Filter

Abstract

A filter disclosed by the present invention comprises a cavity, a cover plate, a debugging rod and a plurality of dielectric resonators, the cavity is provided with at least two resonant cavities, the adjacent resonant cavities can form coupling through coupling windows, the cover plate covers the cavity to seal the cavity, the dielectric resonators are respectively arranged in the resonant cavities, and the debugging rod is connected with the dielectric resonators. The coupling window is arranged on the cover plate and selectively passes through or suppresses signals with specific frequencies, the debugging rod is arranged on the cover plate and extends to the coupling window, the coupling bandwidth range between the resonant cavities is adjusted by adjusting the depth, inserted into the coupling window, of the debugging rod, and the debugging rod is a metal rod, attached to the side wall of the coupling window and electrically connected with the side wall of the coupling window. Therefore, signals can be prevented from leaking between the debugging rod and the coupling window, and the adjustment range of the bandwidth of the filter is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of communication devices, and particularly relates to a filter. Background Art

[0002] A dielectric filter is an important device in a microwave system and is the center of many design problems in radio technology, used to separate and combine different frequency signals.

[0003] The dielectric filter mainly includes a cavity, a cover plate, dielectric resonators and tuning screws. The cavity is provided with a plurality of resonant cavities. Couplings are formed between adjacent resonant cavities through coupling windows. The dielectric resonators are arranged in each resonant cavity. The cover plate covers the cavity. The tuning screws are threadedly connected to the cover plate and extend to the coupling windows. By adjusting the depth of the tuning screws screwed into the windows, the relative bandwidth of the filter can be adjusted.

[0004] Since there are gaps between the existing tuning screws and the side walls of the coupling windows, signals are likely to leak through the gaps, reducing the sensitivity of the tuning screws and limiting the adjustment range of the relative bandwidth. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above technical deficiencies and provide a filter to solve the technical problem of the relatively small adjustment range of the relative bandwidth of the filter in the prior art.

[0006] To achieve the above technical purpose, the present invention adopts the following technical solutions: The present invention provides a filter, including: A cavity; A cover plate, covering the cavity, forming at least two resonant cavities and coupling windows located between adjacent resonant cavities with the cavity; and A plurality of dielectric resonators, respectively arranged in each of the resonant cavities; A debugging rod, the debugging rod is a metal rod, the debugging rod is installed on the cover plate and extends to the coupling window, and one end of the debugging rod extending to the coupling window fits against opposite side walls of the coupling window, forming an electrical connection with the side walls of the coupling window.

[0007] In some embodiments, a closed groove is provided on the side wall of the coupling window, and one end of the debugging rod extending to the coupling window fits against the side wall of the closed groove.

[0008] In some embodiments, the closed groove is an arc-shaped groove, the side wall of the closed groove forms an arc-shaped fitting surface, and the debugging rod fits against the arc-shaped fitting surface.

[0009] In some embodiments, the debugging rod is threadedly connected to the arc-shaped fitting surface.

[0010] In some embodiments, the filter further includes a lock nut, which is threadedly connected to the debugging rod and abuts against the cover plate, so that the lock nut forms a pulling force acting on the debugging rod away from the coupling window.

[0011] In some embodiments, the cover plate is provided with a perforation, which is opposite to the coupling window. The debugging rod passes through the perforation and is spaced from the side wall of the perforation.

[0012] In some embodiments, the cavity has a partition wall located between adjacent resonators. The lower side of the partition wall is connected to the bottom wall of the cavity, and the coupling window is formed in the partition wall.

[0013] In some embodiments, the upper side of the partition wall extends towards the cover plate and fits with the cover plate.

[0014] In some embodiments, the wall thickness of the partition wall is greater than or equal to the diameter of the debugging rod.

[0015] In some embodiments, the coupling window extends to the bottom wall of the cavity.

