Low pass filter

Abstract

The utility model provides a low-pass filter, and relates to the technical field of communication. The low-pass filter comprises a cavity and a transmission main body. Two ends of the cavity are respectively provided with a signal input port and a signal output port. The transmission main body is located in the cavity, the transmission main body is composed of at least one elliptic function branch transmission section and a plurality of first transmission sections and second transmission sections which are connected in series, the impedance of the first transmission sections is larger than that of the second transmission sections, and the first end of each elliptic function branch transmission section is connected to one second transmission section; the second end of each elliptic function branch transmission section is fixed in the cavity. Coaxial mixed-mode low-pass filtering can be formed through the first transmission sections and the second transmission sections which are connected in series, further far-end suppression can be filtered out, meanwhile, by adding the elliptic function branch transmission sections, the characteristic that near-end suppression can be filtered out through an elliptic function can be utilized, and the transmission efficiency can be improved. Therefore, the transmission main body can filter far-end inhibition and also can realize near-end high inhibition.

Description

Technical Field

[0001] The embodiments of the present application relate to but are not limited to the field of communication technology, and in particular, to a low-pass filter. Background Art

[0002] Compared with other types of filters, low-pass filters have the advantages of small size, low insertion loss, high power handling, low intermodulation, and low cost. Therefore, low-bandwidth low-pass filters have gradually become the mainstream application solution to replace traditional coaxial cavity filters. The commonly used low-pass filter is the coaxial low-pass filter, but since the coaxial low-pass filter is mainly used to filter out far-end suppression, it is difficult to attenuate strong near-end suppression. Therefore, there is an urgent need for a low-pass filter that can filter out far-end suppression and achieve high near-end suppression. Utility Model Content

[0003] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of the claims. The present application provides a low-pass filter that can filter out far-end suppression and achieve near-end high suppression.

[0004] The low-pass filter proposed in the embodiment of the present application includes:

[0005] A cavity, wherein two ends of the cavity are respectively provided with a signal input port and a signal output port;

[0006] A transmission body, wherein the transmission body is located in the cavity, and the transmission body is composed of at least one elliptic function branch transmission segment and a plurality of first transmission segments and second transmission segments connected in series, wherein the impedance of the first transmission segment is greater than that of the second transmission segment, and the first end of each of the elliptic function branch transmission segments is connected to one of the second transmission segments; and the second end of each of the elliptic function branch transmission segments is fixed in the cavity.

[0007] Therefore, the above embodiment of the present application has at least the following beneficial effects: a coaxial mixed-mode low-pass filter can be formed by multiple first transmission segments and second transmission segments connected in series to filter out far-end suppression, and by adding an elliptic function branch transmission segment, the characteristic of the elliptic function filtering out near-end suppression can be utilized, so that the transmission body can achieve both far-end suppression filtering and near-end high suppression. Therefore, compared with the related art, the embodiment of the present application can achieve both far-end suppression filtering and near-end high suppression.

[0008] According to some embodiments of the present application, the cavity includes a first cavity and a second cavity that are interconnected, and an angle between the first cavity and the second cavity is less than or equal to 90 degrees.

[0009] According to some embodiments of the present application, a first interval between two adjacent first transmission segments in the second cavity is less than or equal to a second interval between two adjacent first transmission segments in the first cavity, and the second transmission segment in the second cavity is bent.

[0010] According to some embodiments of the present application, the second transmission segment in the second cavity is bent; a plurality of parallel and spaced-apart isolation portions are provided in the second cavity, the first end of the isolation portion is connected to the first side wall of the cavity, and the second end of the isolation portion is spaced a preset distance from the second side wall opposite to the first side wall of the cavity; the isolation portion is used to isolate two adjacent transmission segments distributed along the signal transmission direction in the second cavity.

[0011] According to some embodiments of the present application, at least one of the elliptical function branch transmission segments is located in the second cavity, and at least one of the first protrusions corresponding to the elliptical function branch transmission segment is also provided in the second cavity, and the second end of the elliptical function branch transmission segment is provided on the first protrusion.

[0012] According to some embodiments of the present application, a plurality of second protrusions corresponding one-to-one to the first transmission segments are further disposed in the cavity, and the first transmission segments are disposed on the second protrusions.

