CN112952316A - Dielectric filter - Google Patents
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Abstract
The invention provides a dielectric filter, which comprises at least one first resonator operating in a TE102 mode and at least one second resonator operating in a TE101 mode; the top surface and the bottom surface of the first resonator respectively comprise a top surface center and a bottom surface center which are symmetrical; the top surface of the first resonator is symmetrically provided with a pair of first tuning blind holes around the center of the top surface; a bottom blind hole is formed in the center of the bottom surface of the first resonator; and/or the first resonator is provided with a through hole penetrating through the top surface and the bottom surface, and the through hole is positioned on a perpendicular bisector corresponding to a connecting line of the pair of first tuning blind holes. Therefore, the invention can reduce or increase the frequency of the loading TE101 mode under the condition of less influence on the frequency of the loading TE102 mode, can greatly improve the low-frequency suppression performance, has simple structure and easy realization, and further improves the design flexibility and the adaptability of the dielectric filter.
Description
Technical Field
The invention relates to the technical field of filters, in particular to a dielectric filter.
Background
The filter is an indispensable frequency selection device in wireless communication, and the dielectric filter using ceramic as a carrier has wider and wider application prospect due to compact volume and excellent performance.
Chinese invention patent CN201980001851.9 discloses a ceramic dielectric filter, the capacitive coupling mode of which is realized by loading TE102 mode with double blind hole structure. The capacitive coupling realized by the mode has a simple structure and is easy to realize, but because the resonator working in the TE102 mode still has the TE101 mode and the resonant frequency of the TE101 mode is lower than that of the TE102 mode, the low frequency of the passband of the ceramic dielectric filter can generate spurious harmonics, thereby influencing the suppression performance of the filter at low frequency. Particularly, when the ceramic dielectric filter has at least two resonators operating in TE102 mode, the respective TE101 modes of these resonators generate at least two spurious harmonics at the low frequency of the pass band, and the harmonics overlap each other when their frequencies are close to each other, which seriously affects the suppression performance of the low frequency. Although the resonant frequency interval of the two modes can be adjusted to a certain degree by adjusting the spacing of the double blind holes of the resonator, the change of the spacing not only affects the frequencies of the two modes at the same time, but also changes the adjacent coupling amount, so that the design is more limited, and the adjustment amount of the harmonic frequency is very limited.
In view of the above, the prior art is obviously inconvenient and disadvantageous in practical use, and needs to be improved.
Disclosure of Invention
In view of the above-mentioned drawbacks, an object of the present invention is to provide a dielectric filter that can greatly improve low-frequency suppression performance, and that has a simple structure and is easy to implement.
In order to achieve the above object, the present invention provides a dielectric filter comprising at least one first resonator operating in TE102 mode and at least one second resonator operating in TE101 mode;
the top surface and the bottom surface of the first resonator respectively comprise a top surface center and a bottom surface center which are symmetrical;
the top surface of the first resonator is symmetrically provided with a pair of first tuning blind holes around the center of the top surface;
a bottom blind hole is formed in the center of the bottom surface of the first resonator; and/or
The first resonator is provided with a through hole penetrating through the top surface and the bottom surface, and the through hole is positioned on a perpendicular bisector corresponding to a connecting line of the pair of first tuning blind holes.
According to the dielectric filter provided by the invention, the dielectric filter comprises the first resonator and at least two second resonators, and the bottom surface of the first resonator is provided with the bottom blind hole in the center of the bottom surface.
According to the dielectric filter of the present invention, the dielectric filter includes two first resonators and at least two second resonators, wherein the bottom surface of one of the first resonators has the bottom blind via at the center of the bottom surface, and the other first resonator has the through hole penetrating through the top surface and the bottom surface thereof, and the through hole is located on a midperpendicular line corresponding to a connection line of the pair of first tuning blind vias.
According to the dielectric filter provided by the invention, the dielectric filter comprises two first resonators and at least two second resonators, wherein one first resonator is provided with the through hole penetrating through the top surface and the bottom surface of the first resonator, and the through hole is positioned on a perpendicular bisector corresponding to a connecting line of the pair of first tuning blind holes.
According to the dielectric filter, the depth of the bottom blind hole of the first resonator is increased, the resonant frequency of a loaded TE101 mode is reduced, and the interval between the resonant frequency of the loaded TE102 mode and the resonant frequency of the loaded TE101 mode is increased; and/or
The distance of the through hole of the first resonator from the center of the top surface or the center of the bottom surface decreases, the resonance frequency of the TE 101-loaded mode increases, and the interval from the resonance frequency of the TE 102-loaded mode decreases.
According to the dielectric filter of the present invention, the center of the top surface of the first resonator is a planar center or a predetermined center of the top surface of the first resonator;
the center of the bottom surface of the first resonator is a planar center or a predetermined center of the bottom surface of the first resonator.
