Topological structure, filter and communication equipment

Abstract

The embodiment of the invention relates to the technical field of communication, and discloses a topological structure, a filter and communication equipment, the filter comprises an input end, a first parallel line, a second parallel line, a first transmission line assembly, a second transmission line assembly, a third transmission line assembly and an output end, the input end extends to form a first microstrip line and a second microstrip line, the first microstrip line extends to form a first open-circuit branch, the second microstrip line extends to form a second open-circuit branch, the second parallel line extends to form a third microstrip line and a fourth microstrip line, the third microstrip line extends to form a third open-circuit branch, and the fourth microstrip line extends to form a fourth open-circuit branch. The second transmission line assembly extends to form a fifth open-circuit branch knot, the second transmission line assembly extends to form a sixth open-circuit branch knot, and the third transmission line assembly extends to form a seventh open-circuit branch knot and an eighth open-circuit branch knot. By means of the mode, the topological structure has the advantages of being good in selectivity, compact in structure and small in size.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of communication technology, and in particular, to a topology structure, a filter, and a communication device. Background Art

[0002] With the rapid development of modern wireless communication technology, broadband bandpass filters, as one of the key components of wireless communication systems, have attracted the attention of many scholars. Among them, filters that can suppress in-band interference and transmit signals at high speed, that is, broadband bandpass filters with notch characteristics, have been continuously studied in depth.

[0003] In the process of implementing the embodiments of the present application, the inventors found that, currently, in order to achieve the notch characteristic, an additional notch structure needs to be added, which will increase the size of the filter and is not conducive to the miniaturization of communication equipment. Summary of the invention

[0004] The main technical problem solved by the embodiments of the present application is to provide a topological structure composed of a number of parallel lines, a number of microstrip lines and a number of open branches, and its transmission poles are determined by odd-even mode analysis, and its stop band has three transmission zeros to ensure high isolation. Compared with other broadband notch bandpass filters, it has the advantages of good selectivity, compact structure and miniaturization.

[0005] In order to solve the above technical problems, a technical solution adopted in an embodiment of the present application is: providing a topological structure, including an input end, a first parallel line, a second parallel line, a first transmission line component, a second transmission line component, a third transmission line component and an output end, one end of the input end is respectively extended with a first microstrip line and a second microstrip line, one end of the first microstrip line is extended with a first open-circuit branch, one end of the second microstrip line is extended with a second open-circuit branch, the first microstrip line and the second microstrip line are respectively arranged in parallel with the first parallel lines, one end of the second parallel lines is respectively extended with a third microstrip line and a fourth microstrip line, one end of the third microstrip line is extended with a third open-circuit branch, one end of the fourth microstrip line is extended with a fourth open-circuit branch, and the third A microstrip line and a fourth microstrip line are respectively arranged in parallel with the second parallel line, the first transmission line component is respectively connected to the first parallel line and the second parallel line, a fifth open-circuit branch node is extended at one end of the second microstrip line, a sixth open-circuit branch node is extended at the other end of the second transmission line component, and the first transmission line component is connected to the second transmission line component, a seventh open-circuit branch node is extended at one end of the third transmission line component, an eighth open-circuit branch node is extended at the other end of the third transmission line component, and the first transmission line component is connected to the third transmission line component, the input end, the first parallel line, the second parallel line and the output end are cascaded on the same straight line, and the first parallel line and the second parallel line are symmetrically arranged about the first transmission line component.

[0006] Optionally, the first transmission line component includes a fifth microstrip line and a sixth microstrip line, one end of the fifth microstrip line is connected to one end of the second transmission line component, one end of the sixth microstrip line is connected to one end of the third transmission line component, and both ends of the first transmission line component are respectively perpendicular to the second transmission line component and the third transmission line component.

[0007] Optionally, the second transmission line component includes a seventh microstrip line and an eighth microstrip line, the seventh microstrip line is connected to the eighth microstrip line, and one end of the seventh microstrip line is connected to the fifth open branch, one end of the eighth microstrip line is connected to the sixth open branch, and the fifth open branch, the first open branch, the fifth microstrip line, the third open branch and the sixth open branch are arranged parallel to each other.

