CN109167136B - Microstrip structure - Google Patents
Microstrip structure Download PDFInfo
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- CN109167136B CN109167136B CN201810964939.8A CN201810964939A CN109167136B CN 109167136 B CN109167136 B CN 109167136B CN 201810964939 A CN201810964939 A CN 201810964939A CN 109167136 B CN109167136 B CN 109167136B
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- microstrip
- orthogonal
- handed
- lines
- microstrip lines
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P3/00—Waveguides; Transmission lines of the waveguide type
- H01P3/02—Waveguides; Transmission lines of the waveguide type with two longitudinal conductors
- H01P3/08—Microstrips; Strip lines
-
- 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
- H01P1/20327—Electromagnetic interstage coupling
- H01P1/20354—Non-comb or non-interdigital filters
- H01P1/20381—Special shape resonators
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- Control Of Motors That Do Not Use Commutators (AREA)
Abstract
The invention relates to a microstrip structure for microwave transmission. The invention discloses a microstrip structure which can solve the problems of large size and large attenuation of a filter in the prior art. The microstrip structure is formed by alternately arranging orthogonal right-handed microstrip lines and orthogonal left-handed microstrip lines, and signals are transmitted between the orthogonal right-handed microstrip lines and the orthogonal left-handed microstrip lines through gap coupling; the orthogonal right-handed microstrip line is formed by two microstrip lines in an orthogonal mode, the intersection point is located in the center of the two microstrip lines, and the end parts of the two microstrip lines are bent by 90 degrees in the anticlockwise direction; the orthogonal left-handed microstrip line is formed by two microstrip lines in an orthogonal mode, an intersection point is located in the center of the two microstrip lines, and the end portions of the two microstrip lines are bent by 90 degrees in a clockwise direction. The invention adopts orthogonal structure and bending technique, so that the formed filter has smaller size and better performance than the comb filter. As the resonance unit, the layout is flexible, so that the stop band attenuation of the filter is larger, and the performance of the filter is improved. Due to the symmetry of the resonant cells, the arrangement of the short-circuit points can be chosen as desired.
Description
Technical Field
The invention relates to the technical field of microwave, in particular to a microstrip structure for microwave transmission, and particularly relates to a microstrip structure for forming functional components such as a filter or a frequency selector.
Background
The microstrip system is a common microwave functional system, and its structure includes a top signal layer 11, a middle dielectric substrate 10 and a bottom ground plane 12, as shown in fig. 1, some microwave functional systems may omit the bottom ground plane 12. The signal layer 11 and the ground plane 12 are usually made of a metal material, and may be a metal foil or a metal coating, and the signal layer is also called a microstrip line. The microstrip lines vary in shape according to different circuit functions, and most commonly are rectangular strips (also called rectangular strip microstrip lines), such as various transmission lines, open lines, short-circuit lines, λ/4 open lines, λ/2 short-circuit lines, and so on. These microstrip lines may constitute microwave functional components such as resonant cells, couplers, filters, and the like. Due to the different geometrical sizes of the microstrip lines, the distribution parameters are different. The microstrip line length h determines the resonance frequency of the microstrip line, and the microstrip line width w determines the impedance of the microstrip line. In a specific application occasion, the thin rectangular microstrip line mainly presents inductance characteristics and is called as an inductance microstrip line; the wider rectangular microstrip line mainly exhibits capacitance characteristics, and is called a capacitive microstrip line. By utilizing the distribution parameter characteristics of the microstrip lines, various microwave power components can be formed, and the four-order comb filter shown in fig. 2 is a microstrip filter with wide application, and the structure of the four-order comb filter comprises a substrate 10, a ground plane 12 (not visible in fig. 2) and a microstrip line 111. The ground plane 12 is disposed on the back side of the substrate 10, the microstrip ground line 110 and the microstrip line 111 are disposed on the front side of the substrate 10, and the microstrip ground line 110 may be connected to the ground plane 12 (some microstrip filters may omit the microstrip ground line 110). The filter has an operating frequency f and a wavelength λ, wherein the left and right ends of the filter are an input end 112 and an output end 113, and the middle of the filter is 4 resonance units formed by microstrip lines, and when one end of the microstrip line 111 is grounded (short-circuited) and the other end is open-circuited, the length h of the microstrip line is λ/4, so that resonance can be realized. The resonant units are equivalent to LC parallel circuits, the gaps 13 between the resonant units are equivalent to coupling capacitors Ct, the microstrip lines 111 transmit signals through electromagnetic coupling, and the equivalent circuits share four LC parallel branches as shown in fig. 3. In fig. 3, the coupling capacitance Ct, the resonance capacitance Co, and the resonance inductance Lo are related to the microstrip line structure and size.
