Topological structure of broadband band-pass filter with notch characteristic and filter

Abstract

The utility model discloses a topological structure of a broadband band-pass filter with a notch characteristic and the filter, the topological structure comprises an input end, a first parallel line, a second parallel line, a third parallel line and an output end which are connected in sequence, and the first parallel line and the third parallel line are symmetrical about the second parallel line; the input end is also connected with a first microstrip line, and the first microstrip line is connected with a first open circuit branch; a second microstrip line is connected between the first parallel line and the second parallel line, the other end of the second microstrip line is symmetrically connected with a third microstrip line and a fourth microstrip line, and the other end of the third microstrip line is symmetrically connected with a first short-circuit branch knot and a second short-circuit branch knot. The other end of the fourth microstrip line is symmetrically connected with a third short-circuit branch and a fourth short-circuit branch, and the first short-circuit branch and the third short-circuit branch are symmetrical about the second microstrip line. The miniaturized broadband band-pass filter designed based on the topological structure has the advantages of in-band notch characteristics and high selectivity.

Description

TECHNICAL FIELD

[0001] The utility model relates to filter technical field, especially in a kind of topology structure and filter of wideband band-pass filter with trap feature. BACKGROUND

[0002] With the rapid development of modern 5G communication technology, as one of the key devices of wireless communication system, wideband band-pass filter attracts more and more attention of scholars and engineers. Under this background, miniaturized wideband band-pass filter suitable for handheld terminal is developed. However, the currently reported miniaturized wideband band-pass filter often cannot have the characteristics of in-band notch and high selectivity, cannot effectively suppress in-band interference and efficiently utilize frequency band resources, greatly limits its use in modern wireless communication system. SUMMARY

[0003] The utility model solves technical problem: provide a kind of topology structure of wideband band-pass filter with trap feature, the topology structure can be used to design miniaturized wideband band-pass filter with the in-band notch and high selectivity advantage, and still provide filter based on the topology structure design.

[0004] In order to solve the above technical problem, the technical scheme one that the utility model adopts is as follows: a kind of topology structure of wideband band-pass filter with trap feature, including input end, first parallel line, second parallel line, third parallel line and output end connected in turn, the first parallel line and the third parallel line are about second parallel line symmetry;

[0005] The input end is also connected with first microstrip line, and the first microstrip line is connected with first open-circuit branch;

[0006] Second microstrip line is connected between first parallel line and second parallel line, and the other end of the second microstrip line is symmetrically connected with third microstrip line and fourth microstrip line, the other end of the third microstrip line is symmetrically connected with first short-circuit branch and second short-circuit branch, the other end of the fourth microstrip line is symmetrically connected with third short-circuit branch and fourth short-circuit branch, the first short-circuit branch and the third short-circuit branch are about the second microstrip line symmetry, and the second short-circuit branch and the fourth short-circuit branch are about the second microstrip line symmetry;

[0007] A fifth microstrip line is connected between the second parallel line and the third parallel line, another end of the fifth microstrip line is symmetrically connected with a sixth microstrip line and a seventh microstrip line, another end of the sixth microstrip line is symmetrically connected with a fifth short-circuit stub and a sixth short-circuit stub, another end of the seventh microstrip line is symmetrically connected with a seventh short-circuit stub and an eighth short-circuit stub, the fifth short-circuit stub and the seventh short-circuit stub are symmetric about the fifth microstrip line, and the sixth short-circuit stub and the eighth short-circuit stub are symmetric about the fifth microstrip line.

[0008] The output end is further connected with an eighth microstrip line, and the eighth microstrip line is connected with a second open-circuit stub.

[0009] The first parallel line, the second parallel line, the third parallel line, the first microstrip line, the third microstrip line, the fourth microstrip line, the sixth microstrip line, the seventh microstrip line and the eighth microstrip line are arranged along a first direction; and the second microstrip line, the fifth microstrip line, the first open-circuit stub, the second open-circuit stub, the first short-circuit stub, the second short-circuit stub, the third short-circuit stub, the fourth short-circuit stub, the fifth short-circuit stub, the sixth short-circuit stub, the seventh short-circuit stub and the eighth short-circuit stub are arranged along a second direction, and the first direction is perpendicular to the second direction.

