CN111740190B - Broadband band-stop filter based on transmission line parallel multi-section open circuit stub line and design method thereof - Google Patents
Broadband band-stop filter based on transmission line parallel multi-section open circuit stub line and design method thereof Download PDFInfo
- Publication number
- CN111740190B CN111740190B CN202010736956.3A CN202010736956A CN111740190B CN 111740190 B CN111740190 B CN 111740190B CN 202010736956 A CN202010736956 A CN 202010736956A CN 111740190 B CN111740190 B CN 111740190B
- Authority
- CN
- China
- Prior art keywords
- transmission line
- circuit
- open
- transmission
- sections
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 230000005540 biological transmission Effects 0.000 title claims abstract description 181
- 238000000034 method Methods 0.000 title claims abstract description 18
- 238000013461 design Methods 0.000 title claims abstract description 13
- 239000011159 matrix material Substances 0.000 claims description 22
- 238000012546 transfer Methods 0.000 claims description 13
- 239000000126 substance Substances 0.000 claims description 5
- 238000012885 constant function Methods 0.000 claims description 2
- 238000004088 simulation Methods 0.000 description 8
- 238000010586 diagram Methods 0.000 description 7
- PCTMTFRHKVHKIS-BMFZQQSSSA-N (1s,3r,4e,6e,8e,10e,12e,14e,16e,18s,19r,20r,21s,25r,27r,30r,31r,33s,35r,37s,38r)-3-[(2r,3s,4s,5s,6r)-4-amino-3,5-dihydroxy-6-methyloxan-2-yl]oxy-19,25,27,30,31,33,35,37-octahydroxy-18,20,21-trimethyl-23-oxo-22,39-dioxabicyclo[33.3.1]nonatriaconta-4,6,8,10 Chemical compound C1C=C2C[C@@H](OS(O)(=O)=O)CC[C@]2(C)[C@@H]2[C@@H]1[C@@H]1CC[C@H]([C@H](C)CCCC(C)C)[C@@]1(C)CC2.O[C@H]1[C@@H](N)[C@H](O)[C@@H](C)O[C@H]1O[C@H]1/C=C/C=C/C=C/C=C/C=C/C=C/C=C/[C@H](C)[C@@H](O)[C@@H](C)[C@H](C)OC(=O)C[C@H](O)C[C@H](O)CC[C@@H](O)[C@H](O)C[C@H](O)C[C@](O)(C[C@H](O)[C@H]2C(O)=O)O[C@H]2C1 PCTMTFRHKVHKIS-BMFZQQSSSA-N 0.000 description 5
- 238000004364 calculation method Methods 0.000 description 4
- 238000010606 normalization Methods 0.000 description 3
- 230000001629 suppression Effects 0.000 description 3
- 238000004891 communication Methods 0.000 description 2
- 230000005672 electromagnetic field Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
Images
Classifications
-
- 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
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P11/00—Apparatus or processes specially adapted for manufacturing waveguides or resonators, lines, or other devices of the waveguide type
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Control Of Motors That Do Not Use Commutators (AREA)
Abstract
The invention discloses a broadband band-stop filter based on a transmission line parallel multi-section open circuit stub and a design method thereof, wherein the filter comprises: two source end impedance units; n sections of first transmission lines are connected in series between the two source end impedance units; a first connection region is formed between the source end impedance and the adjacent first transmission line, and a second connection region is formed between two adjacent sections of the first transmission lines; two sets of first open-circuit stubs are arranged in one-to-one correspondence to the first connection regions, and one ends of the first open-circuit stubs are connected to the first connection regions; one or more groups of second open-circuit stub lines which are arranged in one-to-one correspondence with the second connection regions, and one ends of the second open-circuit stub lines are connected to the second connection regions; wherein the first open stub comprises M sections of a second transmission line connected in series, and the second open stub comprises P sections of a third transmission line connected in series; and satisfies: n is more than or equal to 2, M is more than or equal to 1, P is more than or equal to 1, and M is more than or equal to P.
Description
Technical Field
The invention relates to the technical field of manufacturing of microstrip line devices of radio frequency circuits, in particular to a broadband band-stop filter based on a transmission line connected with a plurality of open-circuit stub lines in parallel and a design method thereof.
