Filters and their fabrication methods, communication equipment

Abstract

This disclosure provides a filter comprising: a dielectric block made of a dielectric material, wherein the dielectric block has at least one frequency aperture; the frequency aperture is a blind aperture opening on the surface of the dielectric block, and each frequency aperture sequentially includes a first aperture segment and a second aperture segment along a direction gradually extending into the frequency aperture, wherein the radial dimension of the second aperture segment is larger than the radial dimension of the first aperture segment; and a conductive layer covering the surface of the dielectric block. This disclosure also provides a method for fabricating the filter and a communication device.

Description

Technical Field

[0001] This disclosure relates to the field of filter technology, and in particular to a filter and its fabrication method, as well as a communication device. Background Technology

[0002] As a crucial component of wireless communication equipment, filters play a significant role in the miniaturization of these devices. Since electromagnetic waves propagate through materials with high dielectric constants at shorter wavelengths, dielectric materials can be used instead of metallic materials to obtain filters with smaller dimensions while maintaining the same performance characteristics; these are known as dielectric filters.

[0003] A dielectric filter comprises a dielectric block of dielectric material covered with a metal layer, thereby forming a resonant cavity inside the dielectric block. The dielectric block also has frequency apertures to achieve frequency tuning, reduce the single-cavity frequency, and enable the filter to operate in transverse electromagnetic wave (TEM) mode, further reducing the size of the dielectric filter.

[0004] When the above dielectric filters operate at lower frequencies, the resonant cavity still needs to have a large height (i.e., the dimension of the dielectric block in the direction of the frequency aperture depth), which results in a large size of dielectric filters, and makes molding, processing, design and debugging difficult (because of the large frequency aperture depth), and high cost. Summary of the Invention

[0005] This disclosure provides a filter, its fabrication method, and a communication device.

[0006] In a first aspect, embodiments of this disclosure provide a filter, which includes:

[0007] A dielectric block made of dielectric material, wherein the dielectric block has at least one frequency hole; the frequency hole is a blind hole that opens on the surface of the dielectric block, and each frequency hole sequentially includes a first hole segment and a second hole segment along the direction of gradually penetrating the frequency hole, wherein the radial dimension of the second hole segment is larger than the radial dimension of the first hole segment;

[0008] A conductive layer covering the surface of the dielectric block.

[0009] In some embodiments, the medium block includes a first surface and a second surface that are disposed opposite to each other and parallel to each other;

[0010] At least a portion of the frequency aperture opens on the first surface, and the bottom surface of the frequency aperture opening on the first surface is parallel to the first surface.

[0011] In some embodiments, a portion of the opening of the frequency aperture is located on the second surface, and the bottom surface of the frequency aperture opening on the second surface is parallel to the second surface;

[0012] Each frequency aperture that opens on the second surface is disposed opposite to a frequency aperture that opens on the first surface.

[0013] In some embodiments, the dielectric block includes a first portion made of a first dielectric material and a second portion made of a second dielectric material; the dielectric constant of the first dielectric material is different from the dielectric constant of the second dielectric material.

[0014] The frequency aperture is located in the first portion, and at least a portion of the frequency aperture is provided below it along the depth direction in the second portion.

[0015] In some embodiments, the axis of at least a portion of the first aperture segment of the frequency aperture coincides with the axis of the second aperture segment;

[0016] And / or,

[0017] At least a portion of the axis of the first aperture segment of the frequency aperture does not coincide with the axis of the second aperture segment.

[0018] In some embodiments, at least a portion of the first aperture segment of the frequency aperture has the same shape as the second aperture segment;

[0019] And / or,

[0020] The shape of the first aperture segment of at least a portion of the frequency aperture is different from the shape of the second aperture segment.

[0021] In some embodiments, the shape of the first hole segment includes at least one of a cylinder, a cube, and a prism;

[0022] And / or,

[0023] The shape of the second hole segment includes at least one of cylinder, cube, and prism.

