CN104617362A - Low-pass filter with transmission zero - Google Patents
Low-pass filter with transmission zero Download PDFInfo
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- CN104617362A CN104617362A CN201510049754.0A CN201510049754A CN104617362A CN 104617362 A CN104617362 A CN 104617362A CN 201510049754 A CN201510049754 A CN 201510049754A CN 104617362 A CN104617362 A CN 104617362A
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- pass filter
- low pass
- ground connection
- transmission zero
- conductor portion
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Abstract
The invention discloses a low-pass filter with a transmission zero. The low-pass filter with the transmission zero comprises a signal conductor, a grounding cavity, an open-circuit line and a grounding barrel with a bottom wall. The signal conductor is coaxially arranged inside the grounding cavity and comprises a plurality of low-impedance conductor units and high-impedance conductor units which are alternately connected; the position of the grounding cavity, which corresponds to one of the high-impedance conductor unit, is provided with an opening; the open-circuit line is fixedly connected with the high-impedance conductor unit at the opening through the opening, and the tail end of the portion of the open-circuit line, which is disposed inside the grounding cavity, is arranged inside the grounding barrel. Compared with the prior art, the low-pass filter with the transmission zero achieves generation of the transmission zero by setting the open-circuit line and fixedly connecting the open-circuit line and one of the high-impedance conductor units on the signal conductor, thereby obviously improving inhibition to high-frequency signals and avoiding increasing the length of the low-pass filter or the diameter of a low-impedance line.
Description
Technical field
The present invention relates to coaxial low-pass filter technical field, relate to a kind of low pass filter with transmission zero more specifically.
Background technology
Coaxial low-pass filter of the prior art, its model as shown in Figure 5, wherein thin inner wire (diameter is little) or title high impedance line, it can be equivalent to the inductance of series connection, thick inner wire (diameter is large) or title low-impedance line, it can be equivalent to electric capacity in parallel, by the alternately change of coaxial inner conductor diameter, realizes low-pass filtering performance.But coaxial low-pass filter shown in Fig. 5 has poor high-frequency suppressing characteristic.Please refer to Fig. 6, in Fig. 6, curve A is the transmission amplitude-versus-frequency curve of coaxial low-pass filter in Fig. 5, as shown in Figure 6, the signal being less than a certain frequency (low-pass cut-off frequencies) can pass through coaxial low-pass filter smoothly, and can be increasing with its decay of rising of frequency higher than the signal of low-pass cut-off frequencies.Transmission zero refers to that the obvious frequency of attenuation amplitude appears sudden change and in signal, can significantly improve the degree of decay of low pass filter to high-frequency signal by transmission zero.
But there is not transmission zero in the amplitude-versus-frequency curve of coaxial low-pass filter of the prior art, and comparatively mild higher than the attenuation amplitude of the signal of low-pass cut-off frequencies, good high-frequency suppressing characteristic can not be reached.And in order to realize good high-frequency suppressing characteristic, namely in order to make amplitude-versus-frequency curve comparatively precipitous, need to increase the joint number (length of low pass filter) of low pass filter or increase the diameter of low-impedance line, then said method can cause that the size of low pass filter is comparatively large, cost is higher.
Summary of the invention
The object of the present invention is to provide a kind of low pass filter with transmission zero, to reduce size and the production cost of low pass filter while realizing good high-frequency suppressing characteristic.
For achieving the above object, the invention provides a kind of low pass filter with transmission zero, comprise signal conductor, there is the ground connection cavity of circular hollow inner chamber, open-circuit line and there is the ground connection cylindrical shell of diapire, what described signal conductor was coaxial is arranged in described circular hollow inner chamber, and described signal conductor comprises low-impedance conductor portion and the high impedance conductor portion of multiple alternately connection, described ground connection cavity is offering an opening with the position that wherein described in, high impedance conductor portion is corresponding, described open-circuit line is fixedly connected with the described high impedance conductor portion being positioned at described opening part by described opening, and the end that described open-circuit line is positioned at the external part of described grounded chamber is arranged at described ground connection cylindrical shell.