Background
Band-stop filters are widely used as basic building blocks for radio frequency/microwave devices. Its main function is to make the signal in a given frequency band unable to pass (or be attenuated or suppressed), while in the remaining frequency range the signal passes well. Therefore, the band-stop filter is mainly used for eliminating single interference frequency, and has wide application in the technical field of communication. With the rapid development of modern wireless communication technology, the demand for band stop filters has increased rapidly. At the same time, the performance requirements for band stop filters are also increasing.
This makes wideband bandstop filters (WBSF) a hot issue of research, and a good wideband bandstop filter needs to have several good features: 1. the achievable bandwidth range of the stop band is large; 2. the pass-band loss is small; 3. the stop band signal suppression effect is good; 4. the selectivity is good.
At present, there are two main methods for designing and implementing a band-stop filter: one method is to implement a band-stop filter based on a coupled line structure, and the other is a conventional method, in which an open stub is inserted between lateral transmission lines to construct a band-stop filter.
The band-stop filter constructed by using the coupled line structure in the first method has the advantage that more transmission zeros can be generated, but the band-stop filter generally has a narrower band-stop bandwidth and a more complex circuit structure, so that the performance of the filter is limited. The second traditional design method is simple in circuit structure and convenient to implement, but a basic structure of a classical transverse transmission line with a single open stub inserted between the transmission lines cannot generate a new transmission zero except for a central frequency, and other similar design methods do not have comprehensive method guidance to generate quantitative transmission zero and reflection zero.
Disclosure of Invention
One of the objectives of the present invention is to provide a broadband band-stop filter based on a transmission line connecting multiple open-circuit branch lines in parallel, which can quantitatively increase the number of transmission zeros and reflection zeros, and has a wider stop band bandwidth and better roll-off characteristics.
The invention also aims to provide a design method of the broadband band-stop filter based on the transmission line parallel multi-section open-circuit branch lines, which calculates and determines the impedance value of each section of transmission line according to the circuit transmission function and the constraint condition and can ensure that the designed filter meets the required performance requirement.
The technical scheme provided by the invention is as follows:
a broadband band-stop filter based on a transmission line parallel multi-section open circuit stub comprises:
two source end impedance units;
n sections of first transmission lines are connected in series between the two source end impedance units;
a first connection region is formed between the source end impedance and the adjacent first transmission line, and a second connection region is formed between two adjacent sections of the first transmission lines;
two sets of first open-circuit stubs are arranged in one-to-one correspondence to the first connection regions, and one ends of the first open-circuit stubs are connected to the first connection regions;
one or more groups of second open-circuit stub lines which are arranged in one-to-one correspondence with the second connection regions, and one ends of the second open-circuit stub lines are connected to the second connection regions;
wherein the first open stub comprises M sections of a second transmission line connected in series, and the second open stub comprises P sections of a third transmission line connected in series;
and satisfies: n is more than or equal to 2, M is more than or equal to 1, P is more than or equal to 1, and M is more than or equal to P.
A design method of a broadband band-stop filter based on a transmission line connected with a plurality of open-circuit branch lines in parallel comprises the following steps:
step one, determining the number of sections N of a first transmission line, the number of sections M of a second transmission line, the number of sections P of a third transmission line, a stop band rejection SR and a return loss RL in a filter circuit according to the actual circuit size and performance requirements;
step two, calculating an integral transmission matrix of the filter circuit, and obtaining a transmission function of the filter circuit according to the integral transmission matrix;
and step three, determining the constraint condition of the transmission function, and determining the impedance values of the first transmission line, the second transmission line and the third transmission line according to the transmission function and the constraint condition.
Preferably, in the second step, the overall transmission matrix of the filter circuit is:
wherein the content of the first and second substances,
is the overall transmission matrix of the first set of open truncates,
is the overall transmission matrix of the second open stub set,
a transmission matrix of N sections of the first transmission line.
Preferably, in the second step, the transfer function of the filter circuit is obtained by the following relation:
wherein S is21Is the forward transfer function of the filter circuit, AT、BT、CTAnd DTRespectively, elements of the overall transmission matrix of the filter circuit.
