Filters, feed networks and antennas

Abstract

The embodiment of the present application discloses a filter, a feed network and an antenna, the filter comprising: a first transmission line and a second transmission line, the second transmission line comprising a first end and a second end; the first end of the second transmission line is connected with the first transmission line, and the second end of the second transmission line is close to but not in contact with the first end of the second transmission line, so that the second end of the second transmission line is coupled with a first area close to the first end on the second transmission line, and / or the second end of the second transmission line forms a coupling with a second area close to the first end on the first transmission line to filter a signal of a frequency band to be filtered. Thus, the second transmission line can be made into a bending structure, coupled with the filter itself, grounded without contact, improved filtering characteristics, reduced layout space limitation on the size of the filter, and met the miniaturization design of the filter.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the field of communication equipment, and in particular to a filter, a feed network and an antenna. BACKGROUND

[0002] A filter can pass signals within a working bandwidth and attenuate signals outside the working bandwidth. By using the frequency selection effect of the filter, interference noise can be filtered out or frequency spectrum analysis can be performed. The filter is a frequency selective device and is widely used in communication and broadband services.

[0003] Therefore, as communication technology develops more and more quickly, there is an increasing demand for filters that are small in size and have good filtering characteristics. SUMMARY

[0004] Therefore, the filter provided by embodiments of the present application not only improves the filtering characteristics of the filter, but also achieves miniaturization of the filter.

[0005] In a first aspect, a filter is provided. The filter includes a first transmission line and a second transmission line, the second transmission line including a first end and a second end. The first end of the second transmission line is connected to the first transmission line, and the second end of the second transmission line is close to but does not contact the first end of the second transmission line. The second end of the second transmission line is coupled to a first region of the second transmission line close to the first end, and / or the second end of the second transmission line forms a coupling with a second region of the first transmission line close to the first end to filter signals in a to-be-filtered frequency band. Thus, the second transmission line can be made into a folded structure and coupled to the filter itself, which can avoid grounding and reduce the limitation of layout space on the size of the filter, thereby meeting the miniaturization design of the filter. In addition, the filter can be equivalent to a circuit model composed of a plurality of series inductors and a plurality of grounded capacitors. The second end of the second transmission line is coupled to the first region of the second transmission line close to the first end of the second transmission line, or the second end of the second transmission line forms a coupling with the second region of the first transmission line close to the first end of the second transmission line. On a circuit diagram, a parallel capacitor can be added to the second transmission line. The parallel capacitor increases the power capacity, and the equivalent parallel capacitor increases the electrical coupling. Whether the magnetic coupling changes or remains unchanged, the total coupling is adjusted, high out-of-band rejection of the filter is achieved, and the filtering efficiency of the filter is improved.

[0006] In an optional implementation, the second end of the second transmission line is on the same plane or different planes as the first end of the second transmission line, or the second end of the second transmission line is on the same plane or different planes as the first transmission line. Thus, the flexibility of the filter is improved.

[0007] In an alternative implementation, the second end of the second transmission line is electrically coupled to the first region of the second transmission line close to the first end. In this way, the second transmission line can be folded and coupled to the filter itself, which avoids grounding, improves filter characteristics, and reduces the layout space to limit the size of the filter and meet the miniaturization design of the filter.

[0008] The electric coupling described in the present application refers to the coupling between two conductors (conductor 1 and conductor 2) to form a capacitive coupling, such as the two conductors not being in direct contact and being electrically connected through the coupling. For example, the second end (conductor 1) of the second transmission line is electrically coupled to the main transmission line (conductor 2).

[0009] The magnetic coupling described in the present application refers to the coupling between two conductors (conductor 1 and conductor 2) to form an inductive coupling, such as the two conductors being in direct contact and being electrically connected through the coupling. For example, the first end (conductor 1) of the second transmission line is magnetically coupled to the main transmission line (conductor 2).

[0010] In an alternative implementation, when the second end of the second transmission line is electrically coupled to the first region of the second transmission line close to the first end, the spatial distance between the second end of the second transmission line and the first end of the second transmission line is 0-4mm. Alternatively, the spatial distance between the second end of the second transmission line and the first end of the second transmission line is 0-2mm or 0-3mm. In this way, the electric coupling between the second end of the second transmission line and the first end of the second transmission line is achieved, so that the total coupling of the filter can be changed to improve the filter characteristics of the filter.

[0011] In an alternative implementation, when the second end of the second transmission line is electrically coupled to the first region of the second transmission line close to the first end, the spatial distance between the second end of the second transmission line and the first transmission line is 0-5mm. In this way, the second end of the second transmission line is as close as possible to the first transmission line, which can further achieve the electric coupling between the second end of the second transmission line and the first end of the second transmission line.