[0010] In an embodiment, the electrical length of the first parallel line, the electrical length of the second parallel line and the electrical length of the third parallel line are equal, and each is equal to a quarter wavelength corresponding to a center frequency of the filter.

[0011] In an embodiment, the sum of the electrical length of the first microstrip line and the electrical length of the first open-circuit stub is a quarter wavelength corresponding to a notch center frequency of the filter; and the sum of the electrical length of the eighth microstrip line and the electrical length of the second open-circuit stub is a quarter wavelength corresponding to the notch center frequency of the filter.

[0012] In an embodiment, the electrical length of the second microstrip line and the electrical length of the fifth microstrip line are equal.

[0013] In an embodiment, the electrical length of the third microstrip line, the electrical length of the fourth microstrip line, the electrical length of the sixth microstrip line and the electrical length of the seventh microstrip line are equal.

[0014] In an embodiment, the electrical length of the first short-circuit stub, the electrical length of the second short-circuit stub, the electrical length of the third short-circuit stub, the electrical length of the fourth short-circuit stub, the electrical length of the fifth short-circuit stub, the electrical length of the sixth short-circuit stub, the electrical length of the seventh short-circuit stub and the electrical length of the eighth short-circuit stub are equal.

[0015] In an embodiment, the sum of the electrical length of the second microstrip line, the electrical length of the third microstrip line, and the electrical length of the first short-circuit stub is greater than the corresponding quarter wavelength at the filter center frequency.

[0016] In an embodiment, the odd mode characteristic impedance of the first parallel line is equal to the odd mode characteristic impedance of the third parallel line; the even mode characteristic impedance of the first parallel line is equal to the even mode characteristic impedance of the third parallel line.

[0017] In an embodiment, the characteristic impedance of the first microstrip line, the characteristic impedance of the eighth microstrip line, the characteristic impedance of the first open-circuit stub, the characteristic impedance of the second open-circuit stub are equal; the characteristic impedance of the second microstrip line is equal to the characteristic impedance of the fifth microstrip line; the characteristic impedance of the third microstrip line, the characteristic impedance of the fourth microstrip line, the characteristic impedance of the sixth microstrip line, the characteristic impedance of the seventh microstrip line are equal; the characteristic impedance of the first short-circuit stub, the characteristic impedance of the second short-circuit stub, the characteristic impedance of the third short-circuit stub, the characteristic impedance of the fourth short-circuit stub, the characteristic impedance of the fifth short-circuit stub, the characteristic impedance of the sixth short-circuit stub, the characteristic impedance of the seventh short-circuit stub, the characteristic impedance of the eighth short-circuit stub are equal.

[0018] To solve the above technical problems, the utility model adopts technical scheme two: filter, the filter based on the above topology structure is designed.

[0019] The utility model discloses the beneficial effect lies in: this topology structure of the wideband band -pass filter with wave trap characteristic is novel, and the miniaturized wideband band -pass filter based on the topology structure has the advantages of in -band wave trap characteristic and high selectivity. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical scheme in the embodiment of the utility model or prior art, below will to the drawing needed to be used in the embodiment or prior art description simple introduction, obviously, the drawing in the following description only some embodiments of the utility model, for those skilled in the art, under the premise of not paying the creative labor, can also obtain other drawings according to the structure shown in these drawings.

[0021] Figure 1 It is topology structure's structural schematic diagram for the embodiment one of the utility model;

[0022] Figure 2 It is odd mode form drawing for the topology structure of the embodiment one of the utility model;

[0023] Figure 3 It is even mode form drawing for the topology structure of the embodiment one of the utility model;

[0024] Figure 4 Layout pattern of the filter of the embodiment one of the utility model;

[0025] Figure 5 S parameter simulation result graph of the filter of the embodiment one of the utility model. DETAILED DESCRIPTION

[0026] The utility model realizes, function characteristics and advantages will combine embodiment, refer to the further illustration of the drawing.

