Filter and communication equipment
By designing left-right symmetrical and top-bottom symmetrical filter topologies, the problem of increased filter size was solved, realizing a high-bandwidth and miniaturized filter with good passband performance and easy integration.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2026-03-27
AI Technical Summary
Existing filters require large inductors to achieve broadband characteristics, which increases the filter size and hinders the miniaturization of communication equipment.
A filter structure composed of several parallel lines, microstrip lines and short-circuit stubs is adopted. The transmission poles are determined by odd-even mode analysis. The topology is designed to be symmetrical from left to right and from top to bottom to reduce the number of components, enhance the even-order harmonic suppression capability, and improve selectivity and isolation.
A filter with a bandwidth of up to 80.8% and flat in-band insertion loss was achieved. It features a compact structure, easy integration, and high reliability, reducing the circuit complexity and equipment size of communication systems and lowering equipment costs.
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Figure CN224053375U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The embodiment of the present application relates to the filter technical field, in particular to a kind of filter and communication device. BACKGROUND
[0002] Ultra-wideband filter as important electronic devices in radio frequency system, the good or bad of communication system has not inconsiderable influence. The function of filter is to screen the information needed, as far as possible to deliver useful information, filter out noise and other useless information.
[0003] In the implementation process of the present application, the inventor finds that: at present, in order to realize wideband characteristics, larger inductive element needs to be used, which will lead to the increase of filter size. It is not conducive to the miniaturization of communication device. UTILITY MODEL CONTENT
[0004] The technical problem solved by the embodiment of the present application is to provide a kind of filter and communication device, by a plurality of parallel lines, a plurality of microstrip lines and a plurality of short-circuit stubs are formed, and the transmission pole is determined by odd-even mode analysis, with the characteristics of compact structure, bandwidth up to 80.8%, flat in-band insertion loss.
[0005] To solve the above technical problems, one technical scheme adopted by the embodiment of the present application is to provide a kind of filter, comprising input end, first parallel line, second parallel line, first microstrip line component, second microstrip line component, third microstrip line component and output end, the first microstrip line component is connected with the first parallel line and second parallel line respectively;The first short-circuit stub is extended to one end of the second microstrip line component, the second short-circuit stub is extended to the other end of the second microstrip line component, and the first microstrip line component is connected with the second microstrip line component;The third short-circuit stub is extended to one end of the third microstrip line component, the fourth short-circuit stub is extended to the other end of the third microstrip line component, and the first microstrip line component is connected with the third microstrip line component;The input end, first parallel line, second parallel line and output end are cascaded on the same straight line, and the first parallel line and second parallel line are symmetrically arranged about the first microstrip line component.
[0006] Optionally, the first microstrip line component includes first microstrip line and second microstrip line, the first microstrip line and second microstrip line are cascaded on the same straight line, and one end of the first microstrip line is connected with the second microstrip line component, and the second microstrip line is connected with the third microstrip line component.
[0007] Optionally, the second microstrip line component includes third microstrip line and fourth microstrip line, the third microstrip line and fourth microstrip line are cascaded on the same straight line, and one end of the third microstrip line is connected with the first short-circuit stub, and one end of the fourth microstrip line is connected with the second short-circuit stub.
[0008] Optionally, the third microstrip line assembly comprises a fifth microstrip line and a sixth microstrip line, the fifth microstrip line and the sixth microstrip line are cascaded on the same line, and one end of the fifth microstrip line is connected with the third short-circuit stub, and one end of the sixth microstrip line is connected with the fourth short-circuit stub.
[0009] Optionally, the first parallel line and the second parallel line, the third microstrip line and the fourth microstrip line, the fifth microstrip line and the sixth microstrip line are symmetrically arranged about the first microstrip line assembly, and the first short-circuit stub and the second short-circuit stub are symmetrically arranged about the first microstrip line assembly, and the third short-circuit stub and the fourth short-circuit stub are symmetrically arranged about the first microstrip line assembly.
