CN212874714U - Dielectric filter and communication base station - Google Patents

Abstract

The utility model relates to a dielectric filter and communication base station, including the outer dielectric resonator who has the conducting layer and set up on the dielectric body, the dielectric resonator is equipped with six, is two rows of three rows of settings, and middle one is a pair of dielectric resonator who realizes the capacitive coupling, is provided with first coupling groove, second coupling groove and the through-hole that passes through the body between the first dielectric resonator of a pair of dielectric resonator and second dielectric resonator, and first dielectric resonator and second dielectric resonator are located the upper surface and the lower surface of body respectively; the other four dielectric resonators are disposed on the upper surface of the dielectric body. The utility model discloses have and to realize inhibiting by force, possess strong interference killing feature, ensure that communication system does not receive technical effect such as stray signal interference.

Description

Dielectric filter and communication base station

Technical Field

The utility model relates to a communication equipment especially relates to microwave dielectric filter cross coupling technique.

Background

The microwave filter is a key device of a modern mobile communication system and is widely applied to wireless communication base stations and various communication terminals; the microwave dielectric filter is formed by constructing a plurality of resonator units and coupling units among the resonators by punching a ceramic body, arranging a separation wall, laser engraving and the like, and the resonance frequencies of the plurality of resonator units are distributed in a passband range. The microwave transmission signal selection device has a blocking function for signals outside the resonant frequency, so that the selection function of microwave transmission signals is realized. The dielectric filter has the advantages of miniaturization, light weight, high Q value, small temperature drift, high electrical property and the like, and can adapt to the trend that the requirement of a 5G communication system on the integration level is higher and higher.

The dielectric filter usually needs to introduce capacitive cross coupling to achieve the effect of strong suppression of transmission zero, and a capacitive coupling structure (a single high-end transmission zero does not need to be introduced at times) needs to be introduced to achieve low-end transmission zero and symmetric transmission zero, and the capacitive coupling achieved by the conventional dielectric waveguide filter usually takes the following forms: firstly, a frequency-variable coupling structure is adopted, and although the structure is simple, an additional resonance point is introduced. And secondly, a capacitive coupling structure directly derived from a traditional cavity filter flying rod structure is relatively complex, and parts and processes of a product are increased.

CN 108598635 a discloses a dielectric filter, which realizes capacitive coupling by a deep blind hole with a depth exceeding one-half of the body, and this scheme simplifies the manufacturing process for realizing the capacitive coupling structure, but has the disadvantage of generating harmonics at the low end of the filter passband, reducing the rejection capability of the filter.

CN210468050U discloses a dielectric filter coupling structure for realizing symmetric transmission zeros, which includes two blind 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 groove extends towards one blind hole resonator, the second blind groove extends towards the other blind hole resonator, and the first blind groove and the second blind groove are connected with the through hole penetrating through the body. The scheme can not generate extra resonance outside the passband of the filter, and can improve the out-of-band rejection capability of the filter. However, the two resonators are located on the same surface, the magnetic field coupling is strong, the electric field coupling is weak, and the application scene is narrow.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model lies in, to the above-mentioned defect of prior art, propose one kind and can avoid producing parasitic resonance at wave filter resonant frequency low side, can improve the far end suppression of wave filter at the frequency low side to can avoid the space decay of electric field, increase the dielectric filter of coupling volume.

The utility model provides a technical scheme that its technical problem adopted does:

the dielectric filter comprises a dielectric body with a conducting layer on the outer layer and dielectric resonators arranged on the dielectric body, wherein the dielectric resonators are six and are arranged in two rows and three columns, one column in the middle is a pair of dielectric resonators for realizing capacitive coupling, two coupling grooves and a through hole penetrating through the dielectric body are arranged between a first dielectric resonator and a second dielectric resonator of the pair of dielectric resonators, the first dielectric resonator and the second dielectric resonator are respectively positioned on the upper surface and the lower surface of the dielectric body, the first coupling groove connects the first dielectric resonator with the through hole, and the second coupling groove connects the second dielectric resonator with the through hole; the other four dielectric resonators are disposed on the upper surface of the dielectric body.

