CN115513625A - High out-of-band rejection split dielectric filter - Google Patents
High out-of-band rejection split dielectric filter Download PDFInfo
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- CN115513625A CN115513625A CN202211283885.1A CN202211283885A CN115513625A CN 115513625 A CN115513625 A CN 115513625A CN 202211283885 A CN202211283885 A CN 202211283885A CN 115513625 A CN115513625 A CN 115513625A
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P1/00—Auxiliary devices
- H01P1/20—Frequency-selective devices, e.g. filters
- H01P1/212—Frequency-selective devices, e.g. filters suppressing or attenuating harmonic frequencies
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P1/00—Auxiliary devices
- H01P1/20—Frequency-selective devices, e.g. filters
- H01P1/2002—Dielectric waveguide filters
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P7/00—Resonators of the waveguide type
- H01P7/10—Dielectric resonators
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Abstract
The invention relates to a high out-of-band rejection separating dielectric filter, which comprises a ceramic capacitor sheet, wherein a plurality of dielectric resonators are sequentially arranged below the ceramic capacitor sheet along the length direction of the ceramic capacitor sheet; the bottom surface of the ceramic capacitor plate is provided with a bottom surface metal electrode plate corresponding to each dielectric resonator, and each dielectric resonator is connected with the corresponding bottom surface metal electrode plate through a connecting pin; two input and output electrodes are arranged on the top surface of the ceramic capacitor plate, and transmission zero points with specified frequency are formed between two dielectric resonators located below the input and output electrodes and adjacent dielectric resonators. In the invention, the transmission zero point with the appointed frequency is formed between the input and output resonator and the adjacent transmission resonator, so that the transmission zero point appears outside the high-frequency part of the filter, the order of the separated dielectric filter can be reduced, the number of the resonators is reduced, the volume and the loss of the filter are reduced, and the application effect is improved.
Description
Technical Field
The invention belongs to the technical field of dielectric filters, and relates to a high out-of-band rejection separating type dielectric filter.
Background
The dielectric filter adopts an electronic ceramic material as a medium and is formed into a multi-stage resonant cavity to realize the frequency selection function. The high dielectric constant of the ceramic material can greatly reduce the size of the filter and realize the application of miniaturization and integration. The separated dielectric filter is one of dielectric filters, and each resonator of the separated dielectric filter is independent in structure, and the arrangement structure of the resonators is not easy to realize transmission zero, so that the number of resonators with more out-of-band rejection requirements is increased. It is therefore desirable to provide a split dielectric filter structure that can produce out-of-band transmission zeros, thereby enabling the split dielectric filter to achieve high out-of-band rejection with a reduced number of resonators.
Disclosure of Invention
Aiming at the defects of the prior art, the technical problems to be solved by the invention are as follows: the separated dielectric filter with high out-of-band rejection is suitable for scenes with high harmonic rejection requirements.
In order to achieve the purpose, the invention provides the following technical scheme:
a high out-of-band rejection separating dielectric filter comprises a ceramic capacitor sheet, wherein a plurality of dielectric resonators are sequentially arranged below the ceramic capacitor sheet along the length direction of the ceramic capacitor sheet, and a gap is reserved between every two adjacent dielectric resonators; the ceramic capacitor plate is provided with a top surface and a bottom surface opposite to the top surface, the bottom surface of the ceramic capacitor plate is provided with a bottom surface metal electrode plate corresponding to each dielectric resonator respectively, the bottom surface metal electrode plate is used for realizing the capacitive coupling of the adjacent dielectric resonators, and each dielectric resonator is connected with the corresponding bottom surface metal electrode plate through a connecting pin; the top surface of the ceramic capacitor plate is provided with two input and output electrodes which are respectively positioned above the bottom metal electrode plates on the two sides; two dielectric resonators positioned below the input and output electrodes are input and output resonators, the other dielectric resonators are transmission resonators, and transmission zeros with specified frequency are formed between the input and output resonators and the adjacent transmission resonators.
Further, the dielectric resonator comprises a square dielectric body, the upper end face of the dielectric body is an open-circuit face, the lower end face and four side faces of the dielectric body are covered with a metalized layer, a resonant through hole penetrating through the upper end face and the lower end face of the dielectric body is formed in the dielectric body, and the hole wall of the resonant through hole is covered with the metalized layer.
