A bandpass filter and communication equipment

Abstract

The embodiment of the utility model relates to the field of filter technology, and in particular to a bandpass filter and communication equipment, wherein the bandpass filter includes a substrate and a topological structure; the topological structure is arranged on the substrate, and the topological structure includes an input end, an output end, a first transmission line, a second transmission line, a first open-circuit branch, and a second open-circuit branch; wherein one end of the first transmission line is connected to the input end, one end of the first open-circuit branch is connected to the other end of the first transmission line, one end of the second transmission line is connected to the output end, and one end of the second open-circuit branch is connected to the other end of the second transmission line. The topological structure of the bandpass filter of the embodiment of the utility model only includes two transmission lines and two open-circuit branches, which reduces the size of the topological structure, so that the bandpass filter has the advantage of miniaturization.

Description

Technical Field

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

[0002] With the rapid evolution of modern wireless communication technology, the research and development of high-performance broadband communication systems that can meet people's needs for high-speed data transmission is an inevitable trend. In this context, the research on the broadband and high performance of bandpass filters, one of the key components of communication systems, has extremely high scientific research and commercial value, and has attracted the attention of many scholars and engineers.

[0003] However, in the process of realizing the present utility model, the inventors found that the high-performance broadband filters currently on the market basically have the defect of large size, which is not conducive to the miniaturization of the system and seriously affects its use in modern wireless communication systems. Utility Model Content

[0004] In view of the above problems, the embodiments of the present invention provide a bandpass filter and a communication device, which overcome the above problems or at least partially solve the above problems.

[0005] According to one aspect of an embodiment of the utility model, there is provided a bandpass filter, comprising a substrate and a topological structure; the topological structure is arranged on the substrate, and the topological structure comprises an input end, an output end, a first transmission line, a second transmission line, a first open-circuit branch and a second open-circuit branch; wherein one end of the first transmission line is connected to the input end, one end of the first open-circuit branch is connected to the other end of the first transmission line, one end of the second transmission line is connected to the output end, and one end of the second open-circuit branch is connected to the other end of the second transmission line.

[0006] In some embodiments, the first transmission line and the second transmission line are parallel.

[0007] In some embodiments, the first transmission line is perpendicular to the first open-circuit stub.

[0008] In some embodiments, the second transmission line is perpendicular to the second open-circuit stub.

[0009] In some embodiments, the electrical length of the first transmission line is equal to the electrical length of the second transmission line.

[0010] In some embodiments, the electrical length of the first open stub is equal to the electrical length of the second open stub.

[0011] In some embodiments, the bandpass filter satisfies: θ1+θ2=λ / 4, wherein θ1 is the electrical length of the first transmission line, θ2 is the electrical length of the first open-circuit branch, and λ is the wavelength corresponding to the center frequency of the bandpass filter.

[0012] In some embodiments, the bandpass filter satisfies: θ3+θ4=λ / 4, wherein θ3 is the electrical length of the second transmission line, θ4 is the electrical length of the second open-circuit branch, and λ is the wavelength corresponding to the center frequency of the bandpass filter.

[0013] In some embodiments, the characteristic impedance of the first transmission line, the characteristic impedance of the second transmission line, the characteristic impedance of the first open-circuit stub, and the characteristic impedance of the second open-circuit stub are equal.

[0014] According to one aspect of the embodiments of the present utility model, a communication device is provided, comprising the above-mentioned bandpass filter.

[0015] The beneficial effects of the embodiment of the utility model are as follows: Different from the prior art, the embodiment of the utility model provides a bandpass filter, including a substrate and a topological structure; the topological structure is arranged on the substrate, and the topological structure includes an input end, an output end, a first transmission line, a second transmission line, a first open-circuit branch, and a second open-circuit branch; wherein one end of the first transmission line is connected to the input end, one end of the first open-circuit branch is connected to the other end of the first transmission line, one end of the second transmission line is connected to the output end, and one end of the second open-circuit branch is connected to the other end of the second transmission line. The topological structure of the bandpass filter of the embodiment of the utility model only includes two transmission lines and two open-circuit branches, which reduces the size of the topological structure, so that the bandpass filter has the advantage of miniaturization. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0019] Figure 3 It is a graph showing the variation of the S parameter simulation results of the bandpass filter provided by the embodiment of the utility model with different s1;

[0020] Figure 4 It is a graph showing the variation of the S parameter simulation results of the bandpass filter provided by the embodiment of the utility model with different w1;

[0021] Figure 5 It is a diagram of S parameter simulation results of the bandpass filter provided in an embodiment of the utility model.

[0022] The reference numerals in the specific implementation manner are as follows:

[0023] 1000. Bandpass filter; 100. Topological structure; 10. Input end; 20. First transmission line; 21. Second transmission line; 30. First open-circuit branch; 31. Second open-circuit branch; 40. Output end. DETAILED DESCRIPTION

[0024] 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.