[0016] Compared with the prior art, the filter provided by the present invention includes a cavity, a cover plate, a debugging rod and a plurality of dielectric resonators. The cavity is provided with at least two resonators, and adjacent resonators can form adjacent coupling through a coupling window. The cover plate covers the cavity to seal it. The dielectric resonators are respectively arranged in each resonator to selectively pass or suppress signals of specific frequencies. The debugging rod is installed on the cover plate and extends to the coupling window. By adjusting the depth of the debugging rod inserted into the coupling window, the bandwidth range of the coupling between the resonators can be adjusted. Since the debugging rod is a metal rod and fits with the side wall of the coupling window, signal leakage between the debugging rod and the coupling window can be avoided, thereby effectively improving the adjustment range of the filter bandwidth. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic structural diagram of the filter provided by the embodiment of the present invention; Figure 2 is a side view of the filter provided by the embodiment of the present invention; Figure 3 is along Figure 2 sectional view taken along line A-A in Figure 4 is a schematic structural diagram of the filter with the upper cover hidden provided by the embodiment of the present invention; Figure 5 is a frequency response curve diagram of the existing filter and the filter provided by the embodiment of the present invention.

[0018] Reference numerals in the drawings: 10 - Cavity 11 - Resonant cavity 12 - Coupling window 13 - Partition wall 20 - Dielectric resonator 30 - Cover plate 31 - Cover plate 40 - Debugging rod 50 - Locking nut 121 - Enclosed groove 122 - Arc-shaped fitting surface Detailed implementation mode

[0019] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0020] In order to solve the technical problem that the adjustment range of the relative bandwidth of the filter in the prior art is small, the present invention provides a filter, which significantly improves the adjustment range of the filter bandwidth by eliminating the gap between the debugging rod and the side wall of the coupling window.

[0021] An embodiment of the present invention provides a filter, as Figures 1-4 shown, comprising a cavity 10, a plurality of dielectric resonators 20, a cover plate 30 and a debugging rod 40. The cover plate 30 is covered on the cavity 10 to form at least two resonant cavities 11 and a coupling window 12 located between adjacent resonant cavities 11 with the cavity 10; each dielectric resonator 20 is respectively arranged in each resonant cavity 11; the cover plate 30 is covered on the cavity 10; the debugging rod 40 is installed on the cover plate 30 and extends to the coupling window 12. The debugging rod 40 is a metal rod, and one end of the debugging rod 40 extending to the coupling window 12 fits with the side wall of the coupling window 12 to form an electrical connection with the side wall of the coupling window 12.

[0022] Specifically, the filter is provided with a cavity 10, a cover plate 30, a debugging rod 40 and a plurality of dielectric resonators 20. The cavity 10 is provided with at least two resonant cavities 11. Coupling can be formed between adjacent resonant cavities 11 through the coupling window 12. The cover plate 30 is covered on the cavity 10 to seal the cavity 10. The dielectric resonators 20 are respectively arranged in each resonant cavity 11 to selectively pass or suppress signals of specific frequencies. The debugging rod 40 is installed on the cover plate 30 and extends to the coupling window 12. The bandwidth range of the coupling between the resonant cavities 11 is adjusted by adjusting the depth of the debugging rod 40 inserted into the coupling window 12. Since the debugging rod 40 fits with the side wall of the coupling window 12 and the debugging rod 40 is a metal rod, an electrical connection is formed between the debugging rod 40 made of metal and the side wall of the coupling window 12, thereby preventing signals from leaking between the debugging rod 40 and the coupling window 12, and effectively improving the adjustment range of the filter bandwidth.

[0023] In this embodiment, adjacent coupling is formed between two adjacent resonant cavities 11 through a coupling window 12, and magnetic coupling is formed. An electrical connection is established between a debugging rod 40 made of metal and the side wall of the coupling window 12. The debugging rod 40 made of metal blocks the magnetic signal, and the debugging rod 40 is in contact with the side wall of the coupling window 12. Therefore, the magnetic signal is blocked from passing through between the debugging rod 40 and the side wall of the coupling window 12, thereby effectively blocking the magnetic field signal and achieving the effect of increasing the adjustment range of the filter bandwidth.

[0024] It can be understood that the number of resonant cavities 11 can be adaptively set according to actual needs. For the convenience of demonstration, in this embodiment, the number of resonant cavities 11 and dielectric resonators 20 is set to two as an example.

[0025] In one embodiment, as Figures 3-4 shown, the cavity 10 has a partition wall 13. The partition wall 13 is located between adjacent resonant cavities 11. The lower side of the partition wall 13 is connected to the bottom wall of the cavity 10, and the coupling window 12 is formed in the partition wall 13. Specifically, the partition wall 13 can separate adjacent coupling cavities and form coupling between two cavities 10 by forming the coupling window 12. By adjusting the closing of the partition wall 13 and the size of the coupling window 12, the coupling strength between adjacent coupling cavities can be controlled. The connection between the lower side of the partition wall 13 and the bottom wall of the cavity 10 facilitates the adjustment of the coupling strength between adjacent cavities 10 and improves the sensitivity of the coupling strength adjustment.

