Low pass filter

Abstract

The utility model provides a low pass filter, which relates to the technical field of radio frequency filters in wireless communication, and comprises a filter assembly, a connecting sheet, a joint assembly and a shell assembly, and the shell assembly is used for accommodating the filter assembly, the connecting sheet and the joint assembly; one end of the filter assembly is connected with the joint assembly through a connecting sheet; the connector assembly comprises a connector body and a connector main rod connected with the connector body, an extension piece is arranged at the end, away from the connector body, of the connector main rod, and the connector main rod is used for forming the wave trap through the extension piece. According to the utility model, the technical problem in the prior art that the length or the volume of the low pass is increased due to the fact that the suppression performance is improved by increasing the low pass order or the difference between high and low step impedance is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of radio frequency filters in wireless communications, in particular to a low-pass filter. Background Art

[0002] With the rapid development of wireless communication technology, radio frequency spectrum resources are becoming increasingly tight, which places higher requirements on the high-frequency harmonic suppression performance of communication base station duplexers. The current common practice is to integrate low-pass filters in base station duplexers to suppress useless high-frequency signals, thereby reducing the impact on the system itself and the surrounding electromagnetic environment.

[0003] The suppression performance of the low-pass filter is positively correlated with its order and size. The frequency response curve of the existing coaxial low-pass filter is relatively smooth above the cut-off frequency, and it is impossible to increase the transmission zero point to improve the high-frequency suppression performance. If the high-order harmonics of the system are close to the low-pass cut-off frequency, the suppression performance of the low-pass is limited, and the suppression performance can only be improved by increasing the low-pass order or the difference between the high and low step impedances, which will increase the length or volume of the low-pass, which is not conducive to the miniaturization design of the whole machine. Utility Model Content

[0004] The utility model aims to provide a low-pass filter to alleviate the technical problem in the prior art that the length or volume of the low-pass filter increases due to increasing the low-pass order or the difference between high and low step impedances to improve the suppression performance.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] In a first aspect, the utility model provides a low-pass filter, comprising a filter assembly, a connecting piece, a connector assembly and a housing assembly, wherein the housing assembly is used to accommodate the filter assembly, the connecting piece and the connector assembly;

[0007] One end of the filter assembly is connected to the connector assembly via the connecting piece;

[0008] The joint assembly comprises a joint body and a joint main rod connected to the joint body. An extension piece is provided at one end of the joint main rod away from the joint body. The joint main rod is used to form a wave trap through the extension piece.

[0009] Furthermore, the extension member includes an extended suspended section, one end of the extended suspended section is connected to the joint main rod, and the other end of the extended suspended section passes through the connecting piece.

[0010] Furthermore, the extension piece also includes a disc, and the disc is connected to an end of the extended suspended section away from the joint main rod.

[0011] Furthermore, a plug-in hole is provided at the bottom of the extended suspended section;

[0012] The connecting piece is provided with an inserting portion, and the connecting piece is connected to the connector assembly by inserting the inserting portion into the plug hole;

[0013] The connecting piece is provided with at least one suspended branch.

[0014] Furthermore, the filter assembly includes a low-pass filter and an insulating sleeve wrapped around the outer wall of the low-pass filter;

[0015] The low-pass filter is connected to the connecting piece.

[0016] Furthermore, the housing assembly comprises a housing and a cover plate connected to the housing, a cavity is provided in the housing, and the filter assembly, the connecting sheet and the connector assembly are accommodated in the cavity.

[0017] Furthermore, the shell assembly also includes a fixing member, which is respectively connected to the shell and the cover plate, and is used to fix the cover plate on the shell.

[0018] Furthermore, the low-pass filter further comprises a supporting component, and the supporting component is disposed in the cavity;

[0019] The connecting piece is connected to the shell component through the supporting component.

[0020] Further, the support assembly includes a first support member, and the connecting piece is connected to the housing through the first support member;

[0021] The top of the first support member abuts against the filter assembly.

