CN220895819U - Topological structure of broadband band-stop filter with narrow pass characteristic and filter - Google Patents
Topological structure of broadband band-stop filter with narrow pass characteristic and filter Download PDFInfo
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Abstract
The utility model discloses a topological structure of a broadband band-stop filter with narrow pass characteristics and the filter, wherein the topological structure comprises a first vertical microstrip line, a first end of the first vertical microstrip line is connected with one end of a first horizontal microstrip line and one end of a second horizontal microstrip line, the other end of the first horizontal microstrip line is connected with a first vertical open branch, and the other end of the second horizontal microstrip line is connected with a second vertical open branch; the second end of the first vertical microstrip line is connected with one end of a third horizontal microstrip line, one end of a fourth horizontal microstrip line and one end of a second vertical microstrip line; the other end of the third horizontal microstrip line is connected with an input port, and the other end of the fourth horizontal microstrip line is connected with an output port; and the other end of the second vertical microstrip line is connected with one end of the first horizontal open-circuit branch. The utility model solves the problem that the existing band-stop filter cannot achieve the characteristics of narrow pass characteristic, high selectivity and miniaturization.
Description
Technical Field
The present utility model relates to the field of filters, and in particular, to a topology structure of a broadband band-stop filter with narrow pass characteristics and a filter.
Background
In order to solve the contradiction between limited spectrum resources and increasing information transmission demands, miniaturized radio frequency systems operating in different frequency bands and communication modes have been developed. The high-selectivity and miniaturized broadband band-stop filter serving as one of key devices of the radio frequency system has extremely high scientific research and commercial value, and attracts attention of vast students and engineers.
The wideband band-stop filter having a narrow pass characteristic in the stop band can effectively suppress noise signals and can smoothly pass useful signals with low loss in the stop band, in analogy to the wideband band-stop filter having a notch characteristic. However, in the prior art, the broadband band reject filter cannot achieve the characteristics of narrow pass characteristic, high selectivity and miniaturization.
Disclosure of utility model
The utility model mainly aims to provide a topological structure of a broadband band-stop filter with narrow-pass characteristics and a filter, and aims to solve the problem that the conventional band-stop filter cannot achieve the characteristics of narrow-pass characteristics, high selectivity and miniaturization.
In order to achieve the above-mentioned objective, the present utility model proposes a topology structure of a broadband band reject filter with narrow pass characteristics, comprising a first vertical microstrip line, wherein a first end of the first vertical microstrip line is connected with one end of a first horizontal microstrip line and one end of a second horizontal microstrip line, the other end of the first horizontal microstrip line is connected with a first vertical open branch, and the other end of the second horizontal microstrip line is connected with a second vertical open branch; the first horizontal microstrip line and the second horizontal microstrip line are symmetrically distributed on two sides of the first vertical microstrip line, and the first vertical open-circuit branch and the second vertical open-circuit branch are symmetrically distributed on two sides of the first vertical microstrip line;
The second end of the first vertical microstrip line is connected with one end of a third horizontal microstrip line, one end of a fourth horizontal microstrip line and one end of a second vertical microstrip line; the other end of the third horizontal microstrip line is connected with an input port, the other end of the fourth horizontal microstrip line is connected with an output port, and the third horizontal microstrip line and the fourth horizontal microstrip line are symmetrically distributed on two sides of the second vertical microstrip line; and the other end of the second vertical microstrip line is connected with one end of the first horizontal open-circuit branch.
Optionally, the characteristic impedance of the first horizontal microstrip line, the second horizontal microstrip line, the first vertical open-circuit branch and the second vertical open-circuit branch are all set to be twice the characteristic impedance of the first vertical microstrip line.
Optionally, the characteristic impedance of the second vertical microstrip line, the third horizontal microstrip line, the fourth horizontal microstrip line and the first horizontal open circuit branch are all the same.
Optionally, the sum of the electrical length of the first vertical microstrip line, the electrical length of the first horizontal microstrip line, and the electrical length of the first vertical open stub is equal to twice the electrical length of the second horizontal microstrip line; the sum of the electrical length of the first vertical microstrip line, the electrical length of the second horizontal microstrip line, and the electrical length of the second vertical open stub is equal to twice the electrical length of the third horizontal microstrip line.
