CN111384520A

CN111384520A - Dielectric resonator, dielectric filter, communication equipment and method for preparing dielectric block

Info

Publication number: CN111384520A
Application number: CN201910217618.6A
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 resonator, a dielectric filter, a communication device and a method for preparing a dielectric block. The area adjacent to the first end face is provided with a hollow groove through the dielectric block, the dielectric block is equally divided into two parts in the direction perpendicular to the length direction, the geometric center of the part where the first end face is located in the hollow groove, and the dielectric resonator is made of materials at least including magnesium oxide, calcium oxide, titanium dioxide and zinc oxide. By implementing the dielectric resonator, the ratio of the secondary resonance frequency of the dielectric resonator to the fundamental mode resonance frequency can be improved, so that after the dielectric resonator is applied to the dielectric filter, the out-of-band harmonic characteristic of the dielectric filter is improved, and the dielectric resonator is simple in structure, easy to form and suitable for mass production.

Description

Dielectric resonator, dielectric filter, communication equipment and method for preparing dielectric block

Technical Field

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

Background

With the rapid advance of communication technology, the application of 5G communication technology is becoming more and more widespread, and as an important component in a 5G communication system, a filter with high integration, miniaturization, light weight and low cost is inevitably required in the 5G communication technology.

In the prior art, a resonator forming 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 secondary resonance frequency of the resonator of the structure is close to the resonance frequency of a fundamental mode, and the ratio of the secondary resonance frequency to the fundamental mode is low, so that the far-end out-of-band characteristic of the filter is low.

Disclosure of Invention

The application mainly provides a dielectric resonator, a dielectric filter, communication equipment and a method for preparing a dielectric block, and aims to solve the problem that the secondary resonance frequency of the dielectric resonator is close to the resonance frequency of a fundamental mode, and the ratio is low, so that the far-end out-of-band characteristic of the dielectric filter is low.

In order to solve the technical problem, the application adopts a technical scheme that: there is provided a dielectric resonator comprising: the 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, wherein 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, hollow grooves are formed in adjacent regions of the first end face of the dielectric block, and after the dielectric block is equally divided into two parts perpendicular to the length direction, the geometric center of the part where the first end face is located in the hollow grooves; wherein the material of the dielectric resonator 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 dielectric filter comprising at least two dielectric resonators as described above arranged in cascade.

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

In order to solve the above technical problem, the present application adopts another technical solution: a method of making a dielectric block is provided for making the dielectric block in the foregoing structure. The method comprises the following steps: 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 block; and removing the binder and sintering again to obtain the dielectric block.

The beneficial effect of this application is: be different from prior art's condition, this application sets up the fretwork groove in the adjacent region of first terminal surface through the dielectric block, and in perpendicular to length direction with two parts of dielectric block equidistribution and back, the geometric centre of the part at first terminal surface place is located the fretwork inslot, with the ratio of secondary resonance frequency and the basic mode resonant frequency that improves dielectric resonator, and then make when dielectric resonator is applied to dielectric filter after, improve dielectric filter's outband harmonic characteristic, and simple structure, easily shaping, be fit for mass production. In addition, the dielectric resonator is made of at least magnesium oxide, calcium oxide, titanium dioxide and zinc oxide, has low dielectric constant, low loss and near-zero temperature coefficient, and can improve the dielectric property of the dielectric resonator.

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 resonator provided in the present application.

Fig. 2 is a schematic structural view of another embodiment of the dielectric block of fig. 1.

Fig. 3 is a schematic view of an assembled structure of the dielectric resonator of fig. 1.

Fig. 4 is an exploded schematic view of a second embodiment of a dielectric resonator provided in the present application.

Fig. 5 is a schematic structural view of another embodiment of the dielectric block of fig. 4.

Fig. 6 is a schematic view of an assembled structure of the dielectric resonator of fig. 4.

Fig. 7 is a schematic flow chart of a method of making a dielectric block provided herein.

Fig. 8 is a schematic flow chart of a method for manufacturing a dielectric resonator provided in the present application.

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 view of a dielectric resonator 10 according to a first embodiment of the present application, where the dielectric resonator 10 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 second end surface 112 is disposed flat.

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 resonator 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 (Small Cells) and MIMO systems, and certainly, in other embodiments, the material of the dielectric block 11 can also be made of a material with a dielectric constant similar to that of ceramics.

