Dielectric filter unit, dielectric filter, and communication device

Abstract

Provided in the embodiments of the present disclosure are a dielectric filter unit, a dielectric filter, and a communication device. The dielectric filter unit comprises two dielectric resonant cavities connected as a whole, and a coupling component disposed in a connection region of the two dielectric resonant cavities, wherein each of the dielectric resonant cavities is provided with a first blind hole recessed inwards from a surface, the connection region of the two dielectric resonant cavities is provided with a frequency hole recessed inwards from a surface, and a demetallized pattern is provided around the frequency hole.

Description

Dielectric filter unit, dielectric filter and communication equipment

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] The present disclosure is based on Chinese patent application CN202410250592.6 filed on March 5, 2024, entitled “Dielectric filter unit, dielectric filter and communication equipment”, and claims the priority of the patent application, and all the disclosed contents thereof are incorporated into the present disclosure by reference. Technical Field

[0003] The embodiments of the present disclosure relate to the field of communication technology, and in particular to a dielectric filter unit, a dielectric filter, and a communication device. Background Art

[0004] Dielectric filters are of particular importance to the miniaturization of communication products. When electromagnetic waves propagate in high dielectric constant materials, their wavelengths can be shortened. Based on this theory, dielectric materials can be used to replace traditional metal air cavities. In this way, the volume of the filter can be reduced under the same indicators.

[0005] The dielectric filter may include multiple resonant cavities, and the more resonant cavities there are, the higher the filter order is, and thus the better the suppression performance is. However, the volume will also increase, which cannot meet the demand for miniaturization of dielectric filters in this field. Summary of the Invention

[0006] The embodiments of the present disclosure provide a dielectric filter unit, a dielectric filter, and a communication device, so as to at least solve the problem that the existing dielectric filters in the related art cannot achieve both small size and high order.

[0007] According to one embodiment of the present disclosure, a dielectric filter unit is provided, comprising: two dielectric resonant cavities connected as one body, and a coupling component disposed in the connection region between the two dielectric resonant cavities; wherein each of the dielectric resonant cavities is provided with a first blind hole recessed inwardly from the surface, and the connection region between the two dielectric resonant cavities is provided with a frequency hole recessed inwardly from the surface, and a demetallized pattern is disposed around the frequency hole.

[0008] According to another embodiment of the present disclosure, a dielectric filter is provided, comprising: a plurality of dielectric resonant cavities connected as one body, and a coupling component disposed in a connection region of the dielectric resonant cavities; wherein each of the dielectric resonant cavities is provided with a first blind hole recessed inward from the surface, the dielectric resonant cavity connection region is provided with a frequency hole recessed inward from the surface, and a demetallized pattern is provided around the frequency hole.

[0009] According to another embodiment of the present disclosure, a communication device is provided, comprising one or more dielectric filter units according to the above embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG1 is a top view of a dual-cavity unit structure of a dielectric filter in the related art;

[0011] FIG2 is a top view of a dielectric filter unit according to an embodiment of the present disclosure;

[0012] FIG3 is a front view of a dielectric filter unit according to an embodiment of the present disclosure;

[0013] 4 is a front view of a dielectric filter unit according to yet another embodiment of the present disclosure;

[0014] 5 is a front view of a dielectric filter unit according to yet another embodiment of the present disclosure;

[0015] FIG6 is a schematic diagram of a three-dimensional structure of a dielectric filter unit provided with a semi-closed coupling slot according to an embodiment of the present disclosure;

[0016] FIG7 is a schematic diagram of a three-dimensional structure of a dielectric filter unit with a coupling slot embedded therein according to an embodiment of the present disclosure;

[0017] FIG8 is a top view of a dielectric filter unit according to another embodiment of the present disclosure;

[0018] 9 is a front view of a dielectric filter unit according to another embodiment of the present disclosure;

[0019] FIG10 is a first schematic diagram of a three-dimensional structure of a dielectric filter unit provided with a second blind hole according to an embodiment of the present disclosure;

