Asymmetric microstrip line coupler and radio frequency chip

Abstract

The utility model provides an asymmetric microstrip line coupler and a radio frequency chip, the asymmetric microstrip line coupler comprises a first microstrip line and a second microstrip line coupled with the first microstrip line, and two ends of the first microstrip line are respectively provided with a radio frequency input port and an antenna output port. Two ends of the second microstrip line are respectively provided with an isolation port and a coupling output port; the first micro-strip line and the second micro-strip line are arranged in an asymmetric multi-section structure; a first microstrip branch knot is arranged on the first microstrip line, and a second microstrip branch knot is arranged on the second microstrip line; the asymmetric microstrip line coupler further comprises a plurality of metal strip structures and a first resistor, the metal strip structures are fixed to the side, located on the isolation port, of the second microstrip line, and the isolation port is connected with the first resistor in series and then grounded. According to the asymmetric microstrip line coupler of the utility model, the coupling degree and directivity of the coupler can be improved.

Description

Technical Field

[0001] This utility model relates to the field of wireless communication technology, and in particular to an asymmetric microstrip coupler and radio frequency chip. Background Technology

[0002] With the rapid development of China's economy, the demand for consumer electronics is increasing. As a core component of consumer electronics, the performance of radio frequency (RF) front-end chips directly impacts the user experience. Microstrip directional couplers are important RF and microwave components widely used in signal distribution, coupling, and monitoring. Their basic structure consists of two parallel microstrip lines, achieving efficient signal transmission through electromagnetic coupling. Microstrip directional couplers typically have four ports: an input port, an output port, a coupling port, and a reflection port. This allows them to couple part of the input signal to the coupling port, while the remaining portion continues to the output port. The reflection port is used to receive uncoupled signals.

[0003] Currently, couplers in consumer electronics products typically use microstrip line couplers, such as... Figure 1 As shown, Port1 is the signal input port. Port2 is the antenna output port, used to connect the antenna. Port3 is the coupling port, used to monitor signal power. Port4 is the isolation port, typically connected to a 50Ω resistor and then grounded. Couplers usually have three important specifications: coupling coefficient, isolation coefficient, and directivity. The coupling coefficient is the ratio of the power at the coupling port to the power at the input port; the isolation coefficient is the ratio of the power at the isolation port to the power at the input port; and directivity is the difference between the coupling coefficient and the isolation coefficient. Directivity is a crucial indicator of coupler performance. Traditional microstrip line couplers typically have poor directivity, and once fabricated, their performance cannot be changed through adjustments.

[0004] Therefore, the aforementioned microstrip line coupler has a poor effect on improving directivity. Utility Model Content

[0005] To address the shortcomings of the existing technologies, this invention proposes an asymmetric microstrip line coupler and an RF chip to solve the problem of poor directionality improvement in existing asymmetric microstrip line couplers.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] In a first aspect, this utility model provides an asymmetric microstrip line coupler, which includes a first microstrip line and a second microstrip line coupled to the first microstrip line. The first microstrip line has a radio frequency input port and an antenna output port at its two ends, and the second microstrip line has an isolation port and a coupling output port at its two ends, respectively. Both the first microstrip line and the second microstrip line adopt an asymmetric multi-segment structure. The first microstrip line has a first microstrip stub, and the second microstrip line has a second microstrip stub.

[0008] The asymmetric microstrip line coupler also includes multiple metal strip structures and a first resistor. The multiple metal strip structures are fixed to one side of the second microstrip line located at the isolation port. The isolation port is grounded by connecting the first resistor in series.

[0009] Preferably, the first microstrip line includes a radio frequency input segment connected to the radio frequency input port, a first parallel segment extending vertically from one end of the radio frequency input segment away from the radio frequency input port, a first inclined segment extending from one end of the first parallel segment away from the radio frequency input segment by bending, a second parallel segment extending from one end of the first inclined segment away from the radio frequency input segment by bending, a second inclined segment extending from one end of the second parallel segment away from the radio frequency input segment by bending, a third parallel segment extending from one end of the second inclined segment away from the radio frequency input segment by bending, and an antenna output segment extending vertically from one end of the third parallel segment away from the radio frequency input segment.