[0024] Secondly, embodiments of this disclosure provide a method for fabricating a filter, comprising:

[0025] A preform block with the same shape as the dielectric block is formed by the powder of dielectric material; the dielectric block has at least one frequency hole; the frequency hole is a blind hole that opens on the surface of the dielectric block, and each frequency hole includes a first hole segment and a second hole segment in sequence along the direction of gradually penetrating the frequency hole, the radial dimension of the second hole segment is larger than the radial dimension of the first hole segment;

[0026] The preform is fired to form the dielectric block made of dielectric material;

[0027] A conductive layer is formed covering the surface of the dielectric block.

[0028] In some embodiments, forming a preform with the same shape as the dielectric block using powder of dielectric material includes:

[0029] Through injection molding, a preform with the same shape as the dielectric block is formed from powder of dielectric material.

[0030] Thirdly, embodiments of this disclosure provide a communication device, including:

[0031] The filters mentioned above.

[0032] In this embodiment, the use of a "wide at the bottom and narrow at the top" frequency aperture increases the equivalent capacitance of the resonant cavity and lowers the resonant frequency. Therefore, in the same frequency band (especially the low frequency band, such as 700MHz, 900MHz, etc.), the required height of the resonant cavity (i.e. the size of the dielectric block in the direction of the frequency aperture depth) can be reduced, thereby reducing the size of the filter and making it easier to form, process, design and debug (because the frequency aperture depth is small), resulting in low cost.

[0033] In addition, the above-mentioned frequency aperture structure can make the higher-order modes of the filter further away from the operating mode, and the Q value does not decrease significantly compared with products of related technologies (such as products with equal-diameter blind apertures). Attached Figure Description

[0034] In the accompanying drawings of the embodiments disclosed herein:

[0035] Figure 1 A three-dimensional perspective structural diagram of a filter provided in an embodiment of this disclosure (conductive layer not shown);

[0036] Figure 2 A three-dimensional perspective structural diagram of another filter provided in an embodiment of this disclosure (conductive layer not shown);

[0037] Figure 3 A three-dimensional perspective structural diagram of another filter provided in an embodiment of this disclosure (conductive layer not shown);

[0038] Figure 4 A three-dimensional perspective structural diagram of another filter provided in an embodiment of this disclosure (conductive layer not shown);

[0039] Figure 5 A three-dimensional perspective structural diagram of another filter provided in an embodiment of this disclosure (conductive layer not shown);

[0040] Figure 6 A three-dimensional perspective structural diagram of another filter provided in an embodiment of this disclosure (conductive layer not shown);

[0041] Figure 7 for Figure 1A schematic diagram of the cross-sectional structure at the frequency aperture of the filter;

[0042] Figure 8 for Figure 2 A schematic diagram of the cross-sectional structure at the frequency aperture of the filter;

[0043] Figure 9 for Figure 3 A schematic diagram of the cross-sectional structure at the frequency aperture of the filter;

[0044] Figure 10 for Figure 4 A schematic diagram of the cross-sectional structure at the frequency aperture of the filter;

[0045] Figure 11 A flowchart illustrating a method for fabricating a filter according to an embodiment of this disclosure;

[0046] Figure 12 This is a block diagram of a communication device provided in an embodiment of the present disclosure;

[0047] The meanings of the reference numerals in the attached figures are as follows:

[0048] 1. Dielectric block; 11. First part; 12. Second part; 2. Frequency hole; 21. First hole segment; 22. Second hole segment; 3. Conductive layer. Detailed Implementation

[0049] To enable those skilled in the art to better understand the technical solutions of this disclosure, the filters, their preparation methods, and communication devices provided in the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings.

[0050] The present disclosure will be described more fully below with reference to the accompanying drawings; however, the embodiments shown may be embodied in different forms, and the present disclosure should not be construed as limited to the embodiments set forth below. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will enable those skilled in the art to fully understand the scope of the disclosure.