According to the dielectric filter of the present invention, the top surface and the bottom surface of the second resonator respectively include a top surface center and a bottom surface center that are symmetrical;
and a second tuning blind hole is formed in the center of the top surface of the second resonator, and the depth of the first tuning blind hole is greater than that of the second tuning blind hole.
According to the dielectric filter, the first resonator enables the resonance frequency of the loaded TE102 mode to be close to the preset filter passband frequency by adjusting the diameter, the depth and/or the spacing of the first tuning blind holes; and/or
And the second resonator enables the resonance frequency of the loaded TE101 mode to be close to the preset filter passband frequency by adjusting the diameter, the depth and/or the spacing of the second tuning blind holes.
According to the dielectric filter of the present invention, the center of the top surface of the second resonator is a planar center or a predetermined center of the top surface of the second resonator;
the center of the bottom surface of the second resonator is a planar center or a predetermined center of the bottom surface of the second resonator.
According to the dielectric filter, the dielectric filter comprises at least two second resonators, wherein the centers of the bottom surfaces of the two second resonators are respectively provided with an input port blind hole and an output port blind hole, the input port blind hole is used for inputting signals, and the output port blind hole is used for outputting signals.
According to the dielectric filter, the isolating rings made of non-metal materials are respectively arranged around the input port blind hole and the output port blind hole.
According to the dielectric filter, the dielectric filter comprises a ceramic dielectric block main body, at least one isolation through groove and/or isolation through hole are/is arranged on the ceramic dielectric block main body, and the isolation through groove and/or the isolation through hole divide the ceramic dielectric block main body into at least one first resonator and at least one second resonator; and the first resonator and the second resonator are coupled through a dielectric connecting section of the ceramic dielectric block main body.
According to the dielectric filter of the present invention, the surfaces of the first resonator and the second resonator are coated with plating layers made of a metal material.
The dielectric filter comprises a first resonator working in a TE102 mode and a second resonator working in a TE101 mode, and a bottom blind hole and/or a through hole are/is additionally arranged in the first resonator by utilizing the electromagnetic field distribution difference of two resonance modes of loading TE101 and loading TE102, so that the frequency of loading the TE101 mode can be reduced or increased under the condition of less influence on the frequency of loading the TE102 mode, and the flexible adjustment of low-frequency parasitic harmonics is realized. Preferably, when the bottom surface of the first resonator is provided with the bottom blind hole in the center of the bottom surface, the resonant frequency of the loading TE101 mode is reduced and the interval between the resonant frequency of the loading TE102 mode and the resonant frequency of the loading TE101 mode is increased along with the increase of the depth of the bottom blind hole, so that the low-frequency spurious harmonic is far away from the working passband; when the first resonator is provided with the through holes penetrating through the top surface and the bottom surface, and the through holes are positioned on the perpendicular bisector corresponding to the connecting line of the pair of first tuning blind holes, along with the reduction of the distance between the through holes and the center, the resonant frequency of the TE101 loading mode is increased, and the interval between the resonant frequency of the TE102 loading mode and the resonant frequency of the TE101 loading mode is reduced, so that the low-frequency harmonic of the dielectric filter adopting the TE102 mode capacitive coupling can be effectively improved, and particularly, the condition that the low-frequency harmonic frequencies of at least two parasitic TE101 modes are close to each other and the low-frequency suppression is aggravated due to the. Therefore, the low-frequency rejection performance of the dielectric filter can be greatly improved, the structure is simple, the implementation is easy, and the design flexibility and the adaptability are further improved.
Drawings
Fig. 1 is a schematic structural diagram of a first resonator provided with a bottom blind hole according to a first embodiment of the present invention;
fig. 2 is a schematic diagram of an electric field distribution of a first resonator loaded with TE101 mode according to a first embodiment of the present invention;
fig. 3 is a schematic diagram of the electric field distribution of the first resonator loaded with TE102 mode according to the first embodiment of the present invention;
fig. 4 is a graph of the resonant frequency of the first resonator loaded with TE101 mode and TE102 mode versus the depth of the blind via according to the first embodiment of the present invention;
fig. 5 is a diagram of quality factor Q and blind via depth of the first resonator loaded with TE101 mode and TE102 mode according to the first embodiment of the present invention;
fig. 6 is a schematic structural diagram of a first resonator provided with a through hole according to a second embodiment of the present invention;
fig. 7 is a graph of the resonant frequency of the first resonator loaded with TE101 mode and TE102 mode versus the depth of the blind via according to the second embodiment of the present invention;
fig. 8 is a diagram of quality factor Q and blind via depth of the first resonator loaded with TE101 mode and TE102 mode according to the second embodiment of the present invention;
fig. 9 is a schematic diagram of front and back side structures of a dielectric filter according to a third embodiment of the present invention;
fig. 10 is a graph comparing frequency response curves of a dielectric filter according to a third embodiment of the present invention;
fig. 11 is a schematic diagram of front and back side structures of a dielectric filter according to a fourth embodiment of the present invention;
fig. 12 is a graph comparing frequency response curves of a dielectric filter according to a fourth embodiment of the present invention.