[0010] The second microstrip line includes a coupling segment connecting the coupling output port, a fourth parallel segment extending vertically from one end of the coupling segment away from the coupling output port, a third inclined segment extending from one end of the fourth parallel segment away from the coupling segment, a fifth parallel segment extending from one end of the third inclined segment away from the coupling segment, a fourth inclined segment extending from one end of the fifth parallel segment away from the coupling segment, a sixth parallel segment extending from one end of the fourth inclined segment away from the coupling segment, and an isolation segment extending vertically from one end of the sixth parallel segment away from the coupling segment.

[0011] The first microstrip line and the second microstrip line are symmetrically arranged. The first parallel segment, the second parallel segment, the third parallel segment, the fourth parallel segment, the fifth parallel segment, and the sixth parallel segment all extend along a first direction. The RF input segment and the antenna output segment both extend along a second direction, and the coupling segment and the isolation segment both extend along a third direction. The second direction is opposite to the third direction, and the first direction is perpendicular to the second direction. The distance between the third parallel segment and the sixth parallel segment is greater than the distance between the second parallel segment and the fifth parallel segment, and the distance between the second parallel segment and the fifth parallel segment is greater than the distance between the first parallel segment and the fourth parallel segment.

[0012] Preferably, the RF input segment and the coupling segment extend in directions away from each other, and the antenna output segment and the isolation segment extend in directions away from each other.

[0013] Preferably, the first microstrip branch is disposed on the side of the second parallel segment and the third parallel segment close to the second microstrip line;

[0014] The second microstrip stubs are respectively disposed on the side of the fifth parallel segment and the sixth parallel segment near the first microstrip line;

[0015] The first microstrip branch and the second microstrip branch are directly opposite each other and spaced apart.

[0016] Preferably, the plurality of metal strip structures include a first metal strip, a second metal strip, and a third metal strip that are fixed to the second microstrip line and are spaced apart from each other and parallel to each other; the length of the first metal strip is the same as the length of the third metal strip, and the length of the second metal strip is greater than the length of the first metal strip.

[0017] Preferably, the first metal strip, the second metal strip, and the third metal strip are respectively connected to the isolation section and extend in a direction close to the coupling section.

[0018] Preferably, the first metal strip, the second metal strip, and the third metal strip are all parallel to the sixth parallel segment, and their lengths are all less than that of the sixth parallel segment.

[0019] Secondly, this utility model provides a radio frequency chip, which includes the aforementioned asymmetric microstrip line coupler.

[0020] Compared with related technologies, in the embodiments of this utility model, the first microstrip line is provided with an RF input port and an antenna output port at both ends, and the second microstrip line is provided with an isolation port and a coupling output port at both ends; both the first and second microstrip lines adopt an asymmetrical multi-segment structure; the first microstrip line has a first microstrip stub, and the second microstrip line has a second microstrip stub; the asymmetrical microstrip line coupler also includes multiple metal strip structures and a first resistor, the multiple metal strip structures are fixed to one side of the second microstrip line located at the isolation port, and the isolation port is grounded after being connected in series with the first resistor; by adding multiple metal strip structures to the isolation port, this special isolation stub structure suppresses energy transmission to the isolation end, providing isolation without changing the coupling degree, thereby improving directivity. At the same time, it can also significantly improve the performance of the asymmetrical microstrip line coupler, and can be flexibly debugged, reducing the risk of redesign. Attached Figure Description

[0021] The present invention will now be described in detail with reference to the accompanying drawings. The above and other aspects of the present invention will become clearer and easier to understand through the detailed description in conjunction with the following drawings. (Appendix)

[0022] In the picture:

[0023] Figure 1 This is a schematic diagram of a traditional asymmetric microstrip line coupler.

[0024] Figure 2 for Figure 1 A schematic diagram of the simulation results for the coupling coefficient and isolation coefficient;

[0025] Figure 3 This is a schematic diagram of the structure of the asymmetric microstrip line coupler according to an embodiment of the present invention;

[0026] Figure 4 for Figure 3 A schematic diagram of the simulation results for the coupling coefficient and isolation coefficient.