Compared with prior art, the present invention has the low pass filter of transmission zero by arranging open-circuit line and being fixedly connected with the wherein high impedance conductor portion on signal conductor by open-circuit line and achieving generation one transmission zero, namely a transmission zero is produced at the high band of the low-pass cut-off frequencies higher than low pass filter, thus significantly improve the suppression of low pass filter to high-frequency signal, and the length of low pass filter need not be increased or increase the diameter of low-impedance line, namely when realizing same high-frequency suppressing characteristic, in the present invention, the size of low pass filter is less, production cost is lower.
Preferably, described open-circuit line comprises and to be fixedly connected with described high impedance conductor portion and perpendicular to the vertical section of described high impedance conductor portion and be connected and spiral support portion with described vertical section, described support portion is arranged in described ground connection cylindrical shell.
Preferably, the length of described vertical section is greater than 1/2nd of described grounded chamber body diameter.
Preferably, described vertical section welds with described high impedance conductor portion.
Preferably, described split ring encloses around described ground connection cavity one and is divided into two by described ground connection cavity.
Preferably, the length of the described high impedance conductor portion be connected with described open-circuit line is greater than the length of high impedance conductor portion described in all the other.
Preferably, described signal conductor comprises N number of described low-impedance conductor portion and N+1 described high impedance conductor portion, and described open-circuit line is connected with the described high impedance conductor portion of described signal conductor middle position, and wherein N is even number.
Preferably, described low pass filter is fixedly installed in an elongate slots, and the diapire of described elongate slots is recessed to form the groove of an accommodating described ground connection cylindrical shell in the position corresponding with described ground connection cylindrical shell.
Preferably, described low pass filter also comprises input terminal, lead-out terminal, input connector and out connector, described input connector is connected with one end of described signal conductor by described input terminal, and described out connector is connected with the other end of described signal conductor by described lead-out terminal.
Preferably, described ground connection cavity is polytetrafluoroethylene cavity, and described ground connection cylindrical shell is polytetrafluoroethylene cylindrical shell.
By following description also by reference to the accompanying drawings, the present invention will become more clear, and these accompanying drawings are for explaining embodiments of the invention.
Accompanying drawing explanation
Fig. 1 is the overall structure figure that the present invention has low pass filter one embodiment of transmission zero.
Fig. 2 be have in Fig. 1 the low pass filter of transmission zero and elongate slots assemble after structure chart.
Fig. 3 has the low pass filter of transmission zero and the exploded view of long row groove in Fig. 2.
Fig. 4 has the low pass filter of transmission zero and the elongate slots profile along A-A direction in Fig. 2.
Fig. 5 is the structure chart of coaxial low-pass filter in prior art.
Fig. 6 is the amplitude-versus-frequency curve figure of low pass filter in the present invention and prior art.
Embodiment
With reference now to accompanying drawing, describe embodiments of the invention, element numbers similar in accompanying drawing represents similar element.
Please refer to Fig. 1 to Fig. 4, the invention provides a kind of low pass filter 100 with transmission zero, it comprises signal conductor 11, there is the ground connection cavity 12 of circular hollow inner chamber, open-circuit line 13 and there is the ground connection cylindrical shell 14 of diapire, what signal conductor 11 was coaxial is arranged in the circular hollow inner chamber of ground connection cavity 12, and signal conductor 11 comprises low-impedance conductor portion 111 and the high impedance conductor portion 112 of multiple alternately connection, ground connection cavity 12 offers an opening 121 in the position corresponding with a wherein high impedance conductor portion 112, open-circuit line 13 is fixedly connected with the high impedance conductor portion 112 being positioned at opening 121 place by opening 121, and the end of part that open-circuit line 13 is positioned at outside ground connection cavity 12 is arranged at ground connection cylindrical shell 14.
Compared with prior art, the present invention has the low pass filter 100 of transmission zero by arranging open-circuit line 13, and open-circuit line 13 is fixedly connected with the wherein high impedance conductor portion 112 on signal conductor 11 and achieves generation one transmission zero, namely a transmission zero is produced at the high band of the low-pass cut-off frequencies higher than low pass filter 100, thus significantly improve the suppression of low pass filter to high-frequency signal, and the length of low pass filter need not be increased or increase the diameter of low-impedance line, namely when realizing same high-frequency suppressing characteristic, in the present invention, the size of low pass filter is less, production cost is lower.