Furthermore, the dielectric body is a ceramic dielectric body made of solid high-dielectric-constant ceramic materials.
Further, the connecting needle is a cylinder made of a metal material.
Furthermore, the upper end face of the connecting needle is fixedly connected with the lower end face of the bottom metal electrode plate, and the lower end of the connecting needle extends into the resonance through hole of the dielectric resonator and is connected with the metallization layer covered on the hole wall of the resonance through hole.
Furthermore, the side surface of the dielectric body of the input-output resonator facing the adjacent dielectric resonator is an inductive coupling surface, a windowing region is arranged on the inductive coupling surface, and the windowing region is not covered with a metallization layer; the windowing region is used for realizing inductive coupling between the input and output resonators and the adjacent dielectric resonators.
Furthermore, the windowing region is square.
Further, the windowing region is located at the bottom of the inductive coupling surface.
Further, a gap between the bottom metal electrode plate corresponding to the input/output resonator and the bottom metal electrode plate corresponding to the adjacent transmission resonator is larger than a gap between the bottom metal electrode plates corresponding to the adjacent two transmission resonators.
Furthermore, four dielectric resonators are sequentially arranged below the ceramic capacitor piece along the length direction of the ceramic capacitor piece.
In the invention, a resonant circuit is formed between the input and output resonator and the adjacent transmission resonator through capacitive coupling and inductive coupling, and a transmission zero point with specified frequency is formed, so that the transmission zero point appears out of band of a high-frequency part of the filter, and the high-end out-of-band rejection can be improved by 20dB or more than 20dB. The order of the separated dielectric filter can be effectively reduced by increasing the transmission zero point to promote out-of-band rejection, so that the number of resonators is reduced, the size and the loss of the filter are reduced, and the application effect is improved. The device has the advantages of miniaturization, good temperature characteristic, good harmonic suppression characteristic, good power resistance, low cost, high manufacturing consistency and the like.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:
fig. 1 is a schematic structural diagram of a preferred embodiment of the high out-of-band rejection split dielectric filter of the present invention.
Fig. 2 is a front view of fig. 1.
Fig. 3 is a schematic structural view of a ceramic capacitor plate.
Fig. 4 is a schematic structural diagram of an input-output resonator.
Fig. 5 is a schematic structural view of a transmission resonator.
Figure 6 is a diagram of the electric field profile of the resonator.
Fig. 7 is a magnetic field profile of the resonator.
Fig. 8 is a graph showing a simulation of the performance of a dielectric filter designed according to the prior art in which transmission zeros are not formed out of band in the high frequency part.
Fig. 9 is a graph showing a simulation of the performance of the dielectric filter of the present embodiment.
The meaning of the reference symbols in the drawings is:
ceramic capacitor sheet-100; top-101; a bottom surface-102; a first input-output electrode-111; a second input-output electrode-112; a first bottom metal electrode pad-121; a second bottom metal electrode pad-122; a third bottom metal electrode pad-123; a fourth bottom metal electrode pad-124;
a connecting needle-200;
a dielectric body-300; a resonant via-301; opening a road-302; side-303; an inductive coupling surface-304; windowed area-305; a first dielectric resonator-310; a second dielectric resonator-320; a third dielectric resonator-330; a fourth dielectric resonator-340.
Detailed Description
The embodiments of the invention are explained below by means of specific examples, the illustrations provided in the following examples are merely illustrative of the basic idea of the invention, and features in the following examples and examples can be combined with one another without conflict.