[0051] The accompanying drawings of the embodiments disclosed herein are provided to further illustrate the embodiments of this disclosure and form part of the specification. They are used together with the detailed embodiments to explain this disclosure and do not constitute a limitation thereof. The above and other features and advantages will become more apparent to those skilled in the art from the description of the detailed embodiments with reference to the accompanying drawings.

[0052] This disclosure may be described with reference to plan and / or cross-sectional views using the ideal schematic diagrams of this disclosure. Therefore, the example illustrations may be modified according to manufacturing techniques and / or tolerances.

[0053] Where there is no conflict, the various embodiments of this disclosure and the features thereof in the embodiments may be combined with each other.

[0054] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to limit the disclosure. The term "and / or" as used in this disclosure includes any and all combinations of one or more of the associated enumerated entries. The singular forms "a" and "the" as used in this disclosure are also intended to include the plural forms, unless the context clearly indicates otherwise. The terms "comprising," "made of," etc., as used in this disclosure specify the presence of the stated feature, integral, step, operation, element, and / or component, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof.

[0055] Unless otherwise specified, all terms used in this disclosure (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and this disclosure, and will not be interpreted as having an idealized or overly formal meaning, unless expressly so defined in this disclosure.

[0056] This disclosure is not limited to the embodiments shown in the accompanying drawings, but includes modifications to the configuration based on the manufacturing process. Therefore, the areas illustrated in the drawings are schematic, and the shapes of the areas shown illustrate specific shapes of the areas of an element, but are not intended to be limiting.

[0057] Firstly, referring to Figures 1 to 10 This disclosure provides a filter.

[0058] The filter in this embodiment is a dielectric filter, which can be a duplexer, a duplex-filter integrated module, etc., used in communication equipment (such as a communication base station).

[0059] The filter in this embodiment of the disclosure includes:

[0060] A dielectric block 1 is made of dielectric material, and there is at least one frequency hole 2 in the dielectric block 1. The frequency hole 2 is a blind hole that opens on the surface of the dielectric block 1. Along the direction of gradually penetrating the frequency hole 2, each frequency hole 2 includes a first hole segment 21 and a second hole segment 21 in sequence. The radial dimension of the second hole segment 21 is larger than the radial dimension of the first hole segment 21.

[0061] Conductive layer 3 covering the surface of dielectric block 1.

[0062] The filter in this embodiment includes a dielectric block 1 of insulating dielectric material, thereby constituting a dielectric filter.

[0063] Reference Figures 7 to 10 The surface of the dielectric block 1 is covered with a conductive layer 3, which can shield the transmission of electromagnetic waves, thus also serving as a shielding layer, and forming a resonant cavity inside the dielectric block 1.

[0064] The dielectric material constituting the dielectric block 1 can be ceramic (such as 201 ceramic), and it should have a high dielectric constant, such as 10, 20, 35, 65, etc.

[0065] The material constituting the conductive layer 3 can be a metal, such as silver or copper.

[0066] Each dielectric block 1 can form a resonant cavity (cavity), and each filter can include multiple resonant cavities, thereby including multiple dielectric blocks 1 with specific positional relationships, and each dielectric block 1 should have the above conductive layer 3 on its surface.

[0067] Each dielectric block 1 of the filter in this embodiment of the present disclosure is further provided with a frequency aperture 2 in the form of a blind aperture (i.e., extending from the surface of the dielectric block 1 inward but not penetrating the dielectric block 1) to achieve frequency tuning.

[0068] It should be understood that the hole wall (including the bottom and side walls) of each frequency hole 2 is also part of the surface of the dielectric block 1, therefore, refer to Figures 7 to 10 The wall of the frequency hole 2 should also be covered with a conductive layer 3, and the conductive layer 3 on the hole wall can form an integral structure with the conductive layer 3 on other surfaces of the dielectric block 1.

[0069] Among them, the bottom surface of frequency hole 2 (such as the bottom surface of the second hole segment 21) is the tuning point of the resonant cavity.

[0070] The radial dimension of the hole segment refers to the maximum dimension of the hole segment in all directions perpendicular to the depth direction. For example, if the shape of the hole segment is a cylinder, then its radial dimension is the diameter of the bottom surface of the cylinder.