[0027] The technical scheme in the embodiment of the utility model will be described clearly and completely in combination with the drawings of the embodiment of the utility model, and obviously, the described embodiment is only a part of the embodiment of the utility model, not all the embodiment. Based on the embodiment in the utility model, all other embodiments obtained by the ordinary skill in the art without making creative labor belong to the protection scope of the utility model.

[0028] It needs to be explained that if the embodiment of the utility model has involved directionality indication such as upper, lower, left, right, front, back, the directionality indication is only used to explain the relative position relationship, movement condition etc. between the components in a certain specific posture such as the drawing shows, if the specific posture changes, then the directionality indication also changes accordingly.

[0029] In addition, if the embodiment of the utility model has involved the description of "first", "second" etc., the description of "first", "second" etc. is only for the description purpose, and can not be understood as indicating or suggesting its relative importance or implicitly indicating the number of the indicated technical features. Therefore, the feature with "first", "second" can explicitly or implicitly include at least one feature.

[0030] In addition, the meaning of "and / or" appearing in the whole text is that, including three parallel schemes, taking "and / or" as an example, including scheme, or scheme, or and simultaneously satisfied scheme. In addition, the technical scheme of each embodiment can be combined with each other, but it must be based on the realization of the ordinary skill in the art, when the combination of technical scheme appears mutually contradictory or unachievable, it should be considered that the combination of technical scheme does not exist, also not in the protection scope required by the utility model.

[0031] In this application, unless otherwise expressly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and other terms should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0032] Embodiment one

[0033] Please refer to Figures 1 to 5 , the embodiment of the utility model is: as Figure 1 The topological structure of a wideband band-pass filter with a trap feature, comprising an input end, a first parallel line, a second parallel line, a third parallel line and an output end connected in turn, the first parallel line and the third parallel line are symmetrical about the second parallel line;

[0034] The input end is also connected with a first microstrip line, and the first microstrip line is connected with a first open-circuit stub;

[0035] A second microstrip line is connected between the first parallel line and the second parallel line, the other end of the second microstrip line is symmetrically connected with a third microstrip line and a fourth microstrip line, the other end of the third microstrip line is symmetrically connected with a first short-circuit stub and a second short-circuit stub, the other end of the fourth microstrip line is symmetrically connected with a third short-circuit stub and a fourth short-circuit stub, the first short-circuit stub and the third short-circuit stub are symmetrical about the second microstrip line, and the second short-circuit stub and the fourth short-circuit stub are symmetrical about the second microstrip line;

[0036] A fifth microstrip line is connected between the second parallel line and the third parallel line, the other end of the fifth microstrip line is symmetrically connected with a sixth microstrip line and a seventh microstrip line, the other end of the sixth microstrip line is symmetrically connected with a fifth short-circuit stub and a sixth short-circuit stub, the other end of the seventh microstrip line is symmetrically connected with a seventh short-circuit stub and an eighth short-circuit stub, the fifth short-circuit stub and the seventh short-circuit stub are symmetrical about the fifth microstrip line, and the sixth short-circuit stub and the eighth short-circuit stub are symmetrical about the fifth microstrip line;

[0037] The output end is also connected with an eighth microstrip line, and the eighth microstrip line is connected with a second open-circuit stub;

[0038] The first parallel line, the second parallel line, the third parallel line, the first microstrip line, the third microstrip line, the fourth microstrip line, the sixth microstrip line, the seventh microstrip line and the eighth microstrip line are arranged along a first direction; the second microstrip line, the fifth microstrip line, the first open-circuit stub, the second open-circuit stub, the first short-circuit stub, the second short-circuit stub, the third short-circuit stub, the fourth short-circuit stub, the fifth short-circuit stub, the sixth short-circuit stub, the seventh short-circuit stub and the eighth short-circuit stub are arranged along a second direction, and the first direction is perpendicular to the second direction.

[0039] The electrical length of the first parallel line, the electrical length of the second parallel line and the electrical length of the third parallel line are equal, and all equal to a quarter wavelength corresponding to a filter center frequency.

