Filters and communication base stations

Abstract

The present invention relates to a filter and a communication base station, comprising a body made of dielectric material and at least one pair of dielectric resonators arranged on the surface of the body, two coupling slots are arranged between the first dielectric resonator hole and the second dielectric resonator hole of the pair of dielectric resonators, the first dielectric resonator hole and the second dielectric resonator hole are located on the same surface of the body; the first coupling slot is in the shape of a long strip, located on the same surface as the dielectric resonator hole, and connected to the first dielectric resonator hole; the cross section of the second coupling slot is in the shape of a "human", located on the opposite surface of the dielectric resonator hole; the first coupling slot and the second coupling slot are partially connected, and capacitive coupling is achieved between the first dielectric resonator and the second dielectric resonator through the coupling slot. The present invention has the technical effect of being able to simply and flexibly adjust the coupling bandwidth, not exciting parasitic resonance, and making the far-end out-of-band suppression extremely good and facilitating mass production.

Description

Technical Field

[0001] The invention relates to a communication device, in particular to a dielectric filter cross-coupling technology. Background Art

[0002] With the construction of 5G communication systems, the requirements for the integration of its equipment are getting higher and higher. The miniaturization and lightweight of microwave filters are the future application trends. Dielectric waveguides have the advantages of high Q value and small temperature drift, and are a good solution for filter miniaturization.

[0003] Dielectric filters usually need to introduce capacitive cross-coupling to achieve strong suppression of transmission zeros. To achieve low-end transmission zeros and symmetrical transmission zeros, a capacitive coupling structure needs to be introduced (a single high-end transmission zero sometimes does not require a capacitive coupling structure). Traditional dielectric waveguide filters usually use the following forms to achieve capacitive coupling: 1. The frequency-variable coupling structure is simple, but it will introduce additional resonance points. 2. The capacitive coupling structure derived directly from the flying rod structure of the traditional cavity filter is relatively complex and increases the parts and processes of the product.

[0004] CN 108598635 A discloses a dielectric filter, which realizes capacitive coupling through a deep blind hole with a depth exceeding half of the body. This solution simplifies the manufacturing process of realizing the capacitive coupling structure, but has the disadvantage of generating harmonics at the low end of the filter passband, thereby reducing the suppression ability of the filter.

[0005] CN210468050U discloses a dielectric filter coupling structure for realizing symmetrical transmission zero points, which includes two blind hole resonators located on the same surface, a first blind slot located below the body, and a second blind slot located above the body. The first blind slot extends toward one blind hole resonator, and the second blind slot extends toward the other blind hole resonator. Both the first blind slot and the second blind slot are connected to a through hole passing through the body. This solution will not generate additional resonance outside the filter passband, and can improve the out-of-band suppression capability of the filter. However, in this solution, the two resonators are located on the same surface, the magnetic field coupling is strong, the electric field coupling is weak, and the application scenario is narrow. Summary of the invention

[0006] The technical problem to be solved by the present invention is to propose a filter which can avoid parasitic resonance at the low end of the filter resonant frequency and improve the far-end suppression of the filter at the low end of the frequency in view of the above-mentioned defects of the prior art.

[0007] The technical solution adopted by the present invention to solve the technical problem is:

[0008] Provided is a filter, comprising a body made of dielectric material and at least one pair of dielectric resonators arranged on the surface of the body, wherein two coupling slots are arranged between a first dielectric resonator hole and a second dielectric resonator hole of the pair of dielectric resonators, wherein the first dielectric resonator hole and the second dielectric resonator hole are located on the same surface of the body; the first coupling slot is in the shape of an elongated strip, is located on the same surface as the dielectric resonator hole, and is connected to the first dielectric resonator hole; the cross section of the second coupling slot comprises an arc-shaped portion, and is located on the opposite surface of the dielectric resonator hole; the first coupling slot and the second coupling slot are partially connected, and capacitive coupling is achieved between the first dielectric resonator and the second dielectric resonator through the coupling slot.

[0009] Further:

[0010] A head extends from the back of the arc-shaped portion of the cross section of the second coupling groove so that the cross section of the second coupling groove is in a "herringbone" shape.

[0011] The herringbone-shaped head of the second coupling groove is connected to the first coupling groove, and the arc-shaped portion extends toward the opposite side of the second dielectric resonator hole.

[0012] The communicating portion of the first coupling slot and the second coupling slot is located at the center of the body.

[0013] The portion where the first coupling slot and the second coupling slot communicate is arranged at a position deviating from the center of the body, and the coupling amount is adjusted by adjusting at least one of the following parameters: coupling slot height, coupling slot width, coupling window size or distance between dielectric resonators.

[0014] The portion where the first coupling slot and the second coupling slot communicate is a cylinder, an elliptical cylinder or a prism.

[0015] The second coupling slot and / or the first coupling slot is / are in a stepped shape.