As shown in fig. 1 and fig. 2, a preferred embodiment of the high out-of-band rejection split dielectric filter of the present invention includes a ceramic capacitor plate 100, where several dielectric resonators are sequentially arranged below the ceramic capacitor plate 100 along a length direction of the ceramic capacitor plate 100, and a gap is left between adjacent dielectric resonators. The ceramic capacitor plate 100 is provided with a top surface 101 and a bottom surface 102 opposite to the top surface 101, the bottom surface 102 of the ceramic capacitor plate 100 is provided with a bottom metal electrode plate corresponding to each dielectric resonator, and the bottom metal electrode plates are used for realizing the capacitive coupling of the adjacent dielectric resonators; each dielectric resonator is connected with the corresponding bottom metal electrode plate through a connecting pin 200. The top surface 101 of the ceramic capacitor plate 100 is provided with two input and output electrodes, and the two input and output electrodes are respectively located above the bottom metal electrode plates on the two sides. One of the input and output electrodes is the input end of the filter, and the other input and output electrode is the output end of the filter. Two dielectric resonators located below the input and output electrodes are input and output resonators, the other dielectric resonators are transmission resonators, and transmission zeros of a designated frequency are formed between the input and output resonators and the adjacent transmission resonators.
The present embodiment will be described by taking four dielectric resonators as an example, and as shown in fig. 1 and 2, a first dielectric resonator 310, a second dielectric resonator 320, a third dielectric resonator 330 and a fourth dielectric resonator 340 are sequentially provided below the ceramic capacitor chip 100 in the longitudinal direction of the ceramic capacitor chip 100. As shown in fig. 3, the bottom surface 102 of the ceramic capacitor chip 100 is provided with a first bottom metal electrode pad 121 above the first dielectric resonator 310, a second bottom metal electrode pad 122 above the second dielectric resonator 320, a third bottom metal electrode pad 123 above the third dielectric resonator 330, and a fourth bottom metal electrode pad 124 above the fourth dielectric resonator 340. In order to adjust the capacitive coupling between the adjacent dielectric resonators so as to form a transmission zero between the first dielectric resonator 310 and the second dielectric resonator 320, and so as to form a transmission zero between the third dielectric resonator 330 and the fourth dielectric resonator 340. The gap between the first bottom metal electrode pad 121 and the second bottom metal electrode pad 122, and the gap between the third bottom metal electrode pad 123 and the fourth bottom metal electrode pad 124 are both larger than the gap between the second bottom metal electrode pad 122 and the third bottom metal electrode pad 123.
The first dielectric resonator 310 is connected to the first bottom metal electrode pad 121 through a connection pin 200, the second dielectric resonator 320 is connected to the second bottom metal electrode pad 122 through a connection pin 200, the third dielectric resonator 330 is connected to the third bottom metal electrode pad 123 through a connection pin 200, and the fourth dielectric resonator 340 is connected to the fourth bottom metal electrode pad 124 through a connection pin 200. A first input/output electrode 111 is disposed on the top surface 101 of the ceramic capacitor plate 100 above the first bottom metal electrode plate 121, and a second input/output electrode 112 is disposed above the fourth bottom metal electrode plate 124. The first dielectric resonator 310 located below the first input-output electrode 111 and the fourth dielectric resonator 340 located below the second input-output electrode 112 are input-output resonators; the second dielectric resonator 320 and the third dielectric resonator 330 are transmission resonators.
As shown in fig. 4 and 5, each of the first dielectric resonator 310, the second dielectric resonator 320, the third dielectric resonator 330 and the fourth dielectric resonator 340 includes a square dielectric body 300, and the dielectric body 300 is a ceramic dielectric body made of a solid high-permittivity ceramic material. The upper end face of the dielectric body 300 is an open-road face 302, the lower end face and four side faces 303 of the dielectric body 300 are covered with a metallization layer, the dielectric body 300 is provided with a resonant through hole 301 penetrating through the upper end face and the lower end face, and the hole wall of the resonant through hole 301 is covered with the metallization layer. The connection pin 200 is preferably a cylinder made of a metal material, the upper end surface of the connection pin 200 is fixedly connected with the lower end surface of the corresponding bottom metal electrode plate, and the lower end of the connection pin 200 extends into the corresponding resonance through hole 301 of the dielectric resonator and is connected with the metallization layer covered on the hole wall of the resonance through hole 301.