Preferably, when P ═ 1,
wherein θ is the electrical length of the transmission line, and all the open-circuit stub lines and the transverse transmission line have the same electrical length; n is the number of the first transmission line; m is the number of the second transmission line; w is a characteristic constant function;
and
is a factor characteristic impedance function; h isM,NIs the overall characteristic impedance function.
Preferably, in the third step, the constraint condition of the transfer function is:
wherein D is1、D2… … are the poles of the S function of the filter circuit;
… … is the input reflection function S of the filter circuit11The electrical length at each of the pole points,
… … is the forward transfer function S of the filter circuit21Electrical length at each pole; RL is the return loss of the circuit and SR is the stop-band rejection of the circuit; epsilonRLIs S11Height of corrugation epsilonSRIs S21The height of the corrugations.
The invention has the beneficial effects that:
the broadband band-stop filter based on the transmission line parallel multi-section open-circuit branch line can quantitatively increase the number of transmission zero points and reflection zero points, and has wider stop band bandwidth and better roll-off characteristic.
According to the design method of the broadband band-stop filter based on the transmission line parallel multi-section open circuit stub, the impedance value of each section of transmission line is calculated and determined according to the circuit transmission function and the constraint condition, and the designed filter can meet the required performance requirement.
Drawings
Fig. 1 is a circuit model diagram of a broadband band-stop filter based on a transmission line connected with a plurality of open-circuit branch lines in parallel according to the present invention.
Fig. 2 is a circuit model diagram of a wideband band-stop filter in embodiment 1 of the present invention.
Fig. 3 is a circuit model diagram of a wideband band-stop filter in embodiment 2 of the present invention.
Fig. 4 is an ADS simulation diagram of the circuit model in embodiment 1 of the present invention.
Fig. 5 is an ADS simulation diagram of a circuit model in embodiment 2 of the present invention.
Fig. 6 is a circuit model diagram of a wideband band-stop filter in embodiment 3 of the present invention.
Fig. 7 is an ADS simulation diagram of a circuit model according to embodiment 3 of the present invention.
Detailed Description
The present invention is further described in detail below with reference to the attached drawings so that those skilled in the art can implement the invention by referring to the description text.
The invention provides a broadband band-stop filter based on a transmission line connected with a plurality of open-circuit branch lines in parallel, which is characterized in thatThe structure is symmetrical and has multiple transmission zero points and multiple reflection zero points. As shown in fig. 1, the broadband band-stop filter based on the transmission line parallel multi-section open-circuit stub comprises: two source end impedances Z0(equivalent of two load resistors) and a middle transverse N-section transmission line (Z)1、Z2… …) and N +1 sets of open stubs (Z) interspersed between the transverse transmission liness11、Zs12、…Zs1M，Zs21、Zs22、…Zs2P) (ii) a The number of the transmission line nodes in the open stub needs to be selected according to the practical working requirement and the rule given in the invention. Because the designed broadband band-stop filter is of a symmetrical structure, only the left half part of the circuit is marked. The impedance values of the two source end impedance units are Z0(ii) a The impedance values of the N sections of transverse first transmission lines are respectively as follows: z1，Z2，Z3… …; the impedance values of the second transmission lines in series connection with M sections in the first open circuit cutoff group are respectively as follows: zs11，Zs12，Zs13，……，Zs1M(ii) a The impedance values of the third transmission lines in series with the P sections in the second open circuit cutoff group are respectively as follows: zs21，Zs22，Zs23，……，Zs2P。
For further discussion of the influence of M, N, and P on the circuit structure and the circuit performance, and for convenience of circuit calculation and simplification of the circuit structure as much as possible to explain the most basic rule, the number of transmission line nodes in the (N-1) groups of open-circuit stub sets except the open-circuit stub on the leftmost side and the rightmost side is first selected as one node, that is, P is 1. And analyzing the influence of the M and N changes on the circuit structure and performance to obtain the rule of increasing the transmission zero point and the reflection zero point.