[0071] Reference Figures 1 to 10 In this embodiment of the present disclosure, each frequency hole 2 includes at least a first hole segment 21 and a second hole segment 21 along the depth direction, wherein the second hole segment 21 is "deeper" and the radial dimension of the second hole segment 21 is greater than the radial dimension of the first hole segment 21 (of course, the radial dimension at different positions along the depth direction within each hole segment is equal, otherwise it would be multiple hole segments).

[0072] In other words, the diameter of the "lower section" of each frequency aperture 2 is larger than the diameter of its "upper section", thus each frequency aperture 2 is a "reverse stepped aperture" that is "wider at the bottom and narrower at the top".

[0073] It is also feasible if the frequency hole 2 includes a third hole segment with a different radial size located below the second hole segment 21.

[0074] The dielectric block 1 may also have other known structures such as coupling holes and partitions, and the conductive layer 3 should also cover the walls of these structures, which will not be described in detail here.

[0075] In this embodiment, because the frequency aperture 2 is designed to be wider at the bottom and narrower at the top, the equivalent capacitance of the resonant cavity can be increased, thus lowering the resonant frequency. Therefore, within the same frequency band (especially the low-frequency band, such as 700MHz, 900MHz, etc.), the required height of the resonant cavity (i.e., the dimension of the dielectric block 1 in the depth direction of the frequency aperture 2, for example...) can be reduced. Figure 7 The H dimension in the filter reduces its size and makes it easier to shape, process, design, and debug (because the frequency hole 2 has a small depth), resulting in lower cost.

[0076] In addition, the structure of the frequency aperture 2 described above allows the higher-order modes of the filter to be further away from the operating mode, and the Q value does not decrease significantly compared to products of related technologies (such as products with equal-diameter blind apertures).

[0077] In some embodiments, the medium block 1 includes a first surface and a second surface that are disposed opposite to each other and parallel to each other;

[0078] At least a portion of the frequency aperture 2 is open on the first surface, and the bottom surface of the frequency aperture 2 opening on the first surface is parallel to the first surface.

[0079] Reference Figures 1 to 10 Each medium block 1 may include two parallel surfaces (e.g., the shape of the medium block 1 may be a cube), and at least one of the surfaces is provided with a frequency hole 2 (of course, the frequency hole 2 should extend in a direction perpendicular to the surface).

[0080] In some embodiments, the opening of a portion of the frequency aperture 2 is located on the second surface, and the bottom surface of the frequency aperture 2 opening on the second surface is parallel to the second surface.

[0081] Each frequency aperture 2 opening on the second surface is positioned opposite to a frequency aperture 2 opening on the first surface.

[0082] Reference Figure 2 , Figure 8 As one embodiment of this disclosure, the frequency holes 2 can be arranged in a "paired" manner (of course, the frequency holes 2 arranged in a pair cannot be connected to each other, otherwise they would not be blind holes).

[0083] In some embodiments, the dielectric block 1 includes a first portion 11 made of a first dielectric material and a second portion 12 made of a second dielectric material; the dielectric constant of the first dielectric material is different from the dielectric constant of the second dielectric material.

[0084] The frequency aperture 2 is located in the first part 11, and at least part of the frequency aperture 2 is provided with a second part 12 below along the depth direction.

[0085] Reference Figure 3 , Figure 9 The frequency aperture 2 can be opened in the first part 11 (body part) of the dielectric block 1, while the "below" of the frequency aperture 2 can be the second part 12 (filling part, but also part of the dielectric block) of other dielectric materials with different dielectric constants, thereby appropriately improving the single-cavity unloaded Q value of the filter.

[0086] The specific shape of the second part 12 (filling part) can be varied, such as a cube, cylinder, prism, etc.; moreover, the bottom surface of the frequency hole 2 may also have a first part 11 between it and the second part 12, or the frequency hole 2 may extend all the way to the surface of the second part 12.