[0012] In an alternative implementation, the second end of the second transmission line is electrically coupled to the second region of the first transmission line close to the first end. In this way, the second transmission line can be folded and coupled to the filter itself, which avoids grounding, improves filter characteristics, and reduces the layout space to limit the size of the filter and meet the miniaturization design of the filter.

[0013] In an alternative implementation, when the second end of the second transmission line is electrically coupled to the second region of the first transmission line close to the first end, the spatial distance between the second end of the second transmission line and the first transmission line is 0-4 mm. Alternatively, the spatial distance between the second end of the second transmission line and the first end of the second transmission line is 0-2 mm. In this way, the electrical coupling between the second end of the second transmission line and the first transmission line is achieved, so that the overall coupling of the filter can be changed to improve the filtering characteristics of the filter.

[0014] In an alternative implementation, the port line width of the second end of the second transmission line is wider than the transmission line part line width of the second transmission line. In this way, the coupling surface size can be increased to further increase the electrical coupling between the second end of the second transmission line and the first transmission line.

[0015] In an alternative implementation, the length of the second transmission line is greater than or equal to one fourth of the low cutoff operating wavelength of the signal of the frequency band to be filtered, and less than or equal to one fourth of the high cutoff operating wavelength of the signal of the frequency band to be filtered. In this way, the second transmission line can filter out signals below the low cutoff frequency in the frequency band to be filtered, and filter out signals above the high cutoff frequency in the frequency band to be filtered.

[0016] In an alternative implementation, the length of the second transmission line is one fourth of the center operating wavelength of the signal of the frequency band to be filtered; or the length of the second transmission line is one fourth of the low cutoff operating wavelength of the signal of the frequency band to be filtered; or the length of the second transmission line is one fourth of the high cutoff operating wavelength of the signal of the frequency band to be filtered. In this way, the second transmission line can filter out signals of the frequency band to be filtered.

[0017] In a second aspect of the embodiments of the present application, a feeding network is provided, comprising a phase shifter and a filter as described above, the phase shifter being electrically connected to the filter, and the feeding network being used for transmitting or receiving radio frequency signals. In this way, the feeding network uses the filter as described above, and has the same effects as the filter, which will not be described herein again.

[0018] In a third aspect of the embodiments of the present application, an antenna is provided, comprising at least one antenna array, the antenna array comprising at least one radiating element, a reflector, and a feeding network as described above; the radiating element is arranged above the reflector, and the feeding network is connected to the radiating element. In this way, the antenna comprises the feeding network or the filter as described above, and has the same effects as the feeding network or the filter, which will not be described herein again.

[0019] In an alternative implementation, the antenna further comprises a radome, and the radiating element, the reflector, and the feeding network are located in a cavity surrounded by the radome. In this way, the radome can reduce the interference of the external environment on the antenna. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the structure of a filter;

[0021] Figure 2 It is a structural diagram of another filter;

[0022] Figure 3 for Figure 2 Equivalent circuit diagram of the filter in Figure 2;

[0023] Figure 4 A schematic diagram of the structure of a filter provided in this application;

[0024] Figure 5 for Figure 4 Equivalent circuit diagram of the filter in Figure 2;

[0025] Figure 6 A schematic diagram of the structure of another filter provided in this application;

[0026] Figure 7 for Figure 6 Equivalent circuit diagram of the filter in Figure 2;

[0027] Figure 8 A schematic diagram of the structure of another filter provided in this application;

[0028] Figure 9 A schematic diagram of the structure of another filter provided in this application;

[0029] Figure 10 A schematic diagram of the structure of the filter provided in Example 1 of this application;

[0030] Figure 11 for Figure 10 Provide the amplitude-frequency characteristic curve of the filter;

[0031] Figure 12 A schematic diagram of the structure of the filter provided in Example 2 of this application;

[0032] Figure 13 for Figure 12 Provide the amplitude-frequency characteristic curve of the filter;

[0033] Figure 14 A schematic diagram of the structure of a feed network provided in an embodiment of the present application;

[0034] Figure 15 A schematic diagram of the structure of an antenna provided in an embodiment of the present application;

[0035] Figure 16 A schematic structural diagram of a base station antenna feed system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0036] In order to make the purposes, technical solutions and advantages of the present application clearer, the following further describes the present application with reference to the accompanying drawings.

