阅读说明：本技术 无外壳的小型介质双模滤波器 (Small-sized medium double-mode filter without outer shell ) 是由 江顺喜 梁国春 杜锦杰 王飞 项显 殷实 于 2020-07-30 设计创作，主要内容包括：本发明实施例公开了一种无外壳的小型介质双模滤波器,属于通信技术领域。该滤波器包括：通过金属杆串联的n个谐振腔,且每相邻两个谐振腔之间间隔一个金属片；n个谐振腔中的第一个和最后一个谐振腔为金属谐振腔；n个谐振腔中的剩余n-2个谐振腔为介质双模谐振腔,介质双模谐振腔为对称多边形结构,且介质双模谐振腔的表面实现金属化；n个谐振腔通过金属片上的耦合窗口进行耦合。本发明实施例提供的滤波器无需在介质双模谐振腔的外部设置金属外壳,具有体积紧凑,损耗小,功率容量大,带外抑制高,谐波性能好的特点,从而可以有效提高5G通信系统的抗干扰能力和频谱利用率,降低5G通信系统的功耗,提高5G通信系统的覆盖范围。(The embodiment of the invention discloses a small-sized medium dual-mode filter without a shell, belonging to the technical field of communication. The filter includes: n resonant cavities connected in series through metal rods, and a metal sheet is arranged between every two adjacent resonant cavities at intervals; the first resonant cavity and the last resonant cavity in the n resonant cavities are metal resonant cavities; the rest n-2 resonant cavities in the n resonant cavities are medium dual-mode resonant cavities which are in symmetrical polygonal structures, and the surfaces of the medium dual-mode resonant cavities are metallized; the n resonant cavities are coupled through a coupling window on the metal sheet. The filter provided by the embodiment of the invention does not need to arrange a metal shell outside the medium dual-mode resonant cavity, and has the characteristics of compact volume, small loss, large power capacity, high out-of-band rejection and good harmonic performance, so that the anti-interference capability and the frequency spectrum utilization rate of a 5G communication system can be effectively improved, the power consumption of the 5G communication system is reduced, and the coverage range of the 5G communication system is improved.)

1. A small dielectric dual-mode filter without a housing, the filter comprising: n resonant cavities are connected in series through metal rods, a metal sheet is arranged between every two adjacent resonant cavities at an interval, and n is more than or equal to 3;

the first resonant cavity and the last resonant cavity in the n resonant cavities are metal resonant cavities;

the rest n-2 resonant cavities in the n resonant cavities are medium dual-mode resonant cavities, the medium dual-mode resonant cavities are in symmetrical polygonal structures, and the surfaces of the medium dual-mode resonant cavities are metallized;

the n resonant cavities are coupled through coupling windows on the metal sheet.

2. The small dielectric double-mode filter without a housing of claim 1, wherein the top and the bottom of the dielectric double-mode resonator are recessed inward to form polygonal ring structures, respectively, and the polygonal ring structures are connected with adjacent metal sheets.

3. A small dielectric two-mode filter without a housing according to claim 2, characterized in that the sides of the dielectric two-mode resonator and the top of the polygonal ring structure are metallized.

4. The housingless small-sized dielectric dual-mode filter according to claim 1, wherein the dielectric dual-mode resonator is provided with two symmetrical coupling holes, the two coupling holes are used for generating coupling between two orthogonal resonant frequencies, and the diameter of the coupling hole has a positive correlation with the coupling coefficient between the resonant frequencies.

5. The housingless, compact, two-mode, dielectric filter of claim 1, wherein coupling holes of two adjacent dielectric dual-mode resonators are distributed in a staggered manner, and four resonant frequencies of the two adjacent dielectric dual-mode resonators are negatively cross-coupled and produce two transmission zeros symmetrically at two ends of the pass band of the filter.

6. The small dielectric dual-mode filter without a housing of claim 5, wherein a cross-shaped coupling window is provided on the metal sheet located between the ith and (i + 1) th dielectric dual-mode resonators, i is a positive integer;

the long side in the cross-shaped coupling window is used for generating coupling of the main circuit of the filter, and the short side is used for generating the cross coupling.

