Microstrip line coupler and radio frequency chip
By employing a double-layer substrate and a comb-shaped metal branch structure in the microstrip line coupler, the problems of high cost and poor directivity of the microstrip line coupler are solved, achieving higher directivity and isolation, and reducing processing costs.
Patent Information
- Application Number
- CN202423100163.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-13
- Publication Date
- 2025-11-18
- Estimated Expiration
- 2034-12-13
AI Technical Summary
Existing microstrip line couplers are too expensive, have limited directivity improvement, and lack sufficient bandwidth for high directivity, resulting in excessive size and increased manufacturing costs.
By employing a double-layer substrate structure and adding a comb-shaped metal branch structure at the isolation port, energy transmission is suppressed, isolation and directivity are improved, and the processing cost is reduced by designing the flexibility of the operating bandwidth.
Without changing the coupling degree, the directivity and isolation of the microstrip coupler are significantly improved, the high-directivity frequency band is expanded, and the size and manufacturing cost of the microstrip coupler are reduced.
Smart Images
Figure CN223566861U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of wireless communication technology, and in particular to a microstrip coupler and a 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 and monitoring. They typically have four ports: an input port, an output port, a coupling port, and a reflection port, which couple the input signal to the output through the electromagnetic coupling characteristics of the microstrip line. Compared to waveguide couplers, microstrip directional couplers offer advantages such as miniaturization, ease of integration, and low loss, making them suitable for compact circuit designs. Their design considerations include operating frequency, coupling strength, and bandwidth, enabling their widespread application in wireless communication, RFID, and measurement systems. Through precise geometry and parameter optimization, microstrip directional couplers can meet the diverse needs of modern communication systems.
[0003] Currently, couplers in consumer electronics products typically use microstrip couplers, such as... Figure 1 As shown, Port1 is the RF 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 an important indicator of coupler performance. Traditional microstrip couplers typically have poor directivity, and while some microstrip directional couplers on the market have high directivity within their operating frequency band, the bandwidth of this high directivity is insufficient. Furthermore, some microstrip directional couplers, in order to adapt to certain frequency bands, result in excessively large overall sizes, increasing subsequent manufacturing costs.
[0004] Therefore, the cost of the aforementioned microstrip coupler is too high, and its effect on improving directionality is relatively small. Utility Model Content
[0005] To address the shortcomings of the existing technology, this invention proposes a microstrip line coupler and an RF chip to solve the problems of high cost and low directionality improvement of existing 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 a 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. The microstrip line coupler further includes a substrate, a first resistor, and a metal stub structure. The substrate includes a bottom layer, an intermediate layer, and a top layer stacked sequentially. The first microstrip line is fixed to the top layer, the second microstrip line is fixed to the bottom layer, the intermediate layer is a ground layer, and the bottom layer and the top layer are fixedly connected. The metal stub structure is fixed at the position of the isolation port of the second microstrip line.
[0008] Preferably, the metal branch structure includes a branch body fixed to the second microstrip line and a plurality of branches extending from the side of the branch body away from the first resistor.
[0009] Preferably, the plurality of branches are evenly arranged on opposite sides of the second microstrip line.
[0010] Preferably, the metal branch structure is configured as a comb-like structure.
[0011] Preferably, a clearance groove is formed through the substrate, and the first microstrip line and the second microstrip line are respectively opposite to the clearance groove and are spaced apart from each other.
[0012] Preferably, the first microstrip line includes a first microstrip body, a first segment and a second segment formed by bending the two ends of the first microstrip body respectively, and a first mounting portion protruding from the middle position of the first microstrip body; the radio frequency input port is disposed at the end of the first segment away from the first microstrip body, and the antenna output port is disposed at the end of the second segment away from the first microstrip body.
[0013] The second microstrip line includes a second microstrip body, a third segment and a fourth segment formed by bending the two ends of the second microstrip body respectively, and a second mounting portion protruding from the middle position of the second microstrip body; the coupling output port is located at the end of the third segment away from the second microstrip body, and the isolation port is located at the end of the fourth segment away from the second microstrip body; the metal stub structure is fixed to the fourth segment;
[0014] The first mounting part and the second mounting part are respectively disposed in the clearance groove.
[0015] Preferably, both the first microstrip line and the second microstrip line are configured with a U-shaped structure.
[0016] Secondly, this utility model provides a radio frequency chip, which includes the microstrip line coupler described above.