[0037] Hereinafter, the terms "first", "second", and the like are used only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second", and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0038] In addition, in the present application, the orientation terms such as "upper", "lower", and the like are defined with respect to the orientation in which the components in the drawings are placed, and it should be understood that these directional terms are relative concepts, which are used for relative description and clarification, and can be changed accordingly according to the change of the orientation in which the components are placed in the drawings.

[0039] Hereinafter, the terms appearing in the embodiments of the present application are explained.

[0040] Insertion Loss (IL): The loss of load power due to the insertion of an element or device at some point in a transmission system, which is expressed as the ratio of the power received on the load before the insertion of the element or device to the power received on the same load after the insertion in decibels.

[0041] Passive Intermodulation (PIM): Refers to the mixing of two or more frequencies together in a non-linear device to produce spurious signals.

[0042] Please refer to Figure 1 and Figure 2 The filter shown in the drawings comprises a main transmission line and a branch. Wherein, Figure 1 The branch of the filter shown in the drawings is an open-circuit branch, one end of the open-circuit branch is directly connected with the main transmission line, and the other end of the open-circuit branch is suspended. Figure 2 The branch of the filter shown in the drawings is a short-circuit branch, one end of the short-circuit branch is coupled with the main transmission line, and the other end of the short-circuit branch is grounded.

[0043] Figure 3 For Figure 1 Or Figure 2 The equivalent circuit diagram of the filter in Figure 3As shown in the figure, the filter can be equivalent to a circuit model consisting of several series inductors and several grounded capacitors. These equivalent inductors and capacitors form a resonant circuit. The signal attenuation in the passband frequency band is small, while the signal attenuation in the stopband frequency band is large, so that the passband signal can pass, while the stopband signal is blocked, thereby completing the transmission filtering function.

[0044] Figure 1 The width of the open-circuit branch of the filter shown needs to be designed to be narrow, resulting in a small power capacity of the open-circuit branch, a low quality factor, and poor filtering characteristics.

[0045] Figure 2 The short-circuit branches of the filter shown need to be grounded, which results in unstable grounding, large insertion loss, and poor passive intermodulation performance, thereby affecting the filtering characteristics of the filter.

[0046] In view of this, the present application provides a filter with excellent filtering characteristics. The filter includes a main transmission line and an open branch. The first end (connection end) of the open branch is directly electrically connected to the main transmission line, and the second end (terminal end) of the open branch is coupled and electrically connected to the main transmission line, or the second end (terminal end) of the open branch is coupled to the open branch itself. This coupling is used to adjust the overall coupling of the filter, thereby improving the filtering characteristics.

[0047] Furthermore, when the second end (terminal) of the open branch of the filter is coupled with the open branch itself, in order to achieve better filtering effect, the second end (terminal) of the open branch is as close to the first end (connection end) of the open branch as possible in space.

[0048] Please refer to Figure 4 , which is a structural diagram of the filter provided in an embodiment of the present application. Figure 5 for Figure 4 The filter provided in the embodiment of the present application improves the filtering characteristics of the filter by coupling the second end (terminal end) of the open branch with the open branch itself. Figure 4 The filter 001 shown includes a first transmission line 101 and a second transmission line 102. The first transmission line 101 is a main transmission line, and the second transmission line 102 is an open-circuit branch. For ease of description, the first transmission line 101 and the second transmission line 102 are shown as being coplanar. Alternatively, the first transmission line 101 and the second transmission line 102 may be partially coplanar and partially non-coplanar. For example, the second end 1022 of the second transmission line 102 is not coplanar with the first transmission line.

[0049] The first transmission line 101 comprises a first end 1011 and a second end 1012 opposite to the first end 1011 of the first transmission line 101, the first end 1011 of the first transmission line 101 is configured to be connected with an input port, and the second end 1012 of the first transmission line 101 is configured to be connected with an output port.

[0050] The input port is configured to receive a signal, and the output port is configured to output a signal.

[0051] The second transmission line 102 comprises a first end 1021 and a second end 1022 opposite to the first end 1021 of the second transmission line 102, the first end 1021 of the second transmission line 102 is connected with the first transmission line 101, and the second end 1022 of the second transmission line 102 is close to but not in contact with the first end 1021 of the second transmission line 102.

[0052] In some embodiments of the present application, as shown in Figure 4 The second end 1022 of the second transmission line 102 is electrically coupled with a first area A of the second transmission line 102 close to the first end 1021 of the second transmission line 102, so as to improve the filtering characteristics of the filter.

