CN110707402B - Transmission response reconfigurable coupling line internal loading type low-pass and band-stop microwave transmission line filter - Google Patents
Transmission response reconfigurable coupling line internal loading type low-pass and band-stop microwave transmission line filter Download PDFInfo
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- CN110707402B CN110707402B CN201910921307.8A CN201910921307A CN110707402B CN 110707402 B CN110707402 B CN 110707402B CN 201910921307 A CN201910921307 A CN 201910921307A CN 110707402 B CN110707402 B CN 110707402B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P1/00—Auxiliary devices
- H01P1/20—Frequency-selective devices, e.g. filters
- H01P1/201—Filters for transverse electromagnetic waves
- H01P1/203—Strip line filters
- H01P1/2039—Galvanic coupling between Input/Output
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
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Abstract
The invention discloses a transmission response reconfigurable coupling line internal loading type low-pass and band-stop microwave transmission line filter. The invention comprises an input port, an output port, a section of coupling transmission line section, a section of uniform transmission line, and two sections of open-circuit branch lines loaded inside; according to different filter parameter indexes, the circuit structure meeting the requirements can be quickly synthesized; the structure is simple, and the position of the inner corrugation is adjustable; the position of the transmission zero outside the passband is adjustable, namely, the out-of-band rejection has selectivity.
Description
Technical Field
The invention relates to a transmission response reconfigurable coupling line internal loading type low-pass and band-stop microwave transmission line filter.
Background
Filters are a very important electronic component in communication systems. The frequency point of some specific frequencies or frequency points except the specific frequencies in the communication system can be effectively filtered, so that the communication system can transmit signals more efficiently and more accurately.
With the rapid development of the communication field, the system has higher and higher requirements on the indexes of the filter, so that the filter is smaller and more compact and has low insertion loss. And more selectivity in-band and higher inhibition out-of-band.
Disclosure of Invention
The purpose of the invention is as follows: the invention aims to solve the problems that the existing microstrip filter is not compact in structure and single in-band response, and provides a structural filter which is simple in structure and easy to manufacture, so that the position of in-band ripple is adjustable, and the out-of-band rejection characteristic is selectable.
The technical scheme of the invention is as follows: a low-pass and band-reject microwave transmission line filter of the internally-loaded type for a coupled line with reconfigurable transmission response, comprising: an input port (1), an output port (2), a coupling transmission line section I (3) and a coupling transmission line section II (4), a section of uniform transmission line (5), two sections of open-circuit branch line I (6) and open-circuit branch line II (7) for internal loading,
the coupling transmission line section I (3) comprises a port I (9) and a port II (10), and the coupling transmission line section II (4) comprises a port III (8) and a port IV (11);
the uniform transmission line (5) is connected in series to a port III (8) of the coupling transmission line section II (4) and a port II (10) of the coupling transmission line section I (3), the port III (8) of the coupling transmission line section II (4) is connected in parallel with an internally loaded open-circuit branch line I (6), and the port II (10) of the coupling transmission line section I (3) is connected in parallel with an internally loaded open-circuit branch line II (7); a low-pass and band-stop microwave transmission line filter with an internal loading open-circuit branch line and a self-coupling structure is formed.
Preferably, the two open stub wires for internal loading, i.e. the first (6) and the second (7), have the same impedance value.
Preferably, the position of the ripple in the passband is adjustable when the filter bandwidths are the same.
Preferably, when the filter bandwidths are the same, the positions of the out-of-band transmission zeros are variable, and the selectivity of the out-of-band rejection is increased.
Preferably, the electrical lengths of the first coupling transmission line section (3), the second coupling transmission line section (4), the uniform transmission line (5), the first open-circuit branch line (6) and the second open-circuit branch line (7) are all equal.
Preferably, the physical implementation manner of the transmission line in the filter includes a coaxial line, a microstrip line, a strip line, a parallel strip line, a coplanar waveguide and a combination thereof;
the transmission line comprises a first coupling transmission line section (3), a second coupling transmission line section (4), a uniform transmission line (5), a first open-circuit branch line (6) and a second open-circuit branch line (7).