7. The housing-less compact dielectric dual-mode filter of claim 6, wherein the size of the coupling window is positively correlated to the size of the coupling coefficient between the dielectric dual-mode resonators.

8. The small-sized dielectric dual-mode filter without housing of claim 1, wherein through holes are provided on the metal sheet and the metal resonator, the metal rods penetrate through the through holes and are connected in series with the metal resonator and the metal sheet, and each metal rod is fixed with two metal resonators.

9. A small dielectric dual-mode filter without a housing as claimed in claim 1, wherein the dielectric dual-mode cavity is made of a microwave ceramic material.

10. A housingless, compact, dual-mode, dielectric filter as claimed in any one of claims 1 to 9, wherein the filter is applied in the sub 6GHz band.

Technical Field

The embodiment of the invention relates to the technical field of communication, in particular to a small-sized medium dual-mode filter without a shell.

Background

In Sub 6GHz in 5G (5 th Generation) communication, MIMO (multiple-Input multiple-Output) technology is adopted, and a large number of filters need to be integrated inside an antenna, and therefore, higher requirements are placed on loss of the filters, out-of-band rejection, power capacity, size, weight, and the like.

If the traditional metal filter is selected, the traditional metal filter cannot be integrated in the antenna because the size and the weight of the traditional metal filter are too large. When a small dielectric waveguide filter is used, the small dielectric waveguide filter has a small size, but has a large insertion loss and a low power capacity.

Disclosure of Invention

The embodiment of the invention provides a small-sized medium dual-mode filter without a shell, which is used for solving the problems in the prior art. The technical scheme is as follows:

in one aspect, there is provided a small dielectric dual mode filter without a housing, the filter comprising: n resonant cavities are connected in series through metal rods, a metal sheet is arranged between every two adjacent resonant cavities at an interval, and n is more than or equal to 3;

the first resonant cavity and the last resonant cavity in the n resonant cavities are metal resonant cavities;

the rest n-2 resonant cavities in the n resonant cavities are medium dual-mode resonant cavities, the medium dual-mode resonant cavities are in symmetrical polygonal structures, and the surfaces of the medium dual-mode resonant cavities are metallized;

the n resonant cavities are coupled through coupling windows on the metal sheet.

In a possible implementation manner, the top and the bottom of the dielectric dual-mode resonant cavity are respectively recessed inwards to form a polygonal annular structure, and the polygonal annular structure is connected with the adjacent metal sheet.

In a possible implementation manner, the side surface of the dielectric dual-mode resonant cavity and the top of the polygonal ring structure are subjected to metallization processing.

In a possible implementation manner, two symmetrical coupling holes are formed in the medium dual-mode resonant cavity, the two coupling holes are used for generating coupling between two orthogonal resonant frequencies, and the size of the diameter of each coupling hole is in positive correlation with the size of a coupling coefficient between the resonant frequencies.

In a possible implementation manner, coupling holes on two adjacent dielectric dual-mode resonant cavities are distributed in a staggered manner, and four resonant frequencies contained in the two adjacent dielectric dual-mode resonant cavities generate negative cross coupling, and two symmetrical transmission zeros are generated at two ends of a pass band of the filter.

In a possible implementation mode, a cross-shaped coupling window is arranged on a metal sheet positioned between the ith and (i + 1) th dielectric dual-mode resonant cavities, wherein i is a positive integer;

the long side in the cross-shaped coupling window is used for generating coupling of the main circuit of the filter, and the short side is used for generating the cross coupling.

In a possible implementation manner, the size of the coupling window and the size of the coupling coefficient between the medium dual-mode resonators are in a positive correlation relationship.

In a possible implementation manner, the dielectric dual-mode resonant cavity includes a metal shell and a dielectric block located inside the metal shell, and the two coupling holes are located on the dielectric block.

In a possible implementation manner, through holes are formed in the metal sheet and the metal resonant cavity, the metal rods penetrate through the through holes and are connected in series with the metal resonant cavity and the metal sheet, and each metal rod is fixed with two metal resonant cavities respectively.