The side 303 of the dielectric body 300 of the first dielectric resonator 310 and the fourth dielectric resonator 340 (i.e. the input/output resonator) facing the adjacent dielectric resonator is an inductive coupling surface 304, and the inductive coupling surface 304 is provided with a windowing region 305. Taking the first dielectric resonator 310 as an example, please refer to fig. 4, wherein a side 303 of the dielectric body 300 of the first dielectric resonator 310 facing the second dielectric resonator 320 is an inductive coupling surface 304, and the inductive coupling surface 304 is provided with a windowing region 305; the windowed area 305 is generally square, and the windowed area 305 is located at the bottom of the inductive coupling surface 304. The lower end face of the dielectric body 300 and the three side faces 303 except the inductive coupling face 304 of the first dielectric resonator 310 are all covered with a metallization layer, and after the inductive coupling face 304 is covered with the metallization layer, the metallization layer of the windowing region 305 is removed, so that a gap which is not covered with the metallization layer is formed in the windowing region 305. The structure of the fourth dielectric resonator 340 is the same as that of the first dielectric resonator 310, except that the orientation of the inductive coupling surface 304 is different; the side 303 of the dielectric body 300 of the fourth dielectric resonator 340 facing the third dielectric resonator 330 is an inductive coupling surface 304.
With continued reference to fig. 5, the lower end surface and four side surfaces 303 of the dielectric body 300 of the second dielectric resonator 320 and the third dielectric resonator 330 (i.e., the transmission resonator) are entirely covered with a metallization layer, and the windowing region 305 is not formed.
By breaking the metallization layer in the windowed areas 305 of the designated sides 303 of the input-output resonators (i.e. the first and fourth dielectric resonators 310, 340 and the inductive coupling surface 304), the electric and magnetic fields can transfer energy to the next resonator through the ceramic material and the windowed areas 305 of the inductive coupling surface 304 due to the high dielectric constant of the ceramic material, thereby achieving inductive coupling between the input-output resonator and the adjacent dielectric resonator.
Because the adjacent dielectric resonators are also capacitively coupled through the bottom metal electrode plate, inductive coupling is also realized between the first dielectric resonator 310 and the second dielectric resonator 320 and between the third dielectric resonator 330 and the fourth dielectric resonator 340 through the windowed area 305; by obtaining strong capacitive and inductive coupling between the first dielectric resonator 310 and the second dielectric resonator 320 and between the third dielectric resonator 330 and the fourth dielectric resonator 340, as shown in fig. 6, the electric field energy of each resonator (including the input resonator, the output resonator, and the intermediate resonator) is mainly concentrated at the open-top end thereof; as shown in fig. 7, the magnetic field energy of the resonator is mainly concentrated at its bottom (i.e., a portion adjacent to the bottom surface). The electric field energy corresponds to the capacitance C1 in the circuit, the magnetic field energy corresponds to the inductance L1 in the circuit, and when the electric field and the magnetic field are transmitted between the two resonators at the same time, the total energy transmitted is the absolute value of the difference (namely | C1-L1 |). However, the two are in parallel relation, and according to the resonant frequency calculation formula of the parallel circuit:
F＝2π/(LC)e 0.5
at this time, L1 and C1 may form a resonant circuit together, and form a transmission zero at a specified frequency, thereby achieving an effect of increasing out-of-band rejection.
The position of the transmission zero point is related to the amount of capacitive coupling and inductive coupling, and the gap between the adjacent bottom metal electrode sheets may be set according to the position of the transmission zero point, as well as the shape and area of the windowing region 305.
As shown in fig. 8, a simulation curve of a dielectric filter with a center frequency of 2.4GHz and a bandwidth of 20MHz actually designed by the prior art is shown, and no transmission zero is formed outside the band of the high frequency part. As shown in fig. 9, a simulation curve of a dielectric filter with a center frequency of 2.4GHz and a bandwidth of 20MHz actually designed by using the structure of this embodiment is shown in fig. 9, which generates a transmission zero at 2.53GHz and improves the out-of-band rejection at 2.5GHz by 20dB compared with the conventional structure of fig. 8.
In the embodiment, transmission zero points are generated between the first dielectric resonator 310 and the second dielectric resonator 320 and between the third dielectric resonator 330 and the fourth dielectric resonator 340, so that the transmission zero points appear outside the band of the high-frequency part of the filter, and the high-end out-of-band rejection can be improved by 20dB or more than 20dB. The number of orders of the separated dielectric filter can be effectively reduced by increasing the transmission zero point to promote out-of-band rejection, so that the number of resonators is reduced, the size and the loss of the filter are reduced, and the application effect is improved.
