A topological structure, broadband bandpass filter and communication equipment

Abstract

The embodiment of the utility model relates to the technical field of communication equipment, and in particular discloses a topological structure, a broadband bandpass filter and a communication device, wherein the first parallel line is connected to the first parallel three lines, the first microstrip line and the fifth microstrip line, the first parallel three lines are connected to the input end, the first microstrip line is connected to the second microstrip line, the fifth microstrip line is connected to the sixth microstrip line, the first parallel line is connected to the second parallel three lines, the fourth microstrip line and the eighth microstrip line, the second parallel three lines are connected to the output end, the fourth microstrip line is connected to the third microstrip line, the third microstrip line is connected to the second microstrip line and the first short-circuit branch, the first short-circuit branch is grounded, the eighth microstrip line is connected to the seventh microstrip line, the seventh microstrip line is connected to the sixth microstrip line and the second short-circuit branch, and the second short-circuit branch is grounded. In the above manner, the embodiment of the utility model can obtain a broadband bandpass filter with high selectivity and high isolation based on the above topological structure design.

Description

Technical Field

[0001] The embodiments of the utility model relate to the technical field of communication equipment, and in particular to a topological structure, a broadband bandpass filter and communication equipment. Background Art

[0002] With the rapid development of modern wireless communication technology, people's demand for broadband communication systems that can achieve high-speed data transmission is increasing, which has become the focus of research for practitioners in related fields. As one of the key components of broadband communication systems, broadband bandpass filters play an important role in broadband communication systems with their ultra-wideband characteristics, excellent rectangularity, and low insertion loss. In addition, their high selectivity and miniaturization research have extremely high scientific research and commercial value, attracting the attention of many scholars and engineers.

[0003] The inventor of the present utility model found in the process of realizing the present utility model that the existing miniaturized broadband bandpass filter is subject to defects in its structural design, resulting in poor selectivity of the miniaturized broadband bandpass filter, which seriously affects its use in modern wireless communication systems. Utility Model Content

[0004] The main technical problem solved by the embodiments of the utility model is to provide a topology structure, a broadband bandpass filter and a communication device, which overcome the above problems or at least partially solve the above problems.

[0005] In order to solve the above technical problems, a technical solution adopted by the utility model is: to provide a topological structure, including: an input end, an output end, a first parallel line, a first parallel three lines, a second parallel three lines, a first microstrip line, a second microstrip line, a third microstrip line, a fourth microstrip line, a fifth microstrip line, a sixth microstrip line, a seventh microstrip line, an eighth microstrip line, a first short-circuit branch and a second short-circuit branch; wherein one end of the first parallel line is connected to one end of the first parallel three lines, one end of the first microstrip line and one end of the fifth microstrip line, the other end of the first parallel three lines is connected to the input end, the other end of the first microstrip line is connected to one end of the second microstrip line, and the other end of the fifth microstrip line is connected to the input end. One end of the sixth microstrip line is connected, the other end of the first parallel line is connected to one end of the second parallel three lines, one end of the fourth microstrip line and one end of the eighth microstrip line, the other end of the second parallel three lines is connected to the output end, the other end of the fourth microstrip line is connected to one end of the third microstrip line, the other end of the third microstrip line is connected to the other end of the second microstrip line and one end of the first short-circuit branch, the other end of the first short-circuit branch is grounded, the other end of the eighth microstrip line is connected to one end of the seventh microstrip line, the other end of the seventh microstrip line is connected to the other end of the sixth microstrip line and one end of the second short-circuit branch, and the other end of the second short-circuit branch is grounded.

[0006] Optionally, the first parallel three lines and the second parallel three lines, the input end and the output end, the first microstrip line and the fifth microstrip line, the second microstrip line and the sixth microstrip line, the first short-circuit branch and the second short-circuit branch, the third microstrip line and the seventh microstrip line, the fourth microstrip line and the eighth microstrip line are all symmetrically arranged about the first parallel lines.

[0007] Optionally, the first three parallel lines, the first parallel line, the second three parallel lines, the second microstrip line, the third microstrip line, the sixth microstrip line and the seventh microstrip line are arranged in parallel.

[0008] Optionally, the first three parallel lines, the first parallel line, the second three parallel lines, the second microstrip line, the third microstrip line, the sixth microstrip line and the seventh microstrip line are all perpendicular to the first microstrip line, the first short-circuit branch, the fourth microstrip line, the fifth microstrip line, the second short-circuit branch and the eighth microstrip line.