Reference numerals:
a dielectric filter 100; a first resonator 10; a second resonator 20;
a first tuning blind hole 11; a bottom blind hole 12; a through hole 13;
a second tuning blind hole 21; an input port blind hole 22; an output port blind hole 22;
a spacer ring 30; a ceramic dielectric block body 40; an isolation through groove 41;
isolating the vias 42.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
It should be noted that references in the specification to "one embodiment," "an example embodiment," etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not intended to refer to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.
Moreover, where certain terms are used throughout the description and following claims to refer to particular components or features, those skilled in the art will understand that manufacturers may refer to a component or feature by different names or terms. This specification and the claims that follow do not intend to distinguish between components or features that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. In addition, the term "connected" as used herein includes any direct and indirect electrical connection. Indirect electrical connection means include connection by other means.
Fig. 1 to 12 show the structure of the dielectric filter of the present invention, said dielectric filter 100 is preferably ceramic-based, and comprises at least one first resonator 10 operating in TE102 mode and at least one second resonator 20 operating in TE101 mode, and the dielectric filter 100 realizes capacitive coupling by loading the first resonator 10 in TE102 mode. According to the invention, by utilizing the electromagnetic field distribution difference of two resonance modes of loading TE101 and loading TE102, a bottom blind hole 12 and/or a through hole 13 are/is added in the first resonator 10 working in the TE102 mode, so that the low-frequency parasitic harmonic can be flexibly adjusted.
As shown in fig. 1 and 6, the top and bottom surfaces of the first resonator 10 include symmetrical top and bottom surface centers, respectively. Preferably, the center of the top surface of the first resonator 10 is a planar center of the top surface of the first resonator 10, a predetermined center, or the like, the predetermined center being a predetermined center, and the predetermined center may be an arbitrary point on the top surface. The center of the bottom surface of the first resonator 10 is a planar center of the bottom surface of the first resonator 10, a predetermined center, or the like, and the predetermined center is a predetermined center, and may be an arbitrary point on the bottom surface. The top surface of the first resonator 10 is provided with a pair of first tuning blind holes 11 symmetrically about the center of the top surface. Since the resonance frequency of the loaded TE101 mode is lower than that of the loaded TE102 mode, when the first resonator 10 is integrated in the dielectric filter 100, the loaded TE101 mode generates spurious harmonics at the low frequency of the pass band.
In the first embodiment shown in fig. 1, the bottom surface of the first resonator 10 is provided with a bottom blind hole 12 in the center of the bottom surface. As can be seen from the electric field distribution diagrams of fig. 2 and 3, the electromagnetic field distribution of the loaded TE101 and loaded TE102 modes has a large difference near the bottom blind hole 12. In the loading TE101 mode, the electric field at the bottom of the bottom blind hole 12 is stronger, and the direction is vertical to the bottom surface of the bottom blind hole 12; while in the loading TE102 mode the electric field at the bottom of the bottom blind via 12 is weak, oriented parallel to the bottom surface of the bottom blind via 12. It can be seen that the newly added bottom blind via 12 has a large influence on the resonant frequency of the loaded TE101 mode, but has no influence on the resonant frequency of the loaded TE102 mode.
Preferably, the depth of the bottom blind hole 12 of the first resonator 10 is increased, the resonance frequency of the loaded TE101 mode is decreased, and the interval from the resonance frequency of the loaded TE102 mode is increased. As shown in fig. 4, as the depth of the bottom blind via 12 increases, the resonant frequency of the loaded TE101 mode decreases by nearly 500MHz, while the resonant frequency of the loaded TE102 mode decreases by only about 10 MHz. In this embodiment, the height of the first resonator 10 is 6mm, and the depth of the bottom blind hole 12 is half of the overall height of the first resonator 10 when the depth is equal to 3 mm. Of course, the height of the first resonator 10 can be set according to actual needs, and is not limited in any way. As shown in fig. 5, the addition of the bottom blind via 12 has a small influence on the Q value of the quality factor of the resonator, which indicates that the introduction of the bottom blind via 12 does not substantially affect the pass band performance such as the insertion loss of the dielectric filter 100.
Preferably, the cross-sectional shape of the bottom blind hole 12 introduced by the first resonator 10 includes, but is not limited to, a circle, a square, and the like, and optionally, the cross-sectional shape of the bottom blind hole 12 is set to be a circle in the present embodiment, so as to improve the processing convenience of the bottom blind hole 12 and easily guarantee the processing precision of the bottom blind hole 12.