In one possible implementation manner, the dielectric dual-mode resonant cavity is made of a microwave ceramic material.

In one possible implementation, the filter is applied to the sub 6GHz band.

The technical scheme provided by the embodiment of the invention has the beneficial effects that at least:

because the filter comprises n resonant cavities which are connected in series through metal rods, the first resonant cavity and the last resonant cavity in the n resonant cavities are metal resonant cavities, and the remaining n-2 resonant cavities are medium dual-mode resonant cavities. Therefore, tap coupling can be realized through the two metal resonant cavities, and the far-end harmonic of the filter is suppressed by utilizing the characteristic that the secondary resonant frequency of the metal resonant cavities is far away from the working resonant frequency; the high dielectric constant characteristic and the low loss characteristic of the medium in the medium dual-mode resonant cavity can be utilized to reduce the volume and the in-band insertion loss of the filter. In addition, the surface of the medium dual-mode resonant cavity is metallized, a metal boundary condition can be formed, so that a metal shell can be prevented from being arranged outside the medium dual-mode resonant cavity, the problems that the frequency of the filter is high and serious due to a large gap between the medium dual-mode resonant cavity and the metal shell, and the temperature drift under high and low temperature conditions is large, so that the performance of the filter is influenced are solved, and the problems that the medium dual-mode resonant cavity cannot be pressed into the metal shell due to a small gap between the medium dual-mode resonant cavity and the metal shell, even if the medium dual-mode resonant cavity can be pressed into the metal shell, a metal layer on the surface of the metal shell can be scraped by the medium dual-mode resonant cavity, and the medium dual-mode resonant cavity can. In summary, since a metal shell is not required to be arranged outside the dielectric dual-mode resonant cavity, the problem caused by the gap between the dielectric dual-mode resonant cavity and the metal shell can be solved, the production difficulty of the filter is reduced, and the reliability of the filter is higher; the size and the weight of the filter can be reduced, so that the filter has the characteristics of compact size, low loss, high power capacity, high out-of-band rejection and good harmonic performance, the anti-interference capability and the frequency spectrum utilization rate of a 5G system can be effectively improved, the power consumption of the 5G communication system is reduced, and the coverage range of the 5G communication system is improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic diagram of a small dielectric dual-mode filter without a housing in one embodiment of the invention;

figure 2 is a schematic diagram of a small dielectric dual-mode filter without a housing in one embodiment of the invention;

figure 3 is a schematic diagram of a small dielectric dual-mode filter without a housing in one embodiment of the invention;

figure 4 is a schematic diagram of a small dielectric dual-mode filter without a housing in one embodiment of the invention;

FIG. 5 is a schematic diagram of a dielectric dual-mode resonator in an embodiment of the invention;

FIG. 6 is a schematic diagram of a dielectric dual-mode resonator in an embodiment of the invention;

FIG. 7 is a schematic diagram of a near-end frequency response curve of a filter in one embodiment of the invention;

fig. 8 is a schematic view of a metal sheet in an embodiment of the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the embodiments of the present invention will be described in further detail with reference to the accompanying drawings.

Referring to fig. 1, a small dielectric dual-mode filter without a housing according to an embodiment of the present invention is shown, where the filter includes: n resonant cavities 120 connected in series through metal rod 110, and a metal sheet 130 is arranged between every two adjacent resonant cavities 120, wherein n is more than or equal to 3.

If the number of resonators 120 is n, the number of metal sheets 130 is n-1, and the number of n may be determined according to actual filter specifications, which is not limited in this embodiment.

As illustrated in fig. 1 with n being 6, fig. 1 shows a small dielectric dual-mode filter with a tenth order and a fourth zero. The filter comprises a first resonator 120, a first metal sheet 130, a second resonator 120, a second metal sheet 130, a third resonator 120, a third metal sheet 130, a fourth resonator 120, a fourth metal sheet 130, a fifth resonator 120, a fifth metal sheet 130 and a sixth resonator 120 in sequence.