[0009] Optionally, the first parallel lines include a fourth transmission line and a fifth transmission line, wherein the fourth transmission line and the fifth transmission line are arranged in parallel; the first parallel three lines include a first transmission line, a second transmission line and a third transmission line, wherein the first transmission line, the second transmission line and the third transmission line are arranged in parallel and equidistantly; the second parallel three lines include a sixth transmission line, a seventh transmission line and an eighth transmission line, wherein the sixth transmission line, the seventh transmission line and the eighth transmission line are arranged in parallel and equidistantly.

[0010] Optionally, the electrical length of the first parallel line, the electrical length of the first three parallel lines, and the electrical length of the second three parallel lines are all one-quarter wavelength corresponding to the center frequency of the broadband bandpass filter.

[0011] Optionally, the electrical length of the first microstrip line is equal to the electrical length of the eighth microstrip line; the electrical length of the second microstrip line is equal to the electrical length of the seventh microstrip line; the electrical length of the third microstrip line is equal to the electrical length of the sixth microstrip line; the electrical length of the fourth microstrip line is equal to the electrical length of the fifth microstrip line; the electrical length of the first short-circuit branch is equal to the electrical length of the second short-circuit branch; wherein the sum of the electrical length of the first microstrip line and the electrical length of the second microstrip line is equal to the sum of the electrical length of the third microstrip line and the electrical length of the fourth microstrip line; the sum of the electrical length of the first microstrip line, the electrical length of the second microstrip line, and the electrical length of the first short-circuit branch is greater than one-quarter wavelength corresponding to the center frequency of the broadband bandpass filter.

[0012] Optionally, the characteristic impedance of the first microstrip line, the characteristic impedance of the second microstrip line, the characteristic impedance of the third microstrip line, the characteristic impedance of the fourth microstrip line, the characteristic impedance of the fifth microstrip line, the characteristic impedance of the sixth microstrip line, the characteristic impedance of the seventh microstrip line, the characteristic impedance of the eighth microstrip line, the characteristic impedance of the first short-circuit branch, and the characteristic impedance of the second short-circuit branch are all equal.

[0013] In order to solve the above technical problem, another technical solution adopted by the utility model is: to provide a broadband bandpass filter, which is obtained by the above topological structure design.

[0014] In order to solve the above technical problem, another technical solution adopted by the present invention is: to provide a communication device, including the above broadband bandpass filter.

[0015] The beneficial effects of the embodiments of the utility model are as follows: Different from the prior art, the embodiments of the utility model provide a topological structure, including an input end, an output end, a first parallel line, a first parallel three lines, a second parallel three lines, a first microstrip line, a second microstrip line, a third microstrip line, a fourth microstrip line, a fifth microstrip line, a sixth microstrip line, a seventh microstrip line, an eighth microstrip line, a first short-circuit branch and a second short-circuit branch; wherein one end of the first parallel line is connected to one end of the first parallel three lines, one end of the first microstrip line and one end of the fifth microstrip line, the other end of the first parallel three lines is connected to the input end, the other end of the first microstrip line is connected to one end of the second microstrip line, and the other end of the fifth microstrip line is connected to the input end. One end is connected to one end of the sixth microstrip line, the other end of the first parallel line is connected to one end of the second parallel three lines, one end of the fourth microstrip line and one end of the eighth microstrip line, the other end of the second parallel three lines is connected to the output end, the other end of the fourth microstrip line is connected to one end of the third microstrip line, the other end of the third microstrip line is connected to the other end of the second microstrip line and one end of the first short-circuit branch, the other end of the first short-circuit branch is grounded, the other end of the eighth microstrip line is connected to one end of the seventh microstrip line, the other end of the seventh microstrip line is connected to the other end of the sixth microstrip line and one end of the second short-circuit branch, and the other end of the second short-circuit branch is grounded. The broadband bandpass filter designed based on the above topological structure has five transmission poles in its passband, and these five transmission poles ensure the flatness of the passband, and has four transmission zeros in its stopband, and these four transmission zeros ensure the high selectivity and high isolation of the filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without paying creative work.

[0017] Figure 1 It is a schematic diagram of a topological structure provided by an embodiment of the utility model;

[0018] Figure 2 It is a schematic diagram of a layout of a broadband bandpass filter provided by an embodiment of the utility model;

[0019] Figure 3 It is another schematic diagram of a layout of a broadband bandpass filter provided by an embodiment of the utility model;

[0020] Figure 4 This is a diagram of S-parameter simulation results of a broadband bandpass filter provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0021] In order to facilitate the understanding of the utility model, the utility model 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 the other 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 the other element, or there can be one or more centered elements therebetween. The terms "vertical", "horizontal", "left", "right" and similar expressions used in this specification are for illustrative purposes only.

