Sheet metal resonance filter

Abstract

A sheet metal resonance filter, which comprises a cavity, a cover plate snap-fitted on the cavity, and a first sheet metal resonance assembly arranged in the cavity. The first sheet metal resonance assembly comprises a sheet metal resonance unit; and the sheet metal resonance unit comprises a longitudinal vertical arm, a transverse bending plate and a first vertical cantilever, wherein the longitudinal vertical arm is arranged on a bottom wall of the cavity, the transverse bending plate is in connection with the tail end of the top of the longitudinal vertical arm and extends from the tail end of the top of the longitudinal vertical arm towards a side wall of the cavity, the first vertical cantilever is in connection with the tail end of the transverse bending plate and bends and extends downwards from the tail end of the transverse bending plate, and a slot is formed in the transverse bending plate.

Description

Sheet metal resonant filter Technical Field

[0001] The present application relates to the field of microwave radio frequency passive components, in particular to a filter product, and more specifically to a sheet metal resonant filter. Background Art

[0002] The miniaturization and lightweighting of filters are increasingly becoming the mainstream technical research and development breakthrough direction of filters in this major technological context.

[0003] To meet these demands, the industry is increasingly adopting miniaturized metal filters. Within miniaturized metal filters, there are different types of filters, such as miniaturized coaxial cavity filters and sheet metal filters, based on their implementation. Traditional coaxial cavity filters, however, are large, heavy, and expensive to produce, making them unsuitable for the miniaturized, highly integrated, and high-density 5G network requirements. Furthermore, the resonant structure of existing sheet metal filters is an L-shaped sheet metal structure, which has certain limitations in terms of power capacity and tuning frequency.

[0004] In order to meet the requirements of wider bandwidth, higher power capacity, wider tuning frequency, and make the components of the entire filter lighter, lower cost, easier to assemble, and more consistent under the principle of better index requirements, and meet the increasingly demanding 5G market needs, it is necessary to significantly improve the filters of existing technology in order to overcome the defects of existing technology.

[0005] Summary of the Invention

[0006] The purpose of this application is to solve the above problems and provide a sheet metal resonant filter.

[0007] To meet the purpose of this application, this application adopts the following technical solutions:

[0008] A sheet metal resonant filter comprises: a cavity, a cover plate snapped onto the cavity, and a first sheet metal resonant component arranged in the cavity, the first sheet metal resonant component comprising a sheet metal resonant unit, the sheet metal resonant unit comprising: a longitudinal vertical arm, a transverse bent plate, and a first vertical cantilever, the longitudinal vertical arm being arranged on the bottom wall of the cavity, the transverse bent plate being connected to the top end of the longitudinal vertical arm and extending from the top end of the longitudinal vertical arm toward the side wall of the cavity, the first vertical cantilever being connected to the end of the transverse bent plate and bending downward and extending from the end of the transverse bent plate, and a slot being formed on the transverse bent plate.

[0009] Compared with the prior art, this application has the following advantages:

[0010] The frequency of the corresponding sheet metal resonant component is adjusted by adjusting the size of the sheet metal resonant unit.

[0011] The present application provides a sheet metal resonant filter, which uses a sheet metal structure as the main resonant structure of the filter (sheet metal resonant component). The main body of the resonant structure is in the shape of an "N". Compared with the "L"-shaped sheet metal resonant structure in the prior art, it has an additional 90° bend (cantilever). The presence of the bend increases the corresponding area between the resonant structure and the cover plate and between the resonant structure and the inner side wall of the cavity, thereby increasing the loading capacitance of the resonant structure, which reduces the overall size of the filter. In addition, the "N"-shaped resonant structures in the present application are all integrally formed by bending plates of equal thickness, which greatly reduces the number and types of spare parts, reduces assembly tolerances, increases the consistency of filter debugging indicators, and reduces production costs. In addition, each "N"-shaped resonant structure has a slot on the top, such as a D-shaped slot, which together with the adjustment screw on the cover plate constitutes a frequency debugging structure, so that the performance of the filter can be easily debugged after the filter is assembled. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG1 is an exploded perspective view of a sheet metal resonant filter according to an embodiment of the present application.