[0013] According to some embodiments of the present application, the low-pass filter further includes a plurality of first supporting and isolating gaskets, wherein the first supporting and isolating gaskets are used to isolate the second protrusion and the corresponding first transmission section.

[0014] According to some embodiments of the present application, three elliptic function branch transmission segments are provided, wherein a first end of one of the elliptic function branch transmission segments is connected to the connection between two adjacent second transmission segments, and the other two elliptic function branch transmission segments are adjacently arranged and close to the signal output port.

[0015] According to some embodiments of the present application, the low-pass filter also includes a first connector and a first connecting rod, the first end of the first connector is connected to the first end of the first connecting rod, and the first end of the first connector is fixed to the signal input port; the first connecting rod is arranged in the signal input port, and the second end of the first connecting rod is connected to one end of the transmission body; the first connecting rod is used to perform impedance transformation on the signal entering the transmission body from the first connector.

[0016] According to some embodiments of the present application, the low-pass filter further includes a second connector, a first end of which passes through the signal output port and is connected to the transmission body. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide further understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0018] Figure 1 is a structural schematic diagram of an embodiment of a low-pass filter provided by the present application;

[0019] Figure 2 is a schematic diagram of the cavity structure of an embodiment of the low-pass filter provided by the present application;

[0020] Figure 3 is a schematic diagram of the transmission main structure of an embodiment of the low-pass filter provided by the present application;

[0021] Figure 4 It is a decomposed schematic diagram of an embodiment of the low-pass filter provided by the present application.

[0022] Reference numerals:

[0023] Cavity 100, signal input port 110, signal output port 120, isolation portion 130, first protrusion 140, second protrusion 150, transmission body 200, elliptic function branch transmission section 210, first transmission section 220, second transmission section 230, first support isolation gasket 310, second support isolation gasket 320, first connector 330, first connecting rod 340, second connector 350. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art belonging to the technical field of the present application. The terms used herein are only for the purpose of describing the embodiments of the present application and are not intended to limit the present application. The terms "first", "second", "third", "fourth", etc. (if present) in the specification of the present application and the above-mentioned drawings are used to distinguish similar objects, and need not be used to describe a specific order or sequential order.

[0026] In addition, the described features, structures or characteristics may be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced without one or more of the specific details, or other methods, components, devices, steps, etc. may be adopted. In other cases, known methods, devices, implementations or operations are not shown or described in detail to avoid blurring the various aspects of the present disclosure.

[0027] Reference Figures 1 to 4 As shown, the low-pass filter proposed in the embodiment of the present application includes:

[0028] The cavity 100 has a signal input port 110 and a signal output port 120 disposed at two ends of the cavity 100;

[0029] The transmission body 200 is located in the cavity 100. The transmission body 200 is composed of at least one elliptic function branch transmission segment 210 and a plurality of first transmission segments 220 and second transmission segments 230 connected in series. The impedance of the first transmission segment 220 is greater than that of the second transmission segment 230. The first end of each elliptic function branch transmission segment 210 is connected to a second transmission segment 230. The second end of each elliptic function branch transmission segment 210 is fixed in the cavity 100.

[0030] Therefore, a coaxial mixed-mode low-pass filter can be formed by connecting a plurality of first transmission segments 220 and second transmission segments 230 in series to filter out far-end suppression, and by adding an elliptic function branch transmission segment 210, the characteristic of filtering out near-end suppression by the elliptic function can be utilized, so that the transmission body 200 can achieve both filtering out far-end suppression and achieving near-end high suppression. Therefore, compared with the related art, the embodiment of the present application can achieve both filtering out far-end suppression and achieving near-end high suppression.

[0031] It should be noted that, in some embodiments, the first transmission section 220 and the second transmission section 230 may be implemented by using a microstrip line. In some embodiments, the first transmission section 220 and the second transmission section 230 may have a sheet structure.

[0032] It should be noted that by setting the impedance of the first transmission section 220 to be greater than that of the second transmission section 230, the first transmission section 220 forms a high-impedance transmission section and the second transmission section 230 forms a low-impedance transmission section, thereby achieving mixed-mode low-pass filtering.