[0020] FIG11 is a second schematic diagram of the three-dimensional structure of a dielectric filter unit provided with a second blind hole according to an embodiment of the present disclosure;

[0021] FIG12 is a schematic diagram of a three-dimensional structure of a dielectric filter unit provided with a first blind slot according to an embodiment of the present disclosure;

[0022] FIG13 is a schematic three-dimensional structural diagram of the distribution positions of third blind holes on a dielectric filter unit according to an embodiment of the present disclosure;

[0023] FIG14 is a three-dimensional schematic diagram of electric field distribution when constructing a third frequency according to an embodiment of the present disclosure;

[0024] FIG15 is a three-dimensional schematic diagram of electric field distribution when constructing the third frequency in the related art;

[0025] FIG16 is a schematic diagram of a three-dimensional structure of a 6th-order complete filter according to an embodiment of the present disclosure;

[0026] FIG17 is a schematic diagram of a CT tripole structure according to an embodiment of the present disclosure;

[0027] FIG18 is a schematic diagram of an S-parameter curve of a high-end zero point achieved by a dielectric filter unit according to an embodiment of the present disclosure;

[0028] FIG19 is a schematic diagram of an S-parameter curve of a low-end zero point implemented by a dielectric filter unit according to an embodiment of the present disclosure;

[0029] FIG20 is a schematic diagram of a topological structure of a dielectric filter unit according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0030] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings and in conjunction with embodiments.

[0031] It should be noted that the terms "first", "second", etc. in the specification and claims of the present disclosure and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0032] Figure 1 is a top view of a dual-cavity unit structure of a dielectric filter in the related art. As shown in Figure 1, the dual-cavity unit of the dielectric filter comprises two dielectric resonant cavities 80 connected by a window. The window is implemented by machining a slot 90 at the connection point; the window functions to achieve electromagnetic field coupling between the two resonant cavities. This type of dielectric filter unit has the following disadvantages: Due to the size of the dielectric filter unit, it can only form two resonant cavities, i.e., a two-order resonant unit; and it cannot generate an out-of-band transmission zero.

[0033] The disclosed embodiments provide a dielectric filter unit for use in a base station. This dielectric filter unit features a dual-cavity, three-mode design, enabling the dielectric filter to achieve three transmission modes using only the physical form and volume of two cavities, achieving the performance of a third-order filter while also generating an out-of-band transmission zero point and offering independent debuggability and manufacturability. The dielectric of the dielectric filter unit is comprised of materials with varying dielectric constants, such as ceramics with dielectric constants of 20, 40, or 60.

[0034] Figure 2 is a top view of a dielectric filter unit according to an embodiment of the present disclosure, and Figure 3 is a front view of a dielectric filter unit according to an embodiment of the present disclosure. As shown in Figures 2 and 3, the dielectric filter unit includes: two dielectric resonant cavities 10 connected as one body, and a coupling component arranged in the connection area of ​​the two dielectric resonant cavities; wherein, a coupling slot 20 is provided in the coupling component, a first blind hole 11 recessed inwardly from the surface is provided on each dielectric resonant cavity 10, a frequency hole 30 recessed inwardly from the surface is provided in the connection area of ​​the two dielectric resonant cavities, and a demetallized pattern 31 is provided around the frequency hole 30.

[0035] Based on the design of the above-mentioned dielectric filter unit, a transmission zero point can be generated in the dielectric filter by coordinating the two dielectric resonant cavities with the coupling slot, the frequency hole and the demetallization pattern, forming a third resonant mode in addition to the two existing dielectric resonant cavities, thereby further improving the out-of-band suppression performance of the filter transmission response.

[0036] In this embodiment, the shape of the demetallization pattern 31 includes but is not limited to a circle, a rectangle, a polygon, and an irregular shape. As shown in FIG3 , a circular demetallization pattern is shown. As shown in FIG4 , a non-closed ring demetallization pattern is shown.