[0013] FIG2 is an assembled three-dimensional diagram of the sheet metal resonant component of the sheet metal resonant filter shown in FIG1 .

[0014] FIG3 a is a three-dimensional structural diagram of the first sheet metal resonant component of the sheet metal resonant filter shown in FIG1 .

[0015] FIG3 b is a plan view of the first sheet metal resonant component shown in FIG3 a .

[0016] FIG3 c is a plan view of the first sheet metal resonant component shown in FIG3 a from another angle.

[0017] FIG4 is a three-dimensional structural diagram of the second sheet metal resonant component of the sheet metal resonant filter shown in FIG1 .

[0018] FIG5 is a three-dimensional structural diagram of the third sheet metal resonant component of the sheet metal resonant filter shown in FIG1 .

[0019] FIG6 a is a plan view of the sheet metal resonant filter shown in FIG1 , viewed from above.

[0020] FIG6 b is a cross-sectional view of the sheet metal resonant filter shown in FIG6 a along the AA direction.

[0021] FIG. 7 a is a perspective view of another embodiment of the first sheet metal resonant component of the sheet metal resonant filter shown in FIG. 1 .

[0022] FIG7 b is a perspective view of yet another embodiment of the first sheet metal resonant component of the sheet metal resonant filter shown in FIG1 .

[0023] FIG8 is a distribution diagram of the electric field and magnetic field of the adjustable sheet metal filter of the present application. DETAILED DESCRIPTION

[0024] According to one embodiment, in combination with Figures 1-8, a sheet metal resonant filter 100 includes: a cavity 10, a cover 20 snapped onto the cavity 10, a first sheet metal resonant component 30, a second sheet metal resonant component 40 and a third sheet metal resonant component 50 arranged in the cavity 10 and electrically connected to each other.

[0025] 3a-3c, the first sheet metal resonant assembly 30 includes a group of first sheet metal resonant units 32, wherein each first sheet metal resonant unit 32 includes: a first longitudinal vertical arm 322, a first transverse bent plate 324 formed from the top end of the first longitudinal vertical arm 322, and a first vertical cantilever 326 formed by bending downward from the end of the first transverse bent plate 324, and a first slot 328 is formed on the first transverse bent plate 324; two adjacent first sheet metal resonant units 32 are electrically connected to each other by means of a first connecting arm 321.

[0026] Referring to Figures 3b-3c, the frequency of the corresponding sheet metal resonant component is adjusted by adjusting the dimensional parameters of the first sheet metal resonant unit 32: H1, H2, W1, W2, W3 and W4, the distance W5 (that is, by adjusting any one of the distance between the transverse bending plate and the bottom surface of the cavity, the longitudinal length of the first vertical cantilever, the longitudinal distance between the transverse bending plate and the cover plate, the width of the transverse bending plate, the width of the longitudinal vertical arm, the distance between the longitudinal vertical arm and the side wall of the cavity, the distance between the first vertical cantilever and the side wall of the cavity, and the longitudinal length of the second vertical cantilever), and the distance H7 (the vertical distance between the transverse bending plate and the cover plate of the corresponding sheet metal resonant unit).

[0027] Compared to the prior art, the sheet metal resonant structure of this application has a longitudinal vertical arm that remains parallel to the side wall of the cavity. The distance between the longitudinal vertical arm and the side wall of the cavity has a significant impact on the frequency adjustment. This is mainly because a capacitive effect is formed between the transverse bent plate and the cover plate of the resonant unit of the corresponding sheet metal resonant component, as well as between the longitudinal vertical arm and the side wall of the cavity. The loading capacitance generated by this capacitive effect is equivalent to a portion of the effective length of the resonant structure. The size of this loading capacitance is adjusted by adjusting the size of the slot and the length of the screw, thereby achieving the effect of adjusting the resonant frequency.