[0022] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by technicians in the technical field of the present invention. The terms used in this specification are only for the purpose of describing specific embodiments and are not used to limit the present invention. The term "and / or" used in this specification includes any and all combinations of one or more related listed items.

[0023] See also Figure 1The topological structure 1000 includes an input terminal 101, an output terminal 115, a first parallel line 102, a first parallel three-line 103, a second parallel three-line 104, a first microstrip line 105, a second microstrip line 106, a third microstrip line 107, a fourth microstrip line 108, a fifth microstrip line 109, a sixth microstrip line 110, a seventh microstrip line 111, an eighth microstrip line 112, a first short-circuit branch 113 and a second short-circuit branch 114; wherein one end of the first parallel line 102 is connected to one end of the first parallel three-line 103, one end of the first microstrip line 105 and one end of the fifth microstrip line 109, the other end of the first parallel three-line 103 is connected to the input terminal 101, the other end of the first microstrip line 105 is connected to one end of the second microstrip line 106, the other end of the fifth microstrip line 109 is connected to the sixth microstrip line The first microstrip line 110 is connected to one end of the line 110, the other end of the first parallel line 102 is connected to one end of the second parallel three-line 104, one end of the fourth microstrip line 108 and one end of the eighth microstrip line 112, the other end of the second parallel three-line 104 is connected to the output end 115, the other end of the fourth microstrip line 108 is connected to one end of the third microstrip line 107, the other end of the third microstrip line 107 is connected to the other end of the second microstrip line 106 and one end of the first short-circuit branch 113, the other end of the first short-circuit branch 113 is grounded, the other end of the eighth microstrip line 112 is connected to one end of the seventh microstrip line 111, the other end of the seventh microstrip line 111 is connected to the other end of the sixth microstrip line 110 and one end of the second short-circuit branch 114, and the other end of the second short-circuit branch 114 is grounded.

[0024] In some embodiments, the first parallel three lines 103 and the second parallel three lines 104, the input end 101 and the output end 115, the first microstrip line 105 and the fifth microstrip line 109, the second microstrip line 106 and the sixth microstrip line 110, the first short-circuit branch 113 and the second short-circuit branch 114, the third microstrip line 107 and the seventh microstrip line 111, the fourth microstrip line 108 and the eighth microstrip line 112 are all symmetrically arranged about the first parallel lines 102.

[0025] In some embodiments, the first parallel three lines 103 , the first parallel lines 102 , the second parallel three lines 104 , the second microstrip line 106 , the third microstrip line 107 , the sixth microstrip line 110 , and the seventh microstrip line 111 are arranged in parallel.

[0026] In some embodiments, the first parallel three lines 103, the first parallel lines 102, the second parallel three lines 104, the second microstrip line 106, the third microstrip line 107, the sixth microstrip line 110 and the seventh microstrip line 111 are all perpendicular to the first microstrip line 105, the first short-circuit branch 113, the fourth microstrip line 108, the fifth microstrip line 109, the second short-circuit branch 114 and the eighth microstrip line 112.

[0027] In some embodiments, Figure 2 As shown, the first parallel lines 102 include a fourth transmission line 1021 and a fifth transmission line 1022, wherein the fourth transmission line 1021 and the fifth transmission line 1022 are arranged in parallel; the first parallel three lines 103 include a first transmission line 1031, a second transmission line 1032 and a third transmission line 1033, wherein the first transmission line 1031, the second transmission line 1032 and the third transmission line 1033 are arranged in parallel and equidistantly; the second parallel three lines 104 include a sixth transmission line 1041, a seventh transmission line 1042 and an eighth transmission line 1043, wherein the sixth transmission line 1041, the seventh transmission line 1042 and the eighth transmission line 1043 are arranged in parallel and equidistantly.