[0010] Optionally, the second microstrip line assembly and the third microstrip line assembly are symmetrically arranged about the first parallel line and the second parallel line.
[0011] Optionally, the second microstrip line assembly and the third microstrip line assembly are arranged in parallel with each other, and the second microstrip line assembly and the third microstrip line assembly are perpendicular to the first microstrip line assembly.
[0012] Optionally, the electrical length of the first parallel line and the second parallel line is equal, and is equal to one fourth of the wavelength of the center frequency of the filter.
[0013] Optionally, the odd mode characteristic impedance of the first parallel line and the odd mode characteristic impedance of the second parallel line are equal.
[0014] To solve the above technical problems, another technical scheme adopted by the embodiments of the present application is to provide a communication device comprising any of the above filters.
[0015] The embodiment of the present application provides a filter, which comprises an input end, a first parallel line, a second parallel line, a first microstrip component, a second microstrip component, a third microstrip component and an output end, the first microstrip component is connected with the first parallel line and the second parallel line respectively; one end of the second microstrip component extends a first short-circuit stub, the other end of the second microstrip component extends a second short-circuit stub, and the first microstrip component is connected with the second microstrip component; one end of the third microstrip component extends a third short-circuit stub, the other end of the third microstrip component extends a fourth short-circuit stub, and the first microstrip component is connected with the third microstrip component; the input end, the first parallel line, the second parallel line and the output end are cascaded on the same straight line, and the first parallel line and the second parallel line are symmetrically arranged about the first microstrip component; through the above arrangement, the odd mode frequency and the resonant frequency are coupled to generate multiple passbands; the filter designed in this way is beneficial to miniaturization under the premise of ensuring the passband performance, and has the advantages of easy integration, high reliability, and the like, and can effectively reduce the complexity of the entire circuit of the communication system and the size of the communication equipment, so as to achieve the purposes of simplifying the system and reducing the cost of the equipment. BRIEF DESCRIPTION OF DRAWINGS
[0016] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application or the prior art, the drawings needed to be used in the specific embodiments or prior art description will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn according to the actual proportion.
[0017] Figure 1 FIG. 1 is a schematic diagram of the filter according to the embodiment of the present application;
[0018] Figure 2 FIG. 2 is another schematic diagram of the filter according to the embodiment of the present application;
[0019] Figure 3 FIG. 3 is a layout of the filter according to the embodiment of the present application;
[0020] Figure 4 FIG. 4 is a schematic diagram of the S parameter simulation result of the filter according to the embodiment of the present application.
[0021] The reference signs in the detailed description are as follows: 100, filter; 10, input end; 20, first parallel line; 30, second parallel line; 40, first microstrip line assembly; 401, first microstrip line; 402, second microstrip line; 50, second microstrip line assembly; 501, third microstrip line; 502, fourth microstrip line; 60, third microstrip line assembly; 601, fifth microstrip line; 602, sixth microstrip line; 701, first short-circuit stub; 702, second short-circuit stub; 703, third short-circuit stub; 704, fourth short-circuit stub; 80, output end. DETAILED DESCRIPTION
[0022] For the purpose of this application, the following detailed description will be made in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element or one or more intervening elements can be present therebetween. When an element is described as being "connected to" another element, it can be directly connected to the other element or one or more intervening elements can be present therebetween. The terms "upper", "lower", "inner", "outer", "vertical", "horizontal", and the like used in the present specification indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", and the like are only for the purpose of description and cannot be understood as indicating or implying relative importance.
[0023] Unless otherwise defined, all technical and scientific terms used in the present specification have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used in the present specification includes any and all combinations of one or more related listed items.
[0024] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.