Concrete, as shown in Figure 3 to Figure 4, open-circuit line 13 comprises and to be fixedly connected with high impedance conductor portion 112 and perpendicular to the vertical section 131 of high impedance conductor portion 112 and be connected and spiral support portion 133 with vertical section 131, support portion 133 is arranged in ground connection cylindrical shell 14.Preferably, ground connection cylindrical shell 14 is for having the cylindrical tube of diapire; The length of vertical section 131 is greater than 1/2nd of ground connection cavity 12 external diameter, thus vertical section 131 stretches out the outer segment distance of ground connection cavity 12.In addition, vertical section 131 is fixedly connected with high impedance conductor portion 112, and preferably, vertical section 131 is fixedly connected with welding manner with high impedance conductor portion 112, and the two otherwise achieves a fixed connection and also can certainly.
Please refer to Fig. 3 again, the opening 121 be opened in the present embodiment on ground connection cavity 12 encloses around ground connection cavity 12 1 and is divided into two by ground connection cavity 12, and as being divided into two parts 121 and 123, concrete, opening 121 is a cylindrical breach.Certainly; in other embodiments; also the structure of ground connection cavity 12 in the present invention can be realized by two ground connection cavitys; and the structure of opening 121 is also not restricted to this; opening 121 is connected to produce a transmission zero with the high impedance conductor portion 112 on signal conductor 11, therefore, it is possible to the opening 121 realizing any structure of this function all belongs to the present invention's scope required for protection for allowing open-circuit line 13 through ground connection cavity 12.In addition, the materials such as ground connection cavity 12 is polytetrafluoroethylene (PTFE) cavity, and ground connection cylindrical shell 14 is polytetrafluoroethylene cylindrical shell, and signal conductor 11 and open-circuit line 13 are metal material, as silver-plated in copper.
In addition, in the present embodiment, signal conductor 11 comprises N number of low-impedance conductor portion 111 and N+1 high impedance conductor portion 112, and low-impedance conductor portion 111 is cylindrical with high impedance conductor portion 112, and the diameter in low-impedance conductor portion 111 is greater than the diameter of high Low ESR conductor portion 112, the length in low-impedance conductor portion 111 is less than the length of high impedance conductor portion 112, wherein N is even number, as N=2, 4, 6, 8 etc., simultaneously because low-impedance conductor portion 111 is alternately connected with high impedance conductor portion 112, therefore the two ends of signal conductor 11 are low-impedance conductor portion 111, and the middle position of signal conductor 11 corresponds to a high impedance conductor portion 112.And opening 121 can be arranged at position corresponding with arbitrary high impedance conductor portion 112 on ground connection cavity 12.Preferably, opening 121 is arranged at the middle position of ground connection cavity 12, namely the position of opening 121 and high impedance conductor portion 112 position of signal conductor 11 middle position corresponding, thus open-circuit line 13 is connected with the high impedance conductor portion 112 of middle position on signal conductor 11.In order to realize conveniently, the length of the high impedance conductor portion 112 be connected with open-circuit line 13 is greater than the length of all the other high impedance conductor portion 112.
Please refer to Fig. 6 again, in Fig. 6, curve B is the amplitude-versus-frequency curve figure of the low pass filter 100 in Fig. 1 to Fig. 4 with transmission zero, frequency O (namely curve B being put the frequency corresponding to O) wherein in curve B is transmission zero, when signal frequency is higher than low-pass cut-off frequencies, signal amplitude decays, and signal amplitude in the decay of frequency O place significantly, the amplitude-versus-frequency curve of signal is comparatively precipitous, make not broaden by the frequency range of low pass filter 100, namely achieve good high-frequency suppressing characteristic.It should be noted that, the length of open-circuit line 13 can affect the attenuation degree of the amplitude-versus-frequency curve of low pass filter 100, concrete, when the length of open-circuit line 13 increases, transmission zero offsets left on amplitude-versus-frequency curve figure, the high-frequency suppressing characteristic of low pass filter 100 improves, otherwise, when the length of open-circuit line 13 reduces, transmission zero offsets to the right on amplitude-versus-frequency curve figure, the high-frequency suppressing properties deteriorate of low pass filter 100, thus be that suitable size can realize certain high-frequency suppressing characteristic by design open-circuit line 13.Certainly, also need to consider other factors when designing the length of open-circuit line 13.