[0028] Specifically, one end of the fourth transmission line 1021 is connected to one end of the first microstrip line 105, one end of the second transmission line 1032, and one end of the fifth microstrip line 109, one end of the first transmission line 1031 and one end of the third transmission line 1033 are both connected to the input end 101, the other end of the first microstrip line 105 is connected to one end of the second microstrip line 106, the other end of the fifth microstrip line 109 is connected to one end of the sixth microstrip line 110, one end of the fifth transmission line 1022 is connected to one end of the seventh transmission line 1042, one end of the fourth microstrip line 108, and one end of the eighth microstrip line 112, and the One end of the sixth transmission line 1041 and one end of the eighth transmission line 1043 are both connected to the output end 115, the other end of the fourth microstrip line 108 is connected to one end of the third microstrip line 107, the other end of the third microstrip line 107 is connected to the other end of the second microstrip line 106 and one end of the first short-circuit branch 113, the other end of the first short-circuit branch 113 is grounded, the other end of the eighth microstrip line 112 is connected to one end of the seventh microstrip line 111, the other end of the seventh microstrip line 111 is connected to the other end of the sixth microstrip line 110 and one end of the second short-circuit branch 114, and the other end of the second short-circuit branch 114 is grounded.

[0029] In some embodiments, the electrical length of the first parallel line 102 , the electrical length of the first parallel three lines 103 , and the electrical length of the second parallel three lines 104 are all one-quarter wavelength corresponding to the center frequency of the broadband bandpass filter 2000 .

[0030] In some embodiments, the electrical length of the first microstrip line 105 is equal to the electrical length of the eighth microstrip line 112; the electrical length of the second microstrip line 106 is equal to the electrical length of the seventh microstrip line 111; the electrical length of the third microstrip line 107 is equal to the electrical length of the sixth microstrip line 110; the electrical length of the fourth microstrip line 108 is equal to the electrical length of the fifth microstrip line 109; the electrical length of the first short-circuit branch 113 is equal to the electrical length of the second short-circuit branch 114; wherein the sum of the electrical length of the first microstrip line 105 and the electrical length of the second microstrip line 106 is equal to the sum of the electrical length of the third microstrip line 107 and the electrical length of the fourth microstrip line 108; the sum of the electrical length of the first microstrip line 105, the electrical length of the second microstrip line 106, and the electrical length of the first short-circuit branch 113 is greater than a quarter wavelength corresponding to the center frequency of the broadband bandpass filter 2000.

[0031] In some embodiments, the characteristic impedance of the first microstrip line 105, the characteristic impedance of the second microstrip line 106, the characteristic impedance of the third microstrip line 107, the characteristic impedance of the fourth microstrip line 108, the characteristic impedance of the fifth microstrip line 109, the characteristic impedance of the sixth microstrip line 110, the characteristic impedance of the seventh microstrip line 111, the characteristic impedance of the eighth microstrip line 112, the characteristic impedance of the first short-circuit branch 113 and the characteristic impedance of the second short-circuit branch 114 are all equal.

[0032] It is worth noting that, since there is no typical analysis model for the three parallel lines in the topological structure 1000 in the basic radio frequency theory, the utility model also provides an embodiment of a broadband bandpass filter 2000 and performs simulation experiments on it to illustrate the characteristics of this topological structure 1000. The broadband bandpass filter 2000 includes a circuit board and the above-mentioned topological structure 1000. The structure and function of the topological structure 1000 can be referred to the above-mentioned embodiment, which will not be described one by one here.

[0033] See also Figure 2 and Figure 3 , specifying the dielectric constant of the above circuit board to be 3.38, the dielectric loss to be 0.0022, the length to be 34.4mm, the width to be 12.3mm, the thickness to be 0.813mm, the specific dimensions of the filter are: l T =9.8mm,s T =0.1mm,w T =0.2mm,lp =9.8mm,s p =0.1mm,w p =0.2mm, l1=5.4mm, l2=5.7mm, l3=4.05mm, l4=4.35mm, l5=2.4mm, w1=0.7mm, w2=1.4mm. Among them, l T represents the physical length of the first three parallel lines 103 or the physical length of the second three parallel lines 104, s T represents the spacing between adjacent transmission lines constituting the first parallel three-line 103 or the spacing between adjacent transmission lines constituting the second parallel three-line 104, w T represents the physical width of the transmission line constituting the first parallel three-line 103 or the physical width of the transmission line constituting the second parallel three-line 104, l p represents the physical length of the first parallel line 102, s p represents the spacing of the transmission lines constituting the first parallel line 102, w p represents the physical width of the transmission line constituting the first parallel line 102, l1 represents the physical length of the first microstrip line 105 or the physical length of the eighth microstrip line 112, l2 represents the physical length of the fourth microstrip line 108 or the physical length of the fifth microstrip line 109, l3 represents the physical length of the third microstrip line 107 or the physical length of the sixth microstrip line 110, l4 represents the physical length of the second microstrip line 106 or the physical length of the seventh microstrip line 111, l5 represents the physical length of the first short-circuit branch 113, and l6 represents the physical length of the first short-circuit branch 114. w1 represents the physical width of the first microstrip line 105 or the physical width of the second microstrip line 106 or the physical width of the third microstrip line 107 or the physical width of the fourth microstrip line 108 or the physical width of the fifth microstrip line 109 or the physical width of the sixth microstrip line 110 or the physical width of the seventh microstrip line 111 or the physical width of the eighth microstrip line 112, and w2 represents the physical width of the first short-circuit branch 113 or the physical width of the second short-circuit branch 114.