[0025] Please refer to Figure 1The filter 100 comprises an input end 10, a first parallel line 20, a second parallel line 30, a first microstrip line assembly 40, a second microstrip line assembly 50, a third microstrip line assembly 60 and an output end 70, the first microstrip line assembly 40 is connected with the first parallel line 20 and the second parallel line 30 respectively, one end of the second microstrip line assembly 50 extends a first short-circuit stub 701, the other end of the second microstrip line assembly 50 extends a second short-circuit stub 702, and the first microstrip line assembly 40 is connected with the second microstrip line assembly 50, one end of the third microstrip line assembly 60 extends a third short-circuit stub 703, the other end of the third microstrip line assembly 60 extends a fourth short-circuit stub 704, and the first microstrip line assembly 40 is connected with the third microstrip line assembly 60, the input end 10, the first parallel line 20, the second parallel line 30 and the output end 70 are cascaded on the same straight line, and the first parallel line 20 and the second parallel line 30 are symmetrically arranged about the first microstrip line assembly 40, through the above arrangement, a symmetrical topological structure is formed, which constitutes the filter 100 in the application.
[0026] Specifically, please refer to Figure 2The first microstrip line assembly 40 includes a first microstrip line 401 and a second microstrip line 402, the first microstrip line 401 and the second microstrip line 402 are cascaded on the same line, and one end of the first microstrip line 401 is connected with the second microstrip line assembly 50, and the second microstrip line 402 is connected with the third microstrip line assembly 60; the second microstrip line assembly 50 includes a third microstrip line 501 and a fourth microstrip line 502, the third microstrip line 501 and the fourth microstrip line 502 are cascaded on the same line, and one end of the third microstrip line 501 is connected with the first short-circuit stub 701, and one end of the fourth microstrip line 502 is connected with the second short-circuit stub 702; the third microstrip line assembly 60 includes a fifth microstrip line 601 and a sixth microstrip line 602, the fifth microstrip line 601 and the sixth microstrip line 602 are cascaded on the same line, and one end of the fifth microstrip line 601 is connected with the third short-circuit stub 703, and one end of the sixth microstrip line 602 is connected with the fourth short-circuit stub 704, wherein the first parallel line 20 and the second parallel line 30, the third microstrip line 501 and the fourth microstrip line 502, and the fifth microstrip line 601 and the sixth microstrip line 602 are symmetrically arranged about the 401 assembly 40, and the first short-circuit stub and the second short-circuit stub are symmetrically arranged about the 401 assembly 40, and the third short-circuit stub 703 and the fourth short-circuit stub 704 are symmetrically arranged about the 401 assembly 40, because the odd harmonic cannot form an effective transmission path in the structure-symmetrical filter 100, thereby reducing the out-of-band noise and spurious of the filter 100, therefore, the odd harmonic of the filter 100 can be effectively suppressed by the above-mentioned symmetric structure, further, the even harmonic is more likely to form a transmission path in the structure-symmetrical filter 100, and the left-right symmetric structure can enhance the suppression ability of the even harmonic, thereby improving the selectivity and isolation of the filter 100.
[0027] In the embodiment of the present application, the second microstrip line 402 assembly 50 and the third microstrip line 501 assembly 60 are symmetrically arranged about the first parallel line 20 and the second parallel line 30, and through the above-mentioned arrangement, the up-down symmetric structure reduces the number of elements of the filter 100, and the layout is more compact, which is beneficial to reduce the overall size of the filter 100, so that it is more suitable for the demand of miniaturization in modern wireless communication systems, and the symmetric structure can effectively suppress the parasitic effect and improve the performance stability of the filter 100.
[0028] In the embodiment of the present application, the second microstrip line 402 component 50 and the third microstrip line 501 component 60 are arranged in parallel to each other, and the second microstrip line 402 component 50 and the third microstrip line 501 component 60 are both perpendicular to the 401 component 40. Further, through the above arrangement, the parallel structure can effectively reduce the coupling between elements, thereby improving the isolation and selectivity of the filter 100.