[0053] In some embodiments, the spatial distance L1 between the second end 1022 of the second transmission line 102 and the first end 1021 of the second transmission line 102 is less than or equal to 4 mm, and optionally, the L1 is 0-2 mm. The electrical coupling between the second end 1022 of the second transmission line 102 and the first end 1021 of the second transmission line 102 is achieved, so that the overall coupling of the filter can be changed, thereby improving the filtering characteristics of the filter.

[0054] Further, in order to achieve stronger electrical coupling between the second end 1022 of the second transmission line 102 and the first end 1021 of the second transmission line 102, the second end 1022 of the second transmission line 102 needs to be as close as possible to the first end 1021 of the second transmission line 102, and optionally, the spatial distance L2 between the second end 1022 of the second transmission line 102 and the first transmission line 101 is less than or equal to 5 mm.

[0055] When the second end 1022 of the second transmission line 102 and the first transmission line are not in the same plane (not shown), the spatial distance L4 between the second end 1022 of the second transmission line 102 and the second end 1022 of the second transmission line 102 in the third dimension (height difference direction) is also as small as possible, and optionally, the distance L4 is less than or equal to 4 mm, and optionally, the L4 is 0-2 mm.

[0056] It should be noted that the values of the three-dimensional space distances L1, L2, L4 illustrated in the embodiments of the present application are only examples, as long as the space distance of any dimension meets the range of each dimension described above, so as to achieve the electric coupling effect of the embodiments of the present application, which belongs to the protection scope of the present application.

[0057] In some other embodiments of the present application, the second end (terminal) of the open-circuit branch can also be electrically connected with the main transmission line, such as Figure 6 As shown, the second end 1022 of the second transmission line 102 is coupled with the first transmission line 101 to improve the filtering characteristics of the filter.

[0058] Optionally, the second end 1022 of the second transmission line 102 is coupled with the second region B of the first transmission line 101 close to the first end 1021 of the second transmission line 102.

[0059] In the above embodiment, the second end 1022 of the second transmission line 102 is coupled with the second region B of the first transmission line 101 close to the first end 1021 of the second transmission line 102, which means that the second end 1022 of the second transmission line 102 is as close as possible to the second region B of the first transmission line 101 close to the first end 1021 of the second transmission line 102.

[0060] For example, the space distance L3 between the second end 1022 of the second transmission line 102 and the first transmission line 101 is less than or equal to 4mm, and optionally, the L3 is 0-2mm.

[0061] Therefore, the second transmission line 102 can be made into a bending structure to be coupled with the filter itself, which avoids grounding, improves the filtering characteristics, reduces the limitation of the layout space on the size of the filter 001, and meets the miniaturization design of the filter.

[0062] For reference Figure 5 or Figure 7The filter 001 can be equivalent to a circuit model consisting of several series inductors and several grounded capacitors. The second end 1022 of the second transmission line 102 is coupled to a first region of the second transmission line 102 near the first end 1021 of the second transmission line 102, or the second end 1022 of the second transmission line 102 is coupled to a second region of the first transmission line 101 near the first end 1021 of the second transmission line 102. In the circuit diagram, this can be equivalent to adding a capacitor to the second transmission line 102. The capacitor is connected in parallel with the equivalent capacitance and inductance of the second transmission line 102, which is equivalent to adding a parallel capacitor to the second transmission line 102. The parallel capacitor increases the power capacity. At the same time, the equivalent parallel capacitor is equivalent to increasing the electrical coupling. Regardless of whether the magnetic coupling changes or remains unchanged, the total coupling is adjusted, achieving high suppression outside the filter band, thereby improving the filtering effect of the filter.

[0063] In the embodiment of the present application, coupling is performed at the end of the second transmission line 102 to increase the parallel capacitance, thereby achieving stronger electrical coupling, thereby adjusting the total coupling of the filter and achieving the purpose of improving the filtering characteristics of the filter.

[0064] Furthermore, a larger coupling area results in a stronger electrical coupling. The portion where the second end 1022 of the second transmission line 102 is coupled to the first transmission line 101, or the portion where the second end 1022 of the second transmission line 102 is coupled to the first end 1021 of the second transmission line 102, can also be lengthened or widened to enhance electrical coupling. Alternatively, a closer coupling distance results in a stronger electrical coupling. Alternatively, the distance between the portion where the second end 1022 of the second transmission line 102 is coupled to the first transmission line 101, or the distance between the portion where the second end 1022 of the second transmission line 102 is coupled to the first end 1021 of the second transmission line 102, can be reduced.

[0065] For example, Figure 6 As shown, the port line width of the second end 1022 of the second transmission line 102 is, for example, wider than the line width of the transmission line portion of the second transmission line 102 .

[0066] Thus, the size of the coupling surface can be increased to further enhance the electrical coupling.