[0025] 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.

[0026] With the rapid evolution of modern wireless communication technology, the research and development of high-performance broadband communication systems that can meet people's needs for high-speed data transmission is an inevitable trend. In this context, the research on the broadband and high performance of bandpass filters, one of the key components of communication systems, has extremely high scientific research and commercial value, and has attracted the attention of many scholars and engineers.

[0027] Existing high-performance broadband filters basically have the defect of large size, which is not conducive to the miniaturization of the system and seriously affects their use in modern wireless communication systems.

[0028] The embodiment of the utility model designs a new topological structure including two transmission lines and two open branches, and can be used to design a second-order broadband bandpass filter, which has the advantage of miniaturization.

[0029] In order to facilitate readers to understand the inventive concept of the utility model, the specific structure of the bandpass filter is described below:

[0030] See also Figure 1-2 The bandpass filter 1000 includes a substrate (not shown) and a topological structure 100; the topological structure 100 is arranged on the substrate, and the substrate is used as a carrier of the topological structure 100. It can be understood that the material of the substrate can be selected according to the requirements, for example, the material of the substrate is a polymer material with a metal layer. The topological structure 100 includes an input terminal 10, an output terminal 40, a first transmission line 20, a second transmission line 21, a first open branch 30 and a second open branch 31; wherein one end of the first transmission line 20 is connected to the input terminal 10, one end of the first open branch 30 is connected to the other end of the first transmission line 20, one end of the second transmission line 21 is connected to the output terminal 40, and one end of the second open branch 31 is connected to the other end of the second transmission line 21, so that the external electrical signal can be input into the topological structure 100 from the input terminal 10, and transmitted to each part of the topological structure 100, and can be output from the output terminal 40.

[0031] In some embodiments, the first transmission line 20 and the second transmission line 21 are parallel, the first transmission line 20 is perpendicular to the first open branch 30 , and the second transmission line 21 is perpendicular to the second open branch 31 , so as to simplify the design of the bandpass filter 1000 .

[0032] In some embodiments, the electrical length of the first transmission line 20 is equal to the electrical length of the second transmission line 21 , and the electrical length of the first open-circuit branch 30 is equal to the electrical length of the second open-circuit branch 31 , so as to simplify the design of the bandpass filter 1000 .

[0033] In some embodiments, in order to simplify the design of the bandpass filter 1000, the bandpass filter 1000 satisfies the following conditions:

[0034] (1), θ1+θ2=λ / 4, wherein θ1 is the electrical length of the first transmission line 20, θ2 is the electrical length of the first open-circuit branch 30, and λ is the wavelength corresponding to the center frequency of the bandpass filter 1000.

[0035] (2), θ3+θ4=λ / 4, wherein θ3 is the electrical length of the second transmission line 21, θ4 is the electrical length of the second open-circuit branch 31, and λ is the wavelength corresponding to the center frequency of the bandpass filter 1000.

[0036] In some embodiments, the characteristic impedance of the first transmission line 20 , the characteristic impedance of the second transmission line 21 , the characteristic impedance of the first open-circuit stub 30 , and the characteristic impedance of the second open-circuit stub 31 are equal to simplify the design of the bandpass filter 1000 .

[0037] In some embodiments, in order to simplify the design of the bandpass filter 1000, the following design may be performed: the physical length of the first transmission line 20 is equal to the physical length of the second transmission line 21, the physical length of the first open branch 30 is equal to the physical length of the second open branch 31, and the physical width of the first transmission line 20, the physical width of the second transmission line 21, the physical width of the first open branch 30, or the physical width of the second open branch 31. In this way, the broadband bandpass filter 1000 designed based on the above topological structure 100 has four design parameters, namely: the physical length of the first transmission line 20 or the physical length of the second transmission line 21 l1, the physical length of the first open branch 30 or the physical length of the second open branch 31 l2, the interval s1 between the first transmission line 20 and the second transmission line 21, the physical width of the first transmission line 20, the physical width of the second transmission line 21, the physical width of the first open branch 30, or the physical width of the second open branch 31 w1. It is known from the basic microwave theory that l1 and l2 determine the center frequency of the bandpass filter 1000, and changing the values ​​of l1 and l2 in geometric proportion can inversely change the center frequency of the bandpass filter 1000. s1 and w1 determine the performance of the filter.

[0038] In some typical embodiments, in one of the bandpass filter 1000 cases based on the topological structure 100, the topological structure 100 is designed on a substrate with a dielectric loss of 0.0022 and a thickness of 0.813 mm, and the size of the substrate is 13 mm*5.8 mm. It is understood that the dielectric loss, thickness and size of the substrate are not limited to the above values ​​and can be adjusted according to requirements. One set of typical size parameters is: l1=8.0 mm, l2=2.2 mm, s1=0.1 mm, w1=0.15 mm.