Further:

the through hole is arranged in the center of the body.

The through hole is arranged at a position deviated 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.

The through hole is cylindrical, and the first coupling groove and the second coupling groove are square columns.

The lower surface of the body is provided with a debugging blind hole corresponding to the first dielectric resonator on the upper surface of the body, and/or the upper surface of the body is provided with a debugging blind hole corresponding to the second resonator on the lower surface of the body, and the debugging blind hole and the dielectric resonator are coaxially arranged.

The debugging blind hole is circular, polygonal or oval.

And adjusting the frequency of the corresponding dielectric resonator by removing part of the conductive layer of the debugging blind hole.

The dielectric resonator is provided with six dielectric resonators which are arranged in two rows and three columns, the middle column is a pair of dielectric resonators for realizing capacitive coupling, a first coupling groove, a second coupling groove and a through hole penetrating through the body are arranged between a first dielectric resonator and a second dielectric resonator of the pair of dielectric resonators, and the first dielectric resonator and the second dielectric resonator are respectively positioned on the upper surface and the lower surface of the body; the first coupling groove is located on the upper surface of the body and extends towards two opposite sides from the position of the through hole, the second coupling groove is located on the lower surface of the body and extends towards the second dielectric resonator from the position of the through hole, and the other four dielectric resonators are arranged on the upper surface of the dielectric body.

Further:

the inner bottom surface of the hole of the first coupling groove is in a step shape.

The first coupling groove extends towards the first dielectric resonator to be connected with the first dielectric resonator, and the second coupling groove extends towards the second dielectric resonator to be connected with the second dielectric resonator.

The first coupling groove extends to a position right above the second dielectric resonator.

The second coupling groove extends toward a position right below the first dielectric resonator.

There is provided a communications base station comprising a dielectric filter as claimed in any preceding claim.

Compared with the prior art, the utility model discloses following beneficial effect has:

1. the 6-order resonant cavity combination design of the filter is adopted, and the transmission zero structure is introduced to form two zero points distributed at the high end and the low end of the passband, so that strong suppression is realized, strong anti-interference capability is realized, the communication system is ensured not to be interfered by stray signals, the spatial attenuation of an electric field can be avoided, and the coupling amount is increased.

2. The filter has small volume and low loss, and ensures low energy consumption of the communication module.

3. The filter has simple structure and low cost.

Drawings

Fig. 1 is a schematic perspective view of a dielectric filter according to an embodiment of the present invention;

fig. 2 is a schematic view of the shape of the upper surface of an embodiment of the dielectric filter of the present invention;

fig. 3 is a schematic view of the shape of the lower surface of an embodiment of the dielectric filter of the present invention;

FIG. 4 is a schematic sectional view A-A of FIG. 2;

FIG. 5 is a schematic cross-sectional view B-B of FIG. 2;

fig. 6 is a topological structure diagram of capacitive coupling and inductive coupling of an embodiment of the dielectric filter of the present invention;

fig. 7 is a schematic perspective view of another embodiment of the dielectric filter according to the present invention;

fig. 8 is a schematic view of the shape of the upper surface of another embodiment of the dielectric filter of the present invention;

fig. 9 is a schematic view of the shape of the lower surface of another embodiment of the dielectric filter of the present invention;

FIG. 10 is a schematic sectional view A-A of FIG. 8;

FIG. 11 is a schematic sectional view taken along line B-B of FIG. 8;

fig. 12 is a graph of the frequency response of an embodiment of the dielectric filter of the present invention.