[0027] Among them, 100, asymmetric microstrip line coupler; 1, first microstrip line; 11, RF input segment; 12, first parallel segment; 13, first tilted segment; 14, second parallel segment; 15, second tilted segment; 16, third parallel segment; 17, antenna output segment; 2, second microstrip line; 21, coupling segment; 22, fourth parallel segment; 23, third tilted segment; 24, fifth parallel segment; 25, fourth tilted segment; 26, sixth parallel segment; 27, isolation segment; 3, metal strip structure; 31, first metal strip; 32, second metal strip; 33, third metal strip; 4, first microstrip stub; 5, second microstrip stub. Detailed Implementation

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application, are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0029] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0030] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0031] Example 1

[0032] Please see Figures 3-4 As shown, this utility model embodiment provides an asymmetric microstrip line coupler 100, which includes a first microstrip line 1 and a second microstrip line 2 coupled to the first microstrip line 1. The first microstrip line 1 has a radio frequency input port (Port1) and an antenna output port (Port2) at both ends, and the second microstrip line 2 has an isolation port (Port4) and a coupling output port (Port3) at both ends. Both the first microstrip line 1 and the second microstrip line 2 adopt an asymmetric multi-segment structure. The first microstrip line 1 has a first microstrip stub 4, and the second microstrip line 2 has a second microstrip stub 5.

[0033] Specifically, by loading a first microstrip stub 4 and a second microstrip stub 5 in the middle of the first microstrip line 1 and the second microstrip line 2 respectively, capacitor compensation is formed above and below to change the characteristic impedance of the odd and even modes, thereby offsetting the difference in phase velocity between the two modes; the ground capacitance between each microstrip stub and the ground plane can be used to eliminate the influence of inductance and mutual inductance.

[0034] The asymmetric microstrip line coupler 100 also includes multiple metal strip structures 3 and a first resistor R1. The multiple metal strip structures 3 are fixed to one side of the second microstrip line 2 located at the isolation port. The isolation port is connected to ground via the first resistor R1 in series. Adding multiple metal strip structures 3 to the isolation port allows for a certain degree of energy diversion, resulting in a decrease in the energy output from the isolation port. This improves the isolation coefficient of the coupler without affecting its coupling coefficient, thereby enhancing its directivity. Simultaneously, it significantly improves the performance of the asymmetric microstrip line coupler 100 and allows for flexible debugging, reducing the risk of redesign. Furthermore, the microstrip line routing structure is simple, easy to manufacture, and has low processing costs.

[0035] In this embodiment, the first microstrip line 1 includes an RF input segment 11 connected to the RF input port, a first parallel segment 12 extending vertically from one end of the RF input segment 11 away from the RF input port, a first inclined segment 13 extending from one end of the first parallel segment 12 away from the RF input segment 11 by bending, a second parallel segment 14 extending from one end of the first inclined segment 13 away from the RF input segment 11 by bending, a second inclined segment 15 extending from one end of the second parallel segment 14 away from the RF input segment 11 by bending, a third parallel segment 16 extending from one end of the second inclined segment 15 away from the RF input segment 11 by bending, and an antenna output segment 17 extending vertically from one end of the third parallel segment 16 away from the RF input segment 11.

[0036] The second microstrip line 2 includes a coupling segment 21 connecting the coupling output port, a fourth parallel segment 22 extending vertically from the end of the coupling segment 21 away from the coupling output port, a third inclined segment 23 extending from the end of the fourth parallel segment 22 away from the coupling segment 21 by bending, a fifth parallel segment 24 extending from the end of the third inclined segment 23 away from the coupling segment 21 by bending, a fourth inclined segment 25 extending from the end of the fifth parallel segment 24 away from the coupling segment 21 by bending, a sixth parallel segment 26 extending from the end of the fourth inclined segment 25 away from the coupling segment 21 by bending, and an isolation segment 27 extending vertically from the end of the sixth parallel segment 26 away from the coupling segment 21.

