Laminated microstrip coupler and electronic device

Abstract

The utility model provides a laminated microstrip coupler and an electronic device, and the microstrip coupler comprises a PCB substrate which comprises four layers of PCBs; the first layer of PCB is provided with a transmission line layer which comprises a signal transmission line, and two ends of the signal transmission line are respectively a coupling port and an output port; a coupling line layer is arranged on the second-layer PCB and comprises a coupling line, two ends of the coupling line are respectively a coupling output port and an isolation port, the coupling output port is connected with a first metal through hole in the signal transmission line, and the isolation port is connected with a second metal through hole in the signal transmission line; the two grounding layers are respectively arranged on the third-layer PCB and the fourth-layer PCB; and the two grounding layers are connected with the coupling output port and the isolation port through metal through holes. The microstrip coupler improves the stability and reliability of the coupling degree through the lamination design, improves the directivity, guarantees the effective transmission of energy, and effectively reduces the cost.

Description

Technical Field

[0001] The utility model relates to the technical field of microwave communication, in particular to a laminated microstrip coupler and an electronic device. Background Art

[0002] Microwave communication technology is a technology that uses microwaves for communication. It has the characteristics of large capacity, good quality and can be transmitted over long distances. It is an important communication means of communication networks and is also widely applicable to various special communication networks. In microwave communication technology, couplers and microstrip lines are two important components. Couplers are used to achieve power distribution and signal extraction of microwave signals, while microstrip lines are the basic components of microwave signal transmission. Microstrip lines are a type of microwave transmission line. They are widely used in microwave communication equipment because of their small size, light weight, low cost and easy integration.

[0003] Microstrip coupler is a common microwave transmission line component. Its basic structure consists of two parallel microstrip lines, which are coupled through a certain coupling medium to achieve different coupling coefficients and power distribution ratios to meet different application requirements. However, the coupling degree and directivity of the microstrip line are important factors affecting its performance. How to design a microstrip line with high coupling degree and good directivity is an important research topic in the field of microwave communication technology. At the same time, with the trend of miniaturization of electronic equipment, how to design a high-performance microstrip line in a limited space is also a challenge in the field of miniaturization design of electronic devices.

[0004] Although the traditional microstrip coupler has a simple structure, it occupies a large PCB area, and the coupling degree and directivity are not ideal. Its coupling degree does not meet the requirements and the directivity is small. If an integrated microstrip coupler is used, although the performance is stable, the cost is high. Utility Model Content

[0005] In view of the above-mentioned deficiencies in the prior art, the utility model provides a laminated microstrip coupler and an electronic device, which effectively solve the problem that the microstrip coupler in the prior art cannot meet the requirements of miniaturization design of electronic devices.

[0006] In a first aspect, the utility model provides a laminated microstrip coupler, the microstrip coupler comprising:

[0007] A PCB substrate, wherein the PCB substrate comprises a four-layer PCB board;

[0008] A transmission line layer, wherein the transmission line layer is arranged on the first layer PCB board, the transmission line layer comprises a signal transmission line, and two ends of the signal transmission line are respectively a coupling port and an output port;

[0009] A coupling line layer, wherein the coupling line layer is arranged on the second layer PCB board, the coupling line layer comprises a coupling line, and two ends of the coupling line are respectively a coupling output port and an isolation port, the coupling output port is connected to a first metal through hole on the signal transmission line, and the isolation port is connected to a second metal through hole on the signal transmission line;

[0010] A first grounding layer, wherein the first grounding layer is arranged on a third layer of the PCB board, a first coupling connection through hole and a second coupling connection through hole are arranged on the first grounding layer, the first coupling connection through hole is connected to the coupling output port, and the second coupling connection through hole is connected to the isolation port;

[0011] A second grounding layer, wherein the second grounding layer is arranged on a fourth layer of a PCB board, a third coupling connection through hole and a fourth coupling connection through hole are arranged on the second grounding layer, the third coupling connection through hole is connected to the first coupling connection through hole, and the fourth coupling connection through hole is connected to the second coupling connection through hole.

[0012] Furthermore, the four layers of the PCB substrate are all penetrated by metal through holes.

[0013] Furthermore, the metal through holes are arranged at both ends of the signal transmission line, and the metal through holes three-dimensionally surround the ground.

[0014] Furthermore, the signal transmission line is a copper foil laid on the first layer of PCB board, and the coupling line is a copper foil laid on the second layer of PCB board.