[0040] The sum of the electrical length of the first microstrip line and the electrical length of the first open-circuit stub is a quarter wavelength corresponding to a filter notch center frequency; the sum of the electrical length of the eighth microstrip line and the electrical length of the second open-circuit stub is a quarter wavelength corresponding to a filter notch center frequency; the electrical length of the second microstrip line is equal to the electrical length of the fifth microstrip line; the electrical length of the third microstrip line, the electrical length of the fourth microstrip line, the electrical length of the sixth microstrip line and the electrical length of the seventh microstrip line are equal; the electrical length of the first short-circuit stub, the electrical length of the second short-circuit stub, the electrical length of the third short-circuit stub, the electrical length of the fourth short-circuit stub, the electrical length of the fifth short-circuit stub, the electrical length of the sixth short-circuit stub, the electrical length of the seventh short-circuit stub and the electrical length of the eighth short-circuit stub are equal; the sum of the electrical length of the second microstrip line, the electrical length of the third microstrip line and the electrical length of the first short-circuit stub is greater than a quarter wavelength corresponding to a filter center frequency.

[0041] The odd-mode characteristic impedance of the first parallel line is equal to the odd-mode characteristic impedance of the third parallel line, denoted as Z o1 ; the even-mode characteristic impedance of the first parallel line is equal to the even-mode characteristic impedance of the third parallel line, denoted as Z e1 ; the odd-mode characteristic impedance of the second parallel line is denoted as Z o2 , and the even-mode characteristic impedance of the second parallel line is denoted as Z e2; the characteristic impedance of the first microstrip line, the characteristic impedance of the eighth microstrip line, the characteristic impedance of the first open stub and the characteristic impedance of the second open stub are equal, denoted as Z1; the characteristic impedance of the second microstrip line and the characteristic impedance of the fifth microstrip line are equal, denoted as Z2; the characteristic impedance of the third microstrip line, the characteristic impedance of the fourth microstrip line, the characteristic impedance of the sixth microstrip line and the characteristic impedance of the seventh microstrip line are equal, which is 2Z2; the characteristic impedance of the first short-circuit stub, the characteristic impedance of the second short-circuit stub, the characteristic impedance of the third short-circuit stub, the characteristic impedance of the fourth short-circuit stub, the characteristic impedance of the fifth short-circuit stub, the characteristic impedance of the sixth short-circuit stub, the characteristic impedance of the seventh short-circuit stub and the characteristic impedance of the eighth short-circuit stub are equal, which is 4Z2.

[0042] Since the topology structure can be equivalent to a symmetrical structure, the transmission poles can be calculated in the odd-even mode. To simplify the calculation process, it is first assumed that the sum of the electrical length of the first microstrip line and the electrical length of the first open stub is a quarter wavelength corresponding to the center frequency of the wideband bandpass filter; the sum of the electrical length of the second microstrip line, the electrical length of the third microstrip line and the electrical length of the first short-circuit stub is a quarter wavelength corresponding to the center frequency of the wideband bandpass filter. At this time, Figure 2 is the odd mode form of the topology structure, wherein the electrical length of the odd mode transmission line is the electrical length of the second parallel line; the characteristic impedance of the odd mode transmission line is the odd mode characteristic impedance of the second parallel line.

[0043] When Y ino = 0, it can be obtained that the topology structure has four odd mode transmission poles. When f0 is the center frequency of the bandpass filter, the frequencies corresponding to the four odd mode transmission poles are respectively:

[0044]

[0045]

[0046] Here,

[0047] Δ o1 = 2Z2(Z e1 -Z o1 );

[0048] Δ o2 = 4Z2Z o2 (Z e1 +Z o1 +2)+8Z2Z e1 Z o1 +Z o2 (Z e1 -Z o1 ) 2 +4Z1Z2(Ze1 + Z o1 );

[0049] Δ o3 = 4Z o2 Z e1 Z o1 + Z1Z o2 ;

[0050] Figure 3 is the even-mode form of the topology, where the electrical length of the even-mode transmission line is the electrical length of the second parallel line; and the characteristic impedance of the even-mode transmission line is the even-mode characteristic impedance of the second parallel line.