[0067] The embodiment of the present application does not limit the lengths of the first transmission line 101 and the second transmission line 102 .

[0068] For example, the length of the second transmission line 102 is greater than or equal to one fourth of the low cutoff operating wavelength of the signal of the frequency band to be filtered and less than or equal to one fourth of the high cutoff operating wavelength of the signal of the frequency band to be filtered. For example, the length of the second transmission line 102 is one fourth of the center operating wavelength of the signal of the frequency band to be filtered. Alternatively, the length of the second transmission line 102 is one fourth of the low cutoff operating wavelength of the signal of the frequency band to be filtered. Alternatively, the length of the second transmission line 102 is one fourth of the high cutoff operating wavelength of the signal of the frequency band to be filtered.

[0069] The embodiments of the present application do not limit the specific structure of the second transmission line 102.

[0070] The second end 1022 of the second transmission line 102 and the first end 1021 of the second transmission line 102 are in the same plane or different planes, or the second end 1022 of the second transmission line 102 and the first transmission line 101 are in the same plane or different planes.

[0071] The second transmission line 102 can adopt a zigzag structure as shown in Figure 4 Figure 6 Figure 8 Figure 9 The second transmission line 102 can also adopt a smooth curve structure, which all belong to the protection scope of the present application.

[0072] As shown in Figure 4 Figure 6 Figure 8 Figure 9 The second transmission line 102 includes a first sub-transmission line 1023, a second sub-transmission line 1024 and a third sub-transmission line 1025. The first sub-transmission line 1023 is connected with the first transmission line 101. The first sub-transmission line 1023 and the second sub-transmission line 1024 are arranged in a first direction. The first direction is the extension direction of the first transmission line 101. The first sub-transmission line 1023 and the second sub-transmission line 1024 are connected through the third sub-transmission line 1025.

[0073] Thus, the first sub-transmission line 1023 and the second sub-transmission line 1024 are arranged in the extension direction of the first transmission line 101, which can improve the isolation between the first sub-transmission line 1023 and the second sub-transmission line 1024.

[0074] In some embodiments of the present application, as shown in Figure 4 The second end 1022 of the second transmission line 102 is electrically coupled with the first region of the second transmission line 102 close to the first end 1021 of the second transmission line 102. ​​​​​​

[0075] As shown in Figure 4 The second transmission line 102 further includes a fourth sub-transmission line 1026, one end of the fourth sub-transmission line 1026 is connected with the second sub-transmission line 1024, and the other end of the fourth sub-transmission line 1026 is coupled with the first sub-transmission line 1023.

[0076] Thus, the second transmission line 102 is arranged in the same layer as the first transmission line 101, which reduces the profile height and is beneficial to the miniaturization of the device.

[0077] In some embodiments, as shown in Figure 6 The second end 1022 of the second transmission line 102 is electrically coupled with the second region of the first transmission line 101 close to the first end 1021 of the second transmission line 102.

[0078] As shown in Figure 6 The first sub-transmission line 1023 is arranged in the same layer as the first transmission line 101, and the second sub-transmission line 1024 is arranged in a different layer from the first transmission line 101, one end of the second sub-transmission line 1024 is connected with the third sub-transmission line 1025, and the other end is coupled with the first transmission line 101.

[0079] The third sub-transmission line 1025 includes a first connecting line 10251 and a second connecting line 10252.

[0080] In some embodiments, the first connecting line 10251 is arranged in the same layer as the first transmission line 101, one end of the first connecting line 10251 is connected with the first sub-transmission line 1023, and the other end is connected with the second connecting line 10252. One end of the second connecting line 10252 is connected with the first connecting line 10251, and the other end is connected with the second sub-transmission line 1024.

[0081] In some embodiments, as shown in Figure 8 The second connecting line 10252 is arranged in the same layer as the second sub-transmission line 1024, one end of the second connecting line 10252 is connected with the first connecting line 10251, and the other end is connected with the second sub-transmission line 1024. One end of the first connecting line 10251 is connected with the first sub-transmission line 1023, and the other end is connected with the second connecting line 10252.

[0082] In other embodiments of the present application, the third sub-transmission line 1025 , for example, includes: a first connecting line 10251 , a second connecting line 10252 , and a third connecting line 10253 .

[0083] Among them, such as Figure 9 As shown, the first connecting line 10251, the second connecting line 10252, and the first transmission line 101 are arranged in the same layer. One end of the first connecting line 10251 is connected to the first sub-transmission line 1023, and the other end is connected to the second connecting line 10252. One end of the second connecting line 10252 is connected to the first connecting line 10251, and the other end is connected to one end of the third connecting line 10253. The other end of the third connecting line 10253 is connected to the second sub-transmission line 1024.