Preferably, the first resonator 10 can make the resonance frequency of the loaded TE102 mode near the predetermined desired filter passband frequency by adjusting the diameter, depth and/or spacing of the pair of first tuning blind holes 11. The first tuning blind hole 11 is used to generate a capacitive loading such that the first resonator 10 operates in TE102 mode. The first tuning blind hole 11 is a blind hole, on one hand, a tuning margin can be reserved, and on the other hand, the resonant frequency of the first tuning blind hole 11 can be adjusted by changing the diameter, the depth and/or the distance of the first tuning blind hole 11. The cross-sectional shape of the first tuning blind hole 11 includes, but is not limited to, a circle, a square, and the like, and optionally, the cross-sectional shape of the first tuning blind hole 11 is set to be a circle in this embodiment, so as to improve the processing convenience of the first tuning blind hole 11, and easily guarantee the processing accuracy of the first tuning blind hole 11.
Preferably, the surface of the first resonator 10 is coated with a plating layer made of a metal material. In this embodiment, the electroplated layer is made of copper or silver with high conductivity, which can further reduce the insertion loss of the dielectric filter 100, and further improve the performance of the dielectric filter 100.
Aiming at the design limitation of TE102 mode capacitive coupling of the existing dielectric filter, the dielectric filter 100 in the first embodiment of the present invention optimizes the structure of the first resonator 10 operating in the TE102 mode, and proposes to add one bottom blind via 12 to the first resonator 10 to adjust the TE101 mode frequency thereof, and because of the electromagnetic field distribution difference between the two resonant modes of loading TE101 and loading TE102, the bottom blind via 12 is disposed on the first resonator 10, so that the resonant frequency of the TE101 mode can be reduced under the condition of less influence on the frequency of loading TE102 mode, and the interval between the resonant frequency of loading TE101 mode and the frequency of loading TE102 mode is increased, thereby the low-frequency spurious harmonic is far away from the operation, the adjustment of the low-frequency spurious harmonic frequency of the dielectric filter 100 is realized, the suppression performance of the dielectric filter 100 at low frequency is improved, and the structure is simple and easy to implement.
In the second embodiment shown in fig. 6, the first resonator 10 is provided with a through hole 13 penetrating through the top and bottom surfaces, and the through hole 13 is located on a midperpendicular line corresponding to a connection line between a pair of first tuning blind holes 11. The difference between fig. 6 and the first resonator 10 shown in fig. 1 is that: the bottom blind via 12 disposed at the bottom center is replaced with a through hole 13 disposed on the perpendicular bisector of the connecting line of the pair of first tuning blind vias 11, and due to the difference in electromagnetic field distribution on the perpendicular bisector between the TE 101-loaded mode and the TE 102-loaded mode, the newly added through hole 13 has a large influence on the resonant frequency of the TE 101-loaded mode, and has substantially no influence on the resonant frequency of the TE 102-loaded mode. Specifically, the introduction of via 13 can raise the tuning frequency of the loaded TE101 mode with relatively little effect on the raising of the tuning frequency of the loaded TE102 mode.
Preferably, the distance from the center of the top surface or the center of the bottom surface to the through hole 13 introduced by the first resonator 10 is decreased, the resonance frequency of the TE 101-loaded mode is increased, and the interval from the resonance frequency of the TE 102-loaded mode is decreased. As shown in fig. 7, as the through hole 13 is translated on the perpendicular bisector corresponding to the line connecting the pair of first tuning blind holes 11, the interval between the resonance frequency of the TE101 mode and the resonance frequency of the TE102 mode is continuously reduced as the distance between the through hole 13 and the center (i.e., the center of the top surface or the center of the bottom surface) is reduced. However, in contrast to the aforementioned addition of the bottom blind via 12, as shown in fig. 8, the quality factor Q of the two modes decreases to some extent as the distance between the through hole 13 and the center decreases. It can be seen that the method of introducing the through-hole 13 is generally used to shift a low-frequency spurious harmonic to a specific frequency band in a high-frequency direction or to avoid a plurality of low-frequency harmonics from being superimposed on each other. In practice, the distance between the through hole 13 and the center is increased as much as possible to avoid the influence on the quality factor Q of the first resonator 10.
Preferably, the cross-sectional shape of the through hole 13 introduced by the first resonator 10 includes, but is not limited to, a circle, a square, and the like, and optionally, the cross-sectional shape of the through hole 13 is set to be a circle in the present embodiment, so as to improve the processing convenience of the through hole 13 and easily guarantee the processing precision of the through hole 13.
Aiming at the design limitation of TE102 mode capacitive coupling of the existing dielectric filter, the dielectric filter 100 in the second embodiment of the present invention optimizes the structure of the first resonator 10 operating in TE102 mode, and proposes to add the through hole 13 to the first resonator 10 to adjust the TE101 mode frequency thereof, and because of the electromagnetic field distribution difference between the two resonant modes of TE101 loading and TE102 loading, the through hole 13 is arranged on the first resonator 10, so that the resonant frequency of TE101 mode can be raised under the condition of less influence on the TE102 loading mode frequency, and thus the low frequency harmonics of the dielectric filter 100 adopting TE102 mode capacitive coupling can be effectively improved, especially the low frequency harmonics with at least two parasitic TE101 modes having similar frequencies, which are mutually superposed to cause the aggravation of low frequency suppression, and the structure is simple and easy to implement.