[0029] In the embodiment of the present application, the electrical length of the first parallel line 20 and the second parallel line 30 is equal, and is equal to one fourth of the wavelength of the center frequency of the filter 100. The sum of the electrical length of the first microstrip line 401, the electrical length of the second microstrip line 402, and the electrical length of the first short-circuit stub 701 is equal to the corresponding one fourth of the wavelength at the center frequency of the filter 100. The sum of the electrical length of the first microstrip line 401, the electrical length of the third microstrip line 501, and the electrical length of the second short-circuit stub 702 is equal to the corresponding one fourth of the wavelength at the center frequency of the filter 100. The sum of the electrical length of the fourth microstrip line 502, the electrical length of the fifth microstrip line 601, and the electrical length of the third short-circuit stub 703 is equal to the corresponding one fourth of the wavelength at the center frequency of the filter 100. The sum of the electrical length of the fourth microstrip line 502, the electrical length of the sixth microstrip line 602, and the electrical length of the fourth short-circuit stub 704 is equal to the corresponding one fourth of the wavelength at the center frequency of the filter 100.
[0030] In the embodiment of the present application, the odd-mode characteristic impedance of the first parallel line 20 and the odd-mode characteristic impedance of the second parallel line 30 are equal, and are both Z oo . The even-mode characteristic impedance of the first parallel line 20 and the even-mode characteristic impedance of the second parallel line 30 are equal, and are both Z oe . The characteristic impedance of the first microstrip line 401 and the characteristic impedance of the fourth microstrip line 502 are equal, and are both Z 1. The characteristic impedance of the second microstrip line 402, the characteristic impedance of the third microstrip line 501, the characteristic impedance of the fifth microstrip line 601, the characteristic impedance of the sixth microstrip line 602, the characteristic impedance of the first short-circuit stub 701, the characteristic impedance of the second short-circuit stub 702, the characteristic impedance of the third short-circuit stub 703, and the characteristic impedance of the fourth short-circuit stub 704 are equal, and are all equal to 2 Z 1.
[0031] Since the structure of the filter 100 is a left-right symmetric structure and also an up-down symmetric structure, the transmission poles can be obtained in the odd-even mode. When Y ino = ∞, it can be concluded that the topology structure has two transmission poles. When fWhen 0 is the center frequency of filter 100, the frequencies corresponding to the two odd-mode transmission poles are as follows: ; .
[0032] when Y ine When =∞, it can be concluded that this topology has three even-mode transmission poles. When f When 0 is the center frequency of filter 100, the frequencies corresponding to the three even-mode transmission poles are as follows:
[0033]
[0034] .
[0035] Please see Figure 3 To verify this topology, the filter 100 in this application was designed through simulation. The filter 100 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. Its layout is shown below. Figure 4 As shown. The entire map measures only 29.4 mm. The specific dimensions of filter 100 are as follows: 10.2 mm. l p = 12.0mm, s p = 0.1 mm, w p = 0.4 mm, l 1 = 4.35 mm, l 2 = 6.9 mm, l 3 = 2.7 mm, w 1 = 1.8 mm, w 2 = 0.9mm, w 3 = 0.9 mm.
[0036] The S-parameter simulation results are as follows: Figure 4 As shown, its passband range with a reflection coefficient better than -10 dB is from 2.324 GHz to 5.472 GHz, with a center frequency of 3.898 GHz, an absolute bandwidth of 3.148 GHz, a relative bandwidth of 80.8%, and a maximum in-band loss of 0.72 dB. Furthermore, there are five transmission poles within the passband, located at 2.421, 3.02, 4.1, 4.719, and 5.339 GHz, which ensure the flatness of the in-band insertion loss.