[0084] The embodiment of the present application does not limit the number of open branches. In some embodiments of the present application, such as Figure 10 、 Figure 12 As shown, the filter 001 further includes: a third transmission line 103 and a fourth transmission line 104 .

[0085] In some embodiments of the present application, the third transmission line 103 and the fourth transmission line 104 may adopt the same structure as the second transmission line 102 .

[0086] like Figure 10 As shown, the third transmission line 103 includes: a first end and a second end opposite to each other, the first end of the third transmission line 103 is connected to the first transmission line 101, wherein the resonant frequency of the third transmission line 103 is within the stopband frequency band of the signal received by the input port.

[0087] The second end of the third transmission line 103 is coupled to the first transmission line 101 , or the second end of the third transmission line 103 is coupled to the third transmission line 103 .

[0088] In other embodiments of the present application, only the third transmission line 103 and the fourth transmission line 104 may be configured as a zigzag structure, with the ends of the third transmission line 103 and the fourth transmission line 104 being open-circuit structures. The resonant frequency of the third transmission line 103 is within the stopband frequency band of the signal received by the input port.

[0089] The embodiment of the present application does not limit the material of the filter 001. The first transmission line 101, the second transmission line 102, the third transmission line 103, and the fourth transmission line 104 can be metal strip lines or microstrip lines.

[0090] Example 1:

[0091] like Figure 10As shown, the filter 001 comprises an input port, an output port, a first transmission line 101, a second transmission line 102, a third transmission line 103 and a fourth transmission line 104.

[0092] The input port is configured to receive a signal, and the output port is configured to output a signal.

[0093] One end of the first transmission line 101 is connected to the input port, and the other end is connected to the output port.

[0094] One end of the second transmission line 102, the third transmission line 103 and the fourth transmission line 104 is connected to the first transmission line 101, and the other end is coupled to the first transmission line 101.

[0095] The second transmission line 102 comprises a first sub-transmission line 1023, a second sub-transmission line 1024 and a third sub-transmission line 1025.

[0096] The first sub-transmission line 1023 is parallel to the second sub-transmission line 1024, and the two are spaced apart along the extension direction of the first transmission line 101. The third sub-transmission line 1025 connects the first sub-transmission line 1023 and the second sub-transmission line 1024.

[0097] The third sub-transmission line 1025 comprises a first connecting line 10251, a second connecting line 10252 and a third connecting line 10253, for example. In some embodiments, as shown, Figure 4 The first connecting line 10251, the second connecting line 10252 and the first transmission line 101 are arranged in the same layer. One end of the first connecting line 10251 is connected to the first sub-transmission line 1023, and the other end is connected to the second connecting line 10252. One end of the second connecting line 10252 is connected to the first connecting line 10251, and the other end is connected to one end of the third connecting line 10253. The other end of the third connecting line 10253 is connected to the second sub-transmission line 1024.

[0098] Of course, in other embodiments of the present application, the second connecting line 10252 is arranged in the same layer as the second sub-transmission line 1024. One end of the second connecting line 10252 is connected to the first connecting line 10251, and the other end is connected to the second sub-transmission line 1024. One end of the first connecting line 10251 is connected to the first sub-transmission line 1023, and the other end is connected to the second connecting line 10252.

[0099] The structures of the third transmission line 103 and the fourth transmission line 104 can refer to the second transmission line 102, which will not be described here.

[0100] The first transmission line 101, the second transmission line 102, the third transmission line 103 and the fourth transmission line 104 are, for example, metal strip lines. Figure 11 The amplitude-frequency characteristic curve of the filter shown in Example 1 is shown in the following figure.

[0101] As shown by the S12 curve in Figure 11 The simulation diagram has three troughs, i.e., transmission zeros, corresponding to the second transmission line 102, the third transmission line 103 and the fourth transmission line 104, respectively. The attenuation degree of the filter 001 to high-frequency signals can be improved, thereby optimizing the low-pass performance.

[0102] In this example, the capacitance characteristic is formed by electrically coupling the second transmission line 102 and the first transmission line 101, the third transmission line 103 and the first transmission line 101, and the fourth transmission line 104 and the first transmission line 101. The capacitance characteristic and the inductance equivalent to the second transmission line 102, the third transmission line 103 and the fourth transmission line 104 constitute a parallel resonance circuit to achieve transmission zeros, thereby improving the attenuation degree of the filter 001 to signals.

