Topological structure, filter and communication equipment
By designing a transmission line topology with specific arrangement and connection, the problem of narrow stopband in existing bandpass filters is solved, realizing a wide stopband and high selectivity bandpass filter that can adapt to multi-band communication, reduce signal interference, and improve signal quality.
Patent Information
- Application Number
- CN202520311991.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-24
- Publication Date
- 2026-01-06
- Estimated Expiration
- 2035-02-24
AI Technical Summary
Existing bandpass filters suffer from a narrow stopband in modern wireless communication systems, which limits their use.
Design a topology, including a specific arrangement and connection of transmission lines, to form multiple resonant peaks and transmission zeros, achieving wide stopband and high selectivity.
The topology-designed bandpass filter features a wide stopband and high selectivity, enabling it to adapt to multi-band communication, reduce signal interference, and improve signal quality.
Smart Images
Figure CN223771314U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of filter technology, and in particular to a topology, filter and communication device. Background Technology
[0002] With the rapid development of modern wireless communication technology, the study of bandpass filters, as one of the key components of wireless communication systems, on their wide stopband and high selectivity has extremely high scientific research value and has attracted the attention of many scholars.
[0003] In implementing the embodiments of this application, the inventors discovered that most currently available bandpass filters with high selectivity have a narrow stopband, which greatly limits their use in modern wireless communication systems. Utility Model Content
[0004] The present invention aims to provide a topology, filter, and communication device that have the characteristics of bandwidth.
[0005] To solve the above-mentioned technical problems, one technical solution adopted in this utility model embodiment is: providing a topology structure including an input terminal, an output terminal, a first transmission line, a second transmission line, a third transmission line, a fourth transmission line, a fifth transmission line, a sixth transmission line, a seventh transmission line, and an eighth transmission line. One end of the first transmission line is connected to the input terminal, and the other end of the first transmission line is open-circuited. One end of the second transmission line is connected to one end of the third transmission line, one end of the fifth transmission line, and one end of the seventh transmission line, respectively. The other ends of the second transmission line, the third transmission line, the fifth transmission line, and the seventh transmission line are connected... The other end of the transmission line is open-circuited, one end of the sixth transmission line and one end of the eighth transmission line are short-circuited, the other end of the sixth transmission line and the other end of the eighth transmission line are open-circuited, one end of the fourth transmission line is open-circuited, and the other end of the fourth transmission line is connected to the output terminal; wherein, the first transmission line and the second transmission line are arranged in parallel and spaced apart to form a first parallel line, the third transmission line and the fourth transmission line are arranged in parallel and spaced apart to form a first parallel coupling line, the fifth transmission line and the sixth transmission line are arranged in parallel and spaced apart to form a second parallel line, and the seventh transmission line and the eighth transmission line are arranged in parallel and spaced apart to form a second parallel coupling line.
[0006] Optionally, the first, second, third, and fourth transmission lines are parallel to each other and all perpendicular to the fifth, sixth, seventh, and eighth transmission lines.
[0007] Optionally, the characteristic impedance of the first transmission line is equal to the characteristic impedance of the second transmission line, and the electrical length of the first transmission line is equal to the electrical length of the second transmission line.
[0008] Optionally, the characteristic impedance of the third transmission line is less than the characteristic impedance of the fourth transmission line, and the electrical length of the third transmission line is equal to the electrical length of the fourth transmission line.
[0009] Optionally, the characteristic impedance of the fifth transmission line is equal to the characteristic impedance of the sixth transmission line, and the electrical length of the fifth transmission line is equal to the electrical length of the sixth transmission line.
[0010] Optionally, the characteristic impedance of the seventh transmission line is less than the characteristic impedance of the eighth transmission line, and the electrical length of the seventh transmission line is equal to the electrical length of the eighth transmission line.
[0011] Optionally, the sum of the electrical lengths of the first transmission line and the second transmission line is less than the sum of the electrical lengths of the third transmission line and the fourth transmission line.
[0012] Optionally, the sum of the electrical lengths of the fifth and sixth transmission lines is less than the sum of the electrical lengths of the seventh and eighth transmission lines.
[0013] To solve the above-mentioned technical problems, another technical solution adopted in this utility model embodiment is to provide a filter including the above-mentioned topology.
[0014] To solve the above-mentioned technical problems, another technical solution adopted in this embodiment of the utility model is to provide a communication device including the above-mentioned filter.