[0008] Optionally, the third transmission line component includes a ninth microstrip line and a tenth microstrip line, the ninth microstrip line is connected to the tenth microstrip line, and one end of the ninth microstrip line is connected to the seventh open branch, one end of the tenth microstrip line is connected to the eighth open branch, and the seventh open branch, the second open branch, the sixth microstrip line, the fourth open branch and the eighth open branch are arranged parallel to each other.

[0009] Optionally, the first parallel line and the second parallel line, the first microstrip line and the third microstrip line, the second microstrip line and the fourth microstrip line, the first open branch and the third open branch, the second open branch and the fourth open branch, the seventh microstrip line and the eighth microstrip line, the ninth microstrip line and the tenth microstrip line, the fifth open branch and the sixth open branch, the seventh open branch and the eighth open branch are all symmetrically arranged about the first transmission line component.

[0010] Optionally, the first microstrip line and the second microstrip line, the third microstrip line and the fourth microstrip line, the fifth microstrip line and the sixth microstrip line, the seventh microstrip line and the ninth microstrip line, the eighth microstrip line and the tenth microstrip line, the first open branch and the second open branch, the third open branch and the fourth open branch, the fifth open branch and the seventh open branch, the sixth open branch and the eighth open branch are all symmetrically arranged about the first parallel line or the second parallel line.

[0011] Optionally, the electrical length of the first parallel line is equal to the electrical length of the second parallel line.

[0012] Optionally, the odd-mode characteristic impedance and the even-mode characteristic impedance of the first parallel line and the second parallel line are equal.

[0013] In order to solve the above technical problems, another technical solution adopted in the embodiment of the present application is: providing a filter, including any of the above topological structures.

[0014] In order to solve the above technical problem, another technical solution adopted in the embodiment of the present application is: providing a communication device, including the above filter.

[0015] An embodiment of the present application provides a topological structure, including an input end, a first parallel line, a second parallel line, a first transmission line component, a second transmission line component, a third transmission line component and an output end, wherein one end of the input end is respectively extended with a first microstrip line and a second microstrip line, one end of the first microstrip line is extended with a first open-circuit branch, one end of the second microstrip line is extended with a second open-circuit branch, the first microstrip line and the second microstrip line are respectively arranged in parallel with the first parallel line, one end of the second parallel line is respectively extended with a third microstrip line and a fourth microstrip line, one end of the third microstrip line is extended with a third open-circuit branch, one end of the fourth microstrip line is extended with a fourth open-circuit branch, and the third microstrip line and the fourth microstrip line are respectively arranged in parallel with the second parallel line, the first transmission line component is respectively connected to the first parallel line and the second parallel line, one end of the second microstrip line is extended with a fifth open-circuit branch, and the second A sixth open-circuit branch extends from the other end of the transmission line component, and the first transmission line component is connected to the second transmission line component, a seventh open-circuit branch extends from one end of the third transmission line component, an eighth open-circuit branch extends from the other end of the third transmission line component, and the first transmission line component is connected to the third transmission line component, the input end, the first parallel line, the second parallel line and the output end are cascaded on the same straight line, and the first parallel line and the second parallel line are symmetrically arranged about the first transmission line component. Through the above arrangement, the generated odd and even mode frequencies are coupled with the resonant frequency to generate multiple passbands. The filter formed by the topological structure designed in this way is conducive to miniaturization while ensuring the passband performance, and has the advantages of easy integration and high reliability, and can effectively reduce the complexity of the entire circuit of the communication system and the volume of the communication equipment, thereby achieving the purpose of simplifying the system and reducing the equipment cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the prior art description. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0017] Figure 1 is a schematic diagram of the topological structure of an embodiment of the present application;

[0018] Figure 2 It is an odd-mode form of the topological structure of the embodiment of the present application;

[0019] Figure 3 It is an even mode form of the topological structure of the embodiment of the present application;

[0020] Figure 4 is a layout diagram of the filter in the embodiment of the present application;

[0021] Figure 5 This is a diagram of the S-parameter simulation results of the topological structure of the embodiment of the present application.