In the embodiment, the filter is realized by adopting a metal resonant cavity and a medium dual-mode resonant cavity. In one implementation, the first and last resonators 120 of n resonators 120 are metal resonators, and the remaining n-2 resonators 120 of n resonators 120 are dielectric dual-mode resonators. Still taking the filter of fig. 1 as an example for illustration, the first resonator 120 (the leftmost resonator 120 in fig. 1) and the sixth resonator 120 (the rightmost resonator 120 in fig. 1) are metal resonators, and the second to four resonators 120 in the middle are dielectric dual-mode resonators. For the sake of convenience of distinction, a metal resonant cavity is denoted by 120-1 and a dielectric dual-mode resonant cavity is denoted by 120-2 in fig. 1. Wherein, the metal resonant cavity needs to be grounded to solve the lightning stroke problem.

Because the first resonant cavity 120 is the input end of the filter, the last resonant cavity 120 is the output end of the filter, and the two metal resonant cavities are metal coaxial resonant cavities and are loaded by using the metal resonant columns, the far-end harmonic wave of the filter can be suppressed by utilizing the characteristic that the secondary resonant frequency of the metal resonant cavities is far away from the working resonant frequency, that is, the far-end parasitic passband of the filter can be suppressed.

The high-dielectric-constant dielectric dual-mode resonant cavity is used as a middle-stage resonant cavity, so that the size of the resonant cavity 120 in the filter can be reduced by utilizing the characteristics of high dielectric constant and dual modes. Wherein each dielectric dual-mode resonant cavity has two orthogonal resonant frequencies. In one implementation, the dielectric dual-mode resonant cavity may be made of a microwave ceramic material, and the loss characteristic of the filter may be improved by using the low loss characteristic of the microwave ceramic material.

In this embodiment, the dielectric dual-mode resonant cavity has a symmetric polygonal structure. For example, the dielectric dual-mode resonator may have a hexagonal structure, an octagonal structure, etc., and the hexagonal structure is illustrated in fig. 1.

In one implementation, a metal enclosure is required to be disposed outside the dielectric dual-mode resonator, thereby creating a metal boundary condition. In this implementation, there will be a gap between the dielectric dual-mode resonator and the metal housing. If the gap is too large, the frequency of the filter is high and serious, and the temperature drift under the high and low temperature conditions is large, so that the performance of the filter is influenced; if the gap is small, the dielectric dual-mode resonant cavity cannot be pressed into the metal shell, and even if the dielectric dual-mode resonant cavity can be pressed into the metal shell, the metal layer on the surface of the metal shell may be scraped by the dielectric dual-mode resonant cavity, and the metal shell may crush the dielectric dual-mode resonant cavity at high and low temperatures. In order to solve the above problems, in the present embodiment, the surface of the dielectric dual-mode resonator is metallized, and the metal shell is completely replaced by the metallization, so that the problems caused by the metal shell can be overcome. The metallization may be implemented by silver plating or silver firing, and this embodiment is not limited.

In this embodiment, each metal plate 130 is provided with a coupling window 131, so that n resonators 120 can be coupled through coupling windows 131 in metal plates 130.

The resonant cavity 120 can be manufactured separately as an independent component, the metal sheet 130 can also be manufactured separately as an independent component, and then the filter is obtained by connecting the resonant cavity 120 and the metal sheet 130 in series through the metal rod 110, so that the production difficulty of the filter is reduced, and the production of the filter is facilitated.

Referring to fig. 2-4, fig. 2 is a side view of the filter in fig. 1, fig. 3 is a schematic diagram of the filter in fig. 1 after being rotated by 90 ° counterclockwise, and fig. 4 is a side view of the filter in fig. 2.