[0015] The beneficial effects of this utility model embodiment are as follows: Unlike the prior art, this utility model embodiment provides a topology including an input terminal, an output terminal, a first transmission line, a second transmission line, a third transmission line, a fourth transmission line, a fifth transmission line, a sixth transmission line, a seventh transmission line, and an eighth transmission line. One end of the first transmission line is connected to the input terminal, and the other end of the first transmission line is open-circuited. One end of the second transmission line is connected to one end of the third transmission line, one end of the fifth transmission line, and one end of the seventh transmission line, respectively. The other ends of the second transmission line, the third transmission line, the fifth transmission line, and the seventh transmission line are connected... The seventh transmission line has one open-circuit end, one end of the sixth transmission line and one end of the eighth transmission line are short-circuited, and the other ends of the sixth and eighth transmission lines are open-circuited. One end of the fourth transmission line is open-circuited, and the other end of the fourth transmission line is connected to the output terminal. The first and second transmission lines are parallel and spaced apart to form a first parallel line; the third and fourth transmission lines are parallel and spaced apart to form a first parallel coupling line; the fifth and sixth transmission lines are parallel and spaced apart to form a second parallel line; and the seventh and eighth transmission lines are parallel and spaced apart to form a second parallel coupling line. Through this topology, the bandpass filter designed has the advantages of wide stopband and high selectivity, can adapt to multi-frequency communication, reduces unnecessary signal interference, and improves signal quality. Attached Figure Description
[0016] To more clearly illustrate the technical solutions in the specific embodiments of this utility model or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. 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 to actual scale.
[0017] Figure 1 This is a schematic diagram of the overall structure of the topology provided in this embodiment of the utility model;
[0018] Figure 2 This is a schematic diagram of the simulation structure of the topology provided in this embodiment of the utility model;
[0019] Figure 3 This is a simulation S-parameter diagram of the topology provided in this embodiment of the utility model.
[0020] Explanation of reference numerals in the attached figures:
[0021] 10 input terminals;
[0022] 20 output terminals;
[0023] 31 First transmission line, 32 Second transmission line, 33 Third transmission line, 34 Fourth transmission line, 35 Fifth transmission line, 36 Sixth transmission line, 37 Seventh transmission line, 38 Eighth transmission line;
[0024] 100 topology. Detailed Implementation
[0025] To facilitate understanding of this utility model, a more detailed description is provided below with reference to 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 one or more intermediate elements may exist between them. When an element is described as "connected" to another element, it can be directly connected to the other element, or one or more intermediate elements may exist between them. The terms "upper," "lower," "inner," "outer," "vertical," "horizontal," etc., used in this specification indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0026] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.
[0027] With the rapid development of modern wireless communication technology, the study of the stopband and selectivity of bandpass filters, as one of the key components of wireless communication systems, has extremely high scientific research value and has attracted the attention of many scholars.
[0028] In implementing the embodiments of this application, the inventors discovered that most currently available bandpass filters with high selectivity have a narrow stopband, which greatly limits their use in modern wireless communication systems.
[0029] In view of this, the present invention provides an embodiment of a topology 100. The bandpass filter designed based on this topology 100 has the characteristics of a large impedance bandwidth, can adapt to multi-band communication, reduce unnecessary signal interference, and improve signal quality.
[0030] To facilitate the reader's understanding of the concept of this utility model embodiment, the specific structure of the topology 100 is described below:
[0031] Please see Figure 1A topology 100 includes an input terminal 10, an output terminal 20, a first transmission line 31, a second transmission line 32, a third transmission line 33, a fourth transmission line 34, a fifth transmission line 35, a sixth transmission line 36, a seventh transmission line 37, and an eighth transmission line 38. One end of the first transmission line 31 is connected to the input terminal 10, and the other end of the first transmission line 31 is open-circuited. One end of the second transmission line 32 is connected to one end of the third transmission line 33, one end of the fifth transmission line 35, and one end of the seventh transmission line 37, respectively. The other ends of the second transmission line 32, the third transmission line 33, the fifth transmission line 35, and the seventh transmission line 37 are open-circuited. One end of the sixth transmission line 36 and one end of the eighth transmission line 38 are short-circuited, and the other ends of the sixth transmission line 36 and the eighth transmission line 38 are open-circuited. One end of the fourth transmission line 34 is open-circuited, and the other end of the fourth transmission line 34 is connected to the output terminal 20. The first transmission line 31, the second transmission line 32, the third transmission line 33, and the fourth transmission line 34 are parallel to each other and perpendicular to the fifth transmission line 35, the sixth transmission line 36, the seventh transmission line 37, and the eighth transmission line 38. The first transmission line 31 and the second transmission line 32 are arranged in parallel intervals to form a first parallel line; the third transmission line 33 and the fourth transmission line 34 are arranged in parallel intervals to form a first parallel coupling line; the fifth transmission line 35 and the sixth transmission line 36 are arranged in parallel intervals to form a second parallel line; and the seventh transmission line 37 and the eighth transmission line 38 are arranged in parallel intervals to form a second parallel coupling line. The first parallel line and the first parallel coupling line are located on opposite sides of the second parallel line or the second parallel coupling line, respectively. The second parallel line and the second parallel coupling line are located on opposite sides of the first parallel line or the first parallel coupling line, respectively. The input terminal 10 and the output terminal 20 are located on opposite sides of the second parallel line or the second parallel coupling line and are symmetrically arranged.