[0022] The figure numbers in the specific implementation manner are as follows: 100, topological structure; 10, input end; 20, first microstrip line; 21, second microstrip line; 22, third microstrip line; 23, fourth microstrip line; 30, first open branch; 31, second open branch; 32, third open branch; 33, fourth open branch; 40, first parallel line; 41, second parallel line; 50, output end; 24, fifth microstrip line; 25, sixth microstrip line; 70, second transmission line component; 26, seventh microstrip line; 27, eighth microstrip line; 80, third transmission line component; 28, ninth microstrip line; 29, tenth microstrip line; 34, fifth open branch; 35, sixth open branch; 36, seventh open branch; 37, eighth open branch. DETAILED DESCRIPTION

[0023] In order to facilitate the understanding of the present application, the present application is described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as "fixed to" another element, it can be directly on another element or there can be one or more centered elements therebetween. When an element is described as "connected" to another element, it can be directly connected to another element or there can be one or more centered elements therebetween. The orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "vertical", "horizontal", etc. used in this specification is based on the orientation or positional relationship shown in the accompanying drawings, only for the convenience of describing the present application and simplifying the description, rather than indicating or implying 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 to the present application. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0024] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in this specification includes any and all combinations of one or more of the related listed items.

[0025] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0026] See also Figure 1 The topological structure 100 includes an input end 10, a first parallel line 40, a second parallel line 41, a first transmission line component (not shown), a second transmission line component 70, a third transmission line component 80 and an output end 50, wherein one end of the input end 10 is respectively extended with a first microstrip line 20 and a second microstrip line 21, one end of the first microstrip line 20 is extended with a first open branch 30, one end of the second microstrip line 21 is extended with a second open branch 31, the first microstrip line 20 and the second microstrip line 21 are respectively arranged in parallel with the first parallel line 40, one end of the second parallel line 41 is respectively extended with a third microstrip line 22 and a fourth microstrip line 23, one end of the third microstrip line 22 is extended with a third open branch 32, one end of the fourth microstrip line 23 is extended with a fourth open branch 33, and the third microstrip line 22 and the fourth microstrip line 23 are respectively arranged in parallel with the second parallel line 41, and the first transmission line component (not shown) is respectively connected to the first parallel line 40 and the first microstrip line 21. Two parallel lines 41 are connected, one end of the second transmission line component 70 is extended with a fifth open branch 34, the other end of the second transmission line component 70 is extended with a sixth open branch 35, and the first transmission line component (not shown) is connected to the second transmission line component 70, one end of the third transmission line component 80 is extended with a seventh open branch 36, the other end of the third transmission line component 80 is extended with an eighth open branch 37, and the first transmission line component (not shown) is connected to the third transmission line component 80, the input end 10, the first parallel line 40, the second parallel line 41 and the output end 50 are cascaded on the same straight line, and the first parallel line 40 and the second parallel line 41 are symmetrically arranged with respect to the first transmission line component (not shown). Through the above arrangement, a symmetrical topological structure 100 is formed, ensuring that the topological structure 100 has a flat amplitude-frequency response in two passbands and has high isolation and selectivity in the stopband, constituting the filter in the present application.