Detailed Description

The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

An embodiment of a dielectric filter, as shown in fig. 1 to 5, comprises a dielectric body 110 having a conductive layer on the outer layer and six dielectric resonators 101 to 106 disposed on the dielectric body. Closed or open coupling windows are arranged between every two 6 dielectric resonators, and a capacitive coupling structure and an inductive coupling structure are arranged in the corresponding open coupling windows. The dielectric body 110 is square, six dielectric resonators are arranged in two rows and three columns, and the middle one is the dielectric resonators 101 and 104. The capacitive coupling structure of the present embodiment is provided between the dielectric resonator 101 and the dielectric resonator 104, and includes a through hole 201, a first coupling groove 301, and a second coupling groove 302. Other couplings of this embodiment are inductive couplings, implemented through a dielectric coupling window between the two resonators.

In the 6 dielectric resonators described in this embodiment, the dielectric resonator 104 is disposed in the opposite direction to the other 5 dielectric resonators. The dielectric resonator 104 is disposed on the lower surface of the dielectric body and the other dielectric resonators are disposed on the front surface of the dielectric body. The first coupling groove 301 is located on the upper surface of the dielectric body and connects the dielectric resonator 101 to the via 201. The second coupling slot 302 is located on the lower surface of the dielectric body and connects the dielectric resonator 104 with the through hole 201, and the dielectric resonator 101 and the dielectric resonator 104 are connected through the coupling slot and the through hole to realize capacitive coupling.

The upper surface of the body corresponding to the dielectric resonator 104 is provided with a fine tuning hole 501, and the fine tuning of the silver layer of the hole can be fine tuned by polishing 501. The debugging hole in the technical scheme can be in a special-shaped structure such as a circle, a polygon, an ellipse and the like. In the technical scheme, the coupling groove is preferably in a square column shape, and the through hole is preferably in a cylindrical shape and can also be in other shapes.

In some embodiments, the through hole 201 is disposed in the center of the body. In other embodiments, the through hole 201 may be disposed at a position offset from the center of the body, for example, in an actual product, the requirement may require that the through hole is offset to one side. The off-center affects the frequency of a side and the amount of coupling is reduced accordingly, which allows the amount of coupling to be adjusted appropriately. The coupling amount can be adjusted by adjusting the height of the coupling slot, the size of the window and the distance between the two resonators. The first coupling groove and the second coupling groove are square columns, and the through hole is preferably cylindrical and can be in other shapes.

The tap cavities in this embodiment are disposed in the dielectric resonators 101 and 106, as shown in fig. 6, when a signal is transmitted from the input port to the dielectric resonator 101, the signal is capacitively coupled into the dielectric resonator 104, the dielectric resonator 103 is inductively coupled into the dielectric resonator 104, the inductive coupling amount and the capacitive coupling amount meet each other, and the phase difference thereof is 180 ° to form two transmission zeros; the signal is capacitively coupled into the dielectric resonator 104 by the dielectric resonator 101, is inductively coupled into the dielectric resonator 104 by the dielectric resonator 105, and the inductive coupling quantity meets the capacitive coupling quantity, so that two transmission zero points can be added, and 4 transmission zero points are realized in total, thereby realizing the requirement of strong suppression index.

The strength of this capacitive coupling is controlled by the relative positions of the two dielectric resonators, the dimensions of the coupling slot, the via and the window. The strength of the capacitive coupling is adjusted by removing part of the conductive layer of the coupling groove and the through hole, and can be realized by polishing the metallization layer (conductive layer) of the coupling groove and the through hole. The resonant frequency of the dielectric resonator is adjusted by removing part of the conductive layer of the dielectric resonator, and the resonant frequency can be adjusted by polishing the metallization layer of the blind hole of the resonator.