When M is fixed and N is continuously increased, the number of transmission zero points is unchanged, the number of reflection zero points is continuously increased, and the number of reflection zero points is 2(N +1), which is only related to N, namely, the reflection zero points can be regularly increased by increasing the number of sections of the transverse transmission line, and meanwhile, the transverse size of the circuit is increased.
When N is fixed and M is continuously increased, the number of reflection zero points is unchanged, the number of transmission zero points is continuously increased, and the number of transmission zero points is (M-W +1), where W is related to the value of M only, and W ═ sgn (MOD (M, 2)). That is, increasing the number of sections of the longitudinal transmission line can regularly increase the transmission zero point while the longitudinal size of the circuit increases.
M and N are unchanged, and when only P is increased, transmission zero points can also be increased, and every time P is increased by 1, the transmission zero points are symmetrically increased by 2, and the number of reflection zero points is unchanged.
Example 1(M ═ 4, N ═ 2, P ═ 1)
As shown in fig. 2, the source end impedance Z of the left end0One end of which is connected with the leftmost section Z of the transverse transmission line1One end of the transmission line Z and the first section of the transmission line Z of the leftmost open circuit intercept groups11And the other end is grounded; transmission line Zs11Is connected to the second transmission line Z in the leftmost open-circuit cut-off groups12One end of (a); transmission line Zs12Is connected to the third transmission line Z in the leftmost open-circuit cut-off line groups13One end of (a); transmission line Zs13Is connected to the fourth transmission line Z in the leftmost open-circuit cut-off line groups14(ii) a First section transverse transmission line Z1Is connected to a second set of open stubs Zs2And a second section of transverse transmission line Z1One end of (circuit left-right mirror symmetry); second section transverse transmission line Z1The other end of the transmission line Z is connected with the first section of the transmission line Z of the rightmost open circuit cut-off groups11And source end impedance Z of right end0One end of (circuit left-right mirror symmetry); source end impedance Z of right end0The other end is grounded; transmission line Zs11The other end of the transmission line Z is connected with the second section of transmission line Z in the rightmost open-circuit cut-off line groups12One end of (a); transmission line Zs12Is connected with the third transmission line Z in the rightmost open-circuit cut-off line groups13One end of (a); transmission line Zs13Is connected to the fourth transmission line Z in the leftmost open-circuit cut-off line groups14(circuit left-right mirror symmetry).
Example 2(M ═ 2, N ═ 4, P ═ 1)
As shown in fig. 3, the source end impedance Z of the left end0One end of which is connected with the leftmost section Z of the transverse transmission line1One end of the transmission line Z and the first section of the transmission line Z of the leftmost open circuit intercept groups11And the other end is grounded; transmission lineZs11Is connected to the second transmission line Z in the leftmost open-circuit cut-off groups12(ii) a First section transverse transmission line Z1Is connected to a second set of open stubs Zs2And a second section of transverse transmission line Z2One end of (a); second section transverse transmission line Z2Is connected with the third group of open stub Zs3Transverse to the third section of the transmission line Z2One end of (circuit left-right mirror symmetry); third section transverse transmission line Z2Is connected with the fourth group of open stub Zs2And a fourth section of transverse transmission line Z1One end of (circuit left-right mirror symmetry); fourth section transverse transmission line Z1The other end of the transmission line Z is connected with the first section of the transmission line Z of the rightmost open circuit cut-off groups11Is connected to the source impedance Z0One end of (circuit left-right mirror symmetry); source end impedance Z0The other end is grounded; transmission line Zs11The other end of the transmission line Z is connected with the second section of transmission line Z in the rightmost open-circuit cut-off line groups12(circuit left-right mirror symmetry).