[0027] For details, please continue to refer to Figure 1The first transmission line component (not shown) includes a fifth microstrip line 24 and a sixth microstrip line 25, one end of the fifth microstrip line 24 is connected to one end of the second transmission line component 70, one end of the sixth microstrip line 25 is connected to one end of the third transmission line component 80, and the two ends of the first transmission line component (not shown) are respectively perpendicular to the second transmission line component 70 and the third transmission line component 80, the second transmission line component 70 includes a seventh microstrip line 26 and an eighth microstrip line 27, the seventh microstrip line 26 is connected to the eighth microstrip line 27, and one end of the seventh microstrip line 26 is connected to the fifth open branch 34, one end of the eighth microstrip line 27 is connected to the sixth open branch 35, and the fifth open branch 34, the first open branch 30, the fifth microstrip line 24, the third open branch 32 and the sixth open branch 35 are arranged in parallel with each other, and the first The three transmission line components 80 include a ninth microstrip line 28 and a tenth microstrip line 29, wherein the ninth microstrip line 28 is connected to the tenth microstrip line 29, and one end of the ninth microstrip line 28 is connected to the seventh open branch 36, and one end of the tenth microstrip line 29 is connected to the eighth open branch 37, and the seventh open branch 36, the second open branch 31, the sixth microstrip line 25, the fourth open branch 33 and the eighth open branch 37 are arranged in parallel with each other, wherein a plurality of open branches are arranged to provide a transmission zero point for the filter, enhance the selectivity of the filter, and enable the filter to more effectively filter out out-of-band interference signals, and the first parallel line 40 and the second parallel line 41 are arranged symmetrically, and the fifth microstrip line 24 and the sixth microstrip line 25 are arranged in a stacked manner, so that the two passbands of the topological structure 100 are more symmetrical in frequency, thereby improving the passband flatness and selectivity of the topological structure 100.

[0028] In the embodiment of the present application, the first parallel line 40 and the second parallel line 41, the first microstrip line 20 and the third microstrip line 22, the second microstrip line 21 and the fourth microstrip line 23, the first open branch 30 and the third open branch 32, the second open branch 31 and the fourth open branch 33, the seventh microstrip line 26 and the eighth microstrip line 27, the ninth microstrip line 28 and the tenth microstrip line 29, the fifth open branch 34 and the sixth open branch 35, the seventh open branch 36 and the eighth open branch 37 are all symmetrically arranged about the first transmission line component (not shown). The symmetrical structure can effectively reduce the performance fluctuations caused by processing errors or environmental factors, and improve the stability and reliability of the topological structure 100. At the same time, the symmetrical structure can also simplify the design process of the topological structure 100, reduce the design complexity, and improve the design efficiency.

[0029] In the embodiment of the present application, the first microstrip line 20 and the second microstrip line 21, the third microstrip line 22 and the fourth microstrip line 23, the fifth microstrip line 24 and the sixth microstrip line 25, the seventh microstrip line 26 and the ninth microstrip line 28, the eighth microstrip line 27 and the tenth microstrip line 29, the first open branch 30 and the second open branch 31, the third open branch 32 and the fourth open branch 33, the fifth open branch 34 and the seventh open branch 36, the sixth open branch 35 and the eighth open branch 37 are all symmetrically arranged about the first parallel line 40 or the second parallel line 41. Through the above arrangement, the performance fluctuation caused by processing errors or environmental factors is further reduced, and the stability and reliability of the filter are improved.

[0030] In the embodiment of the present application, the electrical length of the first parallel line 40 and the electrical length of the second parallel line 41 are equal and both are a quarter wavelength corresponding to the center frequency of the stopband between the two passbands; the sum of the electrical length of the first microstrip line 20 and the electrical length of the first open branch 30, the sum of the electrical length of the second microstrip line 21 and the electrical length of the second open branch 31, the sum of the electrical length of the third microstrip line 22 and the electrical length of the third open branch 32, and the sum of the electrical length of the fourth microstrip line 23 and the electrical length of the fourth open branch 33 are equal and both are a quarter wavelength corresponding to the center frequency of the stopband between the two passbands; the electrical length of the fifth microstrip line 24, the electrical length of the seventh microstrip line 26 and the electrical length of the first open branch 30 The sum of the electrical lengths of the five open branches 34 is one-half wavelength corresponding to the center frequency of the stopband in the middle of the two passbands; the sum of the electrical lengths of the fifth microstrip line 24, the eighth microstrip line 27 and the sixth open branch 35 is one-half wavelength corresponding to the center frequency of the stopband in the middle of the two passbands; the sum of the electrical lengths of the sixth microstrip line 25, the ninth microstrip line 28 and the seventh open branch 36 is one-half wavelength corresponding to the center frequency of the stopband in the middle of the two passbands; the sum of the electrical lengths of the sixth microstrip line 25, the tenth microstrip line 29 and the eighth open branch 37 is one-half wavelength corresponding to the center frequency of the stopband in the middle of the two passbands.

