DIELECTRIC FILTER AND COMMUNICATION DEVICE

Abstract

Embodiments of this application disclose a dielectric filter and a communication device. In one example, the dielectric filter includes: a first dielectric block and a second dielectric block that are stacked up, where a first surface of the first dielectric block is opposite to a second surface of the second dielectric block; a first blind hole, a first through hole, and two or more resonance through holes whose openings are located on the first surface of the first dielectric block, and a second through hole whose opening is located on the second surface of the second dielectric block. A metal layer on the first surface of the first dielectric block is connected to a metal layer on the second surface of the second dielectric block.

Claims

1. A dielectric filter, comprising: a first dielectric block and a second dielectric block that are stacked up, wherein the first dielectric block and the second dielectric block respectively comprise a first surface and a second surface that are opposite to each other, and the first surface of the first dielectric block is opposite to the second surface of the second dielectric block; a first blind hole, a first through hole, and two or more resonance through holes whose openings are located on the first surface of the first dielectric block; and a second through hole whose opening is located on the second surface of the second dielectric block, wherein metal layers are disposed on an inner wall of the first blind hole, an inner wall of the first through hole, an inner wall of the resonance through holes, an inner wall of the second through hole, the first surface of the first dielectric block, and the second surface of the second dielectric block; and the metal layer on the first surface of the first dielectric block is opposite to the metal layer on the second surface of the second dielectric block, the metal layer on the first surface of the first dielectric block is connected to the metal layer on the second surface of the second dielectric block, the metal layer on the inner wall of the first through hole is connected to the metal layer on the first surface of the first dielectric block, the metal layer on the inner wall of the first blind hole is connected to the metal layer on the first surface of the first dielectric block, and the metal layer on the inner wall of the second through hole is connected to the metal layer on the second surface of the second dielectric block.

2. The dielectric filter according to claim 1, wherein the metal layers are made of silver.

3. The dielectric filter according to claim 1, wherein the metal layers are formed by using a process of electroplating, chemical plating, sputtering, or ion plating.

4. The dielectric filter according to claim 1, wherein the metal layer on the first surface of the first dielectric block comprises a first metal layer located around the first blind hole, and a third metal layer located around the resonance through holes, the metal layer on the inner wall of the first through hole and the metal layer on the inner wall of the first blind hole are connected to the first metal layer, the metal layer on the inner wall of the resonance through hole is connected to the third metal layer, and the third metal layer is separated from the first metal layer.

5. The dielectric filter according to claim 4, wherein the metal layer on the second surface of the second dielectric block comprises a second metal layer located around the second through hole, and a fourth metal layer opposite to the third metal layer, the second metal layer is connected to the first metal layer, the metal layer on the inner wall of the second through hole is connected to the second metal layer, and the fourth metal layer is separated from the second metal layer.

6. The dielectric filter according to claim 1, wherein projections of both the first through hole and the second through hole on the first surface of the first dielectric block are located in the first blind hole.

7. The dielectric filter according to claim 1, wherein a resonance unit is formed by each resonance through hole and a surrounding body, and a position in which the first blind hole is located is connected to two resonance units.

8. The dielectric filter according to claim 1, wherein the first dielectric block and the second dielectric block are made of a ceramic material.

9. The dielectric filter according to claim 1, wherein a depth of the first through hole is greater than a depth of the second through hole.

10. The dielectric filter according to claim 1 wherein the metal layers are disposed on outer surfaces of the first dielectric block and the second dielectric block.