Optionally, the sum of the electrical length of the second vertical microstrip line and the electrical length of the first horizontal open stub is equal to the electrical length of the second horizontal microstrip line or the third horizontal microstrip line.
Optionally, the electrical length of the second horizontal microstrip line and the electrical length of the third horizontal microstrip line are each set to a quarter wavelength corresponding to the center frequency of the band reject filter.
To achieve the above object, the present utility model further provides a filter, including a filter designed based on any one of the above topologies.
Optionally, the filter further includes a circuit board, where the dielectric constant of the circuit board is 3.38, the dielectric loss is 0.0022, and the thickness is 0.813mm.
Optionally, the filter has a circuit board size of 24.0mm by 9.0mm.
Optionally, the length of the first vertical microstrip line is set to l 4 =5.2 mm, and the width of the first vertical microstrip line is set to w 3 =1.3 mm; the lengths of the first horizontal microstrip line and the second horizontal microstrip line are respectively l 5 =8.6mm, and the widths of the first horizontal microstrip line and the second horizontal microstrip line are respectively w 4 =0.65 mm; the lengths of the first vertical open-circuit branch knot and the second vertical open-circuit branch knot are respectively set to be l 6 =4.05 mm, and the widths of the first vertical open-circuit branch knot and the second vertical open-circuit branch knot are respectively set to be w 5 =0.65 mm; the length of the second vertical microstrip line is set to be i 2 =1.1 mm; the lengths of the third horizontal microstrip line and the fourth horizontal microstrip line are set to be l 1 =8.8 mm, and the widths of the third horizontal microstrip line and the fourth horizontal microstrip line are set to be w 1 =0.1 mm; the length of the first horizontal open stub is set to l 3 =7.7 mm, and the width of the first horizontal open stub is set to w 2 =0.1 mm.
The utility model has the beneficial effects that: the topological structure of the existing filter is improved, and the topological structure provided by the utility model comprises a first vertical microstrip line, wherein a first end of the first vertical microstrip line is connected with one end of a first horizontal microstrip line and one end of a second horizontal microstrip line, the other end of the first horizontal microstrip line is connected with a first vertical open branch, and the other end of the second horizontal microstrip line is connected with a second vertical open branch; the first horizontal microstrip line and the second horizontal microstrip line are symmetrically distributed on two sides of the first vertical microstrip line, and the first vertical open-circuit branch and the second vertical open-circuit branch are symmetrically distributed on two sides of the first vertical microstrip line; the second end of the first vertical microstrip line is connected with one end of a third horizontal microstrip line, one end of a fourth horizontal microstrip line and one end of a second vertical microstrip line; the other end of the third horizontal microstrip line is connected with an input port, the other end of the fourth horizontal microstrip line is connected with an output port, and the third horizontal microstrip line and the fourth horizontal microstrip line are symmetrically distributed on two sides of the second vertical microstrip line; and the other end of the second vertical microstrip line is connected with one end of the first horizontal open-circuit branch. The topological structure based on the utility model can be used for designing the broadband band-stop filter and has the advantages of narrow pass characteristic, high selectivity, miniaturization, simple design process and the like.
Drawings
In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of the topology of the present utility model;
FIG. 2 is a layout of a topology-based filter of the present utility model;
FIG. 3 is a diagram of S-parameter simulation results of a filter designed based on a topological structure;
FIG. 4 is a schematic diagram showing the variation of the S-parameter simulation result of the filter based on the topology structure design according to the present utility model along with the parameter Z 1;
FIG. 5 is a schematic diagram showing the variation of the S-parameter simulation result of the topology-based filter according to the present utility model with the parameter Z 2;
The achievement of the objects, functional features and advantages of the present utility model will be further described with reference to the accompanying drawings, in conjunction with the embodiments.
Detailed Description
The following description of the embodiments of the present utility model will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.