[0037] In this embodiment, the dielectric resonant cavity 10 is in the shape of a polyhedron, that is, a polygon or an irregular cube. A rectangular parallelepiped is used as an example in Figures 2 and 3 .

[0038] In this embodiment, the coupling slot 20 functions as a coupling window, enabling a certain amount of coupling between the two resonant cavities. Preferably, cross-coupling is generated between the two resonant cavities. Cross-coupling is significant in that the phase polarity of electromagnetic waves is reversed after passing through different coupling paths, thereby generating an infinitesimal notch outside the filter band, i.e., an out-of-band transmission zero (abbreviated as a transmission zero). This improves the filter's out-of-band rejection capability without increasing the filter order.

[0039] The transmission zeros are located either on one side or at the upper or lower ends of the dielectric filter's operating passband. When the transmission zeros are located on either side of the filter's passband, their strengths differ, meaning their distances from the passband differ. These characteristics require flexible design adjustments based on specific out-of-band rejection requirements.

[0040] In this embodiment, the entire dielectric filter unit, except for the metallized pattern 31, is metallized on the outer surface, the surface of the frequency hole 30, the first blind hole 11, and the surface of the coupling slot 20. The metallization can be removed from some areas during debugging.

[0041] In this embodiment, the frequency hole 30 is located on the side surface of the connection area of ​​the two dielectric resonant cavities.

[0042] In this embodiment, the first blind hole 11 is used to generate and tune the frequency of the resonant cavity, and the first blind hole 11 may be located on the upper surface and / or the lower surface of the dielectric resonant cavity 10 .

[0043] Figures 2 and 3 illustrate the situation where the first blind holes are located on the upper surface of the dielectric resonant cavity. As shown in Figure 2 or 3, two first blind holes 11 are located on the upper surface of the dielectric resonant cavity 10, and together with the frequency hole 30 on the side, a CT structure is formed. The cross-coupling in the CT structure is manifested as positive coupling, so that the out-of-band transmission zero point falls at the high end of the filter passband.

[0044] In one embodiment, as shown in FIG5 , the two first blind holes 11 can be arranged such that one first blind hole 11 is located on the upper surface of one dielectric resonant cavity 10 and the other first blind hole 11 is located on the lower surface of the other dielectric resonant cavity 10. This arrangement achieves a phase reversal of the transmission phase, i.e., the cross-coupling of the resulting CT structure is negatively coupled, thereby placing the out-of-band transmission zero at the lower end of the filter passband. The additional frequency hole 12 (different from the frequency hole 30) enhances debugging convenience. Product debugging can be achieved by adjusting the holes on the same surface, eliminating the need to flip the holes upside down and adjust the blind holes on both surfaces.

[0045] The two first blind holes 11 can also be located on the lower surface of the dielectric resonant cavity at the same time. Referring to FIG. 2 or 3 , the first blind holes 11 can be respectively arranged on the lower surfaces of the two dielectric resonant cavities. This embodiment will not be described in detail here.

[0046] In this embodiment, the shape of the first blind hole 11 includes but is not limited to a cylinder, a cuboid, a polyhedron, and an irregular shape.

[0047] In this embodiment, the depth of the coupling slot 20 is greater than or equal to zero. By adjusting the depth of the coupling slot, the out-of-band suppression capability of the filter can be adjusted; wherein, when the depth of the coupling slot 20 is zero, the out-of-band suppression capability of the filter is the strongest.

[0048] In this embodiment, the coupling slot 20 is a through slot that passes through the connection area of ​​the two dielectric resonant cavities, or a blind slot that does not pass through the connection area of ​​the two dielectric resonant cavities.

[0049] In this embodiment, the number of the coupling slot 20 on the dielectric filter unit is at least one.

[0050] The coupling slot 20 is semi-enclosed and disposed in the region connecting the two dielectric resonators, as shown in FIG6 , which exhibits a partially broken edge. The coupling slot 20 can also be completely embedded in the region connecting the two dielectric resonators, as shown in FIG7 , which exhibits an embedded configuration within the dielectric filter unit.