In addition, as shown in Figures 2 to 4, low pass filter 100 of the present invention also comprises input terminal 15, lead-out terminal 16, input connector 17 and out connector 18, input connector 17 is connected with one end of signal conductor 11 by input terminal 15, out connector 18 is connected with the other end of signal conductor 11 by lead-out terminal 16, signal inputs from the input of low pass filter 100, exported by the output of low pass filter 100 after filtering, thus achieve by low frequency signal and suppress high-frequency signal.In addition, low pass filter 100 of the present invention is fixedly installed in an elongate slots 20, the diapire of elongate slots 20 is recessed to form the groove 201 of an accommodating ground connection cylindrical shell in the position corresponding with ground connection cylindrical shell 14, and the two opposite sides of elongate slots 20 offers respectively the through hole installing input connector 17 and out connector 18.
More than in conjunction with most preferred embodiment, invention has been described, but the present invention is not limited to the embodiment of above announcement, and should contain various carry out according to essence of the present invention amendment, equivalent combinations.
Claims (10)
1. one kind has the low pass filter of transmission zero, comprise signal conductor and the ground connection cavity with circular hollow inner chamber, what described signal conductor was coaxial is arranged in described circular hollow inner chamber, and described signal conductor comprises low-impedance conductor portion and the high impedance conductor portion of multiple alternately connection, it is characterized in that, described low pass filter also comprises open-circuit line and has the ground connection cylindrical shell of diapire, described ground connection cavity is offering an opening with the position that wherein described in, high impedance conductor portion is corresponding, described open-circuit line is fixedly connected with the described high impedance conductor portion being positioned at described opening part by described opening, and the end that described open-circuit line is positioned at the external part of described grounded chamber is arranged at described ground connection cylindrical shell.
2. there is the low pass filter of transmission zero as claimed in claim 1, it is characterized in that, described open-circuit line comprises and to be fixedly connected with described high impedance conductor portion and perpendicular to the vertical section of described high impedance conductor portion and be connected and spiral support portion with described vertical section, described support portion is arranged in described ground connection cylindrical shell.
3. have the low pass filter of transmission zero as claimed in claim 2, it is characterized in that, the length of described vertical section is greater than 1/2nd of described grounded chamber body diameter.
4. have the low pass filter of transmission zero as claimed in claim 2, it is characterized in that, described vertical section welds with described high impedance conductor portion.
5. the low pass filter with transmission zero as described in any one of Claims 1-4, is characterized in that, described split ring encloses around described ground connection cavity one and is divided into two by described ground connection cavity.
6. have the low pass filter of transmission zero as claimed in claim 5, it is characterized in that, the length of the described high impedance conductor portion be connected with described open-circuit line is greater than the length of high impedance conductor portion described in all the other.
7. there is the low pass filter of transmission zero as claimed in claim 5, it is characterized in that, described signal conductor comprises N number of described low-impedance conductor portion and N+1 described high impedance conductor portion, described open-circuit line is connected with the described high impedance conductor portion of described signal conductor middle position, and wherein N is even number.
8. there is the low pass filter of transmission zero as claimed in claim 1, it is characterized in that, described low pass filter is fixedly installed in an elongate slots, and the diapire of described elongate slots is recessed to form the groove of an accommodating described ground connection cylindrical shell in the position corresponding with described ground connection cylindrical shell.
9. there is the low pass filter of transmission zero as claimed in claim 1, it is characterized in that, described low pass filter also comprises input terminal, lead-out terminal, input connector and out connector, described input connector is connected with one end of described signal conductor by described input terminal, and described out connector is connected with the other end of described signal conductor by described lead-out terminal.