[0031] In the embodiment of the present application, the odd-mode characteristic impedance and the even-mode characteristic impedance of the first parallel line 40 and the second parallel line 41 are equal and are both Z oo and Z oe The characteristic impedance of the first microstrip line 20, the characteristic impedance of the second microstrip line 21, the characteristic impedance of the third microstrip line 22, the characteristic impedance of the fourth microstrip line 23, the characteristic impedance of the first open branch 30, the characteristic impedance of the second open branch 31, the characteristic impedance of the third open branch 32, and the characteristic impedance of the fourth open branch 33 are equal, all of which are Z 1 The characteristic impedance of the fifth microstrip line 24 is equal to the characteristic impedance of the sixth microstrip line 25, and both are Z2 The characteristic impedance of the seventh microstrip line 26, the characteristic impedance of the eighth microstrip line 27, the characteristic impedance of the ninth microstrip line 28, the characteristic impedance of the tenth microstrip line 29, the characteristic impedance of the fifth open branch 34, the characteristic impedance of the sixth open branch 35, the characteristic impedance of the seventh open branch 36 and the characteristic impedance of the eighth open branch 37 are equal and are all 2Z 2 .

[0032] Since the structure of the topology is both left-right symmetrical and top-bottom symmetrical, its transmission poles can be found using the odd-even mode method. ino =∞, it can be concluded that the topology 100 has two transmission poles. For details, please refer to Figure 2 , when f 0 When is the center frequency of topology 100, the frequencies corresponding to the two odd-mode transmission poles are:

[0033] When Y ine =∞, it can be concluded that the topology 100 has three even-mode transmission poles. 0 For the center frequency of the topology 100, please combine Figure 3 , the frequencies corresponding to the three even-mode transmission poles are:

[0034] in,

[0035] For this topology 100, its transmission zero point can be calculated by the following method: multiply the ABCD matrices of the cascade resonators constituting the topology 100 in sequence to obtain the ABCD matrix corresponding to the topology 100; and convert the ABCD matrix of the topology 100 into the corresponding S matrix. 21 When |=0, it can be concluded that the topology 100 has three transmission zeros, and the frequencies corresponding to the three transmission zeros are:

[0036]

[0037] f z2 =f 0 ,

[0039]

[0040] From the above analysis, it can be seen that the filter based on the topology 100 has two odd-mode transmission poles, three even-mode transmission poles and three transmission zeros. oo , Z oe , Z 1 , Z 2 The value of the transmission zero and pole relative position, that is, fz1 <f ep1 <f op1 <f ep2 =f 2 <f op2 <f ep3 <f z3 , will not change. According to the basic knowledge of microwaves, when the transmission zero and transmission pole of the filter coincide, only the characteristics of the transmission pole will be displayed. Therefore, a dual-passband filter can be designed based on this topology 100, and there are two transmission poles in each of the two passbands to ensure its flatness within the band, a transmission zero below the first passband edge and above the fourth passband edge to ensure high selectivity, and a transmission zero between the second passband edge and the third passband edge to ensure high isolation.

[0041] In another embodiment, to verify the topology 100, the filter in the present application is simulated and designed. The filter is designed on a circuit board with a dielectric constant of 3.38, a dielectric loss of 0.0022, and a thickness of 0.813 mm. The layout diagram is as follows: Figure 4 The size of the entire layout is only 20.8mm*11.8mm, and the specific size of the filter is l P =8.2mm,s P =0.1mm,w P =0.25mm,l 1 =6.35mm,s 1 =0.4mm,w 1 =0.25mm,l 2 =2.05mm,w 2 =0.25mm,l 3 =5.35mm,w 3 =0.8mm, l 4 =8.6mm,w 4 =0.4mm,l 5 =3.8mm,w 5 =0.4mm.