[0033] It should be noted that the present application does not limit how the first transmission segments 220 and the second transmission segments 230 are arranged. In some embodiments, at least one second transmission segment 230 may be arranged between two adjacent first transmission segments 220, or a plurality of consecutively arranged first transmission segments 220 and a plurality of consecutively arranged second transmission segments 230 may be arranged alternately.

[0034] It should be noted that, in some embodiments, the cavity 100 is configured as a groove with an upper opening, and the first transmission section 220 , the second transmission section 230 , and the elliptic function branch transmission section 210 are all spaced a certain distance from the bottom of the groove.

[0035] It should be noted that the elliptic function branch transmission section 210 is a signal filtering branch designed using an elliptic function.

[0036] For example, Figure 1 and Figure 3 As shown, the transmission body 200 includes 8 first transmission segments 220, 10 second transmission segments 230 and 3 elliptic function branch transmission segments 210. The 8 first transmission segments 220 are high-resistance transmission segments 1 to 8; the 10 second transmission segments 230 are low-resistance transmission segments 1 to 10; and the 3 elliptic function branch transmission segments 210 are branches 1 to 3. Figure 3 As shown, along the transmission direction of the signal, they are distributed in sequence as high-resistance transmission segment 1, low-resistance transmission segment 1, high-resistance transmission segment 2, low-resistance transmission segment 2, high-resistance transmission segment 3, low-resistance transmission segment 3, high-resistance transmission segment 4, low-resistance transmission segment 4, branch 1, low-resistance transmission segment 5, high-resistance transmission segment 5, low-resistance transmission segment 6, high-resistance transmission segment 6, low-resistance transmission segment 7, high-resistance transmission segment 7, low-resistance transmission segment 8, high-resistance transmission segment 8, low-resistance transmission segment 9, branch 2, low-resistance transmission segment 10, and branch 3; as shown in FIG. Figure 1 As shown, the entire transmission body 200 is disposed in the cavity 100 .

[0037] Understandably, referring to Figure 1 and Figure 2 As shown, the cavity 100 includes a first cavity 100 and a second cavity 100 that are connected to each other, and the angle between the first cavity 100 and the second cavity 100 is less than or equal to 90 degrees.

[0038] It should be noted that by setting the angle between the first cavity 100 and the second cavity 100 to be less than or equal to 90 degrees, the length of the low-pass filter in the horizontal direction can be reduced, thereby further adapting to the use of more filtering scenarios.

[0039] It should be noted that the angle between the first cavity 100 and the second cavity 100 is not limited in the embodiment of the present application, and those skilled in the art can selectively set it according to actual needs, such as 30 degrees, 60 degrees, 90 degrees, etc.

[0040] For example, Figure 1 As shown, the first cavity 100 and the second cavity 100 are vertically arranged, that is, the angle between the first cavity 100 and the second cavity 100 is 90 degrees.

[0041] Understandably, referring to Figure 1 and Figure 2 As shown, the first interval between two adjacent first transmission segments 220 in the second cavity 100 is less than or equal to the second interval between two adjacent first transmission segments 220 in the first cavity 100, and the second transmission segment 230 in the second cavity 100 is bent.

[0042] It should be noted that by shortening the first interval and bending the second transmission section 230 in the second cavity 100 , the length of the second cavity 100 can be made smaller while ensuring the filtering effect, thereby further reducing the size of the low-pass filter.

[0043] For example, Figures 1 to 3 As shown, high-resistance transmission segment 1, low-resistance transmission segment 1, high-resistance transmission segment 2, low-resistance transmission segment 2, high-resistance transmission segment 3, low-resistance transmission segment 3, high-resistance transmission segment 4, low-resistance transmission segment 4, branch 1, low-resistance transmission segment 5, and high-resistance transmission segment 5 are located in the first cavity 100, and high-resistance transmission segment 6, low-resistance transmission segment 7, high-resistance transmission segment 7, low-resistance transmission segment 8, high-resistance transmission segment 8, low-resistance transmission segment 9, branch 2, low-resistance transmission segment 10, and branch 3 are located in the second cavity 100. The low-resistance transmission segment 6 is partially located in the first cavity 100 and partially located in the second cavity 100; the low-resistance transmission segments 6 to 10 are all bent.