Preferably, the dielectric filter 100 includes a ceramic dielectric block body 40, at least one isolation through-groove 41 and/or isolation through-hole 42 are provided on the ceramic dielectric block body 40, and the isolation through-groove 41 and/or isolation through-hole 42 divide the ceramic dielectric block body 40 into at least one first resonator 10 and at least one second resonator 20. The first resonator 10 and the second resonator 20 are coupled by a dielectric connection segment of the ceramic dielectric block body 40. The ceramic dielectric block body 40 of the present invention is preferably a rectangular block structure, although in other embodiments any other shape may be used as desired.
Preferably, the dielectric filter 100 includes a first resonator 10 and at least two second resonators 20, and the bottom surface of the first resonator 10 is provided with a bottom blind hole 12 at the center of the bottom surface.
In the third embodiment shown in fig. 9, the dielectric filter 100 is a sixth-order dielectric filter, and the passband is designed to be 3.4 to 3.6 GHz. The dielectric filter 100 of fig. 9 comprises a ceramic dielectric block body 40, said ceramic dielectric block body 40 being divided into six resonators by a plurality of isolating through-slots 41 and one isolating through-hole 42, five of which are the second resonators 20 operating in the loaded TE101 mode and the other is the first resonator 10 operating in the loaded TE102 mode. The first resonator 10 is capacitively coupled to at least one of the second resonators 20, and is inductively coupled to at least one of the second resonators 20, and any one of the second resonators 20 is inductively coupled to at least one of the other second resonators 20. The top surface of the first resonator 10 is provided with a pair of first tuning blind holes 11 symmetrically about the center of the top surface. The bottom surface of the first resonator 10 is provided with a bottom blind hole 12 in the center of the bottom surface, and the frequency of the first resonator 10 loaded with the TE101 mode is reduced by adjusting the depth of the bottom blind hole 12, so that the low-frequency spurious harmonic is far away from the working passband.
Preferably, the top and bottom surfaces of the second resonator 20 include symmetrical top and bottom surface centers, respectively. The center of the top surface of the second resonator 20 is a planar center of the top surface of the second resonator 20, or a predetermined center, which is a preset center and may be any point on the top surface. The center of the bottom surface of the second resonator 20 is a planar center of the bottom surface of the second resonator 20, a predetermined center, which may be an arbitrary point on the bottom surface, or the like. The top surface of each second resonator 20 is provided with a second tuning blind hole 21 at the center of the top surface, and the depth of the first tuning blind hole 11 is greater than that of the second tuning blind hole 21, so that the first resonator 10 works in a loaded TE102 mode, and thus capacitive coupling is generated between the first resonator and an adjacent resonator.
Preferably, the second resonators 20 adjust the diameter, depth and/or spacing of the second tuning blind holes 21 to make the resonant frequency of the loaded TE101 mode be in the vicinity of the predetermined filter passband frequency, that is, each second resonator 20 adjusts the loading amount of each second resonator 20 by adjusting the depth of each second tuning blind hole 21 to realize the adjustment of the respective frequency. The second tuning blind via 21 is used to create a capacitive loading such that the second resonator 20 operates in TE101 mode. The second tuning blind hole 21 is a blind hole, on one hand, a tuning margin can be reserved, and on the other hand, the resonant frequency of the second tuning blind hole 21 can be adjusted by changing the diameter, the depth and/or the distance of the second tuning blind hole 21. Further, the cross-sectional shape of the second tuning blind hole 21 includes, but is not limited to, a circle, a square, and the like, and optionally, the cross-sectional shape of the second tuning blind hole 21 is set to be a circle in the present embodiment, so as to improve the processing convenience of the second tuning blind hole 21 and easily guarantee the processing precision of the second tuning blind hole 21.
Preferably, the first resonator 10 and the second resonator 20 are coupled by a dielectric connection segment of the ceramic dielectric block body 40. That is, after one first resonator 10 and five second resonators 20 are divided by the isolation through-groove 41 and the isolation through-hole 42, the first resonator 10 and each second resonator 20 are coupled to each other by the remaining dielectric connection sections on the ceramic dielectric block body 40.
Preferably, the dielectric filter 100 includes at least two second resonators 20, wherein the bottom surfaces of the two second resonators 20 respectively have an input port blind hole 22 and an output port blind hole 22 at the center of the bottom surface, the input port blind hole 22 is used for inputting signals, and the output port blind hole 22 is used for outputting signals. Preferably, the input port blind hole 22 and the output port blind hole 22 are respectively provided with a spacer ring 30 made of a non-metallic material around the input port blind hole 22 and the output port blind hole 22 for separating the input port blind hole 22 and the output port blind hole 22 from other surface coatings.