[0032] In the above manner, the first parallel line and the first parallel coupling line can provide multiple resonant peaks and transmission zeros, achieving wide stopband characteristics; in addition, in the above manner, the second parallel line and the second parallel coupling line can not only optimize the reflection coefficient, but also introduce multiple additional reflection zeros, achieving wide stopband and high selectivity characteristics.
[0033] In some embodiments of the above topology 100, the characteristic impedance of the first transmission line 31 is equal to the characteristic impedance of the second transmission line 32, and the electrical length of the first transmission line 31 is equal to the electrical length of the second transmission line 32. When the characteristic impedances and electrical lengths of the first and second transmission lines 31 and 32 are equal, the same transmission characteristics can be maintained over a wider frequency range, promoting good bandpass characteristics.
[0034] In some embodiments of the above topology 100, the characteristic impedance of the third transmission line 33 is less than that of the fourth transmission line 34, and the electrical length of the third transmission line 33 is equal to that of the fourth transmission line 34. This difference in characteristic impedance and equal electrical length causes the third transmission line 33 and the fourth transmission line 34 to generate more reflections within a specific frequency band, thereby increasing the stopband width.
[0035] In some embodiments of the above topology 100, the characteristic impedance of the fifth transmission line 35 is equal to the characteristic impedance of the sixth transmission line 36, and the electrical length of the fifth transmission line 35 is equal to the electrical length of the sixth transmission line 36. When the characteristic impedances and electrical lengths of the fifth transmission line 35 and the sixth transmission line 36 are equal, the same transmission characteristics can be maintained over a wider frequency range, promoting good bandpass characteristics.
[0036] In some embodiments of the above topology 100, the characteristic impedance of the seventh transmission line 37 is less than that of the eighth transmission line 38, and the electrical length of the seventh transmission line 37 is equal to that of the eighth transmission line 38. This difference in characteristic impedance and equal electrical length causes the seventh transmission line 37 and the eighth transmission line 38 to generate more reflections within a specific frequency band, thereby increasing the stopband width.
[0037] For the above topology 100, in some embodiments, the sum of the electrical lengths of the first transmission line 31 and the second transmission line 32 is less than the sum of the electrical lengths of the third transmission line 33 and the fourth transmission line 34, and the sum of the electrical lengths of the fifth transmission line 35 and the sixth transmission line 36 is less than the sum of the electrical lengths of the seventh transmission line 37 and the eighth transmission line 38.
[0038] In this way, the difference in electrical length can change the signal limiting characteristics, causing stronger coupling and reflection effects between different transmission lines, generating more reflection points, which helps to expand the stopband range and further widen the stopband.
[0039] To facilitate readers' understanding of the concept of this utility model embodiment, the design idea of the topology 100 is provided below:
[0040] Assume that the characteristic impedances of the third transmission line 33 and the fourth transmission line 34 are equal, and the characteristic impedances of the seventh transmission line 37 and the eighth transmission line 38 are equal. In this case, the first parallel coupling line can be simplified to the third parallel line, and the second parallel coupling line can be simplified to the fourth parallel line. Here, the odd-mode characteristic impedance of the first parallel line is set to Z. 0o1 The even-mode characteristic impedance of the first parallel line is Z. 0e1 The electrical length of the first parallel line is θ1; the odd-mode characteristic impedance of the second parallel line is Z. 0o2The even-mode characteristic impedance of the second parallel line is Z. 0e2 The electric length of the second parallel line is θ2; the odd-mode characteristic impedance of the third parallel line is Z. 0o3 The even-mode characteristic impedance of the third parallel line is Z. 0e3 The electric length of the third parallel line is θ3; the odd-mode characteristic impedance of the fourth parallel line is Z. 0o4 The even-mode characteristic impedance of the fourth parallel line is Z. 0e4 The electric length of the fourth parallel line is θ4. Furthermore, since the topology 100 is not left-right symmetrical, the ABCD matrix to Y matrix method is used to analyze the transmission poles. According to transmission line theory, the resonant frequency is determined by the resonant condition at the input terminal 10Im(Y). in The resonant frequency f can be obtained by determining that ) = 0. p1 f p2 f p3 The process is as follows:
[0041] First, the transmission poles are analyzed using the ABCD matrix to S-matrix conversion method. The transmission zeros are determined by IS... 11 The equation I = 0 can be derived and expressed by the following formula:
[0042] f z1 =0
[0043]
[0044] f z4 =2n2f0
[0045]
[0046] f z8 =2n3f0
[0047]
[0048] Here
[0049]
[0050] Where θ0 is the electrical length corresponding to the center frequency of the bandpass filter.