As can be seen from fig. 2 and 3, the circuit diagram also has symmetry due to the symmetry of the microstrip line distribution. When the signal frequency is equal to the working frequency, the circuit resonates, the reactance of each branch circuit is large, and most of the signal is output from the input end 112 to the output end 113 through the main circuit; on the contrary, when the signal deviates from the working frequency, because the LC parallel circuit is not resonant, the reactance of each branch circuit is small, most of the signal is attenuated by the LC parallel branch circuit, and a small part of the signal is output from the main circuit. This is the working principle of the filter.
If the microstrip line 111 is not grounded, the microstrip line length is to be λ/2, and resonance can be achieved. It can be seen that the microstrip line grounding is advantageous for the miniaturization of the structure.
The comb-line microstrip filter has a simple structure, is easy to realize, but has a large size and a single topological structure, and can only be used for a linear input and output structure.
The comb-shaped microstrip filter in the prior art often cannot meet the design requirement, and if the order of the filter is increased, the size of the filter is greatly increased, and meanwhile, the attenuation of useful signals is increased.
Disclosure of Invention
The invention mainly aims to provide a microstrip structure which can form microwave functional components such as a filter and the like and can solve the problems of large size and large attenuation of the filter in the prior art.
In order to achieve the above object, according to an aspect of embodiments of the present invention, there is provided a microstrip structure, which is formed by alternately arranging orthogonal right-handed microstrip lines and orthogonal left-handed microstrip lines, and between which signals are transferred by slot coupling;
the orthogonal right-handed microstrip line is formed by two microstrip lines in an orthogonal mode, the intersection point is located in the center of the two microstrip lines, and the end parts of the two microstrip lines are bent by 90 degrees in the anticlockwise direction;
the orthogonal left-handed microstrip line is formed by two microstrip lines in an orthogonal mode, an intersection point is located in the center of the two microstrip lines, and the end parts of the two microstrip lines are bent by 90 degrees in a clockwise direction;
and the centers of each orthogonal right-handed microstrip line and each orthogonal left-handed microstrip line which are parallel to the coupling direction are positioned on a straight line.
Further, the microstrip line length h constituting the orthogonal right-handed microstrip line and the orthogonal left-handed microstrip line is related to the operating wavelength, and the bending length c is (0.2 to 0.3) h.
Furthermore, the orthogonal right-handed microstrip line and the orthogonal left-handed microstrip line both have grounding ends.
Further, the grounding end is positioned at the top end of the bent part.
The microstrip line bending device further comprises an input end and an output end which are formed by microstrip lines, wherein the input end and the output end are respectively connected with the head-tail orthogonal right-handed microstrip line bending part or the orthogonal left-handed microstrip line bending part.
Furthermore, the orthogonal right-handed microstrip line and the orthogonal left-handed microstrip line are arranged in an mxn matrix, wherein m and n are positive integers.
Further, m is 1 or n is 1.
Further, m is n.
Further, the microstrip structure is used for forming a filter.
Further, the microstrip structure is used for forming a frequency selector.
The invention has the advantages that the filter formed by adopting the orthogonal structure and the bending technology has smaller size and better performance than the comb filter. As the resonance units, the layout is flexible, and besides the linear type, the two-dimensional layout can be carried out to form a matrix, so that the stop band attenuation of the filter is larger, and the performance of the filter is improved. Due to the symmetry of the resonant cells, the arrangement of the short-circuit points can be chosen as desired.
The invention is further described with reference to the following figures and detailed description. Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention.
FIG. 1 is a schematic structural diagram of a microstrip system;
FIG. 2 is a diagram of a prior art comb filter structure;
FIG. 3 is a schematic diagram of an equivalent circuit of the filter of FIG. 2;
FIG. 4 is a schematic diagram of an orthogonal right-handed microstrip line structure;
FIG. 5 is a schematic diagram of an orthogonal left-handed microstrip line structure;
FIG. 6 is a schematic structural view of example 1;
FIG. 7 is a schematic structural view of example 2;
FIG. 8 is a schematic structural view of example 3;
FIG. 9 is a schematic structural view of example 4;
FIG. 10 is a schematic structural view of example 5.