[0028] In addition, the coupling amount between the two first sheet metal resonant units is adjusted by adjusting the relevant dimensional parameters of the first connecting arm of the first sheet metal resonant unit 32, such as the parameters H3 and H4 in Figures 3b-3c (that is, by adjusting the distance between the first connecting arm and the bottom surface of the cavity or the longitudinal dimension of the first connecting arm itself to adjust the coupling amount between the two adjacent sheet metal resonant units). The first connecting arm is an overhead design, which reduces the welding area between the first sheet metal resonant unit and the bottom wall of the cavity, and replaces the single large surface contact welding with a multi-branch contact welding method (each first sheet metal resonant unit has a first longitudinal vertical arm, and the first longitudinal vertical arm forms the branch), thereby reducing the risk of poor welding contact.

[0029] In this application, an integrated resonant structure and coupling structure are used. To achieve the filter's function, the resonance and coupling structures need to work together. In this application, the design of the filter's resonant and coupling structures is improved. By integrating the resonant and coupling structures, most of the cavity's coupling structure is removed, simplifying the cavity's processing and design.

[0030] In addition, the resonant structure is composed of a single-ended open-circuit, 1 / 4 wavelength coaxial line with load capacitance adjustment. One end (the vertical arm) is vertically connected to the bottom wall of the cavity, serving as a connection and fixed position. Then, the vertical arm extends to the top and bends to form a horizontal bent plate. The horizontal bent plate increases the corresponding area of ​​the resonant structure, the cover plate on the filter, and the side surface of the cavity, thereby increasing the load capacitance of the resonant structure, which reduces the overall size of the filter.

[0031] Furthermore, the slots and the cover's adjustment screws together form a frequency tuning mechanism, allowing for easy performance tuning after filter assembly. The electric and magnetic field distributions of this resonant structure are shown in Figure 8, which approximate TEM modes. As can be seen, the electric field is primarily distributed near the top surface of the resonant structure, perpendicular to the horizontally bent plate. As shown in the figure, the magnetic field is primarily distributed in the vertical portion of the resonant structure, rotating around it.

[0032] At the same time, in this application, the coupling structure is composed of a connecting plate between corresponding sheet metal resonant structures (components), a notch in the middle of the cavity, and two separate coupling plates. At the same time, there are corresponding tuning screws on the cover plate for debugging. Based on the above design, the number of installation parts of the filter is reduced, and the installation process is simplified. The sheet metal or coaxial cavity solution in the prior art is to process the cavity, resonant structure parts, coupling structure parts, and debugging cover plate components separately and assemble them in subsequent processes. In the structure of the present application, referring to Figure 1, in the actual installation process, the corresponding sheet metal resonant components are assembled with the cavity, low-pass components, and terminal blocks to form a cavity component, and then the cavity component and the cover plate are fixed together by welding to complete the installation process, thereby greatly reducing the assembly workload.

[0033] Moreover, this "N"-shaped sheet metal resonant structure and its implementation method are applicable to filter duplexers with different numbers of resonant cavities and different topological structures, and are applicable to various RF passive devices including but not limited to filters and duplexers.

[0034] Further preferably, the first longitudinal vertical arm 322 of one of the first sheet metal resonant units 32 is bent to form a first sheet metal branch 323 perpendicular to the first connecting arm 321, and the first longitudinal vertical arm 322 of another adjacent first sheet metal resonant unit 32 is bent to form a second sheet metal branch 325 extending in a direction opposite to the first sheet metal branch 323.

[0035] The two sheet metal branches are integrally formed with the corresponding first sheet metal resonant units, eliminating the need for additional welding and assembly. This reduces the filter assembly steps and simplifies the installation process. The width and shape of the second sheet metal branch 325 can be adjusted based on port specifications. The coupling between one of the first sheet metal resonant units and the second sheet metal resonant component can be adjusted by adjusting the position height H5 and size height H6 of the first sheet metal branch 323.

[0036] 4 , the second sheet metal resonant component 40 has a similar structure to the first sheet metal resonant component 30 and also includes a group of second sheet metal resonant units 42, wherein each second sheet metal resonant unit 42 includes: a second longitudinal vertical arm 422, a second transverse bent plate 424 formed from the top end of the second longitudinal vertical arm 422, and a first vertical cantilever 426 bent downward from the end of the second transverse bent plate 424, and a second slot 428 is formed on the second transverse bent plate 424; two adjacent second sheet metal resonant units 42 are electrically connected by means of a second connecting arm 421.