In summary, in the small dielectric dual-mode filter without the housing provided by this embodiment, the filter includes n resonant cavities connected in series through the metal rod, the first and last resonant cavities in the n resonant cavities are metal resonant cavities, and the remaining n-2 resonant cavities are dielectric dual-mode resonant cavities. Therefore, tap coupling can be realized through the two metal resonant cavities, and the far-end harmonic of the filter is suppressed by utilizing the characteristic that the secondary resonant frequency of the metal resonant cavities is far away from the working resonant frequency; the high dielectric constant characteristic and the low loss characteristic of the medium in the medium dual-mode resonant cavity can be utilized to reduce the volume and the in-band insertion loss of the filter. In addition, the surface of the medium dual-mode resonant cavity is metallized, a metal boundary condition can be formed, so that a metal shell can be prevented from being arranged outside the medium dual-mode resonant cavity, the problems that the frequency of the filter is high and serious due to a large gap between the medium dual-mode resonant cavity and the metal shell, and the temperature drift under high and low temperature conditions is large, so that the performance of the filter is influenced are solved, and the problems that the medium dual-mode resonant cavity cannot be pressed into the metal shell due to a small gap between the medium dual-mode resonant cavity and the metal shell, even if the medium dual-mode resonant cavity can be pressed into the metal shell, a metal layer on the surface of the metal shell can be scraped by the medium dual-mode resonant cavity, and the medium dual-mode resonant cavity can. In summary, since a metal shell is not required to be arranged outside the dielectric dual-mode resonant cavity, the problem caused by the gap between the dielectric dual-mode resonant cavity and the metal shell can be solved, the production difficulty of the filter is reduced, and the reliability of the filter is higher; the size and the weight of the filter can be reduced, so that the filter has the characteristics of compact size, low loss, high power capacity, high out-of-band rejection and good harmonic performance, the anti-interference capability and the frequency spectrum utilization rate of a 5G system can be effectively improved, the power consumption of the 5G communication system is reduced, and the coverage range of the 5G communication system is improved.

Referring to the structure diagram of the single dielectric dual-mode resonant cavity shown in fig. 5, the top and the bottom of the dielectric dual-mode resonant cavity in this embodiment are recessed inward to form polygonal ring structures 121, and the polygonal ring structures 121 may be used as supporting partition walls to connect with adjacent metal sheets 130. Still taking the filter in fig. 1 as an example, the polygonal ring structure 121 at the top of the first dielectric dual-mode resonant cavity is connected to the first metal sheet 130, and the polygonal ring structure 121 at the bottom of the first dielectric dual-mode resonant cavity is connected to the second metal sheet 130; the polygonal ring structure 121 at the top of the second dielectric dual-mode resonant cavity is connected to the second metal plate 130, the polygonal ring structure 121 at the bottom of the second dielectric dual-mode resonant cavity is connected to the third metal plate 130, and so on.

In addition, two symmetrical coupling holes 122 are arranged on the medium dual-mode resonant cavity, and the two coupling holes 122 are used for generating coupling between two orthogonal resonant frequencies. Referring to fig. 6, the filter in fig. 6 includes 4 dielectric dual-mode resonators, and since each dielectric dual-mode resonator generates two orthogonal resonant frequencies, the 4 dielectric dual-mode resonators form 8 resonant frequencies.

Wherein, the size of the diameter of the coupling hole 122 is in positive correlation with the size of the coupling coefficient between the resonant frequencies. That is, the larger the diameter of the coupling hole 122 is, the larger the coupling coefficient between the resonance frequencies is; the smaller the diameter of the coupling hole 122, the smaller the coupling coefficient between the resonance frequencies. Thus, the coupling coefficient between the resonance frequencies can be adjusted by adjusting the size of the diameter of the coupling hole 122.

In this embodiment, the side 123 of the dielectric dual-mode cavity and the top of the polygonal ring structure 121 are metalized. Namely, the periphery of the outer surface of the dielectric dual-mode resonator is metallized, and the top of the partition wall is also metallized, which is used as a metal boundary condition of the dielectric dual-mode resonator.

In this embodiment, the coupling holes 122 on two adjacent dielectric dual-mode resonators are distributed in a staggered manner, and four resonant frequencies included in the two adjacent dielectric dual-mode resonators generate negative cross coupling, and two symmetrical transmission zeros are generated at two ends of the passband of the filter.