[0017] 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. The microstrip line coupler also includes a substrate, a first resistor, and a metal stub structure. The substrate includes a bottom layer, an intermediate layer, and a top layer stacked sequentially. The first microstrip line is fixed to the top layer, the second microstrip line is fixed to the bottom layer, the intermediate layer is a ground layer, and the bottom layer and the top layer are fixedly connected. The metal stub structure is fixed at the position of the isolation port of the second microstrip line. By adding a special "comb-shaped" metal stub structure to the isolation port to suppress energy transmission to the isolation port, isolation is provided without changing the coupling degree, thereby improving directivity. The high-directivity frequency band is also wider, further improving the performance of the microstrip coupler. At the same time, the coupler adopts a double-layer substrate structure, which makes the design of the working bandwidth more flexible. The microstrip directional coupler is small in size, which makes it easier to reduce the processing cost later. Attached Figure Description
[0018] 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. In the drawings:
[0019] Figure 1 This is a schematic diagram of a traditional microstrip line coupler.
[0020] Figure 2 for Figure 1 A schematic diagram of the simulation results for the coupling coefficient and isolation coefficient;
[0021] Figure 3 This is a schematic diagram of the structure of the microstrip line coupler according to an embodiment of the present invention;
[0022] Figure 4 for Figure 3 A schematic diagram of the simulation results for the coupling coefficient and isolation coefficient;
[0023] Figure 5 This is a schematic diagram of the structure of the first microstrip line according to an embodiment of the present invention;
[0024] Figure 6 This is a schematic diagram of the structure of the second microstrip line according to an embodiment of the present invention.
[0025] Among them, 100 is a microstrip line coupler, 1 is a first microstrip line, 11 is a first microstrip body, 12 is a first segment, 13 is a second segment, 14 is a first mounting part, 2 is a second microstrip line, 21 is a second microstrip body, 22 is a third segment, 23 is a fourth segment, 24 is a second mounting part, 3 is a substrate, 31 is a bottom layer, 32 is an intermediate layer, 33 is a top layer, 4 is a metal branch structure, 41 is a branch body, 42 is a branch, and 5 is a clearance groove. Detailed Implementation
[0026] 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.
[0027] 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.
[0028] 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.
[0029] Example 1
[0030] Please see Figures 3-6As shown, this embodiment of the present invention provides a 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 its two ends, and the second microstrip line 2 has an isolation port (Port4) and a coupling output port (Port3) at its two ends, respectively. The microstrip line coupler 100 also includes a substrate 3, a first resistor R1, and a metal stub structure 4. The substrate 3 includes a bottom layer 31, an intermediate layer 32, and a top layer 33 stacked sequentially. The first microstrip line 1 is fixed to the top layer 33, and the second microstrip line 2 is fixed to the bottom layer 31. The intermediate layer 32 is a ground layer and fixes the bottom layer 31 and the top layer 33 together. The microstrip line coupler 100 also includes a metal stub structure 4, which is fixed at the position of the isolation port of the second microstrip line 2. By adopting a double-layer dielectric substrate 3 structure with a bottom layer 31 and a top layer 33, the two dielectric substrates 3 are bonded together by an intermediate layer 32, and a special metal branch structure 4 is added after its isolation end, the isolation is effectively improved while ensuring the coupling degree; thereby improving the directivity and further improving the performance of the microstrip coupler.
[0031] In this embodiment, the metal branch structure 4 includes a branch body 41 fixed to the second microstrip line 2 and a plurality of branches 42 extending from the side of the branch body 41 away from the first resistor R1.
[0032] In this embodiment, a plurality of the branches 42 are evenly arranged on opposite sides of the second microstrip line 2.
[0033] In this embodiment, the metal branch structure 4 is configured as a comb-shaped structure. By adding a pair of "comb-shaped" metal branch structures 4 to the isolation port, the "comb-shaped" metal branch structures 4 can dissipate the transmitted energy to a certain extent, resulting in a decrease in the energy output from the isolation port. Without affecting the coupling coefficient of the coupler, the isolation coefficient of the coupler is improved, thereby improving the directivity.
[0034] Meanwhile, the branch body 41 (thick metal branches) of the "comb-like" branch structure mainly forms inductance. Multiple branches 42 (thin metal branches) on the thick metal branches form capacitances with each other, thus creating resonance. This suppresses signal transmission across the entire frequency band to the isolation port, improving the coupler's isolation coefficient across the entire frequency band. Since directivity is the difference between the coupling coefficient and the isolation coefficient, this improves the coupler's directivity in the high-frequency band. The coupler's directivity across the entire frequency band is approximately 25dB, compared to... Figure 2 The directivity of the traditional dual microstrip line coupler 100 is improved by 11 dB. Figure 2In the given values, the coupling coefficient is S(3,1) and the isolation coefficient is S(4,1). Calculations show that the directivity is less than 14dB across the entire frequency band, and is even worse at lower frequencies.