[0051] When Y ine = 0, it can be concluded that the topology has four even-mode transmission poles. When f0is the center frequency of the bandpass filter, the frequencies corresponding to the four even-mode transmission poles are respectively:

[0052]

[0053] Here,

[0054] Δ e1 = 2Z2(Z e1 -Z o1 );

[0055] Δ e2 = 4Z2Z e2 (Z e1 + Z o1 + 2) + 8Z2Z e1 Z o1 + Z e2 (Z e1 -Z o1 ) 2 + 4Z1Z2(Z e1 + Z o1 );

[0056] Δ e3 = 4Z e2 Z e1 Z o1 + Z1Z e2 ;

[0057] For this topology, the transmission zeros can be calculated by the following method: multiply the ABCD matrices of the cascaded resonators that make up the topology in turn to obtain the ABCD matrix corresponding to the topology; and convert the ABCD matrix of the topology into the corresponding S matrix. When ︱S 21 ︱ = 0, it can be concluded that the topology has three transmission zeros, and the frequencies corresponding to the three transmission zeros are respectively:

[0058] f z1= 0;

[0059] f z2 = f0;

[0060] f z3 = 2f0;

[0061] By the above analysis, when the sum of the electrical length of the first microstrip line and the electrical length of the first open-circuit stub is a quarter of the wavelength corresponding to the center frequency of the wideband bandpass filter, and the sum of the electrical length of the second microstrip line, the electrical length of the third microstrip line and the electrical length of the first short-circuit stub is also a quarter of the wavelength corresponding to the center frequency of the wideband bandpass filter, the topology has four odd-mode transmission poles, three even-mode transmission poles and three transmission zeros. Returning to the topology, appropriately increasing the sum of the electrical length of the first microstrip line and the electrical length of the first open-circuit stub and the sum of the electrical length of the second microstrip line, the electrical length of the third microstrip line and the electrical length of the first short-circuit stub will additionally increase three transmission zeros (f z4 , f z5 , f z6 ), but the number of original zeros and poles remains unchanged. Regardless of how the values of the parameters Z o1 , Z e1 , Z o2 , Z e2 , Z1 and Z2 are changed, the relative positions of the transmission zeros and poles, i.e., f z1 , f z4 , f ep1 , f op1 , f op2 , f ep2 , f z2 , f ep3 , f op3 , f op4 , f ep4 , f z5 , f z3 , f z6 , will not change. Therefore, based on this topology, a wideband bandpass filter with a notch characteristic can be designed, and there are eight transmission poles in the passband to ensure the flatness in the passband, there are five transmission zeros in the stopband to ensure high selectivity and high isolation, and there is a transmission zero in the passband to form the required notch.

[0062] The embodiment also provides a filter, which is designed based on the filter according to the above topology.

[0063] The filter example 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 as shown in Figure 4 The size of the entire layout is only 37.2 mm*12.0 mm, and the specific size of the filter is: l P1= 10.2 mm, s P1 = 0.1 mm, w P1 = 0.2 mm, l P2 = 10.2 mm, s P2 = 0.1 mm, w P2 = 0.1 mm, l 1H = 9.8 mm, l 1V = 1.7 mm, l2 = 4.1 mm, l3 = 6.4 mm, l4 = 2.6 mm, w1 = 0.3 mm, w2 = 1.6 mm, w3 = 0.8 mm, w4 = 0.4 mm, s1 = 0.15 mm.

[0064] l P1 represents the physical length of the first parallel line or the physical length of the third parallel line;

[0065] s P1 represents the pitch of the first transmission line and the second transmission line constituting the first parallel line, or the pitch of the fifth transmission line and the sixth transmission line constituting the third parallel line;

[0066] w P1 represents the physical width of the first transmission line, or the physical width of the second transmission line, or the physical width of the fifth transmission line or the physical width of the sixth transmission line;

[0067] l P2 represents the physical length of the second parallel line;

[0068] s P2 represents the pitch of the third transmission line and the fourth transmission line constituting the second parallel line;

[0069] w P2 represents the physical width of the third transmission line or the physical width of the fourth transmission line;

[0070] l 1H represents the physical length of the first microstrip line or the physical length of the eighth microstrip line;