In another embodiment, as shown in fig. 7 to fig. 11, the dielectric filter in this embodiment is a dielectric body with a silver (or other metal) plated whole outer layer, the surface of the dielectric body is provided with 6 dielectric resonators with the number 101-. The capacitive coupling structure of the present embodiment is disposed between the dielectric resonator 101 and the dielectric resonator 104, the dielectric resonator 101 is located on the upper surface of the body, and the dielectric resonator 104 is located on the lower surface of the body. The capacitive coupling structure includes a through hole 201, a first coupling groove 301 on the upper surface of the body and a second coupling groove 302 on the lower surface of the body. The first coupling groove 301 extends from both sides of the through hole 201, respectively, one side of which extends to be connected with the first dielectric resonator 101, and the other side of which extends to be directly above the second dielectric resonator 104. By grinding a part of the conductive layer, e.g. silver layer, of the first coupling groove 301 opposite to the second dielectric resonator 104, the first coupling groove 301 simultaneously has a frequency-tuning effect with respect to the second dielectric resonator 104. In addition, the first coupling groove 301 extends and expands, and also has an effect of increasing the coupling amount. The second coupling slot 302 is located on the lower surface of the body and connected to the through hole 201. The second coupling groove 302 connects the via hole 201 and the dielectric resonator 104. In some embodiments, the second coupling groove 302 may extend slightly toward the right above the first dielectric resonator 101 to enlarge the coupling groove, which has the effect of increasing the amount of coupling. Other couplings of this embodiment are inductive couplings, implemented through a dielectric coupling window between the two resonators.

In other embodiments, the first coupling groove 301 may extend toward the first dielectric resonator 101, or may not be connected to the first dielectric resonator 101, and the second coupling groove 302 may extend toward the second dielectric resonator 104, or may not be connected to the second dielectric resonator 104.

Preferably, the inner bottom surface of the first coupling groove 301 is stepped, that is, the depths of different parts of the first coupling groove 301 are different, in this embodiment, the part of the first coupling groove 301 located between the through hole 201 and the position corresponding to the second coupling groove 302 is the shallowest, the next part is the part corresponding to the second coupling groove 302, and the deepest part is the part located between the through hole 201 and the position corresponding to the second coupling groove 302.

The magnetic field of the dielectric filter resonator surrounds the opening of the blind hole of the resonator, while the electric field is mainly concentrated at the bottom of the blind hole of the resonator, when the resonator is placed on the same surface, only the window is opened, the magnetic field coupling is strong, and the electric field coupling is weak. The utility model discloses a with the upper and lower surface setting of a pair of syntonizer of capacitive cross coupling structure, can let a syntonizer that encircles the upper surface in two magnetic fields, a syntonizer that encircles the lower surface. The utility model discloses the upper and lower surface setting of a pair of syntonizer can be drawn close the distance of electric field to increase the capacitive coupling volume. When the upper and lower surfaces of a pair of resonators are arranged, the coupling grooves are directly connected with the resonators, the magnetic field at the opening of the blind hole of the resonator is converted into surface current to be directly transmitted to another resonator, and compared with the mode that the magnetic field is coupled to the coupling grooves through a space electric field and then transmitted to another dielectric resonator, the mode disclosed in CN210468050U can avoid space attenuation of the electric field and increase the coupling amount. Therefore, the utility model discloses can realize stronger coupling bandwidth, can adapt to more extensive application scene.

And, compare with current frequency conversion structure, the utility model discloses self harmonic peak is far above basic mode frequency, and the outband performance is more excellent. The crosstalk is small and no parasitic coupling exists. Compared with a capacitive coupling structure derived from a traditional cavity filter flying rod structure, the coupling structure in the technical scheme has the advantages of simple implementation mode, easiness in processing and convenience for mass production.

The dielectric filter can be applied to a wireless communication base station, for example, a mobile communication system, and the operating frequency band of the dielectric filter is 3400-3600 MHz. Has the characteristics of small volume, light weight, small in-band loss and strong inhibition.