[0037] 5 , the third sheet metal resonant component 50 has a similar structure to the first sheet metal resonant component 30 , and also includes a group of third sheet metal resonant units 52 , wherein each third sheet metal resonant unit 52 includes: a third longitudinal vertical arm 522 , a third transverse bent plate 524 formed from the top end of the third longitudinal vertical arm 522 , and a first vertical cantilever 526 formed by bending downward from the end of the third transverse bent plate 524 , and a third slot 528 is formed on the third transverse bent plate 524 ; two adjacent third sheet metal resonant units 52 are electrically connected to each other by means of a third connecting arm 521 .

[0038] Similar to the first sheet metal resonant component 30 , the second sheet metal resonant component 40 and the third sheet metal resonant component 50 also adopt similar methods and structures to obtain the frequency and coupling amount.

[0039] Preferably, referring to FIG5 , an L-shaped conductor 523 is provided on the third longitudinal vertical arm 522 of one of the third sheet metal resonant units 52 , and similar frequency and coupling adjustment effects can be obtained by adjusting various size parameters of the conductor.

[0040] Preferably, referring to Figure 7a, according to another embodiment of the present application, the first sheet metal resonant unit 32' of the first sheet metal resonant assembly 30 is bent downward on both sides of its first transversely bent plate 342 to form second vertical cantilevers 327. The frequency of the corresponding sheet metal resonant unit is adjusted by adjusting the dimensions of the second vertical cantilevers 327. In summary, this "N"-shaped sheet metal structure offers a wide variety of structures, allowing flexible adjustment of individual dimensions to meet diverse intracavity frequency requirements.

[0041] It should be noted that the second vertical cantilever 327 may also be provided for other resonance units in the filter, such as the second resonance unit and the third resonance unit.

[0042] In addition, preferably, referring to FIG. 7 b , according to another embodiment of the present application, the opening direction of the first slot 328 ′ provided on the first sheet metal resonant unit 32 ″ of the first sheet metal resonant component 30 is away from the first vertical cantilever 326 .

[0043] Preferably, the cavity 10 includes a bottom wall 12, a pair of first side walls 14 arranged opposite to each other and a pair of second side walls 16 arranged opposite to each other around the periphery of the bottom wall 12, the pair of first side walls 14 and the second side walls 16 and the bottom wall 12 jointly define the cavity accommodating space, a first partition 122 and a second partition 124 located between one of the first side walls 14 and the first partition 12 are provided on the bottom wall 12; the first partition 122 and the second partition 124 divide the cavity accommodating space into three sub-spaces, and the first sheet metal resonant component 30, the second sheet metal resonant component 40 and the third sheet metal resonant component 50 are respectively arranged in the corresponding sub-spaces.

[0044] Preferably, a tuning screw 22 is provided on the cover plate 20 , passing through the cover plate 20 and extending into a slot of a corresponding sheet metal resonant unit of each sheet metal resonant component.

[0045] Preferably, one of the pair of first side walls 14 is provided with two openings 142, each of which is provided with a terminal block 72. The terminal block 72 is electrically isolated from the opening 142 by a supporting medium 74. The terminal blocks 72 are electrically connected to the first sheet metal resonant component 30 and the third sheet metal resonant component 50, respectively. The terminal blocks are provided to facilitate electrical connection of the entire filter 100 to external devices.

[0046] Preferably, the second sheet metal resonant assembly 40 and the first sheet metal resonant assembly 30 are electrically connected to each other via a first coupling piece 62. The first separator 122 is provided with a notch (unnumbered), and the first coupling piece 62 is partially positioned within the notch. A positioning block 66 is used to press the first coupling piece 62 into the notch, thereby improving the installation stability of the first coupling piece 62 and preventing it from loosening due to external vibration, thereby breaking the electrical connection between the two sheet metal resonant assemblies. Further preferably, the first coupling piece 62 is C-shaped.