[0071] l 1V represents the physical length of the first open stub or the physical length of the second open stub;

[0072] l2 represents the physical length of the second microstrip line or the physical length of the fifth microstrip line;

[0073] l3 represents the physical length of the third microstrip line, or the physical length of the fourth microstrip line, or the physical length of the sixth microstrip line, or the physical length of the seventh microstrip line;

[0074] l4 represents the sum of the physical length of the first short-circuit stub and the physical length of the second short-circuit stub, or the sum of the physical length of the third short-circuit stub and the physical length of the fourth short-circuit stub, or the sum of the physical length of the fifth short-circuit stub and the physical length of the sixth short-circuit stub, or the sum of the physical length of the seventh short-circuit stub and the physical length of the eighth short-circuit stub;

[0075] w1 represents the physical width of the first microstrip line, or the physical length of the eighth microstrip line, or the physical width of the first open-circuit stub or the width of the second open-circuit stub;

[0076] w2 represents the physical width of the second microstrip line or the physical width of the fifth microstrip line;

[0077] w3 represents the physical width of the third microstrip line, or the physical width of the fourth microstrip line, or the physical width of the sixth microstrip line, or the physical width of the seventh microstrip line;

[0078] w4 represents the physical width of the first short-circuit stub, or the physical width of the second short-circuit stub, or the physical width of the third short-circuit stub, or the physical width of the fourth short-circuit stub, or the physical width of the fifth short-circuit stub, or the physical width of the sixth short-circuit stub, or the physical width of the seventh short-circuit stub, or the physical width of the eighth short-circuit stub;

[0079] s1 represents the distance between the first microstrip line and the first parallel line, or the distance between the eighth microstrip line and the third parallel line.

[0080] The S-parameter simulation results of the filter of the example are shown in Figure 5 The passband range with a reflection coefficient better than -10 dB is 2.28 GHz to 7.18 GHz, the center frequency is 4.73 GHz, the absolute bandwidth is 4.9 GHz, and the relative bandwidth is 103.6%. In addition, there are eight transmission poles in the passband, respectively at 2.34 GHz, 2.86 GHz, 3.09 GHz, 3.98 GHz, 4.94 GHz, 5.98 GHz, 6.74 GHz, and 7.12 GHz, which ensure the flatness of the passband; there is also a transmission zero in the passband at 4.58 GHz to form the required notch, and the isolation at the center frequency of the notch is 27.6 dB, showing good isolation. There are five transmission zeros in the stopband, respectively at 0 GHz, 0.54 GHz, 8.3 GHz, 10.24 GHz, and 10.78 GHz, which ensure the high selectivity and high isolation of the stopband of the filter.

[0081] The above are only optional embodiments of the utility model, and do not limit the patent range of the utility model, and any equivalent structural transformation made by using the utility model specification and the contents of the drawings, or direct / indirect application in other related technical fields are included in the patent protection range of the utility model.

Claims

1. A topology of a wideband bandpass filter with a notch feature, characterized by: The filter comprises an input end, a first parallel line, a second parallel line, a third parallel line and an output end connected in sequence, and the first parallel line and the third parallel line are symmetrical about the second parallel line; The input end is further connected with a first microstrip line, and the first microstrip line is connected with a first open stub; A second microstrip line is connected between the first parallel line and the second parallel line, and the other end of the second microstrip line is symmetrically connected with a third microstrip line and a fourth microstrip line, the other end of the third microstrip line is symmetrically connected with a first short-circuit stub and a second short-circuit stub, the other end of the fourth microstrip line is symmetrically connected with a third short-circuit stub and a fourth short-circuit stub, the first short-circuit stub and the third short-circuit stub are symmetrical about the second microstrip line, and the second short-circuit stub and the fourth short-circuit stub are symmetrical about the second microstrip line; A fifth microstrip line is connected between the second parallel line and the third parallel line, and the other end of the fifth microstrip line is symmetrically connected with a sixth microstrip line and a seventh microstrip line, the other end of the sixth microstrip line is symmetrically connected with a fifth short-circuit stub and a sixth short-circuit stub, the other end of the seventh microstrip line is symmetrically connected with a seventh short-circuit stub and an eighth short-circuit stub, the fifth short-circuit stub and the seventh short-circuit stub are symmetrical about the fifth microstrip line, and the sixth short-circuit stub and the eighth short-circuit stub are symmetrical about the fifth microstrip line; The output end is further connected with an eighth microstrip line, and the eighth microstrip line is connected with a second open stub; The first parallel line, the second parallel line, the third parallel line, the first microstrip line, the third microstrip line, the fourth microstrip line, the sixth microstrip line, the seventh microstrip line and the eighth microstrip line are arranged along a first direction, and the second microstrip line, the fifth microstrip line, the first open stub, the second open stub, the first short-circuit stub, the second short-circuit stub, the third short-circuit stub, the fourth short-circuit stub, the fifth short-circuit stub, the sixth short-circuit stub, the seventh short-circuit stub and the eighth short-circuit stub are arranged along a second direction, and the first direction is perpendicular to the second direction.