[0015] Furthermore, the coupling line is located directly below the signal transmission line.

[0016] Furthermore, both ends of the coupling line are output through a 90-degree corner, and a 45-degree cut is made at the 90-degree corner.

[0017] Furthermore, the first metal through hole on the signal transmission line is used to connect to the signal input port of the chip.

[0018] Furthermore, the second metal through hole on the signal transmission line is used to connect a load resistor and to be grounded.

[0019] Furthermore, the two grounding layers are arranged in parallel, and through-layer via stumps are formed between the metal through holes connecting the two grounding layers.

[0020] In a second aspect, the utility model provides an electronic device, comprising the laminated microstrip coupler described in the first aspect of the utility model.

[0021] The laminated microstrip coupler and electronic device provided by the utility model are designed to design microstrip lines with high coupling and good directivity in a limited space. The stacked design can ensure the alignment accuracy of the two layers of microstrip lines, increase the coupling between the strip lines, and make full use of the distributed capacitance between the coupled microstrip lines, which can not only balance the phase velocity of odd and even modes, but also further improve the stability and reliability of the coupling, and realize the design requirements of wide-band couplers. At the same time, the parasitic inductance and capacitance of the metal through-holes of the coupling line layer exchange are used to compensate for the phase difference between the coupling end and the isolation end, improve the directivity, and ensure the effective transmission of energy. In addition, the PCB structure layer stacking process is simple, the consistency is good, the cost of the microstrip coupler is reduced, and the industry design requirements can be fully met. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a structural schematic diagram of a laminated microstrip coupler provided by an embodiment of the utility model;

[0024] Figure 2 is a side view of a laminated microstrip coupler provided by an embodiment of the utility model;

[0025] Figure 3 is a front view of a laminated microstrip coupler provided by an embodiment of the utility model;

[0026] Figure 4 It is a diagram of the coupling and isolation simulation results of the laminated microstrip coupler provided in the embodiment of the utility model.

[0027] Description of main component symbols:

[0028] 1. Coupling port; 2. Output port; 3. Coupling output port; 4. Isolation port; 5. First metal through hole; 6. Second metal through hole; 7. Signal input port; 8. Load resistor port; 9. First coupling connection through hole; 10. Second coupling connection through hole; 11. Third coupling connection through hole; 12. Fourth coupling connection through hole. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the utility model clearer, the technical solution of the utility model will be further described clearly and completely in combination with the drawings in the embodiments of the utility model. It should be noted that the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0030] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in this utility model specification are only for the purpose of describing specific embodiments and are not intended to limit the utility model. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0032] Microwave communication technology is a technology that uses microwaves for communication. It has the characteristics of large capacity, good quality and can be transmitted over long distances. It is an important communication means of communication networks and is also widely applicable to various special communication networks. In microwave communication technology, couplers and microstrip lines are two important components. Couplers are used to achieve power distribution and signal extraction of microwave signals, while microstrip lines are the basic components of microwave signal transmission. Microstrip lines are a type of microwave transmission line. They are widely used in microwave communication equipment because of their small size, light weight, low cost and easy integration.

[0033] Microstrip coupler is a common microwave transmission line element. Its basic structure consists of two parallel microstrip lines, which are coupled through a certain coupling medium to achieve different coupling coefficients and power distribution ratios, thereby meeting different application requirements. However, the coupling degree and directivity of the microstrip line are important factors affecting its performance. How to design a microstrip line with high coupling degree and good directivity is an important research topic in the field of microwave communication technology. At the same time, with the trend of miniaturization of electronic equipment, how to design high-performance microstrip lines in a limited space is also a challenge in the field of miniaturization design of electronic devices. Although the traditional microstrip coupler has a simple structure, it occupies a large PCB area, and the coupling degree and directivity are not ideal. Its coupling degree does not meet the requirements and the directivity is small. If an integrated microstrip coupler is used, although the performance is stable, the cost is high.

[0034] In view of the above-mentioned deficiencies in the prior art, the embodiments of the present invention provide a laminated microstrip coupler, which effectively solves the problem that the microstrip coupler in the prior art cannot meet the requirements of miniaturization design of electronic devices. Figure 1 Schematic diagram of the structure of the laminated microstrip coupler provided by the embodiment of the utility model. Figure 1 As shown, the microstrip coupler comprises:

[0035] The PCB substrate includes a four-layer PCB board, wherein the four-layer PCB board is penetrated by metal through holes. In the embodiment of the utility model, the PCB substrate adopts a FR4 four-layer PCB board with a size of 5mm×4mm, a dielectric constant of 4.6, a dielectric loss of 0.022, a plate thickness of 1.6mm, and a copper foil thickness of 0.035mm.