It should be noted that, if directional indications (such as up, down, left, right, front, and rear … …) are included in the embodiments of the present utility model, the directional indications are merely used to explain the relative positional relationship, movement conditions, etc. between the components in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indications are correspondingly changed.
In addition, if there is a description of "first", "second", etc. in the embodiments of the present utility model, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, if the meaning of "and/or" is presented throughout this document, it is intended to include three schemes in parallel, taking "a and/or B" as an example, including a scheme, or B scheme, or a scheme where a and B meet simultaneously. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present utility model.
An embodiment of the present utility model proposes a topology structure of a broadband band reject filter with a narrow pass characteristic, referring to fig. 1, including a first vertical microstrip line, a first end of the first vertical microstrip line is connected with one end of a first horizontal microstrip line and one end of a second horizontal microstrip line, the other end of the first horizontal microstrip line is connected with a first vertical open branch, and the other end of the second horizontal microstrip line is connected with a second vertical open branch; the first horizontal microstrip line and the second horizontal microstrip line are symmetrically distributed on two sides of the first vertical microstrip line, and the first vertical open-circuit branch and the second vertical open-circuit branch are symmetrically distributed on two sides of the first vertical microstrip line;
The second end of the first vertical microstrip line is connected with one end of a third horizontal microstrip line, one end of a fourth horizontal microstrip line and one end of a second vertical microstrip line; the other end of the third horizontal microstrip line is connected with an input port, the other end of the fourth horizontal microstrip line is connected with an output port, and the third horizontal microstrip line and the fourth horizontal microstrip line are symmetrically distributed on two sides of the second vertical microstrip line; and the other end of the second vertical microstrip line is connected with one end of the first horizontal open-circuit branch.
The topological structure of the existing band-stop filter is improved, the topological structure of the embodiment is formed by adopting three open-circuit branches and a plurality of microstrip lines, the whole structure is of a symmetrical structure, and the band-stop filter has simple structural design, so that the band-stop filter has narrow-pass characteristics.
Specifically, the characteristic impedance of the first horizontal microstrip line, the second horizontal microstrip line, the first vertical open-circuit branch and the second vertical open-circuit branch are all set to be twice the characteristic impedance of the first vertical microstrip line; the characteristic impedance of the second vertical microstrip line, the third horizontal microstrip line, the fourth horizontal microstrip line and the first horizontal open circuit branch is the same.
In this embodiment, the characteristic impedance of the first vertical microstrip line is set to Z 2, and the characteristic impedances of the first horizontal microstrip line, the second horizontal microstrip line, the first vertical open branch and the second vertical open branch are all set to 2Z 2; the characteristic impedance of the second vertical microstrip line, the third horizontal microstrip line, the fourth horizontal microstrip line and the first horizontal open circuit branch is Z 1; therefore, the design parameters of the broadband band-stop filter based on the topological structure are two and only two, namely Z 1 and Z 2, and the design method has the advantage of simple design process;
Specifically, referring to fig. 4, as the parameter Z 1 becomes larger, the reflection coefficient in the passband becomes slightly larger, the bandwidth of the stopband is unchanged, the bandwidths of the two narrow passbands in the stopband become smaller, and the center frequencies of the two narrow passbands in the stopband are close to each other. Referring to fig. 5, as the parameter Z 2 becomes larger, the reflection coefficient in the pass band becomes slightly larger, the bandwidth of the stop band becomes smaller, the bandwidths of the two narrow pass bands in the stop band become larger, and the center frequencies of the two narrow pass bands in the stop band are far away from each other. Thus, the reflection coefficient within the passband is affected by parameter Z 1、Z2, the bandwidth of the stopband is mainly affected by parameter Z 2, the bandwidths of the two narrow passbands within the stopband are affected by parameter Z 1、Z2, and the center frequencies of the two narrow passbands within the stopband are affected by parameter Z 1、Z2. By optimizing the value of parameter Z 1、Z2, a filter of desired performance can be obtained.