[0039] Please also read Figure 3 , Figure 3 The effect of changing only s1 on the filter performance is shown. Figure 3 It can be seen that as the value of parameter s1 increases, the operating bandwidth of the bandpass filter 1000 decreases and the reflection coefficient within the passband becomes better.

[0040] Please also read Figure 4 , Figure 4 The effect of changing only w1 on the filter performance is given. Figure 4 It can be seen that as the value of parameter w1 increases, the operating bandwidth of the bandpass filter 1000 decreases and the reflection coefficient within the passband becomes better.

[0041] Depend on Figure 3-4 From the analysis, it can be seen that, as the values ​​of parameters s1 and w1 increase, the working bandwidth of the bandpass filter 1000 decreases and the reflection coefficient in the passband becomes better. In addition, no matter how the parameters s1 and w1 are changed, the filter designed based on the topology 100 can only be the bandpass filter 1000.

[0042] Please also read Figure 5 The S parameter simulation results of the broadband bandpass filter 1000 corresponding to the above typical dimensions are as follows: Figure 5 As shown. As can be seen from the figure, the impedance bandwidth range with a reflection coefficient less than -10dB is 3.36 to 6.42GHz, the passband center frequency is 4.89GHz, the passband absolute bandwidth is 3.06GHz, and the passband relative bandwidth is 62.6%. In addition, in the passband, there are two transmission poles, located at 3.84GHz and 5.96GHz respectively. These two transmission poles not only ensure the flatness of the bandpass filter 1000 in the passband, but also directly prove that the filter designed based on the topology 100 is a second-order bandpass filter 1000; there are two transmission zeros in the stopband, located at 0GHz and 9.8GHz respectively. These two transmission poles can ensure the high selectivity of the filter. It can be understood that the parameters l1, l2, s1 and w1 are not limited to the above values ​​and can be adjusted according to requirements.

[0043] In the embodiment of the utility model, the bandpass filter 1000 includes a substrate and a topological structure 100; the topological structure 100 is arranged on the substrate, and the topological structure 100 includes an input end 10, an output end 40, a first transmission line 20, a second transmission line 21, a first open-circuit branch 30, and a second open-circuit branch 31; wherein one end of the first transmission line 20 is connected to the input end 10, one end of the first open-circuit branch 30 is connected to the other end of the first transmission line 20, one end of the second transmission line 21 is connected to the output end 40, and one end of the second open-circuit branch 31 is connected to the other end of the second transmission line 21. The bandpass filter 1000 of the embodiment of the utility model can be used to design a broadband bandpass filter 1000, and the topological structure 100 of the bandpass filter 1000 only includes two transmission lines and two open-circuit branches, which reduces the size of the topological structure 100, so that the bandpass filter 1000 has the advantage of miniaturization.

[0044] The utility model further provides an embodiment of a communication device, wherein the communication device comprises the above-mentioned bandpass filter 1000. The function and structure of the bandpass filter 1000 may refer to the above-mentioned embodiment, which will not be described in detail here.

[0045] 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 bandpass filter, characterized in that: include: substrate; A topological structure is arranged on the substrate, wherein the topological structure comprises an input end, an output end, a first transmission line, a second transmission line, a first open-circuit branch, and a second open-circuit branch; Among them, one end of the first transmission line is connected to the input end, one end of the first open branch is connected to the other end of the first transmission line, one end of the second transmission line is connected to the output end, and one end of the second open branch is connected to the other end of the second transmission line.

2. The bandpass filter according to claim 1, characterized in that The first transmission line and the second transmission line are parallel.

3. The bandpass filter according to claim 1, characterized in that The first transmission line is perpendicular to the first open branch.

4. The bandpass filter according to claim 1, characterized in that The second transmission line is perpendicular to the second open branch.

5. The bandpass filter according to claim 1, characterized in that: The electrical length of the first transmission line is equal to the electrical length of the second transmission line.

6. The bandpass filter according to claim 1, characterized in that The electrical length of the first open-circuit branch is equal to the electrical length of the second open-circuit branch.

7. The bandpass filter according to claim 1, characterized in that: The bandpass filter satisfies: θ1+θ2=λ / 4 The θ1 is the electrical length of the first transmission line, the θ2 is the electrical length of the first open-circuit branch, and the λ is the wavelength corresponding to the center frequency of the bandpass filter.

8. The bandpass filter according to claim 1, characterized in that The bandpass filter satisfies: θ3+θ4=λ / 4 The θ3 is the electrical length of the second transmission line, the θ4 is the electrical length of the second open-circuit branch, and the λ is the wavelength corresponding to the center frequency of the bandpass filter.

9. The bandpass filter according to any one of claims 1 to 8, characterized in that: The characteristic impedance of the first transmission line, the characteristic impedance of the second transmission line, the characteristic impedance of the first open-circuit stub, and the characteristic impedance of the second open-circuit stub are equal.

10. A communication device, characterized in that: Comprising a bandpass filter as claimed in any one of claims 1 to 9.

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