[0036] The transmission line layer is arranged on the first layer of PCB board, and the transmission line layer includes a signal transmission line. In the embodiment of the utility model, the signal transmission line is a copper foil laid on the first layer of PCB board, and the impedance of the signal transmission line is 50Ω. The two ends of the signal transmission line are respectively a coupling port 1 and an output port 2. The signal of the transmission line layer is input from the coupling port 1 and output from the output port 2 through the signal transmission line.

[0037] The coupling line layer is arranged on the second layer PCB board. The coupling line layer includes coupling lines. In the embodiment of the utility model, the coupling line is a copper foil laid on the second layer PCB board, and its length is 2mm and its width is 7.5mil. The coupling line is located directly below the signal transmission line of the first layer PCB board. The two ends of the coupling line are respectively a coupling output port 3 and an isolation port 4. The coupling output port 3 and the isolation port 4 are output through a 90-degree corner. Since the 90-degree corner is a typical discontinuous structure, it will cause the impedance of the transmission line to abruptly change at the corner. This sudden change will cause signal reflection and affect the transmission quality of the signal. Therefore, a 45-degree cut is made at the 90-degree corner to smooth the right-angle corner, so that the impedance of the transmission line can transition more smoothly at the corner, thereby reducing the reflection of the signal.

[0038] Figure 2 is a side view of a laminated microstrip coupler provided by an embodiment of the utility model, such as Figure 2 As shown, the coupling output port 3 is connected to the first metal through hole 5 on the signal transmission line, and the first metal through hole 5 is connected to the signal input port 7 through the signal transmission line, and the signal input port 7 is connected to the signal input interface of the chip. At the same time, the isolation port 4 is connected to the second metal through hole 6 on the signal transmission line, and the second metal through hole is connected to the load resistance port 8 through the signal transmission line, and the load resistance port 8 is connected to a 50Ω load resistor and grounded.

[0039] A first grounding layer, the first grounding layer is arranged on the third layer of the PCB board, and the first grounding layer is provided with a first coupling connection through hole 9 and a second coupling connection through hole 10, wherein the first coupling connection through hole 9 is connected to the coupling output port 3, and the second coupling connection through hole 10 is connected to the isolation port 4;

[0040] The second grounding layer is arranged on the fourth layer of the PCB board, and a third coupling connection through hole 11 and a fourth coupling connection through hole 12 are arranged on the second grounding layer, wherein the third coupling connection through hole 11 is connected to the first coupling connection through hole 9, and the fourth coupling connection through hole 12 is connected to the second coupling connection through hole 10.

[0041] Specifically, by setting a parallel first grounding layer and a second grounding layer, a section of through-layer via stump will naturally be formed between the metal through holes of the third-layer PCB board and the fourth-layer PCB board. By utilizing the parasitic capacitance and inductance of the through-layer via stump itself, a suitable aperture size of the metal through hole is selected through simulation design, thereby compensating for the phase difference between the coupling end and the isolation end of the coupling device, so that the phase difference of the two ports reaches 180 degrees, that is, the phases are opposite, and then by selecting a suitable characteristic impedance, it is ensured that the amplitudes reaching the two ports at the same time are equal and cancel each other, thereby ensuring that the laminated microstrip coupler has high directivity.

[0042] Figure 3is a front view of a laminated microstrip coupler provided by an embodiment of the utility model, such as Figure 2 As shown, the first metal through hole 5 to the third coupling connection through hole 11 is a coupling transmission connection section, the second metal through hole 6 to the fourth coupling connection through hole 12 is also a coupling transmission connection section, the coupling output port 3 to the first metal through hole 5 is a coupling microstrip line connection section, the isolation port 4 to the second metal through hole 6 is also a coupling microstrip line connection section, the coupling output port 3 to the third coupling connection through hole 11 is a suspended section of the coupling line layer and the ground layer, and the isolation port 4 to the fourth coupling connection through hole 12 is also a suspended section of the coupling line layer and the ground layer. The transmission line of the coupling transmission connection section needs to ensure a 50Ω impedance, and the metal through holes on both sides of the transmission line are three-dimensionally wrapped with the ground, and the diameter of the metal through hole is 4mil.