Further, the dielectric block 11 is provided with the hollow groove 101 in the area adjacent to the first end surface 111, in this embodiment, that is, the hollow groove 101 is provided in the area where at least one of the first side surface 113, the second side surface 114, the third side surface 115 and the fourth side surface 116 of the dielectric block 11 is located, and as shown by the dotted line in fig. 1, after the dielectric block 11 is equally divided into two

parts

11a and 11b in the direction perpendicular to the length direction, the geometric center a of the part 11a where the first end surface 111 is located in the hollow groove 101, so as to improve the ratio of the secondary resonance frequency to the fundamental mode resonance frequency of the dielectric resonator 10, thereby improving the out-of-band harmonic characteristic of the dielectric filter after the dielectric resonator 10 is applied to the dielectric filter, and the coupling among the plurality of dielectric resonators 10 does not generate resonance near the passband, further improving the far-end out-of-band characteristic of the dielectric filter to which the dielectric resonator is applied, and the structure is simple, the forming is easy, and the method is suitable for mass production.

Optionally, the hollow-out groove 101 is configured such that a ratio of the secondary resonance frequency of the dielectric resonator 10 to the fundamental mode resonance frequency is not less than 1.5, for example, the ratio of the secondary resonance frequency of the dielectric resonator 10 to the fundamental mode resonance frequency is 1.5, 1.6, 1.7, or the like.

Optionally, the hollow groove 101 communicates with the third side 115 and the fourth side 116, and in this embodiment, the hollow groove 101 further communicates with the first end surface 111.

Optionally, the inner surface of the hollow groove 101 is exposed to the air.

Referring to fig. 2, fig. 2 is a schematic structural view of another embodiment of the dielectric block 11 in fig. 1, in which the hollow groove 101 communicates with the first side 113 and the third side 114, and in the other arrangement, the hollow groove 101 further communicates with the first end 111.

Further referring to fig. 1, the hollow-out grooves 101 are symmetrically disposed with respect to a central axis disposed along 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.

Further, in the present embodiment, the dielectric resonator 10 further includes an input/output terminal 12 disposed adjacent to the second end surface 112 disposed in a flat manner, that is, the input/output terminal 12 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/input terminal 12 is in the form of a probe, and in other embodiments, it may also be in the form of a printed circuit board, a microstrip line, or the like.

Referring to fig. 1 and fig. 3 together, fig. 3 is a schematic view illustrating an assembly structure of the dielectric resonator 10 in fig. 1, and the dielectric resonator 10 in this embodiment further includes an electromagnetic shielding layer 13, where the electromagnetic shielding layer 13 covers an outer surface of the dielectric block 11 to implement a shielding function.

Optionally, the electromagnetic shielding layer 13 at least includes shielding cover plates 131 covering the hollow-out grooves 101, in this embodiment, the hollow-out grooves 101 are covered on the third side 115 and the fourth side 116 of the dielectric block 11 by two shielding cover plates 131, and other outer surfaces of the dielectric block 11, on which the shielding cover plates 131 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 131 together form the electromagnetic shielding layer 13 in this embodiment.

Wherein, be provided with the tuning screw 14 that extends to in the fretwork groove 101 on the shielding apron 131 to adjust the resonant frequency of dielectric resonator 10 through this tuning screw 14, compare in prior art, adjust resonant frequency's mode through polishing electromagnetic shield 13 and dielectric block 11, easy control has improved stability, uniformity and regulation precision, has reduced the sensitivity to the structure size, and has avoided leading to the cracked condition to appear in dielectric resonator 10 through the mode of polishing among the prior art, improves the yield.

Referring to fig. 4, fig. 4 is an exploded schematic view of a second embodiment of the dielectric resonator 20 provided in the present application, where the dielectric resonator 20 in the present embodiment includes a dielectric block 21.

The 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 as shown in fig. 4, 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 as shown in fig. 4, 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 as shown in fig. 4.

Optionally, in this embodiment, the 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-mentioned direction, but in other embodiments, the dielectric block 21 may also 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 resonator 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 miniaturized and integrated application is highly matched with the technical requirements of 5G micro base stations (Small Cells) and MIMO systems, and certainly, in other embodiments, the dielectric block 21 can also be made of a material with a dielectric constant similar to that of ceramics.

Further, the dielectric block 21 is provided with a first hollow-out groove 201 and a second hollow-out groove 202 in the adjacent area of the first end face 211 and the adjacent area of the second end face 212, and as shown by the dotted line in fig. 4, after the dielectric block 21 is equally divided into two parts 21a and 21B in the direction perpendicular to the length direction, the geometric center B1 of the part 21a where the first end face 211 is located in the first hollow-out groove 201, and the geometric center B2 of the part 21B where the second end face 212 is located in the second hollow-out groove 202, so as to improve the ratio of the secondary resonance frequency to the fundamental mode resonance frequency of the dielectric resonator 20, thereby improving the out-of-band harmonic characteristic of the dielectric filter after the dielectric resonator 20 is applied to the dielectric filter, the coupling among the plurality of dielectric resonators 20 does not generate resonance near the passband, further improving the far-end out-of-band characteristic of the dielectric filter to which the dielectric resonator is applied, and the structure is simple, the forming is easy, and the method is suitable for mass production.