[0044] Understandably, referring to Figure 1 and Figure 2 As shown, the second transmission segment 230 in the second cavity 100 is bent; a plurality of parallel and spaced-apart isolation portions 130 are provided in the second cavity 100, the first end of the isolation portion 130 is connected to the first side wall of the cavity 100, and the second end of the isolation portion 130 is spaced a preset distance from the second side wall opposite to the first side wall of the cavity 100; the isolation portion 130 is used to isolate two adjacent transmission segments distributed along the signal transmission direction in the second cavity 100.

[0045] It should be noted that the adjacent transmission segments in the second cavity 100 may be two first transmission segments 220, or a first transmission segment 220 and an elliptic function branch transmission segment 210, or two elliptic function branch transmission segments 210. By adding the isolation portion 130, signal interference between two adjacent transmission segments can be reduced.

[0046] It should be noted that, by the second end of the isolation portion 130 being spaced apart from the second side wall by a preset distance, two adjacent transmission sections can be connected to each other.

[0047] For example, Figure 2 As shown, there are five isolation parts 130 in the second cavity 100, wherein four consecutive isolation parts 130 close to the first cavity 100 are staggered on the first side wall and the second side wall to isolate the two first transmission sections 220. Another isolation part 130 is connected close to the signal output port 120 to isolate two adjacent elliptic function branch transmission sections 210.

[0048] Understandably, referring to Figures 1 to 4 As shown, at least one elliptical function branch transmission segment 210 is located in the second cavity 100 , and at least one first protrusion 140 corresponding to the elliptical function branch transmission segment 210 is also provided in the second cavity 100 , and the second end of the elliptical function branch transmission segment 210 is provided on the first protrusion 140 .

[0049] It should be noted that the transmission body 200 can be suspended in the air by providing the first protrusion 140 .

[0050] It should be noted that an insulating layer may be provided on the side of the first protrusion 140 opposite to the elliptic function branch transmission section 210. In other embodiments, for example Figure 4 As shown, a second support and isolation gasket 320 may also be provided between the first protrusion 140 and the elliptical branch segment. The second support and isolation gasket 320 is used to support the elliptical function branch transmission segment 210 and isolate the elliptical function branch transmission segment 210 from the first protrusion 140.

[0051] It should be noted that the elliptic function branch transmission section 210 can be fixed to the first protrusion 140 by means of screws or the like.

[0052] Understandably, referring to Figure 2 As shown, a plurality of second protrusions 150 corresponding one-to-one to the first transmission sections 220 are further disposed in the cavity 100 , and the first transmission sections 220 are disposed on the second protrusions 150 .

[0053] By providing the second protrusion 150 , the entire transmission body 200 can be spaced a preset distance from the bottom of the cavity 100 and be more stable.

[0054] It should be noted that an insulating layer may be provided on a side opposite to the second protrusion 150 and the first transmission section 220 . In other embodiments, a first supporting isolation gasket 310 may also be provided between the second protrusion 150 and the first transmission section 220 .

[0055] Understandably, referring to Figure 4As shown, the low-pass filter further includes a plurality of first supporting and isolating pads 310 , and the first supporting and isolating pads 310 are used to isolate the second protrusions 150 and the corresponding first transmission sections 220 .

[0056] Understandably, referring to Figure 1 and Figure 4 As shown, three elliptic function branch transmission segments 210 are provided, wherein a first end of one elliptic function branch transmission segment 210 is connected to the connection between two adjacent second transmission segments 230 , and the other two elliptic function branch transmission segments 210 are adjacently arranged and close to the signal output port 120 .

[0057] Understandably, referring to Figure 1 and Figure 4 As shown, the low-pass filter also includes a first connector 330 and a first connecting rod 340, the first end of the first connector 330 is connected to the first end of the first connecting rod 340, and the first end of the first connector 330 is fixed to the signal input port 110; the first connecting rod 340 is arranged in the signal input port 110, and the second end of the first connecting rod 340 is connected to one end of the transmission body 200; the first connecting rod 340 is used to perform impedance transformation on the signal entering the transmission body 200 from the first connector 330.