[0016] Provided is a filter, comprising a body made of dielectric material and a dielectric resonator arranged on the body, wherein four dielectric resonators are provided and respectively located at four corners of a quadrilateral, wherein a capacitive coupling structure is provided between a pair of adjacent dielectric resonators; two coupling slots are provided between a first dielectric resonator hole and a second dielectric resonator hole of the pair of dielectric resonators, wherein the first dielectric resonator hole and the second dielectric resonator hole are located on the same surface of the body; the first coupling slot is in the shape of a long strip, is located on the same surface as the dielectric resonator hole, and is connected to the first dielectric resonator hole; the cross section of the second coupling slot is in the shape of a human, and is located on the opposite surface of the dielectric resonator hole; the first coupling slot and the second coupling slot are partially connected, and capacitive coupling is achieved between the first dielectric resonator and the second dielectric resonator through the coupling slot.

[0017] On the surface of the main body opposite to the dielectric resonator hole, a debugging blind hole for assisting fine tuning of the dielectric resonator frequency is coaxially arranged with the dielectric resonator hole.

[0018] The debugging blind hole is circular, polygonal or elliptical, and a surface portion of the debugging blind hole is not covered by a conductive layer.

[0019] A communication base station is provided, comprising any filter as described above.

[0020] Compared with the existing capacitive coupling structure, the capacitive coupling structure of the filter and the communication base station of the present invention has the following beneficial effects: more electric fields can be diverted from one dielectric resonator to another resonator, thereby enhancing the capacitive coupling between the resonators. Therefore, while maintaining the same coupling strength, the present invention can increase the distance between the coupling slot and the resonator, thereby facilitating the processing and forming of the dielectric. In addition, without introducing additional parts and processes, the coupling bandwidth can be simply and flexibly adjusted, and parasitic resonance will not be excited to achieve excellent far-end out-of-band suppression, thereby ensuring product performance and design flexibility, reducing production difficulty, and facilitating mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the three-dimensional structure of an embodiment of the filter of the present invention;

[0022] Figure 2 It is a schematic diagram of the upper surface structure of an embodiment of the filter of the present invention;

[0023] Figure 3 It is a schematic diagram of the longitudinal section structure of an embodiment of the filter of the present invention;

[0024] Figure 4 is a schematic diagram of the three-dimensional structure of another embodiment of the filter of the present invention;

[0025] Figure 5 yes Figure 4 Schematic diagram of the longitudinal section structure;

[0026] Figure 6 is a schematic diagram of the three-dimensional structure of another embodiment of the filter of the present invention;

[0027] Figure 7 yes Figure 6 Schematic diagram of the upper surface structure;

[0028] Figure 8 yes Figure 6 Schematic diagram of the longitudinal section structure;

[0029] Fig. 9 It is a three-dimensional structural schematic diagram of an embodiment of a filter with 4 cavities and 2 transmission zero points according to the present invention;

[0030] Fig.10 It is a schematic diagram of the upper surface structure of an embodiment of a filter with 4 cavities and 2 transmission zero points according to the present invention;

[0031] Fig.11 yes Fig.10 Schematic diagram of the cross-sectional structure;

[0032] Fig.12 It is a topological structure diagram of capacitive coupling and inductive coupling of an embodiment of a filter with 4 cavities and 2 transmission zero points of the present invention;

[0033] Fig.13 is a passband near-end frequency response curve diagram of a filter embodiment of the present invention;

[0034] Fig.14 4 is a passband far-end frequency response curve diagram of the filter embodiment of the present invention. DETAILED DESCRIPTION

[0035] Now, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0036] A filter such as Figures 1 to 5 As shown, it includes a body 10 made of dielectric material and at least one pair of dielectric resonators arranged on the surface of the body 10, a coupling window 16 and two coupling slots are arranged between the first dielectric resonator hole 11 and the second dielectric resonator hole 12 of the pair of dielectric resonators, the first dielectric resonator hole 11 and the second dielectric resonator hole 12 are located on the same surface of the body, and the first dielectric resonator hole 11 and the second dielectric resonator hole 12 are both blind holes. The first coupling slot 13 of the two coupling slots is in the shape of a long strip, located on the same surface as the two dielectric resonator holes, and connected to the first dielectric resonator hole 11. The cross section of the second coupling slot 14 is in the shape of an arc, and the opposite surface of the dielectric resonator hole located on the body is not connected to the two dielectric resonator holes. The first coupling slot 13 and the second coupling slot 14 are partially connected, and capacitive coupling is achieved between the first dielectric resonator and the second dielectric resonator through the coupling slot.