Optionally, the first hollow-out groove 201 and the second hollow-out groove 202 are set such that a ratio of a secondary resonance frequency of the dielectric resonator 20 to a fundamental mode resonance frequency is not less than 1.7, for example, the ratio of the secondary resonance frequency of the dielectric resonator 20 to the fundamental mode resonance frequency is 1.7, 1.8, 1.9, and the like.

Optionally, the first hollow groove 201 and the second hollow groove 202 are respectively communicated with the third side surface 215 and the fourth side surface 216, in this embodiment, the first hollow groove 201 is further communicated with the first end surface 211, and the second hollow groove 202 is further communicated with the second end surface 212.

Referring to fig. 5, fig. 5 is a schematic structural diagram of another embodiment of the dielectric block 21 in fig. 4, in which the first hollow groove 201 and the second hollow groove 202 are respectively communicated with the first side surface 213 and the second side surface 214, and in the another arrangement, the first hollow groove 201 and the second hollow groove 202 are also respectively communicated with the first end surface 211 and the second end surface 212.

Optionally, the inner surfaces of the first hollow-out groove 201 and the second hollow-out groove 202 are exposed to the air.

Further referring to fig. 4, the first hollow-out groove 201 and the second hollow-out groove 202 are symmetrically disposed with respect to a central axis disposed along the length direction and perpendicular to the width direction.

Optionally, the first hollow-out groove 201 and the second hollow-out groove 202 are disposed in a rectangular parallelepiped, and it can be understood that in other embodiments, the first hollow-out groove 201 and the second hollow-out groove 202 may also be in other shapes.

Referring to fig. 4 and fig. 6 together, fig. 6 is a schematic view illustrating an assembly structure of the dielectric resonator 20 in fig. 4, and the dielectric resonator 20 in the present embodiment further includes an electromagnetic shielding layer 22, where the electromagnetic shielding layer 22 covers an outer surface of the dielectric block 21 to implement a shielding function.

Optionally, at least a partial region of the first end surface 211 and the second end surface 212 is not covered with the electromagnetic shielding layer 22, and is further used for coupling with another dielectric resonator, that is, the dielectric resonator 20 in this embodiment may be coupled with another dielectric resonator through the first end surface 211 and the second end surface 212.

Optionally, the electromagnetic shielding layer 22 includes a shielding cover 221 at least covering the first hollow-out groove 201 and the second hollow-out groove 202, in this embodiment, the first hollow-out groove 201 and the second hollow-out groove 202 are covered on the third side 215 and the fourth side 216 of the dielectric block 21 by two shielding covers 221, and other outer surfaces of the dielectric block 21 where the shielding cover 221 is not disposed may be formed by coating 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 221 together form the electromagnetic shielding layer 22 in this embodiment.

The shielding cover plate 221 is provided with a first tuning screw 23 and a second tuning screw 24 which respectively extend to the first hollow-out groove 201 and the second hollow-out groove 202, so that the resonant frequency of the dielectric resonator 20 can be adjusted through the first tuning screw 23 and the second tuning screw 24, and compared with the prior art, the method for adjusting the resonant frequency by polishing the electromagnetic shielding layer 22 and the dielectric block 21 is easy to control, stability, consistency and adjustment precision are improved, sensitivity to the structure size is reduced, the condition that the dielectric resonator 20 is broken due to the polishing mode in the prior art is avoided, and the yield is improved.

The present application further provides a dielectric filter, where the dielectric filter includes the dielectric resonator in any of the above embodiments, which may specifically refer to the description in the above embodiments, and details are not repeated here.

The application also provides a communication device comprising the dielectric filter.

Be different from prior art's condition, this application sets up the fretwork groove in the adjacent region of first terminal surface through the dielectric block, and in perpendicular to length direction with two parts of dielectric block equidistribution and back, the geometric centre of the part at first terminal surface place is located the fretwork inslot, with the ratio of secondary resonance frequency and the basic mode resonant frequency that improves dielectric resonator, and then make when dielectric resonator is applied to dielectric filter after, improve dielectric filter's outband harmonic characteristic, and simple structure, easily shaping, be fit for mass production.