[0087] Since the second part 12 is also part of the medium block 1, it is referred to Figure 9 The conductive layer 3 should be located on the surface of the overall structure of the first part 11 and the second part 12, rather than at the interface between the first part 11 and the second part 12.

[0088] In some embodiments, the axis of at least a portion of the first aperture segment 21 of the frequency aperture 2 coincides with the axis of the second aperture segment 21;

[0089] And / or,

[0090] At least part of the axis of the first hole segment 21 of the frequency hole 2 does not coincide with the axis of the second hole segment 21.

[0091] In this embodiment of the disclosure, the two "segments" of a frequency aperture 2 can be referenced. Figures 1 to 3 , Figures 7 to 9 It is "coaxial", or it can be a reference. Figure 4 , Figure 5 , Figure 10 For "different axes".

[0092] In some embodiments, the shape of the first hole segment 21 includes at least one of a cylinder, a cube, and a prism;

[0093] And / or,

[0094] The shape of the second hole segment 21 includes at least one of cylinder, cube, and prism.

[0095] In this embodiment of the disclosure, the shape of each "segment" of the frequency aperture 2 can be referred to Figures 1 to 5 It can take the form of cylinders, cubes, prisms, etc.

[0096] Of course, the specific shape of the hole segment is not limited to this; it can also serve as a reference. Figure 1 The second hole section 21 in the middle Figure 4 The second hole section 21 in the middle Figure 6Other shapes, such as a cube with rounded chamfers, or other polygons, or other "irregular shapes", etc.

[0097] In some embodiments, the shape of at least a portion of the first aperture segment 21 of the frequency aperture 2 is the same as the shape of the second aperture segment 21;

[0098] And / or,

[0099] The shape of the first aperture segment 21 of at least part of the frequency aperture 2 is different from the shape of the second aperture segment 21.

[0100] In this embodiment of the disclosure, the two "segments" of a frequency aperture 2 can be referenced. Figure 2 , Figure 3 , Figure 5 "The same shape", or it could be a reference. Figure 1 , Figure 4 , Figure 6 For "different shapes".

[0101] The term "same shape" only means that the two "segments" of frequency aperture 2 are of the same shape, such as both being cubes or both being cylinders, but it does not mean that the specific dimensions or proportions of the two "segments" are the same (because the radial dimensions of the two "segments" must be different, so the dimensions of the two "segments" must be different).

[0102] Secondly, referring to Figure 11 This disclosure provides a method for fabricating a filter, comprising:

[0103] S201. A preform with the same shape as the dielectric block is formed using powder of dielectric material.

[0104] The dielectric block contains at least one frequency hole; the frequency hole is a blind hole that opens on the surface of the dielectric block. Along the direction of gradually penetrating the frequency hole, each frequency hole includes a first hole segment and a second hole segment in sequence, and the radial dimension of the second hole segment is greater than the radial dimension of the first hole segment.

[0105] S202, Firing preforms to form dielectric blocks made of dielectric material.

[0106] S203, Form a conductive layer covering the surface of the dielectric block.

[0107] The preparation method of this disclosure is used to prepare the above-mentioned preformed blocks.

[0108] In the preparation method of this embodiment, a relatively loose preform is first formed using dielectric material powder (such as 201 ceramic powder) with the same form as the dielectric block (having preformed holes of the same form as the frequency holes). The preform is then fired to harden and shape it, forming a solid dielectric block (which of course has frequency holes). Then, the above conductive layer is formed on the surface of the dielectric block (including the wall surface of the frequency holes), such as by silver plating, copper plating, or other processes.

[0109] Since the frequency hole is in the form of "wider at the bottom and narrower at the top", it is relatively difficult to form the frequency hole in the dielectric block by drilling or other means after the integral dielectric block is formed. Therefore, in this embodiment, a preform with pre-made holes (the same form as the frequency hole) is formed directly by using dielectric material powder (including paste containing powder), and then the preform is formed to obtain a dielectric block with frequency holes.