[0043] In order to verify the coupling and isolation of the laminated microstrip coupler in the embodiment of the utility model, the high-frequency structure simulator HFSS is used to perform modeling simulation. Figure 4 : is a diagram showing the coupling and isolation simulation results of the laminated microstrip coupler provided by the embodiment of the utility model, such as Figure 4 As shown, the S(1,1) curve is the return loss curve, and the points m3 and m4 on the curve represent the return loss values ​​of the microstrip coupler at different frequencies respectively; the S(2,1) curve is the insertion loss curve, and the points m1, m2, m13 and m14 on the curve represent the insertion loss values ​​of the microstrip coupler at different frequencies respectively; the S(3,1) curve is the coupling curve, and the points m5, m6, m9 and m10 on the curve represent the coupling degrees of the microstrip coupler at different frequencies respectively; the S(4,1) curve is the isolation curve, and the points m7, m8, m11 and m12 on the curve represent the isolation degrees of the microstrip coupler at different frequencies respectively, where the directivity of the microstrip coupler = isolation - coupling. Combining the above curves, it can be obtained that within the frequency band, the coupling coefficient of the laminated microstrip coupler is 17.6dB in the 2401-2483MHz band, the insertion loss is <0.16dB, the directivity is >25dB, and the port return loss is <-20dB. In the 5150-5850MHz band, the coupling coefficient is 15dB, the insertion loss is <0.7dB, the directivity is >25dB, and the port return loss is <-13dB.

[0044] The laminated microstrip coupler provided by the embodiment of the utility model designs a microstrip line with high coupling and good directivity in a limited space. The laminated design can ensure the alignment accuracy of the two layers of microstrip lines, increase the coupling between the strip lines, and make full use of the distributed capacitance between the coupled microstrip lines, which can not only balance the phase velocity of odd and even modes, but also further improve the stability and reliability of the coupling, and meet the design requirements of the wide-band coupler. At the same time, the parasitic inductance and capacitance of the metal through hole of the coupling line layer change are used to compensate for the phase difference between the coupling end and the isolation end, improve the directivity, and ensure the effective transmission of energy.

[0045] Based on the same technical concept, an embodiment of the utility model further provides an electronic device, which includes the above-mentioned laminated microstrip coupler.

[0046] The electronic device includes but is not limited to magnetic resonance imaging (MRI), microwave ovens, and wireless charging devices.

[0047] According to the electronic device of the embodiment of the utility model, the above-mentioned laminated microstrip coupler is used to design a microstrip line with high coupling and good directivity in a limited space. The laminated design can ensure the alignment accuracy of the two layers of microstrip lines, increase the coupling between the strip lines, and make full use of the distributed capacitance between the coupled microstrip lines, which can not only balance the phase velocity of odd and even modes, but also further improve the stability and reliability of the coupling, and meet the design requirements of wide-band electronic devices. At the same time, the parasitic inductance and capacitance of the metal through-hole of the coupling line layer are used to compensate for the phase difference between the coupling end and the isolation end, improve the directivity, and ensure the effective transmission of energy. In addition, the PCB structure layer stacking process is simple and the consistency is good, which reduces the cost of electronic devices and can fully meet the design requirements of the industry.

[0048] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0049] The above-mentioned embodiments only express several implementation methods of the utility model, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the utility model. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the utility model, and these all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the utility model.

Claims

1. A laminated microstrip coupler, characterized in that: The microstrip coupler comprises: A PCB substrate, wherein the PCB substrate comprises a four-layer PCB board; A transmission line layer, wherein the transmission line layer is arranged on the first layer PCB board, the transmission line layer comprises a signal transmission line, and two ends of the signal transmission line are respectively a coupling port and an output port; A coupling line layer, wherein the coupling line layer is arranged on the second layer PCB board, the coupling line layer comprises a coupling line, and two ends of the coupling line are respectively a coupling output port and an isolation port, the coupling output port is connected to a first metal through hole on the signal transmission line, and the isolation port is connected to a second metal through hole on the signal transmission line; A first grounding layer, wherein the first grounding layer is arranged on a third layer of the PCB board, a first coupling connection through hole and a second coupling connection through hole are arranged on the first grounding layer, the first coupling connection through hole is connected to the coupling output port, and the second coupling connection through hole is connected to the isolation port; A second grounding layer, wherein the second grounding layer is arranged on a fourth layer of a PCB board, a third coupling connection through hole and a fourth coupling connection through hole are arranged on the second grounding layer, the third coupling connection through hole is connected to the first coupling connection through hole