[0051] Then, when the ratios between the electrical lengths θ1, θ2, θ3, and θ4 of the first parallel line satisfy a certain ratio, regardless of the characteristic impedance Z... 0o1 Z 0e1 Z 0e2 Z 0o3 Z 0e3 Z 0o4 Z 0e4No matter how the value of f changes, the relative positions of the transfer zeros and poles remain unchanged, that is, f z1 <f z2 <f p1 <f p2 <f p3 <f z3 <f z4 <f z5 <f z6 <f z7 <f z8 <f z9 The topology remains unchanged. Therefore, based on this topology 100, a bandpass filter with wide bandwidth and high selectivity can be designed.
[0052] To facilitate readers' understanding of the concept of this utility model embodiment, the following simulation example is provided to verify the design idea of the topology 100:
[0053] Please see Figure 2 The topology 100 is mounted on a circuit board (not shown). The circuit board (not shown) measures 11.03mm x 44.63mm, has a thickness of 0.508mm, a dielectric constant of 3.38, a dielectric loss of 0.0027, and is made of Rogers RO4003C material. To achieve miniaturization of the topology 100, the fifth transmission line 35, the sixth transmission line 36, the seventh transmission line 37, and the eighth transmission line 38 are bent. The specific dimensional parameters of the topology 100 are: L1 = 18.27mm, L2 = 21.425mm, L3 = 21.1mm, L4 = 24.1mm, W1 = 0.075mm, W2 = 0.075mm, W3 = 0.375mm, W... 33 =0.125mm, W4=0.25mm, W 44 =0.45mm, g1=0.2mm, g2=0.1mm, g3=0.1mm, g4=0.1mm. Where L1 is the physical length of the first parallel line; L2 is the physical length of the first parallel coupling line; L3 is the physical length of the second parallel coupling line; L4 is the physical length of the second parallel line; W1 is the physical width of the first transmission line 31 and the second transmission line 32; W2 is the physical width of the fifth transmission line 35 and the sixth transmission line 36; W3 is the physical width of the seventh transmission line 37; W... 33 W is the physical width of the eighth transmission line 38; W4 is the physical width of the third transmission line 33; W 44 g1 is the physical width of the fourth transmission line 34; g2 is the spacing between the first transmission line 31 and the second transmission line 32; g3 is the spacing between the fifth transmission line 35 and the sixth transmission line 36; g4 is the spacing between the seventh transmission line 37 and the eighth transmission line 38; g5 is the spacing between the third transmission line 33 and the sixth transmission line 36.
[0054] Please see Figure 3 The figure shows the S-parameters of a simulation example of topology 100, specifically: its center frequency is 2.4 GHz, its passband range with a reflection coefficient better than -20 dB is 1.8 GHz to 3.1 GHz, its absolute bandwidth is 0.97 GHz, and its relative bandwidth is 54.1%. The passband has three transmission poles located at 2.164 GHz, 2.518 GHz, and 2.872 GHz, ensuring the flatness of the passband; the stopband has nine transmission zeros located at 0 GHz, 1.652 GHz, 3.467 GHz, 5.5 GHz, 6.826 GHz, 7.617 GHz, 8.498 GHz, 9.816 GHz, and 10.58 GHz, ensuring the wide stopband and high selectivity of topology 100.
[0055] Through the simulation example of the above topology 100, it can be verified that the bandpass filter designed based on the above topology 100 has the characteristics of having a large blocking bandwidth.