Further, the electrical length of the second horizontal microstrip line and the electrical length of the third horizontal microstrip line are set to be a quarter wavelength corresponding to the center frequency of the band stop filter; the sum of the electrical length of the first vertical microstrip line, the electrical length of the first horizontal microstrip line and the electrical length of the first vertical open stub is equal to twice the electrical length of the second horizontal microstrip line; the sum of the electrical length of the first vertical microstrip line, the electrical length of the second horizontal microstrip line and the electrical length of the second vertical open stub is equal to twice the electrical length of the third horizontal microstrip line; the sum of the electrical length of the second vertical microstrip line and the electrical length of the first horizontal open stub is equal to the electrical length of the second horizontal microstrip line or the third horizontal microstrip line.
Another embodiment of the present utility model further provides a filter including any one of the above-described topologically designed filters.
To verify the topology described above, the filter in this embodiment includes a circuit board having a dielectric constant of 3.38, a dielectric loss of 0.0022, and a thickness of 0.813mm. The size of the circuit board of the filter is 24.0mm by 9.0mm.
Referring to fig. 2, the length of the first vertical microstrip line is set to l 4 =5.2 mm, and the width of the first vertical microstrip line is set to w 3 =1.3 mm; the lengths of the first horizontal microstrip line and the second horizontal microstrip line are respectively l 5 =8.6mm, and the widths of the first horizontal microstrip line and the second horizontal microstrip line are respectively w 4 =0.65 mm; the lengths of the first vertical open-circuit branch knot and the second vertical open-circuit branch knot are respectively set to be l 6 =4.05 mm, and the widths of the first vertical open-circuit branch knot and the second vertical open-circuit branch knot are respectively set to be w 5 =0.65 mm; the length of the second vertical microstrip line is set to be i 2 =1.1 mm; the lengths of the third horizontal microstrip line and the fourth horizontal microstrip line are set to be l 1 =8.8 mm, and the widths of the third horizontal microstrip line and the fourth horizontal microstrip line are set to be w 1 =0.1 mm; the length of the first horizontal open stub is set to l 3 =7.7 mm, and the width of the first horizontal open stub is set to w 2 =0.1 mm.
Referring to fig. 3, for the above filter, the stopband range of which the isolation is greater than 15dB is 1.837GHz to 8.525GHz, the stopband center frequency is 5.181GHz, the absolute bandwidth is 6.688GHz, and the relative bandwidth is 129.1%. In addition, three transmission zeros are located in the stop band at 2.482,5.543,8.087ghz, respectively. Two pass bands are arranged beside the stop band, five transmission poles are arranged in the pass bands and are respectively positioned at 0,0.782,9.222, 10.348 and 11.703GHz. The three transmission zeroes and the five transmission poles ensure not only the high isolation characteristic of the stop band and the low insertion loss and flatness of the pass band, but also the high selection characteristic of the sidebands of the band-stop filter.
In addition, in the stop band, two pass bands with very narrow bandwidths are arranged, so that the smooth passing of the signals required in the stop band can be ensured. Wherein, for the first passband, the passband range with the reflection coefficient smaller than-10 dB is 4.335GHz to 4.433GHz, the passband center frequency is 4.384GHz, the absolute bandwidth is 0.098GHz, and the relative bandwidth is 2.24%; for the second passband, the passband range with reflection coefficient less than-10 dB is 6.244GHz to 6.326GHz, the passband center frequency is 6.285GHz, the absolute bandwidth is 0.0852GHz, and the relative bandwidth is 1.3%.
In conclusion, the broadband band-stop filter designed based on the topological structure has the advantages of narrow pass characteristic, high selectivity, miniaturization, simple design process and the like through the verification.
The foregoing description is only of the optional embodiments of the present utility model, and is not intended to limit the scope of the utility model, and all the equivalent structural changes made by the description of the present utility model and the accompanying drawings or the direct/indirect application in other related technical fields are included in the scope of the utility model.