[0047] Preferably, the second sheet metal resonant assembly 40 and the third sheet metal resonant assembly 50 are electrically connected to each other via a second coupling piece 64. The first partition plate 122 is provided with a notch (unnumbered), and the second coupling piece 64 is partially positioned within the notch. A positioning block 66 is used to press the second coupling piece 64 into the notch, thereby improving the installation stability of the second coupling piece 64 and preventing it from loosening due to external vibration, thereby breaking the electrical connection between the two sheet metal resonant assemblies. Further preferably, the second coupling piece 64 is a Z-shaped second coupling piece 64.

[0048] The C-shaped first coupling piece 62 allows coupling between one of the first sheet metal resonant units 32 of the first sheet metal resonant component 30 and one of the second sheet metal resonant units 42 of the second sheet metal resonant component 40 to produce a pole; and the Z-shaped second coupling piece 64 allows coupling between one of the second sheet metal resonant units 42 of the second sheet metal resonant component 40 and one of the third sheet metal resonant units 52 of the third sheet metal resonant component 50 to produce a pole.

[0049] Further preferably, a low-pass component is included, comprising a low-pass rod 68 electrically connected to the first sheet metal resonant component 30 and a heat shrink tubing 69 sleeved on the low-pass rod 68. The low-pass component is used to filter high-frequency components in the signal to achieve a better filtering effect, while the heat shrink tubing 69 is wrapped around the outside of the low-pass rod 68 to achieve electrical insulation between the low-pass rod 68 and the cavity 10.

[0050] In the above embodiment, the slot may be a D-shaped slot or a U-shaped slot, and the size of the loading capacitor is adjusted by adjusting the size of the slot, such as the length and width, so as to adjust the resonant frequency.

[0051] It should be noted that although the structures of the three sheet metal resonant components are distinguished by the terms first, second, and third in the above embodiments of the present application, such as the first sheet metal resonant unit, the second sheet metal resonant unit, the third sheet metal resonant unit, the first longitudinal vertical arm, the second longitudinal vertical arm, the third longitudinal vertical arm, the first transverse bent plate, the second transverse bent plate, and the third transverse bent plate, this distinction in order is merely for ease of description and to avoid confusion. In fact, the use of sequential terms does not specifically emphasize the order or priority between them.

[0052] It should also be noted that: for the first sheet metal resonant component, its corresponding resonant unit includes a first vertical cantilever and a second vertical cantilever, which have different structures.

[0053] In summary, each sheet metal resonant assembly can include a sheet metal resonant unit. Each sheet metal resonant unit comprises a longitudinal arm, a transverse bent plate formed from the top end of the longitudinal arm, and a first vertical cantilever formed by bending downward from the end of the transverse bent plate. The transverse bent plate has a slot formed therein. Two adjacent sheet metal resonant units in the same sheet metal resonant assembly are electrically connected to each other via corresponding connecting arms.

Claims

1. A sheet metal resonant filter, comprising: A cavity, a cover plate snapped onto the cavity and a first sheet metal resonance component arranged in the cavity, characterized in that: the first sheet metal resonance component includes a sheet metal resonance unit, and the sheet metal resonance unit includes: a longitudinal vertical arm, a transverse bending plate and a first vertical cantilever, the longitudinal vertical arm is arranged on the bottom wall of the cavity, the transverse bending plate is connected to the top end of the longitudinal vertical arm and extends from the top end of the longitudinal vertical arm toward the side wall of the cavity, the first vertical cantilever is connected to the end of the transverse bending plate and bends downward and extends from the end of the transverse bending plate, and a groove is formed on the transverse bending plate.

2. The sheet metal resonant filter according to claim 1, characterized in that: Second vertical cantilevers extending downwards are respectively provided on both sides of the transverse bending plate.

3. The sheet metal resonant filter according to claim 1, characterized in that: The first vertical cantilever is arranged parallel to the side wall of the cavity.