11. A communication device, comprising a dielectric filter, wherein the dielectric filter comprises: a first dielectric block and a second dielectric block that are stacked up, wherein the first dielectric block and the second dielectric block respectively comprise a first surface and a second surface that are opposite to each other, and the first surface of the first dielectric block is opposite to the second surface of the second dielectric block; a first blind hole, a first through hole, and two or more resonance through holes whose openings are located on the first surface of the first dielectric block; and a second through hole whose opening is located on the second surface of the second dielectric block, wherein metal layers are disposed on an inner wall of the first blind hole, an inner wall of the first through hole, an inner wall of the resonance through holes, an inner wall of the second through hole, the first surface of the first dielectric block, and the second surface of the second dielectric block; and the metal layer on the first surface of the first dielectric block is opposite to the metal layer on the second surface of the second dielectric block, the metal layer on the first surface of the first dielectric block is connected to the metal layer on the second surface of the second dielectric block, the metal layer on the inner wall of the first through hole is connected to the metal layer on the first surface of the first dielectric block, the metal layer on the inner wall of the first blind hole is connected to the metal layer on the first surface of the first dielectric block, and the metal layer on the inner wall of the second through hole is connected to the metal layer on the second surface of the second dielectric block.

12. The communication device according to claim 11, wherein the metal layers are made of silver.

13. The communication device according to claim 11, wherein the metal layers are formed by using a process of electroplating, chemical plating, sputtering, or ion plating.

14. The communication device according to claim 11, wherein the metal layer on the first surface of the first dielectric block comprises a first metal layer located around the first blind hole, and a third metal layer located around the resonance through holes, the metal layer on the inner wall of the first through hole and the metal layer on the inner wall of the first blind hole are connected to the first metal layer, the metal layer on the inner wall of the resonance through hole is connected to the third metal layer, and the third metal layer is separated from the first metal layer.

15. The communication device according to claim 14, wherein the metal layer on the second surface of the second dielectric block comprises a second metal layer located around the second through hole, and a fourth metal layer opposite to the third metal layer, the second metal layer is connected to the first metal layer, the metal layer on the inner wall of the second through hole is connected to the second metal layer, and the fourth metal layer is separated from the second metal layer.

16. The communication device according to claim 11, wherein projections of both the first through hole and the second through hole on the first surface of the first dielectric block are located in the first blind hole.

17. The communication device according to claim 11, wherein a resonance unit is formed by each resonance through hole and a surrounding body, and a position in which the first blind hole is located is connected to two resonance units.

18. The communication device according to claim 11, wherein the first dielectric block and the second dielectric block are made of a ceramic material.

19. The communication device according to claim 11, wherein a depth of the first through hole is greater than a depth of the second through hole.

20. The communication device according to claim 11 wherein the metal layers are disposed on outer surfaces of the first dielectric block and the second dielectric block.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0024] FIG. 1 is a schematic diagram of a structure of a TEM dielectric filter according to the conventional technology;

[0025] FIG. 2 is a schematic diagram of a structure of a coupling structure in FIG. 1;

[0026] FIG. 3 is a schematic diagram of a structure of another TEM dielectric filter according to the conventional technology;

[0027] FIG. 4 is a schematic diagram of a structure of a coupling structure in FIG. 3;

[0028] FIG. 5 is a schematic diagram of a structure of a dielectric filter according to an embodiment of this application;

[0029] FIG. 6 is a schematic diagram of a structure of a first dielectric block in FIG. 5;

[0030] FIG. 7 is a top view of the first dielectric block in FIG. 6;

[0031] FIG. 8 is a schematic diagram of a structure of a second dielectric block in FIG. 5;

[0032] FIG. 9 is a bottom view of the second dielectric block in FIG. 8;

[0033] FIG. 10 is a schematic diagram of a structure of a coupling structure in FIG. 5;

[0034] FIG. 11 is a schematic diagram of a structure of another dielectric filter;

[0035] FIG. 12 is a top view of the dielectric filter in FIG. 11;

[0036] FIG. 13 is a schematic diagram of a structure of another dielectric filter;

[0037] FIG. 14 is a top view of the dielectric filter in FIG. 13;

[0038] FIG. 15 is a top view of another dielectric filter;

[0039] FIG. 16 is a simulation curve graph of a dielectric filter according to an embodiment of this application; and

[0040] FIG. 17 is a locally enlarged diagram of the simulation curve graph in FIG. 16.