A filter synthesis technology is adopted, and according to given filter indexes such as bandwidth, ripple coefficients and the like, the impedance value of an odd-even mode corresponding to a coupling transmission line, the impedance value of a microstrip transmission line and the impedance values of internal and external loaded open-circuit branch lines are calculated; because the precision requirement of the structure on the element value is very high, the specific element value is obtained through software calculation, so that the response of the filter can better meet the requirement of equal ripple.
The invention principle is as follows: the invention is based on the Chebyshev-type filter, so that the response of the filter in the pass band has the characteristics of equal ripple of amplitude; by means of a filter synthesis technology, an adjustable parameter is additionally introduced, the resistance value of a corresponding transmission line can be accurately calculated, and meanwhile, the position of the ripple in a passband can be correspondingly changed.
The invention has the beneficial effects that: (1) according to different filter parameter indexes, a circuit structure meeting the requirements can be quickly synthesized; (2) the invention has simple structure, and the position of the inner corrugation is adjustable; (3) the position of the out-of-band transmission zero point is adjustable, namely the out-of-band rejection has selectivity.
Drawings
FIG. 1 is a circuit schematic of the present invention;
fig. 2 and 3 are characteristic graphs of transmission coefficients and reflection coefficients of a filter calculated using ADS software;
in the figure, 1 is an input port, 2 is an output port, 3 is a first coupled transmission line segment, 4 is a second coupled transmission line segment, 5 is a uniform transmission line, 6 is a first open-circuit branch line, 7 is a second open-circuit branch line, 8 is a third port of the second coupled transmission line segment, and 9 is a first port of the first coupled transmission line segment; reference numeral 10 denotes a second port of the first coupled transmission line segment, and reference numeral 11 denotes a fourth port of the second coupled transmission line segment.
Detailed Description
Example 1:
in the embodiment, the bandwidth of the filter is 0-400MHz, S11 is-15 dB, and the filter formed by ideal transmission line elements is taken as an example.
As shown in fig. 1, a transmission response reconfigurable coupled line internal loading type low-pass and band-stop microwave transmission line filter comprises: an input port (1), an output port (2), a coupling transmission line section I (3) and a coupling transmission line section II (4), a section of uniform transmission line (5), two sections of open-circuit branch line I (6) and open-circuit branch line II (7) for internal loading,
the coupling transmission line section I (3) comprises a port I (9) and a port II (10), and the coupling transmission line section II (4) comprises a port III (8) and a port IV (11);
the uniform transmission line (5) is connected in series to a port III (8) of the coupling transmission line section II (4) and a port II (10) of the coupling transmission line section I (3), the port III (8) of the coupling transmission line section II (4) is connected in parallel with an internally loaded open-circuit branch line I (6), and the port II (10) of the coupling transmission line section I (3) is connected in parallel with an internally loaded open-circuit branch line II (7); a low-pass and band-stop microwave transmission line filter with an internal loading open-circuit branch line and a self-coupling structure is formed.
Preferably, the two open stub wires for internal loading, i.e. the first (6) and the second (7), have the same impedance value.
Preferably, the position of the ripple in the passband is adjustable when the filter bandwidths are the same.
Preferably, when the filter bandwidths are the same, the positions of the out-of-band transmission zeros are variable, and the selectivity of the out-of-band rejection is increased.
Preferably, the electrical lengths of the first coupling transmission line section (3), the second coupling transmission line section (4), the uniform transmission line (5), the first open-circuit branch line (6) and the second open-circuit branch line (7) are all equal.
Preferably, the physical implementation manner of the transmission line in the filter includes a coaxial line, a microstrip line, a strip line, a parallel strip line, a coplanar waveguide and a combination thereof;
the transmission line comprises a first coupling transmission line section (3), a second coupling transmission line section (4), a uniform transmission line (5), a first open-circuit branch line (6) and a second open-circuit branch line (7).