Example 3(M ═ 3, N ═ 2, P ═ 2)
As shown in fig. 6, the source end impedance Z of the left end0One end of which is connected with the leftmost section Z of the transverse transmission line1One end of the transmission line Z and the first section of the transmission line Z of the leftmost open circuit intercept groups11And the other end is grounded; transmission line Zs11Is connected to the second transmission line Z in the leftmost open-circuit cut-off groups12One end of (a); transmission line Zs12Is connected to the third transmission line Z in the leftmost open-circuit cut-off line groups13(ii) a First section transverse transmission line Z1The other end of the first transmission line Z is connected with the second group of open stub liness21One end of (2) and a second section of transverse transmission line Z1One end of (circuit left-right mirror symmetry); transmission line Zs21Is terminated with a second section of transmission line Z in a second set of open stubss22(ii) a Second section transverse transmission line Z1The other end of the transmission line Z is connected with the first section of the transmission line Z of the rightmost open circuit cut-off groups11Source impedance Z of one end and the right end of0(circuit left-right mirror symmetry); source end impedance Z of right end0The other end is grounded; transmission line Zs11Is connected with the rightmost open circuitSecond section transmission line Z in sectional line groups12One end of (a); transmission line Zs12Is connected with the third transmission line Z in the rightmost open-circuit cut-off line groups13(circuit left-right mirror symmetry).
The invention also provides a design method of the broadband band-stop filter based on the transmission line parallel multi-section open circuit stub, which comprises the following steps:
step one, determining the working center frequency F required by a filter circuit according to the working occasion of the filter0Bandwidth of the pass band and the stop band, and stop band rejection SR and return loss RL.
And step two, selecting a proper number N of transverse transmission line sections according to requirements, namely selecting the number P of transmission line sections in other open circuit section line groups except the open circuit section line group at the two sides and the number M of transmission line sections in the open circuit section line groups at the two sides. As can be seen from the above-mentioned rules, M and P determine the number of transmission zeros. When N and P are unchanged, every time M is increased by 2, two transmission zero points are symmetrically increased; when M and N are not changed, every time P is increased by 1, the transmission zero point is symmetrically increased by two. And N determines the number of the reflection zeros, and when M and P are kept unchanged, N is increased by 1 every time, and the reflection zeros are symmetrically increased by two. Meanwhile, when M, N and P are changed, the circuit structure is changed, the number of impedances is changed, the number of degrees of freedom is different, and the number of degrees of freedom needs to meet the proposed performance requirements. In addition, the circuit size selection M, N, P can be used to determine the specific circuit structure.
And step three, calculating the ABCD matrix and the transmission function of the circuit.
The ABCD matrix of the ith transverse transmission line in the filter circuit structure is as follows:
the ABCD matrix of the single-section open-circuit stub is as follows:
the ABCD matrix of the M open circuit intercept groups is as follows:
the ABCD matrix of the entire filter circuit structure is:
wherein the content of the first and second substances,
a transmission matrix that is a first open stub,
a transmission matrix that is a second open stub,
a transmission matrix of N sections of the first transmission line. i is a natural number 0, 1, … …;
the filter is a polynomial only consisting of all normalized characteristic impedances of the filter, and different M and i values correspond to different polynomials; gMAlso a polynomial consisting of only all normalized characteristic impedances of the filter, different M corresponding to different polynomials.
The circuit structure has a transfer function of
Wherein the content of the first and second substances,
S21for the forward transmission coefficient in the circuit structure, stop-band rejection is generally referred to in band stop filters, and S is the case of equal ripple21The value at the ripple extreme point is SR; s11Is a circuit junctionThe input reflection coefficient in the structure, also called input return loss, is S in the case of equiripple11The value at the extreme point of ripple is RL; fcircuitIs S11And S21By the ratio function of FcircuitCan simplify the calculation and conveniently obtain S11And S21The pole zero of (2).
When P is 1, a unified expression can be generalized, and given here, M and N can be directly substituted by:
wherein i is a natural number 0, 1, … …;
b2i,
the filter is a polynomial only consisting of all normalized characteristic impedances of the filter, and different M, N and i values correspond to different polynomials; a isM,N,bM,NAnd cM,NAlso a polynomial consisting of only all normalized characteristic impedances of the filter, different M, N corresponding to different polynomials.
Wherein the content of the first and second substances,
and hM,NIs a polynomial determined by all normalized characteristic impedances of the filter.
