CN117767901B - Open stub loaded band reject filter - Google Patents
Open stub loaded band reject filter Download PDFInfo
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- CN117767901B CN117767901B CN202410195349.9A CN202410195349A CN117767901B CN 117767901 B CN117767901 B CN 117767901B CN 202410195349 A CN202410195349 A CN 202410195349A CN 117767901 B CN117767901 B CN 117767901B
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- 230000008054 signal transmission Effects 0.000 claims abstract description 26
- 230000005540 biological transmission Effects 0.000 claims abstract description 21
- 238000004891 communication Methods 0.000 abstract description 8
- 238000004519 manufacturing process Methods 0.000 abstract description 5
- 238000000034 method Methods 0.000 abstract description 3
- 230000008030 elimination Effects 0.000 abstract 2
- 238000003379 elimination reaction Methods 0.000 abstract 2
- 238000004088 simulation Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 230000007547 defect Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000003780 insertion Methods 0.000 description 2
- 230000037431 insertion Effects 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000011889 copper foil Substances 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
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Abstract
The invention provides a band elimination filter loaded by an open stub. Belonging to the technical field of radio frequency microwave communication. The band elimination filter comprises an input end feeder line, an output end feeder line, a first open-circuit stub line, a first signal transmission line, a second signal transmission line and a second open-circuit stub line. The open stub loaded band-stop filter designed by the invention generates 3 transmission zeros for the stop band and 4 transmission poles for the pass bands at the two sides of the filter by loading the open stub between the quarter-wavelength transmission line and the three-quarter-wavelength transmission line, thereby providing excellent roll-off characteristics for the filter; the topology structure is simple, the manufacture is easy, and the method is applicable to various communication systems.
Description
Technical Field
The invention relates to the technical field of radio frequency microwave communication, in particular to a band-stop filter loaded by an open stub.
Background
With the development of wireless communication technology, spectrum resources are increasingly strained, and electromagnetic interference between systems is also increasingly serious. In order to raise the demodulation threshold of the receiver, the interference signal in the system needs to be suppressed. As a key device of the radio frequency front end, the quality of the technical index of the filter affects the performance of the communication system to a great extent. In order to ensure the signal integrity of the system under various working conditions and avoid electromagnetic noise interference, the radio frequency front-end filter is required to realize the passband characteristics and simultaneously restrict and limit a plurality of indexes such as a topological structure, passband selectivity, a stop band suppression degree, insertion loss and the like.
The band-stop filter designed by the transverse signal interference technology enables a 180-degree phase difference to be generated to a transmission zero point after a specific frequency signal passes through a branch circuit so as to realize stop band, but has the defects of structural redundancy and poor stop band inhibition degree, so that the requirements of miniaturization of devices and complexity of application environments are difficult to meet.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provides a band-stop filter loaded by an open-circuit stub. The band-stop filter has excellent stop band rejection characteristics, has a simple topological structure, is easy to manufacture, and can be applied to various communication systems.
The invention is realized by the following technical scheme, the invention provides an open stub loaded band-stop filter, which comprises an input end feeder line 1, an output end feeder line 2, a first open stub 3, a first signal transmission line 4, a second signal transmission line 5 and a second open stub 6, wherein the input end feeder line 1 of the band-stop filter is connected with the first open stub 3; the output end feeder line 2 of the band-stop filter is connected with a second open stub 6; the band reject filter first signal transmission line 4 and the second signal transmission line 5 are both arranged between the input feed line 1 and the output feed line 2.
Further, the electrical length of the first signal transmission line 4 of the band reject filter is a quarter wavelength.
Further, the electrical length of the second signal transmission line 5 is three-quarter wavelength.
Further, the input feeder 1 and the output feeder 2 have the same characteristic impedance.
Further, the electrical lengths of the first open stub 3 and the second open stub 6 are each one quarter wavelength, and have the same characteristic impedance.
Further, two open stubs can generate 3 transmission zeros for the stop band while also generating 4 transmission poles for the pass band on both sides thereof.
Further, the center frequency of the band-stop filter is set to be 1GHz, and the characteristic impedance of the input end feeder line 1 and the characteristic impedance of the output end feeder line 2 are set to be 50 ohms.
Further, the characteristic impedance of the first open stub 3 and the second open stub 6 is 103 ohms.