[0042] Please combine Figure 5 , the simulation results of the wide dual-channel filter are as follows Figure 5As shown. As can be seen from the figure, in the first passband, the impedance bandwidth range of its reflection coefficient less than -10dB is 3.887 to 4.879GHz, the passband center frequency is 4.383GHz, the passband absolute bandwidth is 0.992GHz, and the passband relative bandwidth is 22.6%; in its second passband, the impedance bandwidth range of its reflection coefficient less than -10dB is 7.121 to 7.883GHz, the passband center frequency is 7.502GHz, the passband absolute bandwidth is 0.762GHz, and the passband relative bandwidth is 10.2%. From the bandwidth simulation of the two passbands, it can be seen that the dual passband filter based on the topological structure 100 is a wide dual passband filter. In the first passband, the maximum insertion loss is 0.58dB; in the second passband, the maximum insertion loss is 0.86dB. It can be seen that the wide dual passband filter based on the topological structure 100 has a low insertion loss characteristic. In addition, there are two transmission poles in the first passband, located at 4.025 and 4.651 GHz respectively; there are also two transmission poles in the second passband, located at 7.286 and 7.775 GHz respectively. These four transmission poles can ensure the flatness in the passband. In the stopband between the two passbands, the stopband bandwidth with an isolation greater than 12dB ranges from 5.792 to 6.564 GHz, the stopband center frequency is 6.178 GHz, the stopband absolute bandwidth is 0.772 GHz, the stopband relative bandwidth is 12.5%, and there are three transmission zeros in the stopband, located at 2.928, 6.225, and 8.549 GHz respectively. These three transmission zeros not only ensure the high selectivity of the wide dual-passband filter, but also ensure the high isolation of the stopband.

[0043] The embodiment of the present application provides a topological structure 100, including an input end 10, a first parallel line 40, a second parallel line 41, a first transmission line component (not shown), a second transmission line component 70, a third transmission line component 80 and an output end 50, wherein one end of the input end 10 is respectively extended with a first microstrip line 20 and a second microstrip line 21, one end of the first microstrip line 20 is extended with a first open branch 30, one end of the second microstrip line 21 is extended with a second open branch 31, and the first microstrip line 20 and the second microstrip line 21 are respectively connected to the output end 50. The first parallel lines 40 are arranged in parallel, the third microstrip line 22 and the fourth microstrip line 23 are respectively extended at one end of the second parallel line 41, the third microstrip line 22 is extended at one end of the third open branch 32, the fourth microstrip line 23 is extended at one end of the fourth open branch 33, and the third microstrip line 22 and the fourth microstrip line 23 are respectively arranged in parallel with the second parallel lines 41, the first transmission line component (not shown) is respectively connected to the first parallel lines 40 and the second parallel lines 41, and the second microstrip line 21 is extended at one end There is a fifth open branch 34, a sixth open branch 35 extends from the other end of the second transmission line component 70, and the first transmission line component (not shown) is connected to the second transmission line component 70, a seventh open branch 36 extends from one end of the third transmission line component 80, an eighth open branch 37 extends from the other end of the third transmission line component 80, and the first transmission line component (not shown) is connected to the third transmission line component 80, the input end 10, the first parallel line 40, the second parallel line 41 and the output end 50 are cascaded on the same straight line, and the first parallel line 40 and the second parallel line 41 are symmetrically arranged about the first transmission line component (not shown). Through the above arrangement, the generated odd and even mode frequencies are coupled with the resonant frequency to generate multiple passbands. The filter formed by the topological structure 100 designed in this way is conducive to miniaturization while ensuring the passband performance, and has the advantages of easy integration and high reliability, and can effectively reduce the complexity of the entire circuit of the communication system and the volume of the communication equipment, thereby achieving the purpose of simplifying the system and reducing the equipment cost.

[0044] The embodiment of the present application also provides a filter embodiment, and the filter includes the above-mentioned topological structure 100. The specific structure and function of the filter can be referred to the above-mentioned embodiment, which will not be repeated here.

[0045] The present application also provides a communication device embodiment, wherein the communication device includes the above-mentioned filter. The specific structure and function of the filter can be referred to the above-mentioned embodiment, which will not be repeated here.