And step four, enabling the obtained circuit transfer function to meet constraint conditions so as to meet the required performance requirements. If the calculation of the third step is combined according to the given theoretical analysis; assuming that the forward transfer function S of the circuit is obtained21With 2m equiripples, the forward transfer function of the circuit is input to the reflection function S11There are 2N equal ripples (the number of M and N is determined by the value of M and N), then:
according to the transmission function F calculated in the step threecircuitThe method comprises the following steps:
wherein D is1、D2… … are the poles of the S function of the filter circuit;
… … is the input reflection function S of the filter circuit11The electrical length at each of the pole points,
… … is the forward transfer function S of the filter circuit21Electrical length at each pole; RL is the return loss of the circuit and SR is the stop-band rejection of the circuit; epsilonRLIs S11Height of corrugation epsilonSRIs S21The height of the corrugations. The set of equations gives the control S11And S21The ripple height at the ripple extreme point makes it meet the requirements of return loss and stop band suppression.
And step five, searching a proper group of transmission line impedance values according to the impedance constraint condition so as to obtain the required band-stop filter.
And sixthly, calculating the actual parameters of the device by using electromagnetic field simulation software to obtain the corresponding line width and line length, then performing electromagnetic field simulation by using Sonnet software, and adjusting the parameters to obtain the optimal waveform. And then manufacturing an actual device according to the optimal data obtained by simulation.
Under the requirement of different circuit performances, other different circuit structures and circuit performance effects can be obtained by repeating the same six steps.
Three circuit configurations are selected for illustration, which are representative:
in example 1 (as shown in fig. 2), the center frequency of the filter circuit was determined to be 1GHz, the stop band rejection SR was determined to be 25dB, and the return loss RL was determined to be 20 dB. To facilitate bandwidth calculation, define θcIs S11And S21The electrical length of the frequency at the equal ripple dB value can be used to measure the equal ripple bandwidth, for S11In other words, θcThe larger the passband bandwidth; to S21In other words, θcThe smaller the stopband bandwidth. In the case of the example 1, the following,
is at an angle of 25 DEG,
at 21.5 deg., M is 4, N is 2, and P is 1.
The unified expression when M is 4, N is 2, and P is 1 is given as:
a4,2＝Zs11Zs2；
b0 up＝Z1；
b2 up＝Z1-2Zs2；
c8 up＝(Z1+2Zs2)(Z1+Zs11)2(Zs11+Zs12)2(Zs12+Zs13)2(Zs13+Zs14)2；
c4 down＝-(Zs11+Zs12)(Zs12+Zs13)(Zs13+Zs14)。
wherein, a4,2，b4,2，c4,2Is the overall characteristic impedance coefficient;
is a factor of the characteristic impedance coefficient; zs11，……，Zs14A second transmission line impedance value Z of M series in the first open-circuit cutoff groups21A third transmission line impedance value, Z, of the P-node series connection in the second open-circuit stub set1Is the transverse first transmission line impedance value.
Calculating in MATLAB according to the previous steps, verifying whether the obtained characteristic impedance value of the model can generate expected ripples in ADS software after obtaining a proper impedance value group, wherein the specific circuit normalization parameters are as shown in Table 1:
table 1 table of parameters of filter in example 1
The simulation result of the circuit ADS obtained under the set of impedance values is shown in fig. 4.
In example 2 (as shown in fig. 3), when M is 2 and N is 4, the filter has 3 transmission zeros and 10 reflection zeros; passband bandwidth: thetac s1136.1 °, stop band bandwidth: theta c s2140 °; the stop band rejection is 50dB and the return loss is 20 dB. The circuit has good stop band suppression and more reflection zeros. The normalization parameters in the circuit are shown in table 2:
table 2 parameter table of filter in example 2
Under the set of impedance values, the simulation result of the circuit ADS is shown in FIG. 5.
In example 3 (as shown in fig. 6), when M is 3 and N is 2, the filter has 5 transmission zeros and 6 reflection zeros; passband bandwidth: thetac s1127.3 °, stop band bandwidth: thetac s2135 °; the stop band rejection is 30dB and the return loss is 20 dB. The circuit has more transmission zero points and ensures S21Is equi-corrugated. The normalization parameters in the circuit are shown in table 3:
table 3 parameter table of filter in example 3
Under the set of impedance values, the simulation result of the circuit ADS is shown in FIG. 7.