Compared with the prior art, the invention has the beneficial effects that:
1. According to the invention, an open-circuit stub is loaded between a quarter-wavelength transmission line and a three-quarter-wavelength transmission line, 3 transmission zero points are generated for a stop band, and meanwhile, 4 transmission poles are generated on pass bands at two sides of the stop band, so that excellent roll-off characteristics are provided for a filter;
2. The characteristic impedance and the center frequency of the transmission line and the open stub in the filter topology can be flexibly adjusted to be suitable for different frequencies and bandwidths;
3. The filter provided by the invention has a simple topological structure and low manufacturing cost, and can be suitable for various communication systems.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.
Fig. 1 is a block diagram of an open stub loaded band reject filter according to the present invention.
Fig. 2 is a schematic structural dimension diagram of an embodiment of an open stub loaded band reject filter.
Fig. 3 is a diagram showing the results of the S-parameter simulation and electromagnetic simulation of the open stub loaded band reject filter embodiment.
The figure indicates: an input end feeder 1, an output end feeder 2, a first open stub 3, a first signal transmission line 4, a second signal transmission line 5, and a second open stub 6.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1-3, the invention provides an open stub loaded band-stop filter, which comprises an input end feeder 1, an output end feeder 2, a first open stub 3, a first signal transmission line 4, a second signal transmission line 5 and a second open stub 6, wherein the input end feeder 1 of the band-stop filter is connected with the first open stub 3; the output end feeder line 2 of the band-stop filter is connected with a second open stub 6; the band reject filter first signal transmission line 4 and the second signal transmission line 5 are both arranged between the input feed line 1 and the output feed line 2.
The electrical length of the first signal transmission line 4 of the band reject filter is a quarter wavelength.
The second signal transmission line 5 has an electrical length of three-quarter wavelength.
The input feed 1 and the output feed 2 have the same characteristic impedance.
The first open stub 3 and the second open stub 6 are each quarter wavelength in electrical length and have the same characteristic impedance.
The two open stubs can generate 3 transmission zeros for the stop band and 4 transmission poles at the pass band on both sides.
Examples
The center frequency of the band-stop filter loaded by the open stub in this embodiment is set to be 1GHz, the characteristic impedance of the input end feeder line and the characteristic impedance of the output end feeder line are both set to be 50 ohms, the characteristic impedance of the first open stub and the characteristic impedance of the second open stub are set to be 103 ohms, the first signal transmission line is 113 ohms, the second signal transmission line is 150 ohms, and the circuit simulation result is shown in fig. 3. And a microstrip structure is adopted to manufacture the micro-strip structure.
The dielectric substrate used was ROGERS RT/duroid 5880. The dielectric constant of the medium was 2.2, the thickness was 0.787 mm, and the copper foil thickness was 0.0175 mm. Under this parameter, the lengths of the first open stub and the second open stub are 56.70 mm, and the line width is 0.63 mm; the length of the first signal transmission line is 57.00 mm, and the line width is 0.50 mm; the length of the second signal transmission line is 173.00 mm (i.e. the combined length of the three transmission lines is 58.00+57.00+58.00), and the line width is 0.21 mm; the length of the feeder lines at the two ends is set to 10.00 mm and the width is set to 2.40 mm. The components are connected according to the technical scheme of the invention, so that the planar layout of the open stub loaded band-stop filter in the embodiment shown in fig. 2 can be obtained, and the S parameters obtained by electromagnetic simulation are shown in fig. 3.
As can be seen from fig. 2, the 20dB stop band absolute bandwidth of the filter is: 360MHz with a relative bandwidth of 36%. In addition, the filter has good performance in the passband range, the standing-wave ratio is smaller than 1.34, the insertion loss is smaller than 1dB, and the excellent band-stop filter characteristic is realized.
The open stub loaded band-stop filter designed by the invention generates 3 transmission zeros for the stop band and 4 transmission poles for the pass bands at the two sides of the filter by loading the open stub between the quarter-wavelength transmission line and the three-quarter-wavelength transmission line, thereby providing excellent roll-off characteristics for the filter; the topology structure is simple, the manufacture is easy, and the method is applicable to various communication systems.
The open stub loaded band reject filter proposed by the present invention has been described in detail above, and specific examples are applied in the present invention to illustrate the principles and embodiments of the present invention, and the description of the above examples is only for helping to understand the method and core ideas of the present invention; meanwhile, as those skilled in the art will have variations in the specific embodiments and application scope in accordance with the ideas of the present invention, the present description should not be construed as limiting the present invention in view of the above.