DESCRIPTION OF EMBODIMENTS

[0041] To make the objectives, technical solutions, and advantages of this application clearer, the following further describes this application in detail with reference to the accompanying drawings.

[0042] The terms “first” and “second” mentioned below are merely intended for a purpose of description, and shall not be understood as an indication or implication of relative importance or implicit indication of a quantity of indicated technical features. Therefore, a feature limited by “first” or “second” may explicitly or implicitly include one or more of the features. In the descriptions of this application, unless otherwise specified, “a plurality of” means two or more.

[0043] In addition, in this application, orientation terms such as “above” and “under” are defined relative to orientations of components shown in the accompanying drawings. It should be understood that these orientation terms are relative concepts, are used for description and clarification of the components, and may be correspondingly changed based on changes of the orientations of the components in the accompanying drawings.

Noun Explanations

[0044] A transverse electromagnetic mode (TEM) is a waveguide mode in which there are no electric field or magnetic field components in a transmission direction of an electromagnetic wave. The transverse electromagnetic mode is an ideal state. Actually, the transverse electromagnetic mode is usually a quasi-TEM mode. To be specific, electric field and magnetic field components in the transmission direction of the electromagnetic wave are far less than a component in a direction perpendicular to the transmission direction.

[0045] A dielectric filter is a filter designed and manufactured by using characteristics such as a low loss, a high permittivity, a small frequency temperature coefficient, a small thermal expansion coefficient, and a tolerable high power of a dielectric (for example, ceramic) material, and may be formed by trapezoidal lines that are formed by several long resonators connected in series or connected in parallel in a longitudinal direction.

[0046] An existing dielectric filter performs resonance by processing a blind hole on a dielectric body to form a resonance through hole, is greatly controllable in depth of the blind hole, has large frequency fluctuation, and has a poor consistency. In addition, a negative coupling structure of the existing dielectric filter is difficult implement, because the negative coupling structure is single and is not suitable for large-scale production.

[0047] FIG. 5 is a schematic diagram of a structure of a dielectric filter according to an embodiment of this application. FIG. 6 is a schematic diagram of a structure of a first dielectric block in FIG. 5. FIG. 7 is a top view of the first dielectric block in FIG. 6. FIG. 8 is a schematic diagram of a structure of a second dielectric block in FIG. 5. FIG. 9 is a bottom view of the second dielectric block in FIG. 8. FIG. 10 is a schematic diagram of a structure of a coupling structure in FIG. 5. As shown in FIG. 5, FIG. 6, FIG. 7, FIG. 8, and FIG. 9, the dielectric filter includes the first dielectric block 100 and the second dielectric block 200 that are stacked up.

[0048] The first dielectric block 100 and the second dielectric block 200 respectively include a first surface and a second surface that are opposite to each other, that is, the first surface of the first dielectric block 100 is opposite to the second surface of the second dielectric block 200.

[0049] Specific structures of the first dielectric block 100 and the second dielectric block 200 are not limited in this embodiment of this application. For example, both the first dielectric block 100 and the second dielectric block 200 are made of a ceramic material.

[0050] Resonance through holes 101 are disposed on the first dielectric block 100, and a quantity of the resonance through holes 101 is two or more than two. In an implementation of this application, for example, there are two resonance through holes 101: a first resonance through hole and a second resonance through hole. A resonance unit is formed by each resonance through hole 101 and a surrounding body. A first resonance unit is formed by the first resonance through hole and the surrounding body, and a second resonance unit is formed by the second resonance through hole and the surrounding bod.

[0051] The coupling structure includes a first blind hole 104 and a first through hole 103 that are disposed in the first dielectric block 100, and a second through hole 201 disposed in the second dielectric block.