[0037] In some embodiments, such as Figures 6 to 8 As shown, a head extends from the back of the arc-shaped portion of the cross section of the second coupling slot 14, so that the cross section of the second coupling slot is in a "herringbone" shape. The herringbone-shaped head of the second coupling slot 14 is connected to the first coupling slot 13, and the arc-shaped portion outside the herringbone-shaped head extends around the second dielectric resonator hole 12, so that the arc-shaped portion of the second coupling slot 14 is symmetrically arranged relative to the herringbone-shaped head portion. The advantage of the herringbone shape of the second coupling slot 14 is that more electric fields can be diverted from one dielectric resonator to another resonator, thereby enhancing the capacitive coupling between the resonators. Therefore, while maintaining the same coupling strength, the distance between the coupling slot and the resonator can be increased, thereby facilitating the processing and molding of the dielectric.

[0038] In some embodiments, Figures 6 to 8As shown, the second coupling slot 14 is stepped, and the stepped second coupling slot 14 extends from the connection point of the two coupling slots toward the second dielectric resonator hole 12, forming a step surrounding the second dielectric resonator hole 12 (i.e., the arc-shaped portion of the above cross section) and another step extending to the bottom of the second dielectric resonator hole 12.

[0039] It is understandable that in another embodiment, the first coupling slot 13 may be configured as a step, or both the first coupling slot 13 and the second coupling slot 14 may be configured as a step. The above-mentioned step-shaped coupling slot expands the area of ​​the coupling slot and correspondingly increases the coupling strength.

[0040] like Figures 1 to 3 As shown, the first dielectric resonator hole 11, the second dielectric resonator hole 12 and the first coupling slot 13 are arranged on the upper surface of the body, and the second coupling slot 14 is arranged on the lower surface of the body. Figure 4 and Figure 5 As shown, the first dielectric resonator hole 11, the second dielectric resonator hole 12 and the first coupling slot 13 are arranged on the lower surface of the body, and the second coupling slot 14 is arranged on the upper surface of the body.

[0041] The surface of the dielectric filter body is covered with a metallization layer. The strength of this capacitive coupling is controlled by the relative position of the two dielectric resonators, the distance between the coupling slot and the dielectric resonator, and the size of the coupling slot and the coupling window.

[0042] In actual products, the strength of capacitive coupling can be adjusted by removing the metallization layer, which can be removed by grinding the metallization layer of the coupling groove. The resonant frequency of the two resonators can be adjusted by removing the metallization layer of the resonator holes. In addition, blind holes can be set on the other side of the two resonator holes to adjust the resonator frequency and reduce the depth of the resonator holes to facilitate the removal of the metallization layer.

[0043] Compared with the traditional capacitive coupling structure, the capacitive coupling structure of the above-mentioned dielectric filter can simply and flexibly adjust the coupling bandwidth without introducing additional parts and processes, and will not excite parasitic resonance, resulting in excellent far-end out-of-band suppression, thereby ensuring product performance and design flexibility, reducing production difficulty, and facilitating mass production.

[0044] The connecting portion of the first coupling slot 13 and the second coupling slot 14 is located at the center of the body, and the connecting portion is also set at a position deviated from the center of the body. When deviated from the center position, the coupling amount is adjusted by adjusting at least one of the following parameters: coupling slot height, coupling slot width, coupling window size or distance between dielectric resonators.

[0045] The filter can be applied in a wireless communication base station.

[0046] The following is a detailed description of the technical solution of the present invention using a 4-cavity 2-transmission zero dielectric filter.

[0047] like Figures 9 to 11 As shown, the entire outer layer of the body 10 of the filter in this embodiment is silver-plated, and four dielectric resonators are arranged on the body. Coupling windows are arranged between two of the dielectric resonators, and capacitive coupling structures and inductive coupling structures are arranged in the corresponding open coupling windows. The capacitive coupling structure of this embodiment is arranged between the dielectric resonator 2 and the dielectric resonator 3, and the dielectric resonator 2 and the dielectric resonator 3 are both located on the lower surface of the body. The capacitive coupling structure includes a first coupling groove 6 located on the lower surface of the body and a second coupling groove 7 located on the upper surface. The first coupling groove 6 is a long strip, and the second coupling groove 7 is a herringbone shape. The first coupling groove and the second coupling groove are connected, and the connected part can be similar to a cylinder, an elliptical column or a prism.

[0048] In this embodiment, except for the capacitive coupling between dielectric resonator 2 and dielectric resonator 3, all other couplings are inductive couplings, which are realized through the dielectric coupling window between the two resonators. The debugging blind hole 5 of dielectric resonator 1, dielectric resonator 2 and dielectric resonator 4 is located on the upper surface of the body. The debugging blind hole 5 is a shallow hole used to fine-tune the frequency of the resonator. The frequency of the resonator is adjusted by removing the metallization layer on the surface of the dielectric resonator, and the coupling between the resonators is adjusted by removing the metallization layer of the coupling window and the coupling slot structure. The debugging hole in this technical solution can be a circular, polygonal, elliptical or other special-shaped structure.

