should generally not exceed 2% by weight of the total weight of all raw materials.

S120: adding an organic solvent and grinding balls and carrying out primary ball milling.

In step S120, deionized water, alcohol, acetone, etc. may be used as the organic solvent, zirconium balls, agate balls, etc. may be used as the grinding balls, and ceramic, polyurethane, nylon, etc. may be used in the grinding tank, and planetary mill, stirring mill, tumbling mill, vibrating mill, etc. may be used for the first ball milling. Wherein, in order to improve the ball milling effect, proper dispersant can be added or the pH value of the slurry can be adjusted.

In some embodiments, alcohol may be used as the organic solvent, and ZrO may be used₂A grinding ball made of the material. In step S120, accurately weighed raw materials are poured into a ball mill pot, and alcohol and ZrO are added₂Grinding balls, wherein the weight ratio of the raw materials to the grinding balls to the alcohol is 1:2:1.5, and performing ball milling for 24 hours.

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

And (3) uniformly mixing the ball-milled materials, discharging and drying, for example, drying the materials at 100-120 ℃.

After the ball milling is finished and the mixture obtained after drying is required to be calcined at a certain temperature to synthesize the ceramic body, wherein the calcining temperature and the heat preservation time depend on the corresponding formula. For example, in this embodiment, the slurry dried after ball milling may be calcined at 900 to 1100 ℃ for 12 hours to synthesize a ceramic body.

S140: and (3) crushing the ceramic body, adding an organic solvent and grinding balls, and carrying out secondary ball milling.

The synthesized ceramic body is pulverized. The method of pulverization is not limited in the present application, and for example, it may be pulverized using a pulverizer. In some embodiments, the crushed ceramic body may also be sieved (e.g., 40 mesh).

And pouring the crushed ceramic body into the ball milling tank again for secondary ball milling, wherein the process of the secondary ball milling can be similar to that of the primary ball milling. For example, the pulverized ceramic body may be ball milled for a second time for 24 hours while maintaining the ratio of the material, alcohol and grinding balls constant. It should be understood that the process of the second ball milling may be different from the first ball milling, for example, the time of the second ball milling may be shorter (or longer) than that of the first ball milling, and is not limited herein.

S150: and drying the slurry obtained by secondary ball milling.

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

S160: mixing the obtained powder with a binder to form slurry, and granulating.

In some embodiments, the binder may be a 10 wt% polyvinyl alcohol solution (i.e., the polyvinyl alcohol in the binder is 10 wt%).

In some embodiments, the granulated powder may also be sieved (e.g., 40 mesh).

S170: and dry-pressing the dielectric filter in a mold matched with the shape of the dielectric filter.

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

In other embodiments, the shape of the mold can be selected as desired, for example, if testing is required, a mold dedicated for testing can be used to dry press the powder into a shape

To facilitate testing. It should be understood that the shape and size of the mold can be arbitrarily selected according to the needs, and is not limited herein.

S180: 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.

The temperature may be selected to perform a heat preservation process so as to remove the binder introduced in step S610, and then the binder is sintered again so as to finally obtain the desired dielectric block and dielectric plate. Specifically, in this embodiment, the molded material may be heat-preserved at 600 ℃ for 2 hours, and then sintered at 1150-1400 ℃ for 2-24 hours. Thus, the adhesive agent added to the material in step S610 can be removed, and a dielectric block and a dielectric plate in a desired shape can be obtained. S190: and coating electromagnetic shielding layers on the outer surfaces of the at least two dielectric blocks and the dielectric plate.

Electromagnetic shielding layers are covered on the surfaces of the at least two dielectric blocks and the dielectric plate, so that an electromagnetic field is limited in the dielectric blocks, and electromagnetic signal leakage is prevented. The electromagnetic shielding layer may be made of a metal material such as silver, copper, aluminum, titanium, tin or gold, and the electromagnetic shielding layer may be covered on the surface of the dielectric block by electroplating, spraying or welding.

The present application also provides a communication device including the dielectric filter in any of the above embodiments.

Be different from prior art's condition, this application sets up the mode in order to form dielectric filter side by side through at least two dielectric blocks, when having reduced only to form dielectric filter through a dielectric block, the required length of dielectric block has improved dielectric filter's range of application, has reduced or even eliminated the risk that dielectric block bending deformation appears in sintering process, improves the yields, and simple structure, easily shaping is fit for mass production.

The above description is only an example of the present application and is not intended to limit the scope of the present application, and all modifications of equivalent structures and equivalent processes, which are made by the contents of the specification and the drawings, or which are directly or indirectly applied to other related technical fields, are intended to be included within the scope of the present application.

Claims

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 magnesium oxide, calcium oxide, titanium dioxide and zinc oxide.

2. The dielectric filter of claim 1, wherein the magnesium oxide accounts for 20-30% of the molar percentage; the calcium oxide accounts for 2 to 10 percent of the molar percentage; the titanium dioxide accounts for 50 to 75 percent of the molar percentage; the zinc oxide accounts for 0.1 to 5 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. A dielectric filter as claimed in any one of claims 1 to 7, characterized in that the chemical composition of the material of the dielectric filter is aMgO-bCaO-cTiO₂-dZnO, wherein the ratio of a, b, c and d is 0.2-0.3: 0.02-0.1: 0.5-0.7: 0.001-0.05.

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 magnesium oxide, calcium oxide, titanium dioxide and zinc 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.