[0022] Furthermore, the support assembly further comprises a second support member, one end of the second support member is connected to the housing, and the other end of the second support member is connected to the cover plate;

[0023] The connecting piece is connected to the second supporting member.

[0024] The utility model can achieve the following beneficial effects:

[0025] In the first aspect, the utility model provides a low-pass filter, including a filter assembly, a connecting plate, a joint assembly and a shell assembly, the shell assembly is used to accommodate the filter assembly, the connecting plate and the joint assembly; one end of the filter assembly is connected to the joint assembly through the connecting plate; the joint assembly includes a joint body and a joint main rod connected to the joint body, an extension piece is provided at one end of the joint main rod away from the joint body, and the joint main rod is used to form a trap through the extension piece.

[0026] In the utility model, a housing space is opened in the shell component, and a filter component, a connecting plate and a joint component are arranged in this housing space. One end of the filter component is connected to the joint component through the connecting plate, and the joint component includes a joint main rod, one end of the joint main rod is connected to the joint body, and the other end is provided with an extended suspended section or a disk to form a notch filter for a specific frequency, and this notch filter introduces a transmission zero point by cooperating with a low-pass filter, thereby greatly improving the high-frequency suppression performance for a specific frequency band.

[0027] Compared with the prior art, the low-pass filter provided by the utility model has an accommodating space in the shell assembly, and a filter assembly, a connecting plate and a joint assembly are arranged in the accommodating space. The filter assembly is connected to the joint assembly through the connecting plate. One end of the joint main rod is connected to the joint body, and the other end is provided with a suspended section extension or a disk to form a notch filter for a specific frequency. The notch filter introduces a transmission zero point by cooperating with the low-pass filter, thereby greatly improving the high-frequency suppression performance for a specific frequency band. The utility model has the advantages of simple structure and easy assembly.

[0028] In summary, the utility model at least alleviates the technical problem in the prior art that the length or volume of the low-pass is increased due to increasing the low-pass order or the difference between high and low step impedances to improve the suppression performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 A three-dimensional schematic diagram of the internal structure of a low-pass filter provided in Embodiment 1 of the present utility model;

[0031] Figure 2 A schematic diagram of the cross-sectional structure of a low-pass filter provided in Embodiment 1 of the present utility model;

[0032] Figure 3 A three-dimensional schematic diagram of the internal structure of a low-pass filter provided in Embodiment 2 of the present utility model;

[0033] Figure 4 A schematic cross-sectional structure diagram of a low-pass filter provided in Embodiment 2 of the present utility model;

[0034] Figure 5A three-dimensional schematic diagram of the internal structure of a low-pass filter provided in Embodiment 3 of the present utility model;

[0035] Figure 6 A schematic diagram of the cross-sectional structure of a low-pass filter provided in Embodiment 3 of the present utility model;

[0036] Figure 7 This is a diagram showing the frequency response of the low-pass filter provided in Embodiment 1 of the present invention and a comparison with the existing solution.

[0037] Icons: 1-filter assembly; 11-low-pass filter; 12-insulating sleeve; 2-connecting plate; 3-connector assembly; 31-connector body; 32-connector main rod; 33-extended suspended section; 34-disc; 4-shell assembly; 41-shell; 411-cavity; 42-cover plate; 43-fixing part; 5-support assembly; 51-first support member; 52-second support member. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0039] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0041] In the description of the present utility model, it should be noted that the terms "upper", "lower", "vertical", "horizontal", "inside", "outside", etc. indicate the orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings, or the orientation or position relationship in which the utility model product is usually placed when in use, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0042] In addition, the terms "horizontal", "vertical" and the like do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0043] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "setting", "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0044] In conjunction with the accompanying drawings, some embodiments of the present invention are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0045] Embodiment 1

[0046] This embodiment provides a low-pass filter. Figure 1 or Figure 2 The low-pass filter includes a filter component 1, a connecting piece 2, a joint component 3 and a shell component 4, wherein the shell component 4 is used to accommodate the filter component 1, the connecting piece 2 and the joint component 3; one end of the filter component 1 is connected to the joint component 3 through the connecting piece 2; the joint component 3 includes a joint body 31 and a joint main rod 32 connected to the joint body 31, an extension piece is provided at one end of the joint main rod 32 away from the joint body 31, and the joint main rod 32 is used to form a wave trap through the extension piece.