[0051] In one embodiment, as shown in FIG. 6 , the demetallization pattern 31 may be disposed on a side surface of the dielectric filter unit and around the frequency hole 30 .

[0052] In this embodiment, the shape of the coupling slot 20 includes but is not limited to a cylinder, a cuboid, a polyhedron, and an irregular shape.

[0053] In this embodiment, the frequency hole 30 is a through hole communicating with the coupling slot 20 .

[0054] In this embodiment, the axis of the frequency hole 30 may be perpendicular to the side end surface, as shown in FIG. 2 , 6 , and 7 , or may not be perpendicular to the side end surface.

[0055] In this embodiment, the number of the frequency hole 30 is at least one.

[0056] FIG8 and FIG9 are top views and front views, respectively, of a dielectric filter unit in which the frequency hole is located on the side of the dielectric filter unit. As shown in FIG8 and FIG9 , the depth of the coupling slot 20 is B. By adjusting the size of B, the out-of-band transmission zero point can be adjusted. The frequency hole 30 is located at the side, and D is the distance from the edge of the dielectric filter unit, where H>D>0 mm.

[0057] In one embodiment, the position of the transmission zero can be flexibly adjusted by adjusting the depth B of the coupling slot 20. A larger value of B indicates a further distance from the transmission zero to the passband; conversely, a smaller value of B indicates a closer distance to the passband. Adjusting the demetallization pattern 31 also allows for flexible adjustment of the frequency of the third mode.

[0058] In one embodiment, as shown in FIG10 , the dielectric filter unit further includes a second blind hole 32 recessed inwardly from the side end surface of the dielectric filter unit, wherein the position of the second blind hole 32 intersects (overlaps) with the frequency hole 30; its shape includes but is not limited to a cylinder, a cuboid, a polyhedron, and an irregular shape.

[0059] As shown in FIG10 , the demetallized pattern 31 may also be disposed at the bottom of the second blind hole 32 of the dielectric filter unit, or as shown in FIG11 , it may also be disposed at the side of the second blind hole 32 .

[0060] The second blind hole is used to reduce the adverse effects caused by the demetallization pattern 31. If necessary, the second blind hole 32 can be sealed by attaching aluminum foil to the side of the product to prevent the demetallization pattern 31 from being exposed on the product surface.

[0061] In one embodiment, as shown in FIG12 , the dielectric filter unit further includes a first blind slot 33 , wherein the first blind slot 33 intersects (overlaps) with the frequency hole 30 , and the first blind slot 33 may be a semi-closed blind slot.

[0062] As shown in FIG. 12 , the demetallization pattern 31 may also be arranged on the side of the first blind groove 33 of the dielectric filter unit.

[0063] In one embodiment, a third blind hole 40 is further provided on the upper and / or lower surface of the dielectric filter unit for adjusting the coupling amount. The third blind hole 40 can be connected to one of the first blind holes 11, or connected to the coupling slot 20, or independently located between the first blind hole 11 and the frequency hole 30. Figure 13 illustrates the third blind hole 40 in three different positions.

[0064] In this embodiment, the shape of the third blind hole 40 includes but is not limited to: a cylinder, a cuboid, a polyhedron, and an irregular shape; and it is located on the top surface and / or the bottom surface of the dielectric resonant cavity 10 .