The two adjacent medium dual-mode resonant cavities are arranged in a crossed mode according to a certain angle, four resonant frequencies contained in the two adjacent medium dual-mode resonant cavities are used as a subset to generate negative cross coupling, and therefore two symmetrical transmission zeros are generated at two ends of a pass band of the filter. Similarly, if there are a plurality of such subsets, a plurality of symmetrical transmission zeroes may be created, such that a steep out-of-band rejection may be achieved with symmetrical transmission zeroes.

Referring to the near-end frequency response curve of the filter shown in fig. 7, it can be seen from the response curve that the mixed-mode filter with the fourth tenth zero shown in this embodiment has four transmission zeros on the left and right sides of the passband.

Referring to the schematic diagram of the metal sheets 130 shown in fig. 8, in the present embodiment, each metal sheet 130 is provided with a coupling window 131, and the size of the coupling window 131 is in positive correlation with the size of the coupling coefficient between the dielectric dual-mode resonators. That is, the larger the coupling window 131, the larger the coupling coefficient; the smaller the coupling window 131, the smaller the coupling coefficient. Therefore, the size of coupling window 131 may be adjusted according to the coupling coefficient requirements between resonators 120.

For example, the coupling coefficient requirement of the metal resonant cavity and the dielectric dual-mode resonant cavity is large, and therefore, the coupling window 131 of the metal sheet 130 between the metal resonant cavity and the dielectric dual-mode resonant cavity is large.

In this embodiment, a cross-shaped coupling window is arranged on the metal sheet 130 located between the ith and (i + 1) th dielectric dual-mode resonators, and i is a positive integer; the long side in the cross-shaped coupling window is used for generating coupling of the main circuit of the filter, and the short side is used for generating cross coupling.

For example, in the metal sheet 130 between the first dielectric dual-mode resonant cavity and the second dielectric dual-mode resonant cavity (i.e., the metal sheet 130 on the right side in fig. 8), and the metal sheet 130 between the third dielectric dual-mode resonant cavity and the fourth dielectric dual-mode resonant cavity (i.e., the metal sheet 130 on the right side in fig. 8), the coupling window 131 is a cross-shaped coupling window. The cross-shaped coupling window structure and two adjacent dielectric dual-mode resonant cavities are coupled with a subset of four resonant frequencies, and transmission zeros can be respectively formed at two sides of the passband of the filter by alternately arranging the dielectric dual-mode resonant cavities and the cross-shaped coupling window structure. In the metal sheet 130 between the second dielectric dual-mode resonator and the third dielectric dual-mode resonator (i.e., the metal sheet 130 on the left side in fig. 8), the coupling window 131 is a line-shaped coupling window. I.e. a cross-shaped coupling window where there is cross-coupling and a straight-line-shaped coupling window where there is no cross-coupling.

The series connection of the resonant cavity 120 and the metal plate 130 will be explained. In this embodiment, a longer metal rod 110 may be used to connect metal resonator 120 and metal plate 130 in series, thereby resulting in an assembled filter.

Referring to fig. 1, in the present embodiment, through holes 132 are disposed on the metal plate 130 and the metal resonant cavity, the metal rods 110 penetrate through the through holes 132 and are connected in series with the metal resonant cavity 120 and the metal plate 130, and each metal rod 110 is fixed to two metal resonant cavities respectively.

In this embodiment, the metal resonant cavity 120 and the metal sheet 130 may be sequentially connected in series on the metal rod 110, and then the tail of the metal rod 110 is locked by a nut 140, thereby preventing the dual-mode dielectric resonant cavity from rotating.

The filter provided in this embodiment may be applied to a sub 6GHz band, and certainly, may also be applied to other bands, which is not limited in this embodiment. The size of the filter in this embodiment can be optimized and determined by electromagnetic simulation software such as HFSS (High Frequency Structure Simulator) according to actual filter indexes.

The above description should not be taken as limiting the embodiments of the invention, and any modifications, equivalents, improvements and the like which are within the spirit and principle of the embodiments of the invention should be included in the scope of the embodiments of the invention.