Preferably, the surfaces of the ceramic dielectric block body 40 except for the spacer ring 30 are coated with a plating layer made of a metal material. In this embodiment, the electroplated layer is made of copper or silver with high conductivity, which can further reduce the insertion loss of the dielectric filter 100, and further improve the performance of the dielectric filter 100.
Fig. 10 is a comparison graph of frequency response curves before and after the dielectric filter provided by the third embodiment of the present invention is introduced into the bottom blind hole, and it can be seen from the graph that before and after the bottom blind hole 12 is additionally arranged at the bottom of the first resonator 10 loaded with the TE102 mode, the frequency response curve of the dielectric filter 100 near the operating passband is basically unchanged, while the low-frequency spurious harmonic is changed from the original 2.95GHz to 2.78GHz, which not only is farther away from the operating passband, but also reduces the amplitude of the harmonic by about 10dB, and greatly improves the suppression performance of the low frequency band.
Preferably, the dielectric filter 100 includes two first resonators 10 and at least two second resonators 20, wherein the bottom surface of one first resonator 10 is provided with a bottom blind via 12 at the center of the bottom surface, the other first resonator 10 is provided with a through hole 13 penetrating through the top surface and the bottom surface thereof, and the through hole 13 is located on a perpendicular bisector corresponding to a connecting line of a pair of first tuning blind vias 11.
In the fourth embodiment as shown in fig. 11, the dielectric filter 100 is an eighth-order dielectric filter, and the passband is designed to be 2.515-2.675 GHz. Apart from the difference between the operating frequency and the order, the greatest difference between the fourth embodiment and the third embodiment is that it includes two first resonators 10 operating in the TE102 mode, which are respectively located in the cross-coupling structure of the two quadrupoles so as to respectively generate two transmission zeros on both sides of the operating passband of the dielectric filter 100, and therefore there are two spurious harmonics introduced by the respective TE101 modes at the low frequencies of the passband.
Specifically, the dielectric filter 100 in fig. 11 includes a ceramic dielectric block body 40, the ceramic dielectric block body 40 is divided into eight resonators by a plurality of isolation through-slots 41 and a plurality of isolation through-holes 42, six of the eight resonators are second resonators 20 operating in the loading TE101 mode, and two first resonators 10 operating in the loading TE102 mode are provided, and a pair of first tuning blind holes 11 is symmetrically provided on top surfaces of the two first resonators 10 with respect to a center of the top surfaces. Any first resonator 10 is capacitively coupled to at least one second resonator 20 and inductively coupled to at least one second resonator 20, and any second resonator 20 is inductively coupled to at least one of the other second resonators 20. In this embodiment, a bottom blind hole 12 is formed in the bottom surface of the first resonator 10 at the lower left corner, and the frequency of the first resonator 10 in the TE101 loading mode is reduced by adjusting the depth of the bottom blind hole 12, so that the low-frequency spurious harmonic is far away from the operating passband. The first resonator 10 at the upper right corner is provided with a through hole 13 penetrating through the top surface and the bottom surface of the first resonator 10, the through hole 13 is located on a perpendicular bisector corresponding to a connecting line of the pair of first tuning blind holes 11, and the introduction of the through hole 13 can increase the tuning frequency of the first resonator 10 at the upper right corner in a loading TE101 mode, so that the problem that two parasitic harmonics generated by the two first resonators 10 are mutually superposed to seriously affect the low-frequency suppression performance is solved.
Fig. 12 is a comparison graph of frequency response curves before and after the dielectric filter provided by the fourth embodiment of the present invention is introduced into the bottom blind hole and the through hole, and the bottom blind hole 12 and the through hole 13 are not introduced into the dielectric filter of the present invention in the original design, because the frequencies of the two parasitic harmonics are close, the two parasitic harmonics are mutually overlapped to a great extent, and the suppression performance on the frequency band of 2.05 to 2.1GHz is large. According to the method, a bottom blind hole 12 is additionally arranged in the center of the bottom surface of a first resonator 10 at the lower left corner to reduce the frequency of a TE101 loading mode in the first resonator 10, so that the lowest-frequency spurious harmonic frequency is further reduced by about 100 MHz; meanwhile, a through hole 13 is introduced into a perpendicular bisector corresponding to a connecting line of a pair of first tuning blind holes 11 in the resonator 10 at the lower right corner to increase the frequency of loading the TE101 mode of the first resonator 10, so that the frequency of the other parasitic harmonic wave is increased by about 40MHz, the distance between the two parasitic harmonic waves is increased, the mutual superposition effect is weakened, the overall harmonic amplitude is reduced by about 20dB, and the low-frequency suppression performance is effectively improved.