[0026] In one embodiment, as Figure 3 shown, the upper side of the partition wall 13 extends towards the cover plate 30 and is in contact with the cover plate 30. Specifically, by the contact between the debugging rod 40 and the side wall of the coupling window 12, the lower end face of the debugging rod 40 and the side wall of the coupling window can enclose to form the structure of the coupling cavity 10. By the contact between the upper side of the partition wall 13 and the cover plate 30, the gap between the partition wall 13 and the cover plate 30 can be eliminated. Combining with the connection between the lower side of the partition wall 13 and the bottom wall of the coupling cavity, the filter signal can only pass through the coupling cavity formed by the enclosure of the lower end face of the debugging rod 40 and the side wall of the coupling window 12. Therefore, by slightly adjusting the size of the coupling cavity, the bandwidth of the filter can be significantly adjusted, thereby obtaining an extremely high bandwidth adjustment range.

[0027] In this embodiment, as Figures 3-4 shown, the height of the partition wall 13 is the same as the depth of the coupling cavity, and the upper surface of the partition wall 13 is flush with the opening of the cavity 10.

[0028] In this embodiment, the bandwidth of the filter is usually determined by its lower limit frequency f1 and upper limit frequency f2. The bandwidth BW = f2 - f1. A flat region is formed between f1 and f2 on the frequency response curve, and this flat region shows the bandwidth range of the filter.

[0029] Please refer to Figure 5 the provided existing filter and the frequency response curve graph provided by the embodiment of the present invention; wherein, curve a in the figure is the frequency response curve of the existing filter, and curve b is the frequency response curve of the filter provided by the embodiment of the present invention. It can be clearly seen from the figure that the range of the flat region of curve a is significantly smaller than the range of the flat region of curve b, that is, it shows that the bandwidth range of the filter provided by the embodiment of the present invention is significantly larger than the bandwidth range of the existing filter. Therefore, through the setting of the metal material of the debugging rod 40 in this embodiment and the fitting setting of the debugging rod 40 with the side wall of the coupling window 12, the bandwidth range of the filter can be significantly increased.

[0030] In this embodiment, through the above setting, compared with the current bandwidth adjustment range (usually about 5%), the coupling relative bandwidth adjustment range of this embodiment can be increased to 200%.

[0031] In one of the embodiments, as Figures 3-4 shown, the wall thickness of the partition wall 13 is greater than or equal to the diameter of the debugging rod 40. Specifically, by making the wall thickness of the partition wall 13 greater than or equal to the diameter of the debugging rod 40, the circumference side of the debugging rod 40 can be prevented from protruding out of the coupling window 12, thereby changing the structure of the resonant cavity 11 and affecting the coupling of the resonant cavity 11.

[0032] In this embodiment, as Figures 3-4 shown, the wall thickness of the partition wall 13 is the same as the diameter of the debugging rod 40.

[0033] In this embodiment, the depth of the coupling window 12 affects the coupling strength between adjacent coupling cavities. At the same time, the coupling strength can be adjusted by the depth of the debugging rod 40 inserted into the coupling window 12. Usually, due to the gap between the debugging rod 40 and the coupling window 12, the debugging sensitivity of the debugging rod 40 is not high, and the adjustment range of the coupling strength is usually small. Therefore, to meet the requirements of different coupling strengths, it is usually necessary to set coupling windows 12 with different depths as the basis, and then the debugging rod 40 is used to perform a small-range adjustment of the coupling strength on this basis. Therefore, usually to meet the requirements of the filter for different coupling strengths, it is usually necessary to use multiple size types of filters with different depths of the coupling window 12.