While embodiments of the invention have been described above, it is not limited to the applications set forth in the description and the embodiments, which are fully applicable in various fields of endeavor to which the invention pertains, and further modifications may readily be made by those skilled in the art, it being understood that the invention is not limited to the details shown and described herein without departing from the general concept defined by the appended claims and their equivalents.
Claims (2)
1. A design method of a broadband band-stop filter based on a transmission line parallel multi-section open-circuit stub is characterized in that the broadband band-stop filter based on the transmission line parallel multi-section open-circuit stub comprises the following steps:
two source end impedance units;
n sections of first transmission lines are connected in series between the two source end impedance units;
a first connection region is formed between the source end impedance and the adjacent first transmission line, and a second connection region is formed between two adjacent sections of the first transmission lines;
two sets of first open-circuit stubs are arranged in one-to-one correspondence to the first connection regions, and one ends of the first open-circuit stubs are connected to the first connection regions;
one or more groups of second open-circuit stub lines which are arranged in one-to-one correspondence with the second connection regions, and one ends of the second open-circuit stub lines are connected to the second connection regions;
wherein the first open stub comprises M sections of a second transmission line connected in series, and the second open stub comprises P sections of a third transmission line connected in series;
and satisfies: n is more than or equal to 2, M is more than or equal to 1, P is more than or equal to 1, and M is more than or equal to P;
the design method comprises the following steps:
step one, determining the number of sections N of a first transmission line, the number of sections M of a second transmission line, the number of sections P of a third transmission line, a stop band rejection SR and a return loss RL in a filter circuit according to the actual circuit size and performance requirements;
step two, calculating an integral transmission matrix of the filter circuit, and obtaining a transmission function of the filter circuit according to the integral transmission matrix;
step three, determining a constraint condition of the transmission function, and determining impedance values of the first transmission line, the second transmission line and the third transmission line according to the transmission function and the constraint condition;
in the second step, the overall transmission matrix of the filter circuit is:
wherein the content of the first and second substances,
is the overall transmission matrix of the first set of open truncates,
is the overall transmission matrix of the second open stub set,
a transmission matrix of N sections of first transmission lines;
in the second step, the transfer function of the filter circuit is obtained by the following relation:
wherein S is21Is the forward transfer function of the filter circuit, AT、BT、CTAnd DTRespectively, elements in the overall transmission matrix of the filter circuit;
in the third step, the constraint conditions of the transfer function are:
wherein D is1、D2… … are the poles of the S function of the filter circuit;
inputting reflection function S for filter circuit11The electrical length at each of the pole points,
as a forward transfer function S of the filter circuit21Electrical length at each pole;RL is the return loss of the circuit and SR is the stop-band rejection of the circuit; epsilonRLIs S11Height of corrugation epsilonSRIs S21The height of the corrugations.
2. The design method of the broadband band-stop filter based on the transmission line parallel multi-section open-circuit stub as claimed in claim 1, wherein when P is 1,
wherein θ is the electrical length of the transmission line, and all the open-circuit stub lines and the transverse transmission line have the same electrical length; n is the number of the first transmission line; m is the number of the second transmission line; w is a characteristic constant function;
and
is a factor characteristic impedance function; h isM,NIs the overall characteristic impedance function.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010736956.3A CN111740190B (en) | 2020-07-28 | 2020-07-28 | Broadband band-stop filter based on transmission line parallel multi-section open circuit stub line and design method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010736956.3A CN111740190B (en) | 2020-07-28 | 2020-07-28 | Broadband band-stop filter based on transmission line parallel multi-section open circuit stub line and design method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111740190A CN111740190A (en) | 2020-10-02 |