In the drawings:
c is the bending length;
h is the microstrip line length;
w is the microstrip line width;
ct is coupling capacitance;
co is a resonance capacitor;
lo is resonance inductance;
1-9 are serial numbers of resonance units;
10 is a dielectric substrate;
11 is a signal layer;
12 is a ground plane;
13 is a gap;
110 is a microstrip grounding wire;
111 is a microstrip line;
112 is an input terminal;
113 is an output end;
114 is a bent portion;
Detailed Description
It should be noted that the specific embodiments, examples and features thereof may be combined with each other in the present application without conflict. The present invention will now be described in detail with reference to the attached figures in conjunction with the following.
In order to make the technical solutions of the present invention better understood, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, but not all embodiments. All other embodiments and examples obtained by a person skilled in the art without any inventive step should fall within the protection scope of the present invention.
The microstrip structure of the invention is formed by alternately arranging orthogonal right-handed microstrip lines and orthogonal left-handed microstrip lines, and signals are transmitted between the orthogonal right-handed microstrip lines and the orthogonal left-handed microstrip lines through gap coupling.
The orthogonal right-handed microstrip line is formed by two identical microstrip lines in an orthogonal manner, the intersection point is located at the center of the two microstrip lines, and the end parts of the two microstrip lines are bent by 90 degrees in the counterclockwise direction, as shown in fig. 4.
The orthogonal left-handed microstrip line is also composed of two identical microstrip lines in an orthogonal manner, the intersection point is also located at the center of the two microstrip lines, and the bending direction of the end parts of the two microstrip lines is opposite to that of the right-handed microstrip line and is clockwise 90 degrees, as shown in fig. 5.
As can be seen from fig. 4 and 5, the microstrip lines forming the orthogonal right-handed microstrip line and the orthogonal left-handed microstrip line have the same size, and the orthogonal right-handed microstrip line and the orthogonal left-handed microstrip line are mirror images of each other. The structure characteristics bring great convenience to product design and generation, can reduce production cost and improve generation efficiency.
The length h of the microstrip line 111 is designed according to the operating frequency, and the length c of the bent portion 114 is about (0.2-0.3) h, and may be 0.25h as a typical value.
When the microstrip line is applied as a filter or a frequency selector, the orthogonal right-handed microstrip line and the orthogonal left-handed microstrip line of the invention are equivalent to a resonance unit.
If the grounding design is adopted, namely the orthogonal right-handed microstrip line and the orthogonal left-handed microstrip line both have grounding ends, the length h of the microstrip line 111 is matched with lambda/4 (h is approximately equal to lambda/4), where lambda is the wavelength corresponding to the working frequency. If the grounding design is not adopted, that is, the resonant unit has no grounding end, the length h of the microstrip line 111 should be matched with λ/2.
As shown in fig. 4 and 5, the resonant unit structure of the present invention has symmetry, and the orthogonal right-handed microstrip line and the orthogonal left-handed microstrip line are mirror images of each other, which provides great convenience for product design and processing, can improve production efficiency, and is beneficial to ensuring precision and consistency of the resonant unit.
Because the structure that the orthogonal right-handed microstrip line and the orthogonal left-handed microstrip line are alternately arranged is adopted, the length c of the bending part 114 ensures the coupling coefficient, and the microstrip line parallel to the coupling direction is positioned on a straight line, thereby being beneficial to improving the signal transmission efficiency and reducing the loss.
Example 1
Referring to fig. 6, the microstrip structure of this embodiment is a 3-order filter, which is formed by alternately arranging orthogonal right-handed microstrip lines and orthogonal left-handed microstrip lines, and includes 3 resonant units.
In the microstrip structure, the No. 1 resonance unit is an orthogonal right-handed microstrip line, the No. 2 resonance unit is an orthogonal left-handed microstrip line, the No. 3 resonance unit is an orthogonal right-handed microstrip line, and signals are coupled and transmitted among the resonance units through the gaps 13. As can be seen from fig. 6, the microstrip lines parallel to the coupling direction are on a straight line, and the microstrip lines have high signal transmission efficiency and low loss.