[0110] In some embodiments, forming a preform with the same shape as the dielectric block using powder of dielectric material (S201) includes:

[0111] S2011. Using injection molding process, a preform of the same shape as the dielectric block is formed from powder of dielectric material.

[0112] As one embodiment of this disclosure, the prefabricated block with pre-set holes can be formed by injection molding.

[0113] It is also feasible to form the prefabricated block by means other than injection molding, or to form the filter as a whole by other means.

[0114] Thirdly, referring to Figure 12 This disclosure provides a communication device, including:

[0115] The filters mentioned above.

[0116] The communication device in this embodiment includes the above-mentioned filter, wherein the communication device may be in the form of a communication base station, and the filter may be a duplexer, a duplex-filter integrated module, etc.

[0117] This disclosure has disclosed exemplary embodiments, and although specific terminology has been used, it is for general illustrative purposes only and should not be construed as limiting. In some instances, it will be apparent to those skilled in the art that features, characteristics, and / or elements described in conjunction with particular embodiments may be used alone, or in combination with features, characteristics, and / or elements described in conjunction with other embodiments, unless otherwise expressly indicated. Therefore, those skilled in the art will understand that various changes in form and detail may be made without departing from the scope of this disclosure as set forth by the appended claims.

Claims

1. A filter comprising: A dielectric block made of dielectric material, wherein the dielectric block has at least one frequency hole; the frequency hole is a blind hole that opens on the surface of the dielectric block, and each frequency hole sequentially includes a first hole segment and a second hole segment along the direction of gradually penetrating the frequency hole, wherein the radial dimension of the second hole segment is larger than the radial dimension of the first hole segment; A conductive layer covering the surface of the dielectric block.

2. The filter according to claim 1, wherein, The medium block includes a first surface and a second surface that are arranged opposite to and parallel to each other; At least a portion of the frequency aperture opens on the first surface, and the bottom surface of the frequency aperture opening on the first surface is parallel to the first surface.

3. The filter according to claim 2, wherein, The opening of a portion of the frequency aperture is located on the second surface, and the bottom surface of the frequency aperture opening on the second surface is parallel to the second surface; Each frequency aperture that opens on the second surface is disposed opposite to a frequency aperture that opens on the first surface.

4. The filter according to claim 1, wherein, The dielectric block includes a first part composed of a first dielectric material and a second part composed of a second dielectric material; the dielectric constant of the first dielectric material is different from the dielectric constant of the second dielectric material. The frequency aperture is located in the first portion, and at least a portion of the frequency aperture is provided below it along the depth direction in the second portion.

5. The filter according to claim 1, wherein, At least a portion of the axis of the first aperture segment of the frequency aperture coincides with the axis of the second aperture segment; And / or, At least a portion of the axis of the first aperture segment of the frequency aperture does not coincide with the axis of the second aperture segment.

6. The filter according to claim 1, wherein, At least a portion of the first aperture segment of the frequency aperture has the same shape as the second aperture segment; And / or, The shape of the first aperture segment of at least a portion of the frequency aperture is different from the shape of the second aperture segment.

7. The filter according to claim 1, wherein, The shape of the first hole segment includes at least one of a cylinder, a cube, and a prism; And / or, The shape of the second hole segment includes at least one of cylinder, cube, and prism.

8. A method for fabricating a filter, comprising: A preform block with the same shape as the dielectric block is formed by the powder of dielectric material; the dielectric block has at least one frequency hole; the frequency hole is a blind hole that opens on the surface of the dielectric block, and each frequency hole includes a first hole segment and a second hole segment in sequence along the direction of gradually penetrating the frequency hole, the radial dimension of the second hole segment is larger than the radial dimension of the first hole segment; The preform is fired to form the dielectric block made of dielectric material; A conductive layer is formed covering the surface of the dielectric block.

9. The preparation method according to claim 8, wherein, The method of forming a preform with the same shape as the dielectric block using dielectric material powder includes: Through injection molding, a preform with the same shape as the dielectric block is formed from powder of dielectric material.

10. A communication device, comprising: The filter according to any one of claims 1 to 7.

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