[0103] Referring to the S11 curve in Figure 11 In this example, the passband frequency range is 690MHz-862MHz, and the first transmission zero is only 18MHz away from the passband, so that the transmission zero is weak and close to the passband while maintaining high suppression degree, thereby improving the filtering characteristics of the filter.

[0104] Example 2

[0105] As shown in Figure 12 The filter 001 comprises an input port, an output port, a first transmission line 101, a second transmission line 102, a third transmission line 103 and a fourth transmission line 104.

[0106] The input port is configured to receive a signal, and the output port is configured to output a signal.

[0107] One end of the first transmission line 101 is connected to the input port, and the other end is connected to the output port.

[0108] The second transmission line 102, the third transmission line 103 and the fourth transmission line 104 are arranged in the same layer as the first transmission line 101, and the second transmission line 102, the third transmission line 103 and the fourth transmission line 104 all adopt a bending structure.

[0109] The second transmission line 102 comprises a first sub-transmission line 1023, a second sub-transmission line 1024 and a third sub-transmission line 1025. The first sub-transmission line 1023 is connected with the first transmission line 101. The first sub-transmission line 1023 and the second sub-transmission line 1024 are arranged at intervals in a first direction. The first direction is the extension direction of the first transmission line 101. The first sub-transmission line 1023 and the second sub-transmission line 1024 are connected through the third sub-transmission line 1025.

[0110] The first sub-transmission line 1023, the second sub-transmission line 1024 and the third sub-transmission line 1025 are arranged in the same layer as the first transmission line 101. The second transmission line 102 further comprises a fourth sub-transmission line 1026. One end of the fourth sub-transmission line 1026 is connected with the second sub-transmission line 1024. The other end of the fourth sub-transmission line 1026 is coupled with a third position of the first sub-transmission line 1023. The third position of the first sub-transmission line 1023 is close to the first end 1021 of the second transmission line 102.

[0111] In order to realize strong electrical coupling, the coupling distance can be reduced. The other end of the fourth sub-transmission line 1026 is close to the first end 1021 of the second transmission line 102.

[0112] The ends of the third transmission line 103 and the fourth transmission line 104 are open circuit structures and are not coupled with the front ends of the transmission lines.

[0113] Figure 13 The amplitude-frequency characteristic curve of the filter 001 shown in Example Two.

[0114] As shown by the S12 curve in Figure 13 on the simulation diagram, the transmission zero point closest to the passband corresponds to the transmission zero point generated by the second transmission line 102. The attenuation degree of the filter 001 to high-frequency signals can be improved, thereby optimizing the low-pass performance.

[0115] In this example, the capacitance characteristic is formed by coupling between the front end and the end of the second transmission line 102. The capacitance characteristic and the inductance equivalent to the second transmission line 102 constitute a parallel resonance loop to realize the transmission zero point, thereby improving the attenuation degree of the filter 001 to signals.

[0116] As shown by the S11 curve in Figure 13 in this example, the passband frequency band is 1710MHz-1880MHz. The first transmission zero point is only 40MHz away from the passband, so that the transmission zero point is weak and close to the passband while maintaining high suppression degree.

[0117] The application embodiment further provides a feeding network 010, as shown in Figure 14As shown, the feed network includes a phase shifter 002 and a filter (or combiner) 001 as described above, and the phase shifter 002 is electrically connected with the filter 001.

[0118] The embodiment of the present application further provides an antenna 01, which comprises at least one antenna array 004, and the antenna array 004 comprises at least one radiation unit 0041, a reflecting plate 0042 and a feed network 010 as described above. Figure 15 As shown, the antenna 01 comprises at least one antenna array 004, and the antenna array 004 comprises at least one radiation unit 0041, a reflecting plate 0042 and a feed network 010 as described above.

[0119] The radiation unit 0041 is a unit constituting the basic structure of the antenna array, which can effectively radiate or receive radio waves. The frequency of each radiation unit 0041 can be the same or different, and the radiation unit 0041 is arranged above the reflecting plate 0042.

[0120] The reflecting plate 0042 (also known as a bottom plate, an antenna panel or a metal reflecting surface) can improve the receiving sensitivity of the antenna signal, and reflect and concentrate the antenna signal on the receiving point. Not only can it greatly enhance the receiving / transmitting capability of the antenna, but also can block and shield other electric waves from the back (opposite direction) to interfere with the received signal.

[0121] The feed network 010 is connected with the radiation unit 0041, and the antenna array 004 can receive or transmit radio frequency signals through the respective feed network 010.