In the fourth embodiment of the invention, by utilizing the electromagnetic field distribution difference of two resonant modes of loading TE101 and loading TE102, the two first resonators 10 are respectively provided with the bottom blind holes 12 and the through holes 13, so that the frequency of loading TE101 mode can be reduced or increased under the condition of less influence on the frequency of loading TE102 mode. When a bottom blind hole 12 is additionally arranged in the center of the bottom of one of the first resonators 10, along with the increase of the depth of the bottom blind hole 12, the frequency of the loading TE101 mode becomes lower, and the frequency interval between the loading TE102 mode and the loading TE101 mode becomes larger; when a through hole 13 is introduced into another first resonator 10 on the perpendicular bisector corresponding to the connecting line of the pair of first tuning blind holes 11, the frequency of the loaded TE101 mode increases and the frequency interval from the loaded TE102 mode decreases as the distance from the center of the through hole 13 decreases. Therefore, the low-frequency parasitic harmonic frequency of the filter is adjusted, the problem that the low-frequency harmonic frequencies of two parasitic TE101 modes are close and superposed to cause aggravation of low-frequency inhibition is solved, the harmonic frequencies can be separated by utilizing the structure of the invention, the low-frequency inhibition performance is greatly improved, the structure is simple, the realization is easy, and the design flexibility and the adaptability are improved.
In the fifth embodiment of the present invention, the dielectric filter 100 includes two first resonators 10 and at least two second resonators 20, wherein one of the first resonators 10 is provided with a through hole 13 penetrating through the top and bottom surfaces thereof, and the through hole 13 is located on a midperpendicular line corresponding to a line connecting a pair of the first tuning blind holes 11. The dielectric filter 100 in the fifth embodiment of the present invention optimizes the structure of the first resonator 10 operating in the TE102 mode, and proposes to add the through hole 13 in the first resonator 10 to adjust the TE101 mode frequency thereof, and because of the electromagnetic field distribution difference between the two resonant modes of loading TE101 and loading TE102, the through hole 13 is provided in the first resonator 10, so that the resonant frequency of the TE101 mode can be raised under the condition of less influence on the TE102 mode frequency, and the problem that the low-frequency harmonic frequencies of at least two parasitic TE101 modes are close and mutually superposed to cause aggravated low-frequency suppression can be solved, thereby realizing the suppression of the low-frequency parasitic harmonics.
Preferably, each first resonator 10 and each second resonator 20 in the dielectric filter 100 according to the present invention are integrally formed. Based on the above arrangement, on one hand, the production convenience of the dielectric filter 100 can be improved to a certain extent, that is, the production efficiency of the dielectric filter 100 is improved, which is beneficial to the mass production thereof; on the other hand, the processing error between each first resonator 10 and each second resonator 20 can be reduced, so that the position accuracy between each first resonator 10 and each second resonator 20 is guaranteed, and the accurate control of the coupling amount between each first resonator 10 and each second resonator 20, that is, the manufacturing accuracy of the dielectric filter 100, is facilitated.
In summary, the dielectric filter of the present invention includes a first resonator operating in TE102 mode and a second resonator operating in TE101 mode, and a bottom blind via and/or a through via is added to the first resonator by using the electromagnetic field distribution difference between two resonant modes of loading TE101 and loading TE102, which can reduce or increase the frequency of loading TE101 mode under the condition of less influence on the frequency of loading TE102 mode, thereby realizing flexible adjustment of low-frequency spurious harmonics. Preferably, when the bottom surface of the first resonator is provided with the bottom blind hole in the center of the bottom surface, the resonant frequency of the loading TE101 mode is reduced and the interval between the resonant frequency of the loading TE102 mode and the resonant frequency of the loading TE101 mode is increased along with the increase of the depth of the bottom blind hole, so that the low-frequency spurious harmonic is far away from the working passband; when the first resonator is provided with the through holes penetrating through the top surface and the bottom surface, and the through holes are positioned on the perpendicular bisector corresponding to the connecting line of the pair of first tuning blind holes, along with the reduction of the distance between the through holes and the center, the resonant frequency of the TE101 loading mode is increased, and the interval between the resonant frequency of the TE102 loading mode and the resonant frequency of the TE101 loading mode is reduced, so that the low-frequency harmonic of the dielectric filter adopting the TE102 mode capacitive coupling can be effectively improved, and particularly, the condition that the low-frequency harmonic frequencies of at least two parasitic TE101 modes are close to each other and the low-frequency suppression is aggravated due to the. Therefore, the low-frequency rejection performance of the dielectric filter can be greatly improved, the structure is simple, the implementation is easy, and the design flexibility and the adaptability are further improved.
The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it should be understood that various changes and modifications can be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (13)
1. A dielectric filter comprising at least one first resonator operating in TE102 mode and at least one second resonator operating in TE101 mode;
the top surface and the bottom surface of the first resonator respectively comprise a top surface center and a bottom surface center which are symmetrical;
the top surface of the first resonator is symmetrically provided with a pair of first tuning blind holes around the center of the top surface;
a bottom blind hole is formed in the center of the bottom surface of the first resonator; and/or
The first resonator is provided with a through hole penetrating through the top surface and the bottom surface, and the through hole is positioned on a perpendicular bisector corresponding to a connecting line of the pair of first tuning blind holes.