[0037] The embodiment of the present application provides a filter 100, which comprises an input end 10, a first parallel line 20, a second parallel line 30, a first microstrip line component, a second microstrip line component, a third microstrip line component and an output end 70, the first microstrip line component 40 is connected with the first parallel line 20 and the second parallel line 30 respectively; one end of the second microstrip line 402 component 50 extends a first short-circuit stub 701, the other end of the second microstrip line 402 component 50 extends a second short-circuit stub 702, and the first microstrip line component 40 is connected with the second microstrip line 402 component 50; one end of the third microstrip line 501 component 60 extends a third short-circuit stub 703, the other end of the third microstrip line 501 component 60 extends a fourth short-circuit stub 704, and the first microstrip line component 40 is connected with the third microstrip line 501 component 60; the input end 10, the first parallel line 20, the second parallel line 30 and the output end 70 are cascaded on the same straight line, and the first parallel line 20 and the second parallel line 30 are symmetrically arranged about the 401 component 40, through the above arrangement, the generated odd-even mode frequency is coupled with the resonant frequency to generate a multi-passband, the filter 100 designed in this way is beneficial to realize miniaturization under the premise of ensuring the passband performance, and has the advantages of easy integration, high reliability, and can effectively reduce the complexity of the whole circuit of the communication system and the volume of the communication equipment, so that the purposes of simplifying the system and reducing the equipment cost are achieved.
[0038] The embodiment of the present application further provides a communication device, which comprises the filter 100, and the specific structure and functions of the filter 100 can be referred to the above embodiment, and details are not described herein.
[0039] The above only describes the embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent flow transformation by using the content of the specification and the drawings, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.
Claims
1. A filter, characterized by, Comprising: an input terminal; a first parallel line; a second parallel line; a first microstrip line assembly connected with the first and second parallel lines respectively; a second microstrip line assembly, one end of which extends with a first short-circuit stub, the other end of which extends with a second short-circuit stub, and the first microstrip line assembly is connected with the second microstrip line assembly; a third microstrip line assembly, one end of which extends with a third short-circuit stub, the other end of which extends with a fourth short-circuit stub, and the first microstrip line assembly is connected with the third microstrip line assembly; an output terminal, the input terminal, the first and second parallel lines and the output terminal are cascaded on the same line, and the first and second parallel lines are symmetrically arranged about the first microstrip line assembly.
2. The filter according to claim 1, wherein the first microstrip line assembly comprises a first microstrip line and a second microstrip line, the first and second microstrip lines are cascaded on the same line, and one end of the first microstrip line is connected with the second microstrip line assembly, and the second microstrip line is connected with the third microstrip line assembly.
3. The filter of claim 2, wherein, the second microstrip line assembly comprises a third microstrip line and a fourth microstrip line, the third and fourth microstrip lines are cascaded on the same line, and one end of the third microstrip line is connected with the first short-circuit stub, and one end of the fourth microstrip line is connected with the second short-circuit stub.
4. The filter according to claim 1, wherein the third microstrip line assembly comprises a fifth microstrip line and a sixth microstrip line, the fifth and sixth microstrip lines are cascaded on the same line, and one end of the fifth microstrip line is connected with the third short-circuit stub, and one end of the sixth microstrip line is connected with the fourth short-circuit stub.
5. The filter according to claim 4, wherein the first and second parallel lines, the third and fourth microstrip lines, the fifth and sixth microstrip lines are symmetrically arranged about the first microstrip line assembly, and the first and second short-circuit stubs are symmetrically arranged about the first microstrip line assembly, and the third and fourth short-circuit stubs are symmetrically arranged about the first microstrip line assembly.
6. The filter according to claim 1, wherein the second and third microstrip line assemblies are symmetrically arranged about the first and second parallel lines.
7. The filter according to claim 1, wherein the second and third microstrip line assemblies are arranged in parallel with each other, and the second and third microstrip line assemblies are perpendicular to the first microstrip line assembly.
8. The filter according to claim 1, wherein the first and second parallel lines have equal electrical lengths, and the electrical lengths are equal to one fourth of the wavelength of the center frequency of the filter.
9. The filter according to claim 1, wherein the odd mode characteristic impedance of the first parallel line and the odd mode characteristic impedance of the second parallel line are equal.
10. A communication device, characterized by A filter comprising any one of claims 1-9.