[0065] Figure 14 is a schematic diagram of the electric field distribution at the third frequency created by the frequency hole 30 and the demetallized pattern 31. As can be seen from Figure 14, the electric field is primarily distributed near the demetallized pattern 31. Figure 15 is a schematic diagram of the electric field distribution at the third frequency created in the related art. This is achieved by drilling a blind hole 34 from the side between the two cavities. As can be seen from Figure 15, the electric field is primarily distributed at the bottom of the blind hole 34. In actual production, the solution in Figure 15 suffers from difficulties in controlling the depth and dimensional accuracy of the blind hole 34, resulting in drastic variations in the electric field at the bottom of the blind hole 34 and poor production stability. Generally, the lower the frequency band and the deeper the blind hole, the worse the manufacturability. The solution in Figure 14 of the disclosed embodiment, constructed from the frequency hole 30 and the demetallized pattern 31, can be fine-tuned in actual production by fine-tuning the dimensions of the demetallized pattern 31, thereby fine-tuning the third resonant frequency without causing drastic changes in the electric field distribution. The solution described in the disclosed embodiment is applicable to both low and high frequency bands, is simple to manufacture, and has high manufacturability.

[0066] Through the above-disclosed embodiments, the frequency holes, coupling slots, and demetallized patterns in the dielectric filter unit are coordinated to stimulate a third resonant mode between the two dielectric resonant cavities. This allows the dielectric filter to achieve three transmission modes and achieve the performance of a third-order filter while utilizing the physical form and volume of only two cavities. Furthermore, out-of-band transmission zeros can be generated, providing independent debuggability and manufacturability. This solves the problem of existing dielectric filters in related art, which cannot achieve both small size and high performance.

[0067] The present disclosure also provides a dielectric filter, comprising: a plurality of dielectric resonant cavities 10 connected as one body, and a coupling slot 20 arranged in the connection area of ​​the dielectric resonant cavities; wherein each of the dielectric resonant cavities 10 is provided with a first blind hole 11 recessed inward from the surface, and the dielectric resonant cavity connection area is provided with a frequency hole 30 recessed inward from the surface, and a demetallized pattern 31 is provided around the frequency hole 30.

[0068] For example, Figure 16 shows the design of a 6th-order, 2-zero dielectric filter, which incorporates two sets of dielectric filter units described in the aforementioned embodiments. As mentioned above, the strength of the transmission zero, i.e., its proximity to the passband, can be adjusted by adjusting the dimensions of coupling slot 20. It should be noted that Figure 16 illustrates only one example of an overall filter product implemented using the dielectric filter units of the disclosed embodiments. Multiple such dielectric filter units can be cascaded to form filters of varying orders, topologies, modes, and materials.

[0069] An embodiment of the present disclosure further provides a communication device comprising one or more dielectric filter units as described above.

[0070] The following is a brief description of the operating principle of the dielectric filter (unit) in the embodiment of the present disclosure:

[0071] The filter's transmission zero is generated by superimposing the signal in opposite phase with the main coupling path through cross-coupling paths between non-adjacent cavities. This blocks the signal at a specific frequency, creating a theoretically infinitesimal notch point, or zero. As shown in Figure 17, a common CT tripole structure consisting of three cavities has two signal transmission paths: "1-->2-->3" and "1-->3." The zero is generated by superimposing the two paths in opposite phase. The "+" sign indicates positive coupling (inductive coupling), and the "-" sign indicates negative coupling (capacitive coupling). The positive coupling between 1-->3 determines that the filter's transmission zero falls at the high end of the passband, as shown in Figure 18; the negative coupling between 1-->3 determines that the filter's transmission zero falls at the low end of the passband, as shown in Figure 19.

[0072] Taking the dielectric filter unit in Figure 2 as an example, in terms of material structure, the frequency hole 30 in the disclosed embodiment cooperates with the coupling slot 20 and the demetallized pattern 31 (see the previous description for details of this cooperation relationship). This excites a third resonant mode within the dual-cavity structure, namely the mode marked "2" in Figure 20. In this specific configuration, these three modes complete the aforementioned CT tripole structure. The specific methods for adjusting the third resonant mode and the zero point position can be found in the previous description.