The frequency response curve of the dielectric filter of the present invention is shown in fig. 12, wherein the X-axis represents the frequency, the left Y-axis represents the transmission loss amplitude, and the right Y-axis represents the reflection loss amplitude; m1, M2 represent insertion loss; m3 to M10 represent out-of-band rejection points. As can be seen from the figure, the left side and the right side of the passband of the frequency response diagram of the structural embodiment respectively generate two transmission zeros, the out-of-band rejection is enhanced, no additional harmonic wave is generated at the low end of the passband, and the product performance requirements can be better met.

Compared with the traditional capacitive coupling structure form, the capacitive coupling structure scheme can simply and flexibly realize the coupling bandwidth without introducing extra parts and procedures, and no harmonic wave is generated, thereby ensuring the performance and the design flexibility of the product, reducing the production difficulty and facilitating the mass production.

It should be understood that the above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same, and those skilled in the art can modify the technical solutions described in the above embodiments, or make equivalent substitutions for some technical features; and that such modifications and substitutions are intended to be included within the scope of the appended claims.

Claims (10)

1. A dielectric filter comprises a dielectric body with a conductive layer on the outer layer and a dielectric resonator arranged on the dielectric body, and is characterized in that: the dielectric resonators are arranged in two rows and three columns, the middle column is a pair of dielectric resonators for realizing capacitive coupling, two coupling grooves and a through hole penetrating through the body are arranged between a first dielectric resonator and a second dielectric resonator of the dielectric resonators for realizing capacitive coupling, the first dielectric resonator and the second dielectric resonator are respectively positioned on the upper surface and the lower surface of the body, the first coupling groove connects the first dielectric resonator with the through hole, and the second coupling groove connects the second dielectric resonator with the through hole; the other four dielectric resonators are disposed on the upper surface of the dielectric body.

2. A dielectric filter as recited in claim 1, wherein: the through hole is arranged in the center of the body; or the through hole is arranged at a position deviated 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.

3. A dielectric filter as recited in claim 1, wherein: the depth of the first coupling groove is smaller than that of the first dielectric resonator, and the depth of the second coupling groove is smaller than that of the second dielectric resonator.

4. A dielectric filter as recited in claim 1, wherein: the lower surface of the body is provided with a debugging blind hole corresponding to the first dielectric resonator on the upper surface of the body, and/or the upper surface of the body is provided with a debugging blind hole corresponding to the second resonator on the lower surface of the body, and the debugging blind hole and the dielectric resonator are coaxially arranged.

5. The dielectric filter of claim 4, wherein: the debugging blind hole is circular, polygonal or elliptical, and the frequency of the corresponding dielectric resonator is adjusted by removing part of the conducting layer of the debugging blind hole.

6. A dielectric filter comprises a dielectric body with a conductive layer on the outer layer and a dielectric resonator arranged on the dielectric body, and is characterized in that: the dielectric resonators are arranged in two rows and three columns, the middle column is a pair of dielectric resonators for realizing capacitive coupling, a first coupling groove, a second coupling groove and a through hole penetrating through the body are arranged between a first dielectric resonator and a second dielectric resonator of the pair of dielectric resonators, and the first dielectric resonator and the second dielectric resonator are respectively positioned on the upper surface and the lower surface of the body; the first coupling groove is located on the upper surface of the body and extends towards two opposite sides from the position of the through hole, the second coupling groove is located on the lower surface of the body and extends towards the second dielectric resonator from the position of the through hole, and the other four dielectric resonators are arranged on the upper surface of the dielectric body.

7. The dielectric filter of claim 6, wherein: the first coupling groove extends towards the first dielectric resonator to be connected with the first dielectric resonator, and the second coupling groove extends towards the second dielectric resonator to be connected with the second dielectric resonator.

8. A dielectric filter as claimed in any one of claims 6 to 7, characterized in that: the first coupling groove extends to a position right above the second dielectric resonator.

9. A dielectric filter as claimed in any one of claims 6 to 7, characterized in that: the second coupling groove extends toward a position right below the first dielectric resonator.

10. A communication base station, characterized by: comprising a dielectric filter according to any of claims 1 to 9.

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