4. The sheet metal resonant filter according to claim 1, characterized in that: The sheet metal resonance unit is configured to adjust the frequency of the first sheet metal resonance component by adjusting any one of the distance between the transverse bending plate and the bottom surface of the cavity, the longitudinal length of the first vertical cantilever, the longitudinal distance between the transverse bending plate and the cover plate, the width of the transverse bending plate, the width of the longitudinal vertical arm, the distance between the longitudinal vertical arm and the side wall of the cavity, and the distance between the first vertical cantilever and the side wall of the cavity.

5. The sheet metal resonant filter according to claim 2, characterized in that: The frequency of the first sheet metal resonant component is adjusted by adjusting the longitudinal length of the second vertical cantilever.

6. The sheet metal resonant filter according to claim 1, characterized in that: The slot is a D-shaped or U-shaped slot.

7. The sheet metal resonant filter according to claim 6, characterized in that: The D-shaped slot is provided between the longitudinal vertical arm and the transverse bending plate, or between the transverse bending plate and the first vertical cantilever.

8. The sheet metal resonant filter according to claim 1, characterized in that: The first sheet metal resonance component includes a group of sheet metal resonance units arranged at intervals, and two adjacent sheet metal resonance units are connected by a first connecting arm. The first connecting arm is configured to adjust the coupling amount between two adjacent sheet metal resonance units by adjusting the distance between the first connecting arm and the bottom surface of the cavity or the longitudinal dimension of the first connecting arm itself.

9. The sheet metal resonant filter according to claim 8, characterized in that: The longitudinal vertical arm of one of the sheet metal resonance units of the first sheet metal resonance component is bent to form a first sheet metal branch perpendicular to the first connecting arm, while the longitudinal vertical arm of another adjacent sheet metal resonance unit is bent to form a second sheet metal branch extending in the opposite direction to the first sheet metal branch.

10. The sheet metal resonant filter according to claim 1, characterized in that: It also includes a second sheet metal resonant component and a third sheet metal resonant component, the second sheet metal resonant component includes a group of sheet metal resonant units; the third sheet metal resonant component also includes a group of sheet metal resonant units; the first, second and third sheet metal resonant components are electrically connected to each other.

11. The sheet metal resonant filter according to claim 1, characterized in that: An L-shaped conductor is arranged on the longitudinal vertical arm of the sheet metal resonance unit.

12. The sheet metal resonant filter according to claim 10, characterized in that: The cavity comprises a bottom wall, a pair of first side walls disposed opposite to each other and a pair of second side walls disposed opposite to each other and arranged around the periphery of the bottom wall, wherein the pair of first side walls, the second side walls and the bottom wall jointly define a cavity accommodating space, and a first partition plate and a second partition plate located between one of the first side walls and the first partition plate are disposed on the bottom wall; The first partition plate and the second partition plate divide the cavity accommodating space into three sub-spaces, and the first sheet metal resonant component, the second sheet metal resonant component and the third sheet metal resonant component are respectively arranged in the corresponding sub-spaces.

13. The sheet metal resonant filter according to claim 12, characterized in that: The cover plate is provided with a tuning screw which passes through the cover plate and extends into a slot of a corresponding sheet metal resonance unit of each sheet metal resonance component.

14. The sheet metal resonant filter according to claim 12, characterized in that: Two openings are arranged on one of the pair of first side walls, and a wiring terminal is arranged in each opening. The wiring terminal is electrically isolated from the opening by means of a supporting medium; the wiring terminal is electrically connected to the first sheet metal resonant component and the third sheet metal resonant component respectively.

15. The sheet metal resonant filter according to claim 12, characterized in that: The second sheet metal resonant component and the first sheet metal resonant component are electrically connected to each other through a first coupling plate; a notch is provided on the first partition plate, and the first coupling plate is inserted into the notch; the first coupling plate is a C-shaped first coupling plate.

16. The sheet metal resonant filter according to claim 12, characterized in that: The second sheet metal resonant component and the third sheet metal resonant component are electrically connected to each other through a second coupling plate; a notch is provided on the first partition plate, and the second coupling plate is inserted into the notch; the second coupling plate is a Z-shaped second coupling plate.

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