[0046] The above descriptions are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A topological structure, characterized in that: include: An input end, wherein a first microstrip line and a second microstrip line are respectively extended from one end of the input end, a first open-circuit branch is extended from one end of the first microstrip line, and a second open-circuit branch is extended from one end of the second microstrip line; a first parallel line, wherein the first microstrip line and the second microstrip line are respectively arranged parallel to the first parallel line; a second parallel line, a third microstrip line and a fourth microstrip line are respectively extended from one end of the second parallel line, a third open-circuit branch is extended from one end of the third microstrip line, a fourth open-circuit branch is extended from one end of the fourth microstrip line, and the third microstrip line and the fourth microstrip line are respectively arranged parallel to the second parallel line; a first transmission line assembly, the first transmission line assembly being connected to the first parallel line and the second parallel line respectively; a second transmission line component, wherein a fifth open-circuit branch extends from one end of the second transmission line component, a sixth open-circuit branch extends from the other end of the second transmission line component, and the first transmission line component is connected to the second transmission line component; a third transmission line component, wherein a seventh open-circuit branch extends from one end of the third transmission line component, an eighth open-circuit branch extends from the other end of the third transmission line component, and the first transmission line component is connected to the third transmission line component; The output end, the input end, the first parallel line, the second parallel line and the output end are cascaded on the same straight line, and the first parallel line and the second parallel line are symmetrically arranged with respect to the first transmission line component.

2. The topological structure according to claim 1, characterized in that: The first transmission line component includes a fifth microstrip line and a sixth microstrip line, one end of the fifth microstrip line is connected to one end of the second transmission line component, one end of the sixth microstrip line is connected to one end of the third transmission line component, and both ends of the first transmission line component are respectively perpendicular to the second transmission line component and the third transmission line component.

3. The topological structure according to claim 2, characterized in that: The second transmission line component includes a seventh microstrip line and an eighth microstrip line, the seventh microstrip line is connected to the eighth microstrip line, and one end of the seventh microstrip line is connected to the fifth open branch, one end of the eighth microstrip line is connected to the sixth open branch, and the fifth open branch, the first open branch, the fifth microstrip line, the third open branch and the sixth open branch are arranged parallel to each other.

4. The topological structure according to claim 3, characterized in that: The third transmission line component includes a ninth microstrip line and a tenth microstrip line, the ninth microstrip line is connected to the tenth microstrip line, and one end of the ninth microstrip line is connected to the seventh open branch, one end of the tenth microstrip line is connected to the eighth open branch, and the seventh open branch, the second open branch, the sixth microstrip line, the fourth open branch and the eighth open branch are arranged parallel to each other.

5. The topological structure according to claim 4, characterized in that: The first parallel line and the second parallel line, the first microstrip line and the third microstrip line, the second microstrip line and the fourth microstrip line, the first open branch and the third open branch, the second open branch and the fourth open branch, the seventh microstrip line and the eighth microstrip line, the ninth microstrip line and the tenth microstrip line, the fifth open branch and the sixth open branch, the seventh open branch and the eighth open branch are all symmetrically arranged about the first transmission line component.

6. The topological structure according to claim 5, characterized in that: The first microstrip line and the second microstrip line, the third microstrip line and the fourth microstrip line, the fifth microstrip line and the sixth microstrip line, the seventh microstrip line and the ninth microstrip line, the eighth microstrip line and the tenth microstrip line, the first open branch and the second open branch, the third open branch and the fourth open branch, the fifth open branch and the seventh open branch, the sixth open branch and the eighth open branch are all symmetrically arranged about the first parallel line or the second parallel line.

7. The topological structure according to claim 1, characterized in that: The electrical length of the first parallel line is equal to the electrical length of the second parallel line.

8. The topological structure according to claim 1, characterized in that: The odd-mode characteristic impedance and the even-mode characteristic impedance of the first parallel line and the second parallel line are equal.

9. A filter, characterized in that: Comprising a topological structure as described in any one of claims 1-8.

10. A communication device, characterized in that: Comprising the communication device as claimed in claim 9.

Images