[0035] In this embodiment, a clearance slot 5 is formed through the substrate 3. The first microstrip line 1 and the second microstrip line 2 are respectively directly opposite the clearance slot 5 and are spaced apart from each other. Installing the first microstrip line 1 and the second microstrip line 2 in the clearance slot 5 facilitates the sharing of a common ground between the first microstrip line 1 and the second microstrip line 2, thereby increasing the coupling degree of the microstrip line directional coupler.
[0036] In this embodiment, the first microstrip line 1 includes a first microstrip body 11, a first segment 12 and a second segment 13 formed by bending the two ends of the first microstrip body 11 respectively, and a first mounting portion 14 protruding from the middle position of the first microstrip body 11; the radio frequency input port is disposed at the end of the first segment 12 away from the first microstrip body 11, and the antenna output port is disposed at the end of the second segment 13 away from the first microstrip body 11. The second microstrip line 2 includes a second microstrip body 21, a third segment 22 and a fourth segment 23 formed by bending the two ends of the second microstrip body 21 respectively, and a second mounting portion 24 protruding from the middle position of the second microstrip body 21; the coupling output port is disposed at the end of the third segment 22 away from the second microstrip body 21, and the isolation port is disposed at the end of the fourth segment 23 away from the second microstrip body 21; the metal stub structure 4 is fixed to the fourth segment 23; the first mounting portion 14 and the second mounting portion 24 are respectively disposed in the clearance slot 5.
[0037] In this embodiment, both the first microstrip line 1 and the second microstrip line 2 are configured with a U-shaped structure.
[0038] Example 2
[0039] This invention provides a radio frequency (RF) chip, which includes the microstrip line coupler 100 described in Embodiment 1 above. The technical problem solved and the technical effects achieved by the RF chip are the same as those of the microstrip line coupler 100 described above, and will not be repeated here.
[0040] 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. A microstrip line coupler, the 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, The microstrip line coupler further includes a substrate, a first resistor, and a metal stub structure; the substrate includes a bottom layer, an intermediate layer, and a top layer stacked sequentially, the first microstrip line is fixed to the top layer, the second microstrip line is fixed to the bottom layer, the intermediate layer is a ground layer, and the bottom layer and the top layer are fixedly connected; the metal stub structure is fixed at the position of the isolation port of the second microstrip line.
2. The microstrip line coupler according to claim 1, characterized in that, The metal branch structure includes a branch body fixed to the second microstrip line and a plurality of branches extending from the side of the branch body away from the first resistor.
3. The microstrip line coupler according to claim 2, characterized in that, The multiple branches are evenly distributed on opposite sides of the second microstrip line.
4. The microstrip line coupler according to claim 1, characterized in that, The metal branch structure is configured as a comb-like structure.
5. The microstrip line coupler according to claim 1, characterized in that, A clearance groove is formed through the substrate, and the first microstrip line and the second microstrip line are respectively opposite to the clearance groove and are spaced apart from each other.
6. The microstrip line coupler according to claim 5, characterized in that, The first microstrip line includes a first microstrip body, a first segment and a second segment formed by bending the two ends of the first microstrip body respectively, and a first mounting portion protruding from the middle position of the first microstrip body; the radio frequency input port is disposed at the end of the first segment away from the first microstrip body, and the antenna output port is disposed at the end of the second segment away from the first microstrip body. The second microstrip line includes a second microstrip body, a third segment and a fourth segment formed by bending the two ends of the second microstrip body respectively, and a second mounting portion protruding from the middle position of the second microstrip body; the coupling output port is located at the end of the third segment away from the second microstrip body, and the isolation port is located at the end of the fourth segment away from the second microstrip body; the metal stub structure is fixed to the fourth segment; The first mounting part and the second mounting part are respectively disposed in the clearance groove.
7. The microstrip line coupler according to claim 6, characterized in that, Both the first microstrip line and the second microstrip line are configured with a U-shaped structure.
8. A radio frequency chip, characterized in that, The radio frequency chip includes a microstrip line coupler as described in any one of claims 1-7.