The normalized impedance of the input port (1) and the normalized impedance of the output port (2) are both 10 hm; the even mode impedance value of the coupling transmission line section I (3) and the coupling transmission line section II (4) is 2.894210 hm, the odd mode impedance value is 1.663560 hm, the impedance value of the parallel uniform transmission line (5) is 2.293020 hm, and the impedance values of the internally loaded open-circuit branch line I (6) and the open-circuit branch line II (7) are 0.5117010 hm; the position of the ripple in the pass band is moved, and the normalized impedance value of the input port (1) and the normalized impedance value of the output port (2) are both 10 hm through software calculation, the even mode impedance value of the coupling transmission line section I (3) and the coupling transmission line section II (4) is 2.144960 hm, the odd mode impedance value is 2.124180 hm, the impedance value of the parallel uniform transmission line (5) is 3.140910 hm, and the impedance values of the internally loaded open-circuit branch line I (6) and the open-circuit branch line II (7) are 0.5990290 hm.
The adjustable amplitude of the ripple position in this embodiment is various, and the impedance values of the obtained coupled transmission line and the parallel uniform transmission line have various values, so the values mentioned in the above embodiment are not the only preferable value results.
Performing analog simulation on the circuit schematic diagram by using ADS simulation software, wherein an S parameter curve is shown in FIG. 2, wherein S11 is a signal reflection coefficient, and S12 is a signal transmission coefficient; as can be seen from the figure, the two corrugations of the curve S11 are equal in height, and the positions of the corrugations are variable in the case that the bandwidth and the corrugation coefficient are consistent; the position of the transmission zero point outside the passband is changed by changing the position of the ripple inside the passband, namely the suppression outside the passband is improved.
Example 2:
in the embodiment, the bandwidth of a group of filters is 0-200MHz, and S11 is-20 dB; the bandwidth of another group of filters is 0-400MHz, S11 is-20 dB, and a novel filter formed by ideal transmission line elements is taken as an example.
As shown in fig. 1, a transmission response reconfigurable coupled line internal loading type low-pass and band-stop microwave transmission line filter comprises: an input port (1), an output port (2), a coupling transmission line section I (3) and a coupling transmission line section II (4), a section of uniform transmission line (5), two sections of open-circuit branch line I (6) and open-circuit branch line II (7) for internal loading,
the coupling transmission line section I (3) comprises a port I (9) and a port II (10), and the coupling transmission line section II (4) comprises a port III (8) and a port IV (11);
a uniform transmission line (5) is connected in parallel to a port III (8) of the coupling transmission line section II (4) and a port II (10) of the coupling transmission line section I (3), the port III (8) of the coupling transmission line section II (4) is connected in parallel to an internally loaded open-circuit branch line I (6), and the port II (10) of the coupling transmission line section I (3) is connected in parallel to an internally loaded open-circuit branch line II (7); a low-pass and band-stop microwave transmission line filter with an internal loading open-circuit branch line and a self-coupling structure is formed.
Preferably, the two open stub wires for internal loading, i.e. the first (6) and the second (7), have the same impedance value.
Preferably, the position of the ripple in the passband is adjustable when the filter bandwidths are the same.
Preferably, when the filter bandwidths are the same, the positions of the out-of-band transmission zeros are variable, and the selectivity of the out-of-band rejection is increased.
Preferably, the electrical lengths of the first coupling transmission line section (3), the second coupling transmission line section (4), the uniform transmission line (5), the first open-circuit branch line (6) and the second open-circuit branch line (7) are all equal.
Preferably, the physical implementation manner of the transmission line in the filter includes a coaxial line, a microstrip line, a strip line, a parallel strip line, a coplanar waveguide and a combination thereof;
the transmission line comprises a first coupling transmission line section (3), a second coupling transmission line section (4), a uniform transmission line (5), a first open-circuit branch line (6) and a second open-circuit branch line (7).
The normalized impedance of the input port (1) and the normalized impedance of the output port (2) are both 10 hm; when the bandwidth of the filter is 0-200MHz, the even mode impedance value of the coupling transmission line node I (3) and the coupling transmission line node II (4) is 4.11150 hm, the odd mode impedance value is 2.631490 hm, the impedance value of the parallel uniform transmission line (5) is 4.714410 hm, and the impedance values of the internally loaded open-circuit branch line I (6) and the open-circuit branch line II (7) are 0.225190 hm; when the bandwidth of the filter is 0-400MHz, the normalized impedance values of the input port (1) and the output port (2) are all 10 hm through software calculation, the even mode impedance values of the coupling transmission line node I (3) and the coupling transmission line node II (4) are 1.819560 hm, the odd mode impedance value is 1.718330 hm, the impedance value of the parallel uniform transmission line (5) is 2.677160 hm, and the impedance values of the internally loaded open-circuit branch line I (6) and the open-circuit branch line II (7) are 0.6138740 hm.