[0047] The embodiments of the utility model at least alleviate the technical problem in the prior art that the length or volume of the low-pass is increased due to increasing the low-pass order or the difference between high and low step impedances to improve the suppression performance.

[0048] In an embodiment of the utility model, an accommodating space is opened in the shell component 4, and a filter component 1, a connecting plate 2 and a joint component 3 are arranged in this accommodating space. One end of the filter component 1 is connected to the joint component 3 through the connecting plate 2, and the joint component 3 includes a joint main rod 32, one end of the joint main rod 32 is connected to the joint body 31, and the other end is provided with an extended suspended section 33 or a disk 34 to form a notch filter for a specific frequency, and this notch filter introduces a transmission zero point by cooperating with a low-pass filter, thereby greatly improving the high-frequency suppression performance for a specific frequency band.

[0049] Compared with the prior art, the low-pass filter provided in the embodiment of the utility model has an accommodation space in the shell component 4, and the filter component 1, the connecting plate 2 and the joint component 3 are arranged in the accommodation space, the filter component 1 is connected to the joint component 3 through the connecting plate 2, and one end of the joint main rod 32 is connected to the joint body 31, and the other end is provided with an extended suspended section 33 or a disk 34 to form a notch filter for a specific frequency, and this notch filter introduces a transmission zero point by cooperating with the low-pass filter, thereby greatly improving the high-frequency suppression performance for a specific frequency band; and the utility model has the advantages of simple structure and easy assembly.

[0050] In an optional implementation manner of this embodiment, refer to Figure 1 or Figure 2 The extension piece includes an extended suspended section 33 , one end of the extended suspended section 33 is connected to the joint main rod 32 , and the other end of the extended suspended section 33 passes through the connecting piece 2 .

[0051] Specifically: an extended suspended section 33 is provided at one end of the joint main rod 32 away from the joint body 31, and the extended suspended section 33 and the joint main rod 32 extend in the same direction, and the extended suspended section 33 passes through the connecting piece 2. By providing the extended suspended section 33, the length of the joint main rod 32 and the extended suspended section 33 connection body is correspondingly extended, so that the extended suspended section 33 forms a quarter-wavelength notch filter, so as to introduce a transmission zero point at a specific frequency to improve the suppression performance of the frequency band near the frequency. According to the transmission line theory, the frequency of the transmission zero point is approximately equal to the speed of light divided by the length of the suspended section and then multiplied by one quarter.

[0052] In an optional implementation manner of this embodiment, refer to Figures 1 to 6 The filter assembly 1 includes a low-pass filter 11 and an insulating sleeve 12 wrapped around the outer wall of the low-pass filter 11; the low-pass filter 11 is connected to the connecting piece 2.

[0053] Specifically: the outer wall of the low-pass filter 11 is covered with an insulating sleeve 12; and one end of the low-pass filter 11 is connected to the connecting piece 2, which is preferably plugged in, and the other end of the low-pass filter 11 is used to connect the duplex module.

[0054] In an optional implementation manner of this embodiment, refer to Figure 1 , Figure 3 or Figure 5 The shell assembly 4 includes a shell 41 and a cover plate 42 connected to the shell 41 . A cavity 411 is provided in the shell 41 . The filter assembly 1 , the connecting sheet 2 and the connector assembly 3 are arranged in the cavity 411 .