[0034] In one of the embodiments, as Figures 3-4As shown, the coupling window 12 extends to the bottom wall of the cavity 10. Specifically, the deeper the coupling window 12 is, the higher the coupling strength between the two resonators 11. Therefore, the coupling window 12 extends to the bottom wall of the cavity 10, forming a window structure with a fixed depth and penetrating the partition wall 13 in the height direction, which can make the coupling strength between adjacent resonators 11 reach the maximum value. Since the debug rod 40 is set without clearance with the side wall of the coupling window 12, the debugging sensitivity of the debug rod 40 can be significantly enhanced, thereby increasing the debugging range of the coupling strength. Therefore, by extending the coupling window 12 to the bottom wall of the cavity 10 and matching the debug rod 40 with the side wall of the coupling window 12 without clearance, the coupling strength within any range can be debugged. Therefore, through the above fixed depth dimension and the setting of the debug rod 40 without clearance with the side wall of the coupling window 12, it is possible to meet the requirements of the filter for the coupling strength in various ranges without replacing or modifying the filter with coupling windows 12 of different sizes, thereby reducing the usage cost of the filter.

[0035] It can be understood that the side wall of the coupling window 12 can be a plane, an arc surface structure, etc. that can form a fit with one end of the debug rod 40 extending into the coupling window 12.

[0036] In one embodiment, as Figures 3-4 shown, a closed groove 121 is provided on the side wall of the coupling window 12, and one end of the debug rod 40 extending into the coupling window 12 fits with the side wall of the closed groove 121. Specifically, by separately providing a closed groove 121 structure for the debug rod 40 to fit on the side wall of the coupling window 12, while ensuring the fit degree between the debug rod 40 and the side wall of the coupling window 12, the debug rod 40 can be limited by the closed groove 121, thereby ensuring the stability of the filter signal.

[0037] It can be understood that the debug rod 40 can be any structure such as a square, a polygon, a circle, etc. that can fit the coupling window 12, and the closed groove 121 can be any groove structure such as a square groove, a multi-sided groove, etc. that can accommodate the side part of the debug rod 40. The debug rod 40 can be connected to the closed groove 121 in a form such as a sliding connection, and only needs to keep fitting with the side wall of the closed groove 121.

[0038] In one embodiment, as Figures 3-4 shown, the closed groove 121 is an arc groove, and the side wall of the closed groove 121 forms an arc fitting surface 122, and the debug rod 40 fits with the arc fitting surface 122. Specifically, the arc groove matches the circular structure of the debug rod 40, can keep stable fitting with the debug rod 40, and at the same time, can make the debug rod 40 rotate. Therefore, the debug rod 40 can meet the adjustment in the form of rotation.

[0039] It can be understood that the cover plate 30 can be provided with a thinning area. The upper end of the debugging rod 40 is fixedly connected to the thinning area, and the lower end is slidably connected to the coupling window 12. By deforming the thinning area, the debugging rod 40 is driven to slide along the coupling window 12 to adjust the insertion depth of the debugging rod 40; or it is fixedly connected to the cover plate 30 by screwing the upper end to the cover plate 30, and the side of the lower end is attached to the side wall of the coupling window 12. By turning the debugging rod 40, the insertion depth of the debugging rod 40 is adjusted.

[0040] In one embodiment, to ensure the stability of the fit between the debugging rod 40 and the coupling window 12 and completely eliminate the gap between the debugging rod 40 and the side wall of the coupling window 12, as Figures 3-4 shown, the debugging rod 40 is threadedly connected to the arc-shaped fitting surface 122. Specifically, by turning the debugging rod 40, the screwing depth of the debugging rod 40 screwed into the coupling window 12 can be adjusted to achieve bandwidth adjustment. Through the threaded fit between the debugging rod 40 and the arc-shaped fitting surface 122, the gap between the debugging rod 40 and the side wall of the coupling window 12 can be effectively eliminated, and the formation of a gap between the debugging rod 40 and the arc-shaped fitting surface 122 due to long-term wear can be avoided. In addition, there is no need to separately provide a threaded structure at the cover plate 30 for the debugging rod 40 to connect. While ensuring the fit between the debugging rod 40 and the coupling window 12, the filter structure is simplified. In this embodiment, the debugging rod 40 is a threaded rod, and the arc-shaped fitting surface 122 is provided with a corresponding threaded surface.

[0041] In one embodiment, as Figure 3 shown, the cover plate 30 is provided with a through hole 31, the through hole 31 is opposite to the coupling window 12, and the debugging rod 40 passes through the through hole 31 and is spaced from the side wall of the through hole 31. Specifically, since the lower end of the debugging rod 40 is threadedly fixed to the arc-shaped fitting surface 122, there is no need to separately provide a fixing structure at the upper cover to fix the debugging rod 40. Therefore, only the through hole 31 structure needs to be provided for the debugging rod 40 to extend into the coupling window 12. Through the spacing between the debugging rod 40 and the side wall of the through hole 31, the debugging rod 40 can be prevented from wearing against the side wall of the through hole 31 during the turning process, thereby better protecting the cover plate 30 and preventing debris from forming at the cover plate 30 and falling into the cavity 10, affecting the performance of the filter.