10. have the low pass filter of transmission zero as claimed in claim 1, it is characterized in that, described ground connection cavity is polytetrafluoroethylene cavity, and described ground connection cylindrical shell is polytetrafluoroethylene cylindrical shell.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510049754.0A CN104617362B (en) | 2015-01-30 | 2015-01-30 | Low pass filter with transmission zero |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510049754.0A CN104617362B (en) | 2015-01-30 | 2015-01-30 | Low pass filter with transmission zero |
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| Publication Number | Publication Date |
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| CN104617362A true CN104617362A (en) | 2015-05-13 |
| CN104617362B CN104617362B (en) | 2017-11-28 |
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| CN201510049754.0A Active CN104617362B (en) | 2015-01-30 | 2015-01-30 | Low pass filter with transmission zero |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110311197A (en) * | 2019-07-16 | 2019-10-08 | 深圳市威富通讯技术有限公司 | Low-pass filter with transmission zero |
| CN113193315A (en) * | 2021-04-29 | 2021-07-30 | 中航光电科技股份有限公司 | Whole machine solderless low pass filter |
| CN114243237A (en) * | 2021-12-20 | 2022-03-25 | 大富科技(安徽)股份有限公司 | Low-pass filtering structure and filter |
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| JPH07154101A (en) * | 1993-11-26 | 1995-06-16 | Nec Eng Ltd | Low pass filter |
| JPH09246804A (en) * | 1996-03-08 | 1997-09-19 | Nec Eng Ltd | Coaxial low pass filter |
| CN1288597A (en) * | 1998-11-12 | 2001-03-21 | 三菱电机株式会社 | Low-pass filter |
| JP2004282573A (en) * | 2003-03-18 | 2004-10-07 | Nec Corp | Low-pass filter |
| CN101630765A (en) * | 2009-08-25 | 2010-01-20 | 华为技术有限公司 | Coaxial low-pass filter and amplitude-frequency characteristic improving method |
| CN202217767U (en) * | 2011-08-16 | 2012-05-09 | 武汉凡谷电子技术股份有限公司 | Low-pass filter with transmission zero |
| CN203300776U (en) * | 2013-05-06 | 2013-11-20 | 京信通信技术(广州)有限公司 | Communication cavity device and low-pass filtering path |
| CN204481103U (en) * | 2015-01-30 | 2015-07-15 | 东莞鸿爱斯通信科技有限公司 | There is the low pass filter of transmission zero |
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2015
- 2015-01-30 CN CN201510049754.0A patent/CN104617362B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07154101A (en) * | 1993-11-26 | 1995-06-16 | Nec Eng Ltd | Low pass filter |
| JPH09246804A (en) * | 1996-03-08 | 1997-09-19 | Nec Eng Ltd | Coaxial low pass filter |
| CN1288597A (en) * | 1998-11-12 | 2001-03-21 | 三菱电机株式会社 | Low-pass filter |
| JP2004282573A (en) * | 2003-03-18 | 2004-10-07 | Nec Corp | Low-pass filter |
| CN101630765A (en) * | 2009-08-25 | 2010-01-20 | 华为技术有限公司 | Coaxial low-pass filter and amplitude-frequency characteristic improving method |
| CN202217767U (en) * | 2011-08-16 | 2012-05-09 | 武汉凡谷电子技术股份有限公司 | Low-pass filter with transmission zero |
| CN203300776U (en) * | 2013-05-06 | 2013-11-20 | 京信通信技术(广州)有限公司 | Communication cavity device and low-pass filtering path |
| CN204481103U (en) * | 2015-01-30 | 2015-07-15 | 东莞鸿爱斯通信科技有限公司 | There is the low pass filter of transmission zero |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110311197A (en) * | 2019-07-16 | 2019-10-08 | 深圳市威富通讯技术有限公司 | Low-pass filter with transmission zero |
| CN113193315A (en) * | 2021-04-29 | 2021-07-30 | 中航光电科技股份有限公司 | Whole machine solderless low pass filter |
| CN114243237A (en) * | 2021-12-20 | 2022-03-25 | 大富科技(安徽)股份有限公司 | Low-pass filtering structure and filter |
| CN114243237B (en) * | 2021-12-20 | 2023-04-11 | 大富科技(安徽)股份有限公司 | Low-pass filtering structure and filter |
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| CN104617362B (en) | 2017-11-28 |
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