[0052] For example, an opening of the first blind hole 104 and an opening of the first through hole 103 are located on the first surface of the first dielectric block 100.

[0053] The second through hole 201 is disposed in the second dielectric block 200, and an opening of the second through hole 201 is located on the second surface of the second dielectric block 200.

[0054] Metal layers are disposed on an inner wall of the first blind hole 104, an inner wall of the first through hole 103, an inner wall of the second through hole 201, the first surface of the first dielectric block 100, and the second surface of the second dielectric block 200.

[0055] The metal layer on the inner wall of the first through hole 103 and the metal layer on the inner wall of the first blind hole 104 are connected to the metal layer on the first surface of the first dielectric block 100, and the metal layer on the inner wall of the second through hole 201 is connected to the metal layer on the second surface of the second dielectric block 200.

[0056] The metal layer on the first surface of the first dielectric block 100 is connected to the metal layer on the second surface of the second dielectric block 200, and after the first dielectric block and the second dielectric block are combined together, a closed capacitive coupling structure with a small electromagnetic leakage and a high power capacity is formed.

[0057] When the dielectric filter operates, an electromagnetic wave in a quasi-TEM mode in the first resonance through hole generates an induced current on the first through hole 103, and the induced current moves from the first blind hole 104 to the second through hole 201 to form a loop. The induced current on the surface of the first blind hole 104 excites generation of an electromagnetic wave in the quasi-TEM mode in the second resonance through hole, thereby implementing capacitive coupling of electromagnetic energy.

[0058] The dielectric filter provided in this embodiment of this application has a structure in which the dielectric blocks are stacked up, so that the dielectric filter has a smaller size, to facilitate miniaturization of the dielectric filter. In addition, capacitive coupling between the resonance through holes is implemented after a coupling structure is disposed in the dielectric block. Compared with the quasi-TEM mode dielectric filter using a stub in FIG. 1, the dielectric filter using the coupling structure has a small electromagnetic leakage and a greatly improved power capacity, and avoids deterioration of low-end outband suppression performance of the filter.

[0059] A material of the metal layers is not limited in this embodiment of this application. In an implementation of this application, for example, the metal layers of the inner wall of the first blind hole 104, the inner wall of the first through hole 103, the inner wall of the second through hole 201, the first surface of the first dielectric block 100, and the second surface of the second dielectric block 200 are made of silver. The metal layers may be formed on the inner wall of the first blind hole 104, the inner wall of the first through hole 103, the inner wall of the second through hole 201, the first surface of the first dielectric block 100, and the second surface of the second dielectric block 200 by using a process, for example, electroplating, chemical plating, sputtering, or ion plating.

[0060] A range of the metal layers on the first surface of the first dielectric block 100 and the second surface of the second dielectric block 200 is not limited in this embodiment of this application. In an implementation of this application, as shown in FIG. 5, the metal layer on the first surface of the first dielectric block 100 includes a first metal layer 1041 disposed around an opening that is of the first blind hole 104 and that is on the first surface of the first dielectric block 100.

[0061] The first metal layer 1041 is disposed around the first blind hole 104, and the metal layer on the inner wall of the first blind hole 104 and the metal layer on the inner wall of the first through hole 103 are connected to the first metal layer 1041.

[0062] Still with reference to FIG. 5, the metal layer on the second surface of the second dielectric block 200 includes a second metal layer 2011 that is located around the second through hole 201 and that is opposite to the first metal layer 1041.

[0063] In an implementation of this application, the second metal layer 2011 is opposite to the first metal layer 1041. In addition, the second metal layer 2011 covers the first blind hole 104 and the first metal layer 1041, and the metal layer on the inner wall of the second through hole 201 is connected to the second metal layer 2011.

[0064] In addition, still with reference to FIG. 5, the metal layer on the first surface of the first dielectric block 100 further includes a third metal layer 1011 disposed around openings that are of the resonance through holes 101 and that are on the first surface of the first dielectric layer, and the third metal layer 1011 is separated from the first metal layer 1041.