[0055] Specifically: a cavity 411 is provided in the shell 41 for accommodating the filter assembly 1, the connecting sheet 2 and the connector assembly 3, and a cover plate 42 is provided on the top of the shell 41 for closing the cavity 411, and the cover plate 42 is detachably connected to the shell 41.

[0056] Further, refer to Figure 1 , Figure 3 or Figure 5 The housing assembly 4 further includes a fixing member 43 , which is connected to the housing 41 and the cover plate 42 respectively, and is used to fix the cover plate 42 on the housing 41 .

[0057] Specifically, there are multiple fixing members 43 , and the multiple fixing members 43 are used to fix the cover plate 42 on the shell 41 . The fixing members 43 are preferably bolts, and the shell 41 is provided with threaded holes, and the screws pass through the cover plate 42 and are fixed in the corresponding threaded holes of the shell 41 .

[0058] In an optional implementation manner of this embodiment, refer to Figure 2 , Figure 4 or Figure 6 The low-pass filter also includes a supporting component 5 , which is disposed in the cavity 411 ; the connecting sheet 2 is connected to the housing component 4 via the supporting component 5 .

[0059] Specifically: the support assembly 5 is disposed in the cavity 411 , the support assembly 5 is connected to the connecting piece 2 , and the support assembly 5 is used to support the connecting piece 2 so that the connecting piece 2 is fixed relative to the shell assembly 4 .

[0060] Further, refer to Figure 2 , Figure 4 or Figure 6 The support assembly 5 includes a first support member 51 , and the connecting piece 2 is connected to the housing 41 via the first support member 51 ; the top of the first support member 51 abuts against the filter assembly 1 .

[0061] Specifically, the first support member 51 is connected to the housing 41 and is provided with a through hole. The connecting piece 2 is a bent structure, and one end thereof is bent upward to pass through the through hole and is connected to the low-pass filter 11 .

[0062] Further, refer to Figure 2 or Figure 4The support assembly 5 also includes a second support member 52 , one end of the second support member 52 is connected to the shell 41 , and the other end is connected to the cover plate 42 ; the connecting sheet 2 is connected to the second support member 52 .

[0063] Specifically, the bottom end of the second support member 52 is connected to the housing 41 , and the top end of the second support member 52 is supported on the bottom of the cover plate 42 , so as to enhance the use strength of the cover plate 42 at the position of the cavity 411 .

[0064] Reference Figure 7 The notch filter proposed in this embodiment forms a transmission zero at 3.7GHz, which greatly improves the suppression performance near this frequency point; and the connection scheme of this embodiment has improved the suppression performance in the range of 2.5-4.2GHz to varying degrees compared with the traditional scheme, among which the 3.6-4GHz frequency band can be improved by about 15dB, maintaining a suppression performance of more than 85dB. Therefore, by changing the depth of the cavity installation groove and the length of the suspended section of the joint main rod, the frequency of the transmission zero point can be adjusted to meet the requirements of different high-frequency suppression performance.

[0065] Embodiment 2

[0066] This embodiment provides a low-pass filter. Figure 3 or Figure 4 The extension piece also includes a disc 34 , which is connected to one end of the extended suspended section 33 away from the joint main rod 32 .

[0067] Specifically: a disc 34 is provided at one end of the extended suspended section 33 away from the joint main rod 32, and the disc 34 is perpendicular to the extension direction of the extended suspended section 33. A disc 34 with a larger diameter is provided at the end of the extended suspended section 33. The suspended disc 34 and the bottom and side walls of the installation slot form a capacitive load, thereby continuing to reduce the transmission zero frequency of the wave trap when the length of the extended suspended section 33 is limited. The loading capacitance of the wave trap can be adjusted by the cross-sectional area of ​​the disc 34 and the distance between the disc 34 and the bottom and side walls of the installation slot, and the frequency of the transmission zero can be adjusted to meet the requirements of different high-frequency suppression performance.