[0056] This utility model embodiment provides a topology 100, including an input terminal 10, an output terminal 20, a first transmission line 31, a second transmission line 32, a third transmission line 33, a fourth transmission line 34, a fifth transmission line 35, a sixth transmission line 36, a seventh transmission line 37, and an eighth transmission line 38. One end of the first transmission line 31 is connected to the input terminal 10, and the other end of the first transmission line 31 is open-circuited. One end of the second transmission line 32 is connected to one end of the third transmission line 33, one end of the fifth transmission line 35, and one end of the seventh transmission line 37, respectively. The other ends of the second transmission line 32, the third transmission line 33, the fifth transmission line 35, and the seventh transmission line 37 are also connected. The other end of the transmission line 34 is open-circuited, one end of the sixth transmission line 36 and one end of the eighth transmission line 38 are short-circuited, the other end of the sixth transmission line 36 and the other end of the eighth transmission line 38 are open-circuited, one end of the fourth transmission line 34 is open-circuited, and the other end of the fourth transmission line 34 is connected to the output terminal 20. The first transmission line 31 and the second transmission line 32 are parallel and spaced apart to form a first parallel line; the third transmission line 33 and the fourth transmission line 34 are parallel and spaced apart to form a first parallel coupling line; the fifth transmission line 35 and the sixth transmission line 36 are parallel and spaced apart to form a second parallel line; and the seventh transmission line 37 and the eighth transmission line 38 are parallel and spaced apart to form a second parallel coupling line. Through the above method, the bandpass filter designed based on this topology 100 has the advantages of wide stopband and high selectivity, can adapt to multi-frequency band communication, reduce unnecessary signal interference, and improve signal quality.
[0057] This utility model also provides an embodiment of a filter, which includes the above-described topology 100. For the specific structure and function of the above-described topology 100, please refer to the above embodiments, which will not be repeated here.
[0058] This utility model also provides an embodiment of a communication device, which includes the above-mentioned filter. For the specific structure and function of the filter, please refer to the above embodiment, which will not be repeated here.
[0059] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the description and drawings of this utility model, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.
Claims
1. A topology, characterized in that, The filter comprises an input terminal, an output terminal, a first transmission line, a second transmission line, a third transmission line, a fourth transmission line, a fifth transmission line, a sixth transmission line, a seventh transmission line, and an eighth transmission line. One end of the first transmission line is connected to the input terminal, and the other end of the first transmission line is open. One end of the second transmission line is connected to one end of the third transmission line, one end of the fifth transmission line, and one end of the seventh transmission line, respectively. The other end of the second transmission line, the other end of the third transmission line, the other end of the fifth transmission line, and the other end of the seventh transmission line are open. One end of the sixth transmission line and one end of the eighth transmission line are shorted, and the other end of the sixth transmission line and the other end of the eighth transmission line are open. One end of the fourth transmission line is open, and the other end of the fourth transmission line is connected to the output terminal. The first transmission line and the second transmission line are arranged in parallel and form a first parallel line. The third transmission line and the fourth transmission line are arranged in parallel and form a first parallel coupled line. The fifth transmission line and the sixth transmission line are arranged in parallel and form a second parallel line. The seventh transmission line and the eighth transmission line are arranged in parallel and form a second parallel coupled line.
2. The topology of claim 1, wherein the first transmission line, the second transmission line, the third transmission line, and the fourth transmission line are parallel to each other and perpendicular to the fifth transmission line, the sixth transmission line, the seventh transmission line, and the eighth transmission line.
3. The topology of claim 1, wherein a characteristic impedance of the first transmission line is equal to a characteristic impedance of the second transmission line, and an electrical length of the first transmission line is equal to an electrical length of the second transmission line.
4. The topology of claim 1, wherein a characteristic impedance of the third transmission line is less than a characteristic impedance of the fourth transmission line, and an electrical length of the third transmission line is equal to an electrical length of the fourth transmission line.
5. The topology of claim 1, wherein a characteristic impedance of the fifth transmission line is equal to a characteristic impedance of the sixth transmission line, and an electrical length of the fifth transmission line is equal to an electrical length of the sixth transmission line.
6. The topology of claim 1, wherein a characteristic impedance of the seventh transmission line is less than a characteristic impedance of the eighth transmission line, and an electrical length of the seventh transmission line is equal to an electrical length of the eighth transmission line.
7. The topology of claim 1, wherein a sum of an electrical length of the first transmission line and an electrical length of the second transmission line is less than a sum of an electrical length of the third transmission line and an electrical length of the fourth transmission line.
8. The topology of claim 1, wherein a sum of an electrical length of the fifth transmission line and an electrical length of the sixth transmission line is less than a sum of an electrical length of the seventh transmission line and an electrical length of the eighth transmission line. The filter comprises the topology of any one of claims 1-8. The filter comprises the topology of claim 9. 9. A filter, characterized by 10. A communication device, characterized by