In order to reduce the size, the orthogonal right-handed microstrip line and the orthogonal left-handed microstrip line in the microstrip structure of this embodiment have a ground terminal, as shown in fig. 6, and each ground terminal is located at the top end of the bent portion 114.
In order to facilitate signal input and output, the microstrip structure of this embodiment further includes an input end 112 and an output end 113 formed by input microstrip lines. By adjusting the size and shape of the microstrip lines at the input end 112 and the output end 113, impedance matching can be realized, and signal attenuation and reflection are reduced.
As can be seen from fig. 6, in this example, the input end 112 is located at the bent portion 114 of the No. 1 resonance unit, and the output end is located at the bent portion 114 of the No. 3 resonance unit.
The microstrip structure of this embodiment can also be regarded as an m × n matrix formed by alternately arranging orthogonal right-handed microstrip lines and orthogonal left-handed microstrip lines. Where m is 1 and n is 3, i.e. the resonant cells are arranged along a transverse line.
It is obvious that when n is 1, it is a case where the resonance units are arranged along a vertical line.
Example 2
As shown in fig. 7, this is a 4-step filter, which is formed by arranging 4 resonant cells on a plane, and is a 2 × 2 matrix arrangement where m ═ n ═ 2.
As can be seen from fig. 7, due to the cross coupling (i.e., the coupling of the gap 13 between the No. 1 resonant cell and the No. 4 resonant cell), a zero point exists near the passband of the filter, which is beneficial to improving out-of-band rejection.
For other structures of the filter in this embodiment, reference may be made to the description of embodiment 1, and details are not described here.
Example 3
As shown in fig. 8, this is a 2 x 3 matrix comprising 6 resonant cells. Can be seen as a 6 th order filter.
In this example, the input end 112 of the microstrip filter is located in the No. 1 resonance unit, the output end 113 is located in the No. 6 resonance unit, and the signal transmission is output from the No. 1 resonance unit through the No. 2 resonance unit, the No. 3 resonance unit, the No. 4 resonance unit, the No. 5 resonance unit and the No. 6 resonance unit in sequence.
As can be seen from fig. 8, cross-coupling exists between the No. 1 resonance unit and the No. 6 resonance unit, and between the No. 2 resonance unit and the No. 5 resonance unit.
Example 4
Referring to fig. 9, the microstrip structure of this example is the same as embodiment 3 except that the output terminal 113 is disposed in the No. 5 resonant cell.
It can be seen that the microstrip structure signal of this example can be transmitted through 2 paths, which are respectively: the device comprises a No. 1 resonance unit, a No. 2 resonance unit, a No. 3 resonance unit and a No. 4 resonance unit; the number 1 resonance unit, the number 6 resonance unit, the number 5 resonance unit and the number 4 resonance unit.
As can be seen from embodiments 3 and 4, the same microstrip structure can realize different circuit functions by arranging different positions of the input terminal and the output terminal.
The microstrip structure of the invention has flexible arrangement of the grounding end, the input end and the output end and the resonance unit, can form various functional circuits and realize different functions.
Example 5
As shown in fig. 10, this is a 3 × 3 matrix structure, and is formed by arranging 9 resonance units. It can be seen that by arranging the positions of the input and output ends, the function and effect of the microstrip structure can be varied to achieve different technical goals.
As can be seen from fig. 10, the orthogonal right-handed microstrip line and the direct left-handed microstrip line of this embodiment have no ground, which is a symmetrical structure, and further illustrates the flexibility of the arrangement of the resonant unit and the diversity of the circuit functions.
As can be seen from the foregoing embodiments, in the microstrip structure of the present invention, the orthogonal right-handed microstrip line and the orthogonal left-handed microstrip line are alternately arranged in the transverse direction or the longitudinal direction, and the microstrip lines of the resonant unit are all located on a straight line in the coupling direction in the transverse direction or the longitudinal direction. The structure has high microwave transmission efficiency and low loss. The bending part increases the coupling coefficient, and is beneficial to reducing the passband impedance. The microstrip structure has flexible arrangement of the resonance units and wide application.