Finally, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. A high out-of-band rejection split dielectric filter, comprising: the ceramic capacitor comprises a ceramic capacitor piece, wherein a plurality of dielectric resonators are sequentially arranged below the ceramic capacitor piece along the length direction of the ceramic capacitor piece, and a gap is reserved between every two adjacent dielectric resonators; the ceramic capacitor plate is provided with a top surface and a bottom surface opposite to the top surface, the bottom surface of the ceramic capacitor plate is provided with a bottom surface metal electrode plate corresponding to each dielectric resonator respectively, the bottom surface metal electrode plate is used for realizing the capacitive coupling of the adjacent dielectric resonators, and each dielectric resonator is connected with the corresponding bottom surface metal electrode plate through a connecting pin; the top surface of the ceramic capacitor plate is provided with two input and output electrodes which are respectively positioned above the bottom metal electrode plates on two sides; two dielectric resonators located below the input and output electrodes are input and output resonators, the other dielectric resonators are transmission resonators, and transmission zeros of a designated frequency are formed between the input and output resonators and the adjacent transmission resonators.
2. The high out-of-band rejection split dielectric filter of claim 1, wherein: the dielectric resonator comprises a square dielectric body, the upper end face of the dielectric body is an open-circuit face, the lower end face and four side faces of the dielectric body are covered with metalized layers, a resonant through hole penetrating through the upper end face and the lower end face of the dielectric body is formed in the dielectric body, and the hole wall of the resonant through hole is covered with the metalized layers.
3. The high out-of-band rejection split dielectric filter of claim 2, wherein: the dielectric body is a ceramic dielectric body made of solid high-dielectric-constant ceramic materials.
4. The high out-of-band rejection split dielectric filter of claim 2, wherein: the connecting needle is a cylinder made of metal materials.
5. The high out-of-band rejection split dielectric filter of claim 4, wherein: the upper end face of the connecting needle is fixedly connected with the lower end face of the bottom metal electrode plate, and the lower end of the connecting needle extends into the resonance through hole of the dielectric resonator and is connected with the metallization layer covered on the hole wall of the resonance through hole.
6. The high out-of-band rejection split dielectric filter of claim 2, wherein: the side surface of the medium body of the input and output resonator facing to the adjacent medium resonator is an inductive coupling surface, a windowing region is arranged on the inductive coupling surface, and the windowing region is not covered with a metallization layer; the windowing region is used for realizing inductive coupling between the input and output resonator and the adjacent dielectric resonator.
7. The high out-of-band rejection split dielectric filter of claim 6, wherein: the windowing area is square.
8. The high out-of-band rejection split dielectric filter of claim 6, wherein: the windowing region is located at the bottom of the inductive coupling surface.
9. The high out-of-band rejection split dielectric filter of claim 1, wherein: and the gap between the bottom metal electrode plate corresponding to the input and output resonator and the bottom metal electrode plate corresponding to the adjacent transmission resonator is larger than the gap between the bottom metal electrode plates corresponding to the two adjacent transmission resonators.
10. The high out-of-band rejection split dielectric filter of any one of claims 1 to 9, wherein: four dielectric resonators are sequentially arranged below the ceramic capacitor plate along the length direction of the ceramic capacitor plate.
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| CN202211283885.1A CN115513625A (en) | 2022-10-20 | 2022-10-20 | High out-of-band rejection split dielectric filter |
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| CN202211283885.1A CN115513625A (en) | 2022-10-20 | 2022-10-20 | High out-of-band rejection split dielectric filter |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117200728A (en) * | 2023-11-07 | 2023-12-08 | 江苏灿勤科技股份有限公司 | Split type band elimination filter with good in-band inhibition effect |
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2022
- 2022-10-20 CN CN202211283885.1A patent/CN115513625A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117200728A (en) * | 2023-11-07 | 2023-12-08 | 江苏灿勤科技股份有限公司 | Split type band elimination filter with good in-band inhibition effect |
| CN117200728B (en) * | 2023-11-07 | 2024-02-02 | 江苏灿勤科技股份有限公司 | Split type band elimination filter with good in-band inhibition effect |
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