[0034] The simulation results of the broadband bandpass filter 2000 under the above-mentioned limited conditions are as follows: Figure 4 As shown by Figure 4It can be seen that the passband range with a reflection coefficient better than -10dB is 2.334GHz to 6.868GHz, the center frequency is 4.601GHz, the absolute bandwidth is 4.534GHz, and the relative bandwidth is 98.5%. In addition, there are five transmission poles in the passband, located at 2.485GHz, 3.343GHz, 4.081GHz, 5.698GHz, and 6.363GHz, respectively. These five transmission poles ensure the flatness of the passband. There are four transmission zeros in the stopband, located at 0GHz, 1.564GHz, 7.499GHz, and 10.513GHz, respectively. These four transmission zeros ensure the high selectivity and high isolation of the broadband bandpass filter 2000.

[0035] In the embodiment of the utility model, the topological structure 1000 includes an input end 101, an output end 115, a first parallel line 102, a first parallel three-line 103, a second parallel three-line 104, a first microstrip line 105, a second microstrip line 106, a third microstrip line 107, a fourth microstrip line 108, a fifth microstrip line 109, a sixth microstrip line 110, a seventh microstrip line 111, an eighth microstrip line 112, a first short-circuit branch 113 and a second short-circuit branch 114; wherein, one end of the first parallel line 102 is connected to one end of the first parallel three-line 103, one end of the first microstrip line 105 and one end of the fifth microstrip line 109, the other end of the first parallel three-line 103 is connected to the input end 101, the other end of the first microstrip line 105 is connected to one end of the second microstrip line 106, and the other end of the fifth microstrip line 109 is connected to the The first microstrip line 102 is connected to one end of the sixth microstrip line 110, the other end of the first parallel line 102 is connected to one end of the second parallel three-line 104, one end of the fourth microstrip line 108 and one end of the eighth microstrip line 112, the other end of the second parallel three-line 104 is connected to the output end 115, the other end of the fourth microstrip line 108 is connected to one end of the third microstrip line 107, the other end of the third microstrip line 107 is connected to the other end of the second microstrip line 106 and one end of the first short-circuit branch 113, the other end of the first short-circuit branch 113 is grounded, the other end of the eighth microstrip line 112 is connected to one end of the seventh microstrip line 111, the other end of the seventh microstrip line 111 is connected to the other end of the sixth microstrip line 110 and one end of the second short-circuit branch 114, and the other end of the second short-circuit branch 114 is grounded. The broadband bandpass filter 2000 designed based on the above topological structure 1000 has five transmission poles in the passband to ensure the flatness of the passband, and four transmission zeros in the stopband to ensure high selectivity and high isolation of the broadband bandpass filter 2000.

[0036] The present invention also provides a communication device embodiment, wherein the communication device includes the above-mentioned broadband bandpass filter 2000. The structure and function of the broadband bandpass filter 2000 can be referred to the above-mentioned embodiment, which will not be described in detail here.

[0037] It should be noted that the preferred embodiments of the utility model are given in the specification and drawings of the utility model, but the utility model can be implemented in many different forms and is not limited to the embodiments described in the specification. These embodiments are not used as additional restrictions on the content of the utility model. The purpose of providing these embodiments is to make the understanding of the disclosure of the utility model more thorough and comprehensive. In addition, the above-mentioned technical features continue to be combined with each other to form various embodiments not listed above, which are all regarded as the scope of the description of the utility model; further, for ordinary technicians in this field, they can be improved or transformed according to the above description, and all these improvements and transformations should belong to the scope of protection of the claims attached to the utility model.