[0065] The third metal layer 1011 is disposed around the openings that are of the resonance through holes 101 and that are on the first surface of the first dielectric block 100. Inner walls of the resonance through holes 101 are covered with the metal layers, and the metal layers of the inner walls of the resonance through holes 101 are connected to the third metal layer 1011.

[0066] A position in which the first blind hole 104 is located is connected to the two resonance units, and the third metal layer 1011 is separated from the first metal layer 1041, so that a short circuit between the resonance through holes 101 or between the resonance through holes 101 and the coupling structure 300 is avoided.

[0067] The metal layer on the second surface of the second dielectric block 200 further includes a fourth metal layer 202. The fourth metal layer 202 is opposite to the third metal layer 1011, and a shape and a size of the fourth metal layer 202 are the same as those of the third metal layer 1011. The third metal layer 1011 is connected to the fourth metal layer 202.

[0068] A position in which the first blind hole 104 is located is connected to the two resonance units, and the fourth metal layer 202 is separated from the second metal layer 2011, so that the short circuit between the resonance through holes 101 or between the resonance through holes 101 and the coupling structure 300 is avoided.

[0069] Shapes of the first blind hole 104, the first through hole 103, and the second through hole 201 are not limited in this embodiment of this application. As shown in FIG. 5 and FIG. 10, the first blind hole 104, the first through hole 103, and the second through hole 201 in the coupling structure 300 may be parallel to the resonance through holes 101, thereby facilitating coupling between the coupling structure 300 and the resonance through holes 101. In addition, the first blind hole 104, the first through hole 103, and the second through hole 201 may have a plurality of shapes of cross section. For example, the first blind hole 104, the first through hole 103, and the second through hole 201 may be circular holes, flat holes, or elliptical holes. The shapes and sizes of the first blind hole 104, the first through hole 103, and the second through hole 201 may be set according to an actual requirement.

[0070] In an implementation of this application, as shown in FIG. 5, projections of the first through hole 103 and the second through hole 201 on the first surface of the first dielectric block 100 are located in the first blind hole 104, and are tangent to an inner side of the first blind hole 104. Therefore, the metal layer on the inner wall of the first blind hole 104 and the metal layer on the inner wall of the first through hole 103 may be connected to the first metal layer 1041 that is around the first blind hole 104, and the metal layer on the inner wall of the second through hole 201 may be connected to the second metal layer 2011.

[0071] Still with reference to FIG. 5, the first through hole 103 is located in the first blind hole 104, and an opening of the second through hole 201 on the second surface of the second dielectric block overlaps the opening of the first blind hole 104. As shown in FIG. 5, the opening that is of the first blind hole 104 and that is on the first surface of the first dielectric block has a strip structure. The first through hole 103 and the second through hole 201 are disposed in a length direction of the first blind hole 104, and the projections of the first through hole 103 and the second through hole 201 on the first surface of the first dielectric block are respectively located at two ends of the first blind hole 104. Diameters of the first through hole 103 and the second through hole 201 are equal to a width of the first blind hole 104, and a length of the first blind hole 104 is greater than or equal to a sum of the diameters of the first through hole 103 and the second through hole 201.

[0072] In this embodiment of this application, different the coupling amounts may be implemented by changing a spacing between the first through hole 103 and the second through hole and the depth of the first blind hole 104. For example, a larger spacing between the first through hole 103 and the second through hole 201 leads to a larger coupling amount, and a deeper depth of the first blind hole 104 leads to a larger coupling amount. The spacing between the first through hole 103 and the second through hole and the depth of the first blind hole 104 may be set based on an actual required coupling amount. Therefore, the first blind hole is a coupling hole, and the coupling hole is used for coupling between adjacent resonance units or cross coupling between non-adjacent resonance units. The coupling amount between the resonance through holes may be changed by changing a size and a position of the coupling hole, so that the coupling amount between two adjacent or non-adjacent resonance through holes may be increased without changing the size of the dielectric filter, and the capacitive coupling between the two resonance units may be enhanced. In addition, the coupling amount between the resonance through holes may be changed by changing a distance between the first through hole and the second through hole, so that the coupling amount between the two adjacent resonance through holes may be increased without changing the size of the dielectric filter, and the capacitive coupling between the two resonance units may be enhanced.