[0042] In this embodiment, the dielectric resonator 20 is made of a ceramic material with a high dielectric constant.

[0043] In this embodiment, the cover plate 30 is fixed to the cavity 10 by bolts to seal the cavity 10.

[0044] In one embodiment, as Figures 1-2As shown, the filter further includes a lock nut 50. The lock nut 50 is threadedly connected to the debugging rod 40 and abuts against the cover plate 30, so that the lock nut 50 forms a pulling force acting on the debugging rod 40 away from the coupling window 12. Specifically, after the bandwidth adjustment is completed, the lock nut 50 is threadedly connected to the upper end of the debugging rod 40 to lock the debugging rod 40. And through the abutment with the cover plate 30, the lock nut 50 forms a pulling force acting on the debugging rod 40 away from the coupling window 12. This pulling force is opposite to the pulling force of the arc-shaped fitting surface 122 acting on the debugging rod 40, and the debugging rod 40 does not come into contact with the cover plate 20. Therefore, the arc-shaped fitting surface 122 and the lock nut 50 act on each other to pull the two ends of the debugging rod 40. Under the pulling action at both ends, the debugging rod 40 can maintain high stability, effectively avoiding axial displacement of the debugging rod 40. And the lock nut 50 can fit with the cover plate 30 to block the gap between the debugging rod 40 and the side wall of the through hole 31, thereby preventing signal leakage from the gap between the debugging rod 40 and the side wall of the through hole 31.

[0045] In this embodiment, since the upper side of the partition wall 13 fits with the cover plate 30, it can support the cover plate 30, thereby preventing the cover plate 20 from deforming under the reverse acting force of the lock nut 50. In this case, the locking force of the lock nut 50 acting on the debugging rod 40 can be increased as much as possible to ensure the stability of the debugging rod 40.

[0046] The specific embodiments of the present invention described above do not constitute a limitation to the protection scope of the present invention. Any other corresponding changes and deformations made according to the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A filter, characterized in that: include: Cavity; A cover plate, which is arranged on the cavity and forms at least two resonant cavities and a coupling window between adjacent resonant cavities with the cavity; and A plurality of dielectric resonators are respectively arranged in each of the resonant cavities; A debugging rod, wherein the debugging rod is a metal rod, which is installed on the cover plate and extends to the coupling window. One end of the debugging rod extends to the coupling window and fits with the two side walls opposite to the coupling window to form an electrical connection with the side walls of the coupling window.

2. The filter according to claim 1, characterized in that The side wall of the coupling window is provided with a closed groove, and the debugging rod extends to one end of the coupling window and fits with the inner wall of the closed groove.

3. The filter according to claim 2, characterized in that The closed groove is an arc-shaped groove, the side wall of the closed groove forms an arc-shaped fitting surface, and the debugging rod fits with the arc-shaped fitting surface.

4. The filter according to claim 3, characterized in that The debugging rod is threadedly connected to the arc-shaped fitting surface.

5. The filter according to any one of claims 1 to 4, characterized in that: The filter further comprises a locking nut, which is threadedly connected to the debugging rod and abuts against the cover plate, so that the locking nut forms a pulling force acting on the debugging rod to move away from the coupling window.

6. The filter according to any one of claims 1 to 4, characterized in that: The cover plate is provided with a through hole, the through hole is opposite to the coupling window, the debugging rod passes through the through hole and is spaced apart from the side wall of the through hole.

7. The filter according to any one of claims 1 to 4, characterized in that: The cavity has a partition wall, the partition wall is located between adjacent resonant cavities, the lower side of the partition wall is connected to the cavity bottom wall, and the coupling window is formed on the partition wall.

8. The filter according to claim 7, characterized in that The upper side of the partition wall extends toward the cover plate and is in contact with the cover plate.

9. The filter according to claim 8, characterized in that The wall thickness of the partition wall is greater than or equal to the diameter of the debugging rod.

10. The filter according to claim 8, characterized in that The coupling window extends to the bottom wall of the cavity.

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