Claims

1. A topological structure, characterized in that: include An input end, an output end, a first parallel line, a first parallel three lines, a second parallel three lines, a first microstrip line, a second microstrip line, a third microstrip line, a fourth microstrip line, a fifth microstrip line, a sixth microstrip line, a seventh microstrip line, an eighth microstrip line, a first short-circuit branch, and a second short-circuit branch; Among them, one end of the first parallel line is connected to one end of the first three parallel lines, one end of the first microstrip line and one end of the fifth microstrip line, the other end of the first three parallel lines is connected to the input end, the other end of the first microstrip line is connected to one end of the second microstrip line, the other end of the fifth microstrip line is connected to one end of the sixth microstrip line, the other end of the first parallel line is connected to one end of the second three parallel lines, one end of the fourth microstrip line and one end of the eighth microstrip line, the other end of the second three parallel lines is connected to the output end, the other end of the fourth microstrip line is connected to one end of the third microstrip line, the other end of the third microstrip line is connected to the other end of the second microstrip line and one end of the first short-circuit branch, the other end of the first short-circuit branch is grounded, the other end of the eighth microstrip line is connected to one end of the seventh microstrip line, the other end of the seventh microstrip line is connected to the other end of the sixth microstrip line and one end of the second short-circuit branch, and the other end of the second short-circuit branch is grounded.

2. The topological structure according to claim 1, characterized in that: The first parallel three lines and the second parallel three lines, the input end and the output end, the first microstrip line and the fifth microstrip line, the second microstrip line and the sixth microstrip line, the first short-circuit branch and the second short-circuit branch, the third microstrip line and the seventh microstrip line, the fourth microstrip line and the eighth microstrip line are all symmetrically arranged about the first parallel lines.

3. The topological structure according to claim 1, characterized in that: The first three parallel lines, the first parallel line, the second three parallel lines, the second microstrip line, the third microstrip line, the sixth microstrip line and the seventh microstrip line are arranged in parallel.

4. The topological structure according to claim 1, characterized in that: The first three parallel lines, the first parallel line, the second three parallel lines, the second microstrip line, the third microstrip line, the sixth microstrip line and the seventh microstrip line are all perpendicular to the first microstrip line, the first short-circuit branch, the fourth microstrip line, the fifth microstrip line, the second short-circuit branch and the eighth microstrip line.

5. The topological structure according to claim 1, characterized in that: The first parallel lines include a fourth transmission line and a fifth transmission line, wherein the fourth transmission line and the fifth transmission line are arranged in parallel; The first parallel three lines include a first transmission line, a second transmission line and a third transmission line, wherein the first transmission line, the second transmission line and the third transmission line are arranged in parallel and equidistantly; The second parallel three lines include a sixth transmission line, a seventh transmission line and an eighth transmission line, wherein the sixth transmission line, the seventh transmission line and the eighth transmission line are arranged in parallel and equidistantly.

6. The topological structure according to claim 1, characterized in that The electrical length of the first parallel line, the electrical length of the first three parallel lines, and the electrical length of the second three parallel lines are all a quarter wavelength corresponding to the center frequency of the broadband bandpass filter.

7. The topological structure according to claim 1, characterized in that The electrical length of the first microstrip line is equal to the electrical length of the eighth microstrip line; The electrical length of the second microstrip line is equal to the electrical length of the seventh microstrip line; The electrical length of the third microstrip line is equal to the electrical length of the sixth microstrip line; The electrical length of the fourth microstrip line is equal to the electrical length of the fifth microstrip line; The electrical length of the first short-circuit branch is equal to the electrical length of the second short-circuit branch; The sum of the electrical length of the first microstrip line and the electrical length of the second microstrip line is equal to the sum of the electrical length of the third microstrip line and the electrical length of the fourth microstrip line; The sum of the electrical length of the first microstrip line, the electrical length of the second microstrip line, and the electrical length of the first short-circuit branch is greater than a quarter wavelength corresponding to the center frequency of the broadband bandpass filter.

8. The topological structure according to any one of claims 1 to 7, characterized in that: The characteristic impedance of the first microstrip line, the characteristic impedance of the second microstrip line, the characteristic impedance of the third microstrip line, the characteristic impedance of the fourth microstrip line, the characteristic impedance of the fifth microstrip line, the characteristic impedance of the sixth microstrip line, the characteristic impedance of the seventh microstrip line, the characteristic impedance of the eighth microstrip line, the characteristic impedance of the first short-circuit branch and the characteristic impedance of the second short-circuit branch are all equal.

9. A broadband bandpass filter, characterized in that: The method is obtained by designing the topological structure as described in any one of claims 1 to 8.

10. A communication device comprising the broadband bandpass filter according to claim 9.

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