| CN111740190B true CN111740190B (en) | 2021-07-30 |
Family
ID=72656230
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010736956.3A Active CN111740190B (en) | 2020-07-28 | 2020-07-28 | Broadband band-stop filter based on transmission line parallel multi-section open circuit stub line and design method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111740190B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113285192B (en) * | 2021-04-01 | 2022-05-03 | 西安理工大学 | Parallel open-circuit stub type broadband band elimination filter based on TSV |
| CN113488750B (en) * | 2021-06-09 | 2022-07-29 | 电子科技大学 | S21 transmission matrix adjustable broadband band elimination filter |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0437201A (en) * | 1990-05-31 | 1992-02-07 | Matsushita Electric Ind Co Ltd | Microwave filter |
| JPH1065402A (en) * | 1996-06-26 | 1998-03-06 | Korea Electron Telecommun | Low pass filter adopting microstrip open stub line system and its manufacture |
| CN109286055A (en) * | 2018-10-25 | 2019-01-29 | 成都会讯科技有限公司 | A kind of symmetric double detail parallel resonator and bandpass filter and design method |
| CN109638394A (en) * | 2018-11-01 | 2019-04-16 | 深圳华中科技大学研究院 | A kind of chip-scale millimeter wave multi-pass band bandpass filter based on multimode resonator |
| CN109766657B (en) * | 2019-01-25 | 2020-08-07 | 吉林大学 | Wilkinson power divider with Chebyshev filtering characteristic with isolation frequency point alignment and preparation method thereof |
| CN109687834B (en) * | 2019-01-25 | 2020-11-27 | 吉林大学 | Chebyshev filtering impedance converter and method for multi-order transmission line and short-circuit line |
| CN210006871U (en) * | 2019-08-22 | 2020-01-31 | 成都安普利电子有限责任公司 | wide stop band low-pass filter |
-
2020
- 2020-07-28 CN CN202010736956.3A patent/CN111740190B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN111740190A (en) | 2020-10-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111740190B (en) | Broadband band-stop filter based on transmission line parallel multi-section open circuit stub line and design method thereof | |
| Mandal et al. | Design of sharp-rejection, compact, wideband bandstop filters | |
| CN109818123B (en) | Coupling line cascaded Chebyshev filter impedance converter and establishment method thereof | |
| CN111027265B (en) | Method for establishing ultra-wideband first-class Chebyshev multi-node Wilkinson power divider with equal-ripple isolation characteristic | |
| Chen et al. | Synthesis of multi-port filtering power divider for mixed topology using matrix optimization | |
| CN108287937B (en) | High-selectivity compact band-pass filter and design method thereof | |
| KR100328145B1 (en) | Microwave Multiplexer with Variable Non-Bandwidth Channels | |
| CN109687086B (en) | Coupling line cascaded Chebyshev filtering type Wilkinson power divider | |
| US20220238975A1 (en) | Electrical filter structure | |
| US5101181A (en) | Logarithmic-periodic microwave multiplexer | |
| Leong et al. | A new class of dual-band waveguide filters based on Chebyshev polynomials of the second kind | |
| CN113140882B (en) | Miniaturized filtering crossing directional coupler | |
| Padmavathi et al. | Analysis and design of reflectionless filters for c band applications | |
| CN111326836B (en) | Y-shaped interdigital capacitance adjustable coupling structure and superconducting filter | |
| CN110798175A (en) | Broadband linear phase filter based on negative group delay circuit | |
| CN111834726A (en) | Broadband filtering power divider capable of realizing high power division ratio | |
| Wenzel | The modern network theory approach to microwave filter design | |
| Zhao et al. | Fast Synthesis of Elliptic Prototype Filters | |
| TWI758932B (en) | Electrical filter structure | |
| CN220984830U (en) | Low-pass filter and communication equipment | |
| CN113972456B (en) | Three-order wide stop band 5G microstrip filter | |
| JP2002076703A (en) | Distributed constant filter | |
| CN118263649A (en) | Preparation method of adjustable filter attenuator and adjustable filter attenuator | |
| CN117977141A (en) | Band-stop filter with quasi-elliptic response and design method thereof | |
| CN115774979A (en) | Design method of high-order ultra-wideband filter and terminal |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20240521 Address after: 215500 No.9, Sihai Road, Changshu Economic and Technological Development Zone, Suzhou City, Jiangsu Province Patentee after: Suzhou zhimaixin Information Technology Co.,Ltd. Country or region after: China Address before: 130000 No. 2699 Qianjin Street, Jilin, Changchun Patentee before: Jilin University Country or region before: China |