Claims (10)
1. A microstrip structure is formed by alternately arranging orthogonal right-handed microstrip lines and orthogonal left-handed microstrip lines, and signals are transmitted between the orthogonal right-handed microstrip lines and the orthogonal left-handed microstrip lines through gap coupling;
the orthogonal right-handed microstrip line is formed by two microstrip lines in an orthogonal mode, the intersection point is located in the center of the two microstrip lines, and the end parts of the two microstrip lines are bent by 90 degrees in the anticlockwise direction;
the orthogonal left-handed microstrip line is formed by two microstrip lines in an orthogonal mode, an intersection point is located in the center of the two microstrip lines, and the end parts of the two microstrip lines are bent by 90 degrees in a clockwise direction;
and the centers of each orthogonal right-handed microstrip line and each orthogonal left-handed microstrip line which are parallel to the coupling direction are positioned on a straight line.
2. The microstrip structure according to claim 1, wherein the microstrip line length h constituting the orthogonal right-handed microstrip line and the orthogonal left-handed microstrip line is related to the operating wavelength, and the bending length c is (0.2-0.3) h.
3. The microstrip structure of claim 1 wherein the orthogonal right-handed microstrip and the orthogonal left-handed microstrip each have a ground.
4. A microstrip structure according to claim 3 wherein said ground terminal is located at the top of the bend.
5. The microstrip structure according to claim 1, further comprising an input and an output formed by microstrip lines, wherein the input and the output are respectively connected to the head-to-tail orthogonal right-handed microstrip line bending portion or the orthogonal left-handed microstrip line bending portion.
6. The microstrip structure according to any one of claims 1 to 5, wherein the orthogonal right-handed microstrip line and the orthogonal left-handed microstrip line are arranged in an mxn matrix, where m and n are positive integers.
7. The microstrip structure of claim 6, wherein m-1 or n-1.
8. A microstrip structure according to claim 6 wherein m-n.
9. A microstrip structure according to claim 6 wherein the microstrip structure is for forming a filter.
10. A microstrip structure according to claim 6 wherein the microstrip structure is adapted to form a frequency selector.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810964939.8A CN109167136B (en) | 2018-08-23 | 2018-08-23 | Microstrip structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201810964939.8A CN109167136B (en) | 2018-08-23 | 2018-08-23 | Microstrip structure |
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| CN109167136A CN109167136A (en) | 2019-01-08 |
| CN109167136B true CN109167136B (en) | 2021-04-06 |
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| CN201810964939.8A Expired - Fee Related CN109167136B (en) | 2018-08-23 | 2018-08-23 | Microstrip structure |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0938153A1 (en) * | 1998-02-24 | 1999-08-25 | Murata Manufacturing Co., Ltd. | Bandpass filter, duplexer , high-frequency module and communications device |
| CN201222527Y (en) * | 2008-06-27 | 2009-04-15 | 电子科技大学 | Microstrip groove cross coupling loop microwave band-pass filter |
| CN102544654A (en) * | 2012-02-28 | 2012-07-04 | 中国科学院微电子研究所 | Varactor electrically-adjustable microstrip filter |
| CN205680768U (en) * | 2016-06-27 | 2016-11-09 | 成都信息工程大学 | Micro-strip open loop wave filter |
| CN108376817A (en) * | 2018-02-06 | 2018-08-07 | 雄安华讯方舟科技有限公司 | Terahertz bandstop filter unit based on Meta Materials and Terahertz bandstop filter |
-
2018
- 2018-08-23 CN CN201810964939.8A patent/CN109167136B/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0938153A1 (en) * | 1998-02-24 | 1999-08-25 | Murata Manufacturing Co., Ltd. | Bandpass filter, duplexer , high-frequency module and communications device |
| CN201222527Y (en) * | 2008-06-27 | 2009-04-15 | 电子科技大学 | Microstrip groove cross coupling loop microwave band-pass filter |
| CN102544654A (en) * | 2012-02-28 | 2012-07-04 | 中国科学院微电子研究所 | Varactor electrically-adjustable microstrip filter |
| CN205680768U (en) * | 2016-06-27 | 2016-11-09 | 成都信息工程大学 | Micro-strip open loop wave filter |
| CN108376817A (en) * | 2018-02-06 | 2018-08-07 | 雄安华讯方舟科技有限公司 | Terahertz bandstop filter unit based on Meta Materials and Terahertz bandstop filter |
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| CN109167136A (en) | 2019-01-08 |
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