[0058] It should be noted that the first connector 330 can be connected to a cable, so the inner conductor of the first connector 330 is a cylinder. By adding a first connecting rod 340, the sheet-like transmission body 200 and the first connector 330 can be connected, and impedance transformation between the two can be achieved.

[0059] Understandably, referring to Figure 1 and Figure 4 As shown, the low-pass filter further includes a second connector 350 , and a first end of the second connector 350 is connected to the transmission body 200 through the signal output port 120 .

[0060] It should be noted that the low-pass filter of the embodiment of the present application has lower production cost and smaller volume than the cavity 100 filter, has less impact on processing errors, and is simpler and faster to assemble and adjust. In terms of electrical performance and low intermodulation, the embodiment of the present application has lower insertion loss, higher power handling, and can also achieve low intermodulation.

[0061] The above is a specific description of the preferred implementation of the present application, but the present application is not limited to the above-mentioned implementation mode. Technical personnel familiar with the field can also make various equivalent deformations or substitutions without violating the spirit of the present application. These equivalent deformations or substitutions are all included in the scope defined by the claims of the present application.

Claims

1. A low-pass filter, characterized in that: include: A cavity, wherein two ends of the cavity are respectively provided with a signal input port and a signal output port; A transmission body, wherein the transmission body is located in the cavity, and the transmission body is composed of at least one elliptic function branch transmission segment and a plurality of first transmission segments and second transmission segments connected in series, wherein the impedance of the first transmission segment is greater than that of the second transmission segment, and the first end of each of the elliptic function branch transmission segments is connected to one of the second transmission segments; and the second end of each of the elliptic function branch transmission segments is fixed in the cavity.

2. The low-pass filter according to claim 1, characterized in that The cavity includes a first cavity and a second cavity which are connected to each other, and an angle between the first cavity and the second cavity is less than or equal to 90 degrees.

3. The low-pass filter according to claim 2, characterized in that A first interval between two adjacent first transmission segments in the second cavity is less than or equal to a second interval between two adjacent first transmission segments in the first cavity, and the second transmission segment in the second cavity is bent.

4. The low-pass filter according to claim 2, characterized in that The second transmission segment in the second cavity is bent; a plurality of parallel and spaced-apart isolation portions are provided in the second cavity, a first end of the isolation portion is connected to a first side wall of the cavity, and a second end of the isolation portion is spaced a preset distance from a second side wall opposite to the first side wall of the cavity; the isolation portion is used to isolate two adjacent transmission segments distributed along a signal transmission direction in the second cavity.

5. The low-pass filter according to claim 2, characterized in that At least one of the elliptic function branch transmission segments is located in the second cavity, and at least one first protrusion corresponding to the elliptic function branch transmission segment is also arranged in the second cavity, and the second end of the elliptic function branch transmission segment is arranged on the first protrusion.

6. The low-pass filter according to claim 1, characterized in that The cavity is further provided with a plurality of second protrusions corresponding one-to-one to the first transmission sections, and the first transmission sections are arranged on the second protrusions.

7. The low-pass filter according to claim 6, characterized in that It also includes a plurality of first supporting and isolating gaskets, wherein the first supporting and isolating gaskets are used to isolate the second protrusion and the corresponding first transmission section.

8. The low-pass filter according to claim 6, characterized in that There are three elliptic function branch transmission segments, wherein a first end of one of the elliptic function branch transmission segments is connected to the connection between two adjacent second transmission segments, and the other two elliptic function branch transmission segments are adjacently arranged and close to the signal output port.

9. The low-pass filter according to claim 1, characterized in that: It also includes a first connector and a first connecting rod, wherein the first end of the first connector is connected to the first end of the first connecting rod, and the first end of the first connector is fixed to the signal input port; the first connecting rod is arranged in the signal input port, and the second end of the first connecting rod is connected to one end of the transmission body; the first connecting rod is used to perform impedance transformation on the signal entering the transmission body from the first connector.

10. The low-pass filter according to claim 1, characterized in that It also includes a second connector, a first end of which passes through the signal output port and is connected to the transmission body.

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