2. A dielectric filter according to claim 1, wherein the dielectric filter comprises one of the first resonators and at least two of the second resonators, and wherein the bottom surface of the first resonator is provided with the bottom blind via at the center of the bottom surface.
3. A dielectric filter as recited in claim 1, wherein said dielectric filter includes two of said first resonators and at least two of said second resonators, wherein a bottom surface of one of said first resonators has said bottom blind via at a center of said bottom surface, and another of said first resonators has said through hole extending through a top surface and a bottom surface thereof, and said through hole is located on a midperpendicular line corresponding to a line connecting said pair of first tuning blind vias.
4. A dielectric filter according to claim 1, wherein the dielectric filter includes two of the first resonators and at least two of the second resonators, one of the first resonators is provided with the through hole penetrating through its top and bottom surfaces, and the through hole is located on a midperpendicular line corresponding to a line connecting the pair of first tuning blind holes.
5. A dielectric filter as recited in any one of claims 1 to 4, wherein the depth of the bottom blind via of the first resonator increases, the resonant frequency of the TE 101-loaded mode decreases, and the spacing from the resonant frequency of the TE 102-loaded mode increases; and/or
The distance of the through hole of the first resonator from the center of the top surface or the center of the bottom surface decreases, the resonance frequency of the TE 101-loaded mode increases, and the interval from the resonance frequency of the TE 102-loaded mode decreases.
6. The dielectric filter of claim 1, wherein the center of the top surface of the first resonator is a planar center or a predetermined center of the top surface of the first resonator;
the center of the bottom surface of the first resonator is a planar center or a predetermined center of the bottom surface of the first resonator.
7. The dielectric filter of claim 1, wherein the top and bottom surfaces of the second resonator comprise symmetrical top and bottom surface centers, respectively;
and a second tuning blind hole is formed in the center of the top surface of the second resonator, and the depth of the first tuning blind hole is greater than that of the second tuning blind hole.
8. The dielectric filter of claim 7, wherein the first resonator is configured to have the resonant frequency of the loaded TE102 mode near a predetermined filter passband frequency by adjusting the diameter, depth and/or spacing of the first tuning blind holes; and/or
And the second resonator enables the resonance frequency of the loaded TE101 mode to be close to the preset filter passband frequency by adjusting the diameter, the depth and/or the spacing of the second tuning blind holes.
9. The dielectric filter of claim 7, wherein the center of the top surface of the second resonator is a planar center or a predetermined center of the top surface of the second resonator;
the center of the bottom surface of the second resonator is a planar center or a predetermined center of the bottom surface of the second resonator.
10. The dielectric filter of claim 7, comprising at least two of the second resonators, wherein the bottom surfaces of the two second resonators have an input port blind hole and an output port blind hole respectively at the center of the bottom surfaces, the input port blind hole is used for inputting signals, and the output port blind hole is used for outputting signals.
11. The dielectric filter of claim 10, wherein isolating rings made of non-metallic materials are respectively arranged around the input port blind hole and the output port blind hole.
12. The dielectric filter according to claim 1, wherein the dielectric filter comprises a ceramic dielectric block body, at least one isolation through groove and/or isolation through hole are formed in the ceramic dielectric block body, and the isolation through groove and/or the isolation through hole divide the ceramic dielectric block body into at least one first resonator and at least one second resonator; and the first resonator and the second resonator are coupled through a dielectric connecting section of the ceramic dielectric block main body.
13. The dielectric filter according to claim 1, wherein surfaces of the first resonator and the second resonator are coated with plating layers made of a metal material.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20210328315A1 (en) * | 2018-12-26 | 2021-10-21 | Huawei Technologies Co., Ltd. | Dielectric filter, duplexer, and communications device |
| CN113839158A (en) * | 2021-09-26 | 2021-12-24 | 华南理工大学 | Four-mode dielectric waveguide filter |
| WO2024114230A1 (en) * | 2022-11-30 | 2024-06-06 | 华为技术有限公司 | Resonator, filter, dynamic antenna unit, and remote radio unit |
-
2021
- 2021-03-09 CN CN202110256335.XA patent/CN112952316A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20210328315A1 (en) * | 2018-12-26 | 2021-10-21 | Huawei Technologies Co., Ltd. | Dielectric filter, duplexer, and communications device |
| US11909086B2 (en) * | 2018-12-26 | 2024-02-20 | Huawei Technologies Co., Ltd. | Dielectric filter, duplexer, and communications device |
| CN113839158A (en) * | 2021-09-26 | 2021-12-24 | 华南理工大学 | Four-mode dielectric waveguide filter |
| CN113839158B (en) * | 2021-09-26 | 2022-04-22 | 华南理工大学 | Four-mode dielectric waveguide filter |
| WO2024114230A1 (en) * | 2022-11-30 | 2024-06-06 | 华为技术有限公司 | Resonator, filter, dynamic antenna unit, and remote radio unit |
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