The adjustable amplitude of the ripple position in this embodiment is various, and the impedance values of the obtained coupled transmission line and the parallel uniform transmission line have various values, so the values mentioned in the above embodiment are not the only preferable value results.
The circuit schematic diagram is subjected to analog simulation by using ADS simulation software, and an S parameter curve is obtained as shown in FIG. 3, wherein S11 is a signal reflection coefficient and S12 is a signal transmission coefficient. As can be seen from the figure, the novel filter can meet the requirements of different bandwidths, and the transmission response in the pass band has the characteristic of equal ripple of amplitude.
Claims (1)
1. A transmission response reconfigurable coupling line internal loading type low-pass and band-stop microwave transmission line filter is characterized in that: the method comprises the following steps: an input port (1), an output port (2), a coupling transmission line section I (3) and a coupling transmission line section II (4), a section of uniform transmission line (5), two sections of open-circuit branch line I (6) and open-circuit branch line II (7) for internal loading,
the coupling transmission line section I (3) comprises a port I (9) and a port II (10), and the coupling transmission line section II (4) comprises a port III (8) and a port IV (11);
the uniform transmission line (5) is connected in series with a port III (8) of the coupling transmission line section II (4) and a port II (10) of the coupling transmission line section I (3), the port III (8) of the coupling transmission line section II (4) is connected in parallel with an internally loaded open-circuit branch line I (6), and the port II (10) of the coupling transmission line section I (3) is connected in parallel with an internally loaded open-circuit branch line II (7);
the input port (1) is connected with a first port (9); the output port (2) is connected with a port four (11);
the port I (9) is opposite to the port III (8) in parallel; the second port (10) is opposite to the fourth port (11) in parallel;
thereby forming a low-pass and band-stop microwave transmission line filter with an internal loading open-circuit branch line and a self-coupling structure;
the impedance values of the two sections of the first open-circuit branch line (6) and the second open-circuit branch line (7) for internal loading are the same;
when the filter bandwidths are the same, the positions of the ripples in the pass bands are adjustable;
when the bandwidths of the filters are the same, the positions of out-of-band transmission zeros are variable, and the selectivity of out-of-band rejection is increased;
the electrical lengths of the coupling transmission line section I (3), the coupling transmission line section II (4), the uniform transmission line (5), the open-circuit branch line I (6) and the open-circuit branch line II (7) are equal;
the physical realization mode of the transmission line in the filter comprises a coaxial line, a microstrip line, a strip line, a parallel strip line, a coplanar waveguide and a combination thereof;
the transmission line comprises a first coupling transmission line section (3), a second coupling transmission line section (4), a uniform transmission line (5), a first open-circuit branch line (6) and a second open-circuit branch line (7).
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910921307.8A CN110707402B (en) | 2019-09-27 | 2019-09-27 | Transmission response reconfigurable coupling line internal loading type low-pass and band-stop microwave transmission line filter |
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| CN201910921307.8A CN110707402B (en) | 2019-09-27 | 2019-09-27 | Transmission response reconfigurable coupling line internal loading type low-pass and band-stop microwave transmission line filter |
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| CN110707402B true CN110707402B (en) | 2021-11-12 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US5015976A (en) * | 1988-11-11 | 1991-05-14 | Matsushita Electric Industrial Co., Ltd. | Microwave filter |
| JP2000183603A (en) * | 1998-12-10 | 2000-06-30 | Mitsubishi Electric Corp | Lowpass filter |
| KR100401124B1 (en) * | 2001-03-14 | 2003-10-10 | 주식회사 텔웨이브 | The High Temperature Superconductor low-pass filter for broadband harmonic rejection |
| CN204407450U (en) * | 2014-11-20 | 2015-06-17 | 中国航空工业集团公司雷华电子技术研究所 | A kind of low pass filter with coupling function |
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