Claims (10)
1. The topological structure of the broadband band-stop filter with the narrow-pass characteristic is characterized by comprising a first vertical microstrip line, wherein a first end of the first vertical microstrip line is connected with one end of a first horizontal microstrip line and one end of a second horizontal microstrip line, the other end of the first horizontal microstrip line is connected with a first vertical open branch, and the other end of the second horizontal microstrip line is connected with a second vertical open branch; the first horizontal microstrip line and the second horizontal microstrip line are symmetrically distributed on two sides of the first vertical microstrip line, and the first vertical open-circuit branch and the second vertical open-circuit branch are symmetrically distributed on two sides of the first vertical microstrip line;
The second end of the first vertical microstrip line is connected with one end of a third horizontal microstrip line, one end of a fourth horizontal microstrip line and one end of a second vertical microstrip line; the other end of the third horizontal microstrip line is connected with an input port, the other end of the fourth horizontal microstrip line is connected with an output port, and the third horizontal microstrip line and the fourth horizontal microstrip line are symmetrically distributed on two sides of the second vertical microstrip line; and the other end of the second vertical microstrip line is connected with one end of the first horizontal open-circuit branch.
2. The topology of a wideband band reject filter with narrow pass characteristics of claim 1, wherein the characteristic impedance of the first horizontal microstrip line, the second horizontal microstrip line, the first vertical open stub, and the second vertical open stub are each set to be twice the characteristic impedance of the first vertical microstrip line.
3. The topology of claim 1, wherein the characteristic impedances of the second vertical microstrip line, the third horizontal microstrip line, the fourth horizontal microstrip line, and the first horizontal open stub are all the same.
4. The topology of a broadband band reject filter with narrow pass characteristics of claim 1, wherein a sum of an electrical length of the first vertical microstrip line, an electrical length of the first horizontal microstrip line, and an electrical length of the first vertical open stub is equal to twice an electrical length of the second horizontal microstrip line; the sum of the electrical length of the first vertical microstrip line, the electrical length of the second horizontal microstrip line, and the electrical length of the second vertical open stub is equal to twice the electrical length of the third horizontal microstrip line.
5. The topology of a broadband band reject filter with narrow pass characteristics of claim 1, wherein a sum of an electrical length of the second vertical microstrip line and an electrical length of the first horizontal open stub is equal to an electrical length of the second horizontal microstrip line or a third horizontal microstrip line.
6. The topology of a broadband band reject filter with narrow pass characteristics according to claim 4 or 5, wherein the electrical length of the second horizontal microstrip line and the electrical length of the third horizontal microstrip line are each set to a quarter wavelength corresponding to the center frequency of the band reject filter.
7. A filter characterized in that the claims comprise a filter designed based on a topology according to any one of claims 1 to 6.
8. The filter of claim 7, further comprising a circuit board having a dielectric constant of 3.38, a dielectric loss of 0.0022, and a thickness of 0.813mm.
9. The filter of claim 7, wherein the filter has a circuit board size of 24.0mm by 9.0mm.
10. The filter of claim 7, wherein the length of the first vertical microstrip line is set to l 4 =5.2 mm and the width of the first vertical microstrip line is set to w 3 =1.3 mm; the lengths of the first horizontal microstrip line and the second horizontal microstrip line are respectively l 5 =8.6mm, and the widths of the first horizontal microstrip line and the second horizontal microstrip line are respectively w 4 =0.65 mm; the lengths of the first vertical open-circuit branch knot and the second vertical open-circuit branch knot are respectively set to be l 6 =4.05 mm, and the widths of the first vertical open-circuit branch knot and the second vertical open-circuit branch knot are respectively set to be w 5 =0.65 mm; the length of the second vertical microstrip line is set to be i 2 =1.1 mm; the lengths of the third horizontal microstrip line and the fourth horizontal microstrip line are set to be l 1 =8.8 mm, and the widths of the third horizontal microstrip line and the fourth horizontal microstrip line are set to be w 1 =0.1 mm; the length of the first horizontal open stub is set to l 3 =7.7 mm, and the width of the first horizontal open stub is set to w 2 =0.1 mm.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202322555928.3U CN220895819U (en) | 2023-09-19 | 2023-09-19 | Topological structure of broadband band-stop filter with narrow pass characteristic and filter |
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| CN202322555928.3U CN220895819U (en) | 2023-09-19 | 2023-09-19 | Topological structure of broadband band-stop filter with narrow pass characteristic and filter |
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