[0068] Embodiment 3

[0069] This embodiment provides a low-pass filter. Figure 5 or Figure 6 A plug-in hole is provided at the bottom of the extended suspended section 33; the connecting piece 2 is provided with an insertion portion, and the connecting piece 2 is connected to the connector assembly 3 by inserting the insertion portion into the plug-in hole; the connecting piece 2 is provided with at least one suspended branch.

[0070] Specifically: one or more suspended branches are provided on the connecting piece 2 to form one or more transmission zero points, so as to achieve the goal of improving the high-frequency suppression performance of a specific frequency band; and a plug-in hole is provided at the bottom of the extended suspended section 33; the connecting piece 2 is provided with an insertion portion, and the connecting piece 2 is connected to the connector assembly 3 by inserting the insertion portion into the plug-in hole.

[0071] Finally, it should be noted that: the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referenced to each other; the above embodiments in this specification are only used to illustrate the technical solution of the utility model, rather than to limit it; although the utility model is described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that: it is still possible to modify the technical solutions recorded in the aforementioned embodiments, or to replace some or all of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. A low-pass filter, characterized in that: It comprises a filter assembly (1), a connecting piece (2), a connector assembly (3) and a housing assembly (4), wherein the housing assembly (4) is used to accommodate the filter assembly (1), the connecting piece (2) and the connector assembly (3); One end of the filter component (1) is connected to the connector component (3) via the connecting piece (2); The joint assembly (3) comprises a joint body (31) and a joint main rod (32) connected to the joint body (31); an extension piece is provided at one end of the joint main rod (32) away from the joint body (31); and the joint main rod (32) is used to form a wave trap through the extension piece.

2. The low-pass filter according to claim 1, characterized in that The extension piece comprises an extended suspended section (33), one end of the extended suspended section (33) is connected to the joint main rod (32), and the other end of the extended suspended section (33) passes through the connecting piece (2).

3. The low-pass filter according to claim 2, characterized in that The extension piece further comprises a disc (34), and the disc (34) is connected to an end of the extended suspended section (33) away from the joint main rod (32).

4. The low-pass filter according to claim 2, characterized in that A plug-in hole is provided at the bottom of the extended suspended section (33); The connecting piece (2) is provided with an insertion portion, and the connecting piece (2) is connected to the connector assembly (3) by inserting the insertion portion into the plug hole; The connecting piece (2) is provided with at least one suspended branch.

5. The low-pass filter according to any one of claims 2 to 4, characterized in that: The filter assembly (1) comprises a low-pass filter (11) and an insulating sleeve (12) coated on the outer wall of the low-pass filter (11); The low-pass filter (11) is connected to the connecting piece (2).

6. The low-pass filter according to any one of claims 2 to 4, characterized in that: The housing assembly (4) comprises a housing (41) and a cover plate (42) connected to the housing (41); a cavity (411) is provided in the housing (41); and the filter assembly (1), the connecting sheet (2) and the connector assembly (3) are accommodated in the cavity (411).

7. The low-pass filter according to claim 6, characterized in that The housing assembly (4) further comprises a fixing member (43), wherein the fixing member (43) is respectively connected to the housing (41) and the cover plate (42), and the fixing member (43) is used to fix the cover plate (42) on the housing (41).

8. The low-pass filter according to claim 6, characterized in that The low-pass filter further comprises a supporting component (5), wherein the supporting component (5) is arranged in the cavity (411); The connecting piece (2) is connected to the housing component (4) via the supporting component (5).

9. The low-pass filter according to claim 8, characterized in that The support assembly (5) comprises a first support member (51), and the connecting piece (2) is connected to the housing (41) via the first support member (51); The top of the first support member (51) abuts against the filter assembly (1).

10. The low-pass filter according to claim 9, characterized in that The support assembly (5) further comprises a second support member (52), one end of the second support member (52) being connected to the housing (41), and the other end of the second support member (52) being connected to the cover plate (42); The connecting piece (2) is connected to the second supporting member (52).

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