2. The topology of a wideband bandpass filter with a notch feature according to claim 1, characterized in that: The electrical length of the first parallel line, the electrical length of the second parallel line and the electrical length of the third parallel line are equal, and all equal to a quarter wavelength corresponding to a center frequency of the filter.

3. The topology of a wideband bandpass filter with a notch feature according to claim 1, characterized in that: The sum of the electrical length of the first microstrip line and the electrical length of the first open stub is a quarter wavelength corresponding to a notch center frequency of the filter, and the sum of the electrical length of the eighth microstrip line and the electrical length of the second open stub is a quarter wavelength corresponding to the notch center frequency of the filter.

4. The topology of a wideband bandpass filter with a notch feature according to claim 1, characterized in that: The electrical length of the second microstrip line is equal to the electrical length of the fifth microstrip line.

5. The topology of a wideband bandpass filter with a notch feature according to claim 1, characterized in that: The electrical length of the third microstrip line, the electrical length of the fourth microstrip line, the electrical length of the sixth microstrip line and the electrical length of the seventh microstrip line are equal.

6. The topology of a wideband bandpass filter with a notch feature according to claim 1, characterized in that: The electrical length of the first short-circuit stub, the electrical length of the second short-circuit stub, the electrical length of the third short-circuit stub, the electrical length of the fourth short-circuit stub, the electrical length of the fifth short-circuit stub, the electrical length of the sixth short-circuit stub, the electrical length of the seventh short-circuit stub and the electrical length of the eighth short-circuit stub are equal.

7. The topology of a wideband bandpass filter with a notch feature according to claim 1, characterized in that: The sum of the electrical length of the second microstrip line, the electrical length of the third microstrip line and the electrical length of the first short-circuit stub is greater than the corresponding quarter wavelength at the filter center frequency.

8. The topology of a wideband bandpass filter with a notch feature according to claim 1, characterized in that: The odd mode characteristic impedance of the first parallel line is equal to the odd mode characteristic impedance of the third parallel line; the even mode characteristic impedance of the first parallel line is equal to the even mode characteristic impedance of the third parallel line.

9. The topology of a wideband bandpass filter with a notch feature according to claim 1, characterized in that: The characteristic impedance of the first microstrip line, the characteristic impedance of the eighth microstrip line, the characteristic impedance of the first open-circuit stub, the characteristic impedance of the second open-circuit stub are equal; the characteristic impedance of the second microstrip line is equal to the characteristic impedance of the fifth microstrip line; the characteristic impedance of the third microstrip line, the characteristic impedance of the fourth microstrip line, the characteristic impedance of the sixth microstrip line, the characteristic impedance of the seventh microstrip line are equal; the characteristic impedance of the first short-circuit stub, the characteristic impedance of the second short-circuit stub, the characteristic impedance of the third short-circuit stub, the characteristic impedance of the fourth short-circuit stub, the characteristic impedance of the fifth short-circuit stub, the characteristic impedance of the sixth short-circuit stub, the characteristic impedance of the seventh short-circuit stub, the characteristic impedance of the eighth short-circuit stub are equal.

10. Filter, characterized in that: A filter designed based on the topology of any one of claims 1-9.

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