Claims (7)
1. The open-circuit stub-loaded band-stop filter is characterized by comprising an input end feeder line (1), an output end feeder line (2), a first open-circuit stub line (3), a first signal transmission line (4), a second signal transmission line (5) and a second open-circuit stub line (6), wherein the band-stop filter input end feeder line (1) is connected with the first open-circuit stub line (3); the output end feeder line (2) of the band-stop filter is connected with a second open-circuit stub line (6); the band-stop filter is characterized in that the first signal transmission line (4) and the second signal transmission line (5) are both arranged between the input end feeder line (1) and the output end feeder line (2);
The two open stubs can generate 3 transmission zeros for the stop band and 4 transmission poles at the pass band on both sides.
2. The band reject filter according to claim 1, characterized in that the electrical length of the first signal transmission line (4) of the band reject filter is a quarter wavelength.
3. The band reject filter according to claim 2, characterized in that the electrical length of the second signal transmission line (5) is three-quarter wavelength.
4. The band reject filter according to claim 1, characterized in that the input feed line (1) and the output feed line (2) have the same characteristic impedance.
5. The band reject filter according to claim 1, characterized in that the first open stub (3) and the second open stub (6) are each quarter wavelength in electrical length and have the same characteristic impedance.
6. The band-stop filter according to claim 4, characterized in that the center frequency of the band-stop filter is set to 1GHz, and the characteristic impedance of the input feeder (1) and the output feeder (2) is set to 50 ohms.
7. The band reject filter according to claim 5, characterized in that the characteristic impedance of the first open stub (3) and the second open stub (6) are both 103 ohms.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410195349.9A CN117767901B (en) | 2024-02-22 | 2024-02-22 | Open stub loaded band reject filter |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410195349.9A CN117767901B (en) | 2024-02-22 | 2024-02-22 | Open stub loaded band reject filter |
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| Publication Number | Publication Date |
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| CN117767901A CN117767901A (en) | 2024-03-26 |
| CN117767901B true CN117767901B (en) | 2024-05-28 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202410195349.9A Active CN117767901B (en) | 2024-02-22 | 2024-02-22 | Open stub loaded band reject filter |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5256990A (en) * | 1992-05-08 | 1993-10-26 | Skydata, Inc. | Compact, die-cast precision bandstop filter structure |
| CN103825561A (en) * | 2014-01-24 | 2014-05-28 | 浙江纺织服装职业技术学院 | Radio frequency amplifier adjustable in frequency and bandwidth |
| CN105359334A (en) * | 2013-07-04 | 2016-02-24 | 汤姆逊许可公司 | Band rejection filter |
| CN107834134A (en) * | 2017-10-26 | 2018-03-23 | 上海海事大学 | Miniaturization difference filter based on T-shaped branch's cable architecture |
| CN110011004A (en) * | 2019-03-20 | 2019-07-12 | 南京航空航天大学 | A kind of amount of phase shift distinguishes controllable double frequency phase shifter |
| CN113346861A (en) * | 2021-05-12 | 2021-09-03 | 南京邮电大学 | Bandwidth-adjustable reflection-free filter of full-open branch transmission line |
| CN117317551A (en) * | 2023-10-31 | 2023-12-29 | 深圳市信维通信股份有限公司 | Filter and communication equipment |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050012676A1 (en) * | 2003-07-16 | 2005-01-20 | Mccarthy Robert Daniel | N-port signal divider/combiner |
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2024
- 2024-02-22 CN CN202410195349.9A patent/CN117767901B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5256990A (en) * | 1992-05-08 | 1993-10-26 | Skydata, Inc. | Compact, die-cast precision bandstop filter structure |
| CN105359334A (en) * | 2013-07-04 | 2016-02-24 | 汤姆逊许可公司 | Band rejection filter |
| CN103825561A (en) * | 2014-01-24 | 2014-05-28 | 浙江纺织服装职业技术学院 | Radio frequency amplifier adjustable in frequency and bandwidth |
| CN107834134A (en) * | 2017-10-26 | 2018-03-23 | 上海海事大学 | Miniaturization difference filter based on T-shaped branch's cable architecture |
| CN110011004A (en) * | 2019-03-20 | 2019-07-12 | 南京航空航天大学 | A kind of amount of phase shift distinguishes controllable double frequency phase shifter |
| CN113346861A (en) * | 2021-05-12 | 2021-09-03 | 南京邮电大学 | Bandwidth-adjustable reflection-free filter of full-open branch transmission line |
| CN117317551A (en) * | 2023-10-31 | 2023-12-29 | 深圳市信维通信股份有限公司 | Filter and communication equipment |
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| CN117767901A (en) | 2024-03-26 |
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