The material of the dielectric resonator disclosed in the above embodiment may be ceramic, and the ceramic 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 microwave dielectric 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. By varying the ratio between the chemical components of the ceramic, microwave dielectric properties of the ceramic can be achievedThe performance is further adjusted.

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 ∈ r ═ 20.6, dielectric loss Q ═ f ═ 83000GHz, and temperature coefficient τ f ═ 2ppm/° c.

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. Therefore, the microwave dielectric property of the dielectric resonator can be improved by implementing the ceramic provided by the application.

The present application further provides methods of making the dielectric blocks in the foregoing embodiments. As shown in fig. 7, the method includes:

s301: 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 oxides of the metal elements correspond directly to the constituents of the material of the dielectric block to be produced, while carbonates of some metal elements can be converted into oxides of the metal elements under the action of heat or the like and thus can likewise be used as starting materials. 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 may be prepared in accordance with the proportions of the respective components of the material of the dielectric block to be prepared. 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.

S302: adding an organic solvent and grinding balls and carrying out primary ball milling.

In step S302, 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 used₂Made of materialsAnd (5) grinding balls. In step S302, 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.

S303: 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.

S304: 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.

S305: 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).

S306: 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).

S307: and (4) carrying out dry pressing forming in a die matched with the shape of the medium block.

Specifically, the granulated powder is placed into a mold matched with the shape of the medium block to be prepared, and is subjected to dry pressing under a proper pressure, for example, the powder can be subjected to dry pressing 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.

S308: the binder is removed and sintered again to obtain the dielectric block.

The temperature may be selected to be a suitable temperature for the heat preservation process to remove the binder introduced in step S306, and then the binder is sintered again to finally obtain the desired dielectric block. 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. In this way, the binder added to the material in step S306 can be removed and the desired dielectric block can be obtained.

The application further provides a preparation method of the dielectric resonator, which is used for preparing the dielectric resonator in the previous embodiment. As shown in fig. 8, the method includes:

s401: a dielectric block is provided.

The dielectric block is prepared by the method for preparing the dielectric block, namely the dielectric block prepared by the steps S301 to S308. Wherein the shape of the dielectric block is the same as the preset shape of the dielectric resonator.

S402: and covering a metal layer on the surface of the dielectric block to obtain the dielectric resonator.

The surface of the dielectric block is covered with a metal layer, so that an electromagnetic field is limited in the dielectric block, and the electromagnetic signal is prevented from leaking. The metal layer may be made of silver, copper, aluminum, titanium, tin or gold, and the metal layer may be coated on the surface of the dielectric block by electroplating, spraying or welding.

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 resonator, characterized in that the dielectric resonator comprises:

the 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 sizes of the dielectric block along the width direction and the thickness direction;

the dielectric block is provided with a hollow groove in an adjacent area of the first end face, and after the dielectric block is equally divided into two parts in a direction perpendicular to the length direction, the geometric center of the part where the first end face is located in the hollow groove;

wherein the material of the dielectric resonator at least comprises magnesium oxide, calcium oxide, titanium dioxide and zinc oxide.

2. The dielectric resonator of claim 1, wherein the magnesium oxide accounts for 20-30 mol%, the calcium oxide accounts for 2-10 mol%, the titanium dioxide accounts for 50-75 mol%, and the zinc oxide accounts for 0.1-5 mol%.

3. The dielectric resonator of claim 1, wherein the hollowed-out groove communicates with the first side and the second side, or communicates with the third side and the fourth side;

the size of the dielectric block along the width direction is larger than that along the thickness direction, and the hollow groove is communicated with the third side face and the fourth side face.

4. The dielectric resonator according to claim 3, wherein the hollowed-out groove is further communicated with the first end face;

the dielectric blocks and the hollow grooves are symmetrically arranged relative to a central axis which is arranged along the length direction and is vertical to the width direction;

the hollow-out groove is arranged in a cuboid shape.

5. The dielectric resonator of claim 4, wherein the second end surface is disposed flat, the dielectric resonator further comprising an input/output terminal disposed adjacent the second end surface.

6. The dielectric resonator of claim 1, further comprising an electromagnetic shielding layer covering an outer surface of the dielectric block, wherein an inner surface of the hollow-out groove is exposed to air.

7. A dielectric resonator as claimed in any one of claims 1 to 6, characterized in that the material of the dielectric resonator has a chemical composition 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.

8. A method of making a dielectric block, wherein the method is used to make the dielectric block of claim 1, 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 block; and

removing the binder and sintering again to obtain the dielectric block.

9. A dielectric filter comprising at least two dielectric resonators as claimed in any one of claims 1 to 7 arranged in cascade.

10. A communication device, characterized in that it comprises a dielectric filter as claimed in claim 9.