[0073] The thickness of the first dielectric block 100 is greater than that of the second dielectric block 200. When the thickness of the second dielectric block 200 is reduced, resonance performance between the resonance through holes 101 may be improved, and sizes of the resonance through holes 101 may be correspondingly reduced, to facilitate the miniaturization of the dielectric filter.

[0074] In another implementation of this application, the metal layers are disposed on outer surfaces of the first dielectric block 100 and the second dielectric block 200. Therefore, the metal layers may effectively shield a signal, to prevent signal energy leakage and external signal interference, thereby improving a capability of suppressing background noise. Therefore, the dielectric filter in this application may prevent signal leakage and implement the miniaturization of the filter.

[0075] The foregoing coupling structure 300 may be used in a cross coupling structure. In an implementation of this application, as shown in FIG. 11 and FIG. 12, the coupling structure 300 may be disposed in a cascaded triplet (CT) type cross coupling structure.

[0076] In another implementation of this application, as shown in FIG. 13 and FIG. 14, the coupling structure 300 may be disposed in a cascaded quadruplet (CQ) type cross coupling structure or a BOX type cross coupling structure.

[0077] In another implementation of this application, as shown in FIG. 15, the coupling structure 300 may alternatively be used in a cross coupling structure of a combination of a CT type and a Box type.

[0078] The dielectric filter shown in FIG. 15 includes eight resonance through holes. Four resonance through holes on the left are arranged in the CT type, and four resonance through holes on the right are arranged in the Box type. One coupling structure 300 is disposed between a lower left corner and an upper right corner of the resonance through holes arranged in the CT type, and one coupling structure 300 is disposed between a lower left corner and a lower right corner of the resonance through holes arranged in the BOX type. The coupling structure 300 may be configured to adjust a coupling amount and a resonance frequency.

[0079] An outband suppression experiment is performed on the dielectric filter shown in FIG. 15. The following describes a filtering effect of the dielectric filter in this embodiment of this application with reference to experimental data.

[0080] As shown in FIG. 16 and FIG. 17, the coupling structure 300 used in the cross coupling structure of the combination of the CT type and the Box type may implement two transmission zeros. A line 1 is a curve graph in which a reflection factor changes with a frequency, and a line 2 is a curve graph in which an insertion loss changes with the frequency. The dielectric filter provided in this embodiment of this application introduces two low-end transmission zeros by using cross coupling, thereby effectively enhancing a capability of the dielectric filter to suppress an out-of-band signal.

[0081] Therefore, the coupling structure 300 can implement both strong coupling and weak coupling, and is applicable to common cross coupling structures such as a CT type cross coupling structure and a CQ type cross coupling structure.

[0082] In addition, this application further provides a communication device. The communication device includes the dielectric filter disclosed in embodiments of the present invention.

[0083] The communication device provided in this embodiment of this application uses the dielectric filter disclosed in embodiments of the present invention, so that the miniaturization of the filter can be implemented, and an overall size of the communication device may be smaller.

[0084] It should be noted that the communication device provided in this embodiment of this application may be a transceiver, a base station, a microwave communication device, a Wi-Fi communication device, or the like, or may be terminal devices of various types.

[0085] The foregoing descriptions are merely specific implementations of this application, but are not intended to limit the protection scope of this application. Any variation or replacement within the technical scope disclosed in this application shall fall within the protection scope of this application. Therefore, the protection scope of this application shall be subject to the protection scope of the claims.