[0037] The first microstrip line 1 and the second microstrip line 2 are symmetrically arranged. The first parallel segment 12, the second parallel segment 14, the third parallel segment 16, the fourth parallel segment 22, the fifth parallel segment 24, and the sixth parallel segment 26 all extend along a first direction. The RF input segment 11 and the antenna output segment 17 both extend along a second direction, and the coupling segment 21 and the isolation segment 27 both extend along a third direction. The second direction is opposite to the third direction, and the first direction is perpendicular to the second direction. The distance between the third parallel segment 16 and the sixth parallel segment 26 is greater than the distance between the second parallel segment 14 and the fifth parallel segment 24, and the distance between the second parallel segment 14 and the fifth parallel segment 24 is greater than the distance between the first parallel segment 12 and the fourth parallel segment 22. By using multiple microstrip lines, a wider operating bandwidth can be achieved.

[0038] In this embodiment, the radio frequency input segment 11 and the coupling segment 21 extend in directions away from each other, and the antenna output segment 17 and the isolation segment 27 extend in directions away from each other.

[0039] In this embodiment, the first microstrip stub 4 is respectively disposed on the side of the second parallel segment 14 and the third parallel segment 16 near the second microstrip line 2; the second microstrip stub 5 is respectively disposed on the side of the fifth parallel segment 24 and the sixth parallel segment 26 near the first microstrip line 1; the first microstrip stub 4 and the second microstrip stub 5 are directly opposite each other and spaced apart from each other. This makes the overall structure small and saves costs.

[0040] In this embodiment, the plurality of metal strip structures 3 include a first metal strip 31, a second metal strip 32, and a third metal strip 33 fixed side-by-side to the second microstrip line 2; the length of the first metal strip 31 is the same as the length of the third metal strip 33, and the length of the second metal strip 32 is greater than the length of the first metal strip 31. A certain capacitance is also generated between the first metal strip 31, the second metal strip 32, and the third metal strip 33, which dissipates some of the transmitted energy. The three added metal strip structures 3 resonate through the generated capacitance and inductance, hindering the transmission of high-frequency signals to the isolation end, thus improving the isolation coefficient of the coupler at the high-frequency end. Since the directivity is the difference between the coupling coefficient and the isolation coefficient, the directivity of the coupler in the high-frequency range is improved. The directivity of the coupler in the high-frequency range is approximately 33dB. In contrast, traditional... Figure 2 In the figure, S(3,1) is the coupling coefficient and S(4,1) is the isolation coefficient. Calculations show that the directivity is less than 14 dB across the entire frequency band, and is even worse at lower frequencies. Therefore, this asymmetric microstrip line coupler 100 is superior to... Figure 2 The directivity of the traditional dual microstrip line coupler 100 is improved by 19 dB.

[0041] Specifically, the asymmetric microstrip line coupler 100 with an added metal strip structure 3 at the isolation end was simulated. The basic structure of the coupler is as follows: Figure 3 As shown, the simulation results are as follows: Figure 4 As shown in the figure, it can be seen that the directionality of the coupler is significantly improved after adding metal strip structure 3 at the isolation end.

[0042] In this embodiment, the first metal strip 31, the second metal strip 32, and the third metal strip 33 are respectively connected to the isolation section 27 and extend towards the coupling section 21. The three added metal strip structures 3 resonate through the generated capacitance and inductance, hindering the transmission of high-frequency signals to the isolation end and improving the isolation coefficient of the coupler at the high-frequency end.

[0043] In this embodiment, the first metal strip 31, the second metal strip 32, and the third metal strip 33 are all parallel to the sixth parallel segment 26, and their lengths are all less than that of the sixth parallel segment 26. This reduces production costs.

[0044] Example 2

[0045] This invention provides a radio frequency (RF) chip, which includes the asymmetric microstrip line coupler 100 described in Embodiment 1 above. The technical problem solved and the technical effects produced by the RF chip are the same as those of the asymmetric microstrip line coupler 100 described above, and will not be repeated here.

[0046] It should be noted that the various embodiments described above with reference to the accompanying drawings are only illustrative of the present invention and not intended to limit its scope. Those skilled in the art should understand that any modifications or equivalent substitutions made to the present invention without departing from its spirit and scope should be covered within the scope of the present invention. Furthermore, unless the context otherwise requires, singular terms include plural forms, and vice versa. Additionally, unless specifically stated otherwise, all or part of any embodiment may be used in conjunction with all or part of any other embodiment.