[0122] The feed network 010 can feed signals to the radiation unit 0041 according to a certain amplitude and phase, or transmit the received wireless signals to the signal processing unit of the base station according to a certain amplitude and phase. The feed network 010 is usually composed of a controlled impedance transmission line, and usually includes a phase shifter, and in some cases, can also include a combiner, a filter and the like.

[0123] The feed network 010 can realize different radiation beam pointing through a transmission component, or is connected with a transmission network (or calibration network) 003 to obtain a calibration signal required by the system.

[0124] The antenna 01 further comprises a radome 006, and the radiation unit 0041, the reflecting plate 0042 and the feed network 010 are located in a cavity surrounded by the radome 006.

[0125] The radome 006 is a structural member for protecting the antenna 01 from the external environment, has good electromagnetic wave penetration characteristics in electrical performance, and can withstand the action of external harsh environment in mechanical performance.

[0126] The embodiment of the present application further provides a base station antenna feed system, which comprises at least one antenna 01 and at least one base station 02. Figure 16As shown, the base station feeder system comprises the antenna 01 as described above. Further comprising: a feeder 05, a guyed mast 02, an antenna adjusting support 03, the feeder 05 is connected with the antenna 01 through an antenna joint 005 for example, and the outside of the antenna joint 005 is provided with a joint sealing member 04 for example. The joint sealing member 04 can be one of an insulating sealing tape or a PVC insulating sealing tape.

[0127] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto, any change or replacement within the technical scope disclosed in the present application should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A filter, characterized by, The filter comprises: a first transmission line and a second transmission line, the second transmission line comprising a first end and a second end; the first end of the second transmission line is connected to the first transmission line, and the end of the second transmission line is close to the connection point of the second transmission line and the first transmission line; the second end of the second transmission line is coupled to a first region of the second transmission line close to the first end, and the second end of the second transmission line is in the same plane as the first end of the second transmission line.

2. The filter of claim 1, wherein, The spatial distance between the second end of the second transmission line and the first end of the second transmission line is 0-4mm.

3. The filter of claim 1, wherein, The spatial distance between the second end of the second transmission line and the first transmission line is 0-5mm.

4. The filter of claim 1, wherein, The length of the second transmission line is greater than or equal to one fourth of the low cutoff operating wavelength of the to-be-filtered frequency band signal and less than or equal to one fourth of the high cutoff operating wavelength of the to-be-filtered frequency band signal.

5. The filter of claim 4, wherein, The length of the second transmission line is one fourth of the center operating wavelength of the to-be-filtered frequency band signal; or The length of the second transmission line is one fourth of the low cutoff operating wavelength of the to-be-filtered frequency band signal; or The length of the second transmission line is one fourth of the high cutoff operating wavelength of the to-be-filtered frequency band signal.

6. A filter characterized by, The filter comprises: a first transmission line and a second transmission line, the second transmission line comprising a first end and a second end; the first end of the second transmission line is connected to the first transmission line, and the end of the second transmission line is close to the connection point of the second transmission line and the first transmission line; the second end of the second transmission line is coupled to a second region of the first transmission line close to the first end to filter the to-be-filtered frequency band signal, and the second end of the second transmission line is in a different plane from the first transmission line; the port line width of the second end of the second transmission line is wider than the transmission line part line width of the second transmission line.

7. The filter of claim 6, wherein, The spatial distance between the second end of the second transmission line and the first transmission line is 0-4mm.

8. The filter of claim 6, wherein, The length of the second transmission line is greater than or equal to one fourth of the low cutoff operating wavelength of the to-be-filtered frequency band signal and less than or equal to one fourth of the high cutoff operating wavelength of the to-be-filtered frequency band signal.

9. The filter of claim 8, wherein, The length of the second transmission line is one fourth of the center operating wavelength of the to-be-filtered frequency band signal; or The length of the second transmission line is one fourth of the low cutoff operating wavelength of the to-be-filtered frequency band signal; or The length of the second transmission line is one fourth of the high cutoff operating wavelength of the to-be-filtered frequency band signal.

10. A feed network, characterized in that The filter comprises: a phase shifter and a filter according to any one of claims 1-9, the phase shifter being electrically connected to the filter, and the feed network being used for transmitting or receiving radio frequency signals.

11. An antenna, characterized by The filter comprises: at least one antenna array, the antenna array comprising: at least one radiating element, a reflecting plate, and a feed network according to claim 10; the radiating element is arranged above the reflecting plate, and the feed network is connected to the radiating element.

12. The antenna according to claim 11, characterized in that, The antenna further comprises: a radome, and the radiating element, the reflecting plate, and the feed network are located in a cavity surrounded by the radome.

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