[0049] The topological structure of the dielectric filter in this embodiment is as follows Fig.12 As shown, a total of 2 transmission zero points are realized, thereby achieving the near-end strong suppression index requirement, such as Fig.13 shown. Fig.14 The far-end suppression and parasitic resonance of the filter are demonstrated. Since the input ports of the filter of the present invention are close to each other, the coupling between the two ports causes the filter to generate an additional pair of transmission zeros, further enhancing the filter's out-of-band suppression. In addition, the coupling structure shown in the present invention does not produce parasitic resonance at the low end of the filter passband, and the far-end suppression at the low end of the passband is good. The coupling structure will produce parasitic resonance at the high end of the passband, and the example shows that it is around 4.5 GHz. The parasitic resonance is close to the secondary resonance frequency of the resonator and is not effectively excited, so that the high end of the filter passband has very good far-end suppression.

[0050] The coupling structure of the technical solution is simple to implement, easy to process, and convenient for mass production. The filter using the present invention is not limited to the order, number of transmission zeros, and topological structure of the example. The resonator hole is not limited to a single surface or an upper surface, and can be all single-sided, partially double-sided, and all double-sided.

[0051] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. For those skilled in the art, the technical solutions described in the above embodiments can be modified, or some of the technical features therein can be replaced by equivalents; and these modifications and replacements should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. A filter comprising a body made of a dielectric material and at least one pair of dielectric resonators arranged on the surface of the body, wherein two coupling slots are arranged between a first dielectric resonator hole and a second dielectric resonator hole of the pair of dielectric resonators, characterized in that: The first dielectric resonator hole and the second dielectric resonator hole are located on the same surface of the body; The first coupling slot is in the shape of a long strip, is located on the same surface as the dielectric resonator hole, and is connected to the first dielectric resonator hole; the cross section of the second coupling slot includes an arc portion, which is located on the opposite surface of the dielectric resonator hole; a head portion extends from the back of the arc portion of the cross section of the second coupling slot, so that the cross section of the second coupling slot is in a "herringbone" shape; the herringbone-shaped head portion of the second coupling slot is connected to the first coupling slot, and the arc portion other than the herringbone-shaped head portion extends around the second dielectric resonator hole, so that the arc portion of the second coupling slot is symmetrically arranged relative to the herringbone-shaped head portion; the first coupling slot and the second coupling slot are partially connected, and capacitive coupling is achieved between the first dielectric resonator and the second dielectric resonator through the coupling slot.

2. The filter according to claim 1, characterized in that: The communicating portion of the first coupling slot and the second coupling slot is located at the center of the body.

3. The filter according to claim 1, characterized in that: The portion where the first coupling slot and the second coupling slot communicate is arranged at a position deviating from the center of the body, and the coupling amount is adjusted by adjusting at least one of the following parameters: coupling slot height, coupling slot width, coupling window size or distance between dielectric resonators.

4. The filter according to claim 1, characterized in that: The portion where the first coupling slot and the second coupling slot communicate is a cylinder, an elliptical cylinder or a prism.

5. The filter according to claim 1, characterized in that: The second coupling slot and / or the first coupling slot is / are in a stepped shape.

6. A filter comprising a body made of a dielectric material and a dielectric resonator arranged on the body, characterized in that: There are four dielectric resonators, which are respectively located at the four corners of the quadrilateral, and a capacitive coupling structure is provided between a pair of adjacent dielectric resonators; Two coupling slots are provided between the first dielectric resonator hole and the second dielectric resonator hole of the pair of dielectric resonators, and the first dielectric resonator hole and the second dielectric resonator hole are located on the same surface of the body; The first coupling slot is in the shape of a long strip, is located on the same surface as the dielectric resonator hole, and is connected to the first dielectric resonator hole; the cross section of the second coupling slot is in the shape of a "herringbone", and is located on the opposite surface of the dielectric resonator hole; a head extends from the back of the arc-shaped portion of the cross section of the second coupling slot so that the cross section of the second coupling slot is in the shape of a "herringbone", the herringbone-shaped head of the second coupling slot is connected to the first coupling slot, and the arc portion other than the herringbone-shaped head extends around the second dielectric resonator hole, so that the arc portion of the second coupling slot is symmetrically arranged relative to the herringbone-shaped head portion; the first coupling slot and the second coupling slot are partially connected, and capacitive coupling is achieved between the first dielectric resonator and the second dielectric resonator through the coupling slot.

7. The filter according to claim 6, characterized in that: On the surface of the main body opposite to the dielectric resonator hole, a debugging blind hole for assisting fine tuning of the dielectric resonator frequency is coaxially arranged with the dielectric resonator hole.

8. A communication base station, characterized in that: Comprising a filter as claimed in any one of claims 1 to 7.

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