[0073] Through the above-described embodiments of the present disclosure, a third resonant mode can be generated without increasing the volume of the dielectric filter unit, that is, an additional resonant cavity is added, thereby improving the out-of-band suppression performance of the filter transmission response. In other words, while maintaining the same number of cavities, the volume is significantly reduced. Furthermore, the third resonant mode of the dielectric filter unit in the embodiments of the present disclosure is independently adjustable, and the resulting transmission zero is also independently adjustable, making it highly manufacturable. The quality factor (Q) of the dielectric filter unit does not decrease due to the generation of the third resonant mode. Therefore, the dielectric filter unit in the embodiments of the present disclosure is easy to process and form, and at the same order, the material cost is lower and the weight is lighter.

[0074] The foregoing description is merely a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. Those skilled in the art will readily appreciate that various modifications and variations of the present disclosure are possible. Any modifications, equivalent substitutions, or improvements made within the principles of the present disclosure shall be included within the scope of protection of the present disclosure.

Claims

1. A dielectric filter unit, wherein: include: Two dielectric resonant cavities (10) connected as one body, and a coupling component arranged in the connection area of ​​the two dielectric resonant cavities; wherein each of the dielectric resonant cavities (10) is provided with a first blind hole (11) recessed inwardly from the surface, and the connection area of ​​the two dielectric resonant cavities is provided with a frequency hole (30) recessed inwardly from the surface, and a demetallized pattern (31) is provided around the frequency hole (30).

2. The dielectric filter unit according to claim 1, wherein The dielectric resonant cavity (10) is a polyhedron.

3. The dielectric filter unit according to claim 1, wherein The first blind hole (11) is located on the upper surface and / or lower surface of the dielectric resonant cavity (10), and the frequency hole (30) is located on the side surface of the connection area of ​​the two dielectric resonant cavities.

4. The dielectric filter unit according to claim 1, wherein A coupling groove (20) is provided in the coupling component, and the depth of the coupling groove (20) is greater than or equal to zero.

5. The dielectric filter unit according to claim 4, wherein The coupling slot (20) is a through slot that runs through the connection area of ​​the two dielectric resonant cavities, or a blind slot that does not run through the connection area of ​​the two dielectric resonant cavities.

6. The dielectric filter unit according to claim 4, wherein The number of the coupling slot (20) is at least one.

7. The dielectric filter unit according to claim 4, wherein The coupling slot (20) is arranged in a semi-enclosed form on the connection area of ​​the two dielectric resonant cavities; or is completely embedded in the connection area of ​​the two dielectric resonant cavities.

8. The dielectric filter unit according to claim 1, wherein The frequency hole (30) is a through hole communicating with the coupling component.

9. The dielectric filter unit according to claim 1, wherein The number of the frequency hole (30) is at least one.

10. The dielectric filter unit according to claim 1, wherein Also includes: A second blind hole (32), wherein the position of the second blind hole (32) intersects with the frequency hole (30).

11. The dielectric filter unit according to claim 1, wherein Also includes: A first blind slot (33), wherein the position of the first blind slot (33) intersects with the frequency hole (30).

12. The dielectric filter unit according to claim 10 or 11, wherein The demetallization pattern (31) is arranged at the bottom end of the second blind hole (32) on the side of the dielectric filter unit; or, is arranged at the side of the second blind hole (32) on the side of the dielectric filter unit; or, is arranged at the side of the first blind groove (33) on the side of the dielectric filter unit.

13. The dielectric filter unit according to claim 1, wherein The invention also includes: a third blind hole (40) located on the upper surface and / or the lower surface of the dielectric filter unit, wherein the third blind hole (40) is connected to the first blind hole (11); or is connected to the coupling component; or is independently located between the first blind hole (11) and the frequency hole (30).

14. A dielectric filter comprising: A plurality of dielectric resonant cavities (10) connected as one body and a coupling component arranged in a dielectric resonant cavity connection area; wherein each dielectric resonant cavity (10) is provided with a first blind hole (11) recessed inwardly from the surface; a frequency hole (30) recessed inwardly from the surface is provided in the dielectric resonant cavity connection area; and a demetallized pattern (31) is provided around the frequency hole (30).

15. A communication device comprising one or more dielectric filter units according to any one of claims 1 to 13.

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