Claims

1. An asymmetric microstrip line coupler, the asymmetric microstrip line coupler comprising a first microstrip line and a second microstrip line coupled to the first microstrip line, wherein the first microstrip line has a radio frequency input port and an antenna output port respectively at its two ends, and the second microstrip line has an isolation port and a coupling output port respectively at its two ends; characterized in that, Both the first microstrip line and the second microstrip line adopt an asymmetrical multi-segment structure; the first microstrip line has a first microstrip branch, and the second microstrip line has a second microstrip branch. The asymmetric microstrip line coupler also includes multiple metal strip structures and a first resistor. The multiple metal strip structures are fixed to one side of the second microstrip line located at the isolation port. The isolation port is grounded by connecting the first resistor in series.

2. The asymmetric microstrip line coupler according to claim 1, characterized in that, The first microstrip line includes an RF input segment connected to the RF input port, a first parallel segment extending vertically from one end of the RF input segment away from the RF input port, a first inclined segment extending from one end of the first parallel segment away from the RF input segment by bending, a second parallel segment extending from one end of the first inclined segment away from the RF input segment by bending, a second inclined segment extending from one end of the second parallel segment away from the RF input segment by bending, a third parallel segment extending from one end of the second inclined segment away from the RF input segment by bending, and an antenna output segment extending vertically from one end of the third parallel segment away from the RF input segment. The second microstrip line includes a coupling segment connecting the coupling output port, a fourth parallel segment extending vertically from one end of the coupling segment away from the coupling output port, a third inclined segment extending from one end of the fourth parallel segment away from the coupling segment, a fifth parallel segment extending from one end of the third inclined segment away from the coupling segment, a fourth inclined segment extending from one end of the fifth parallel segment away from the coupling segment, a sixth parallel segment extending from one end of the fourth inclined segment away from the coupling segment, and an isolation segment extending vertically from one end of the sixth parallel segment away from the coupling segment. The first microstrip line and the second microstrip line are symmetrically arranged. The first parallel segment, the second parallel segment, the third parallel segment, the fourth parallel segment, the fifth parallel segment, and the sixth parallel segment all extend along a first direction. The RF input segment and the antenna output segment both extend along a second direction, and the coupling segment and the isolation segment both extend along a third direction. The second direction is opposite to the third direction, and the first direction is perpendicular to the second direction. The distance between the third parallel segment and the sixth parallel segment is greater than the distance between the second parallel segment and the fifth parallel segment, and the distance between the second parallel segment and the fifth parallel segment is greater than the distance between the first parallel segment and the fourth parallel segment.

3. The asymmetric microstrip line coupler according to claim 2, characterized in that, The radio frequency input segment and the coupling segment extend in directions away from each other, and the antenna output segment and the isolation segment extend in directions away from each other.

4. The asymmetric microstrip line coupler according to claim 2, characterized in that, The first microstrip branch is respectively disposed on the side of the second parallel segment and the third parallel segment near the second microstrip line; The second microstrip stubs are respectively disposed on the side of the fifth parallel segment and the sixth parallel segment near the first microstrip line; The first microstrip branch and the second microstrip branch are directly opposite each other and spaced apart.

5. The asymmetric microstrip line coupler according to claim 2, characterized in that, The plurality of metal strip structures include a first metal strip, a second metal strip, and a third metal strip that are fixed to the second microstrip line and are spaced apart from each other and parallel to each other; the length of the first metal strip is the same as the length of the third metal strip, and the length of the second metal strip is greater than the length of the first metal strip.

6. The asymmetric microstrip line coupler according to claim 5, characterized in that, The first metal strip, the second metal strip, and the third metal strip are respectively connected to the isolation section and extend in a direction close to the coupling section.

7. The asymmetric microstrip line coupler according to claim 6, characterized in that, The first metal strip, the second metal strip, and the third metal strip are all parallel to the sixth parallel segment, and their lengths are all less than that of the sixth parallel segment.

8. A radio frequency chip, characterized in that, The radio frequency chip includes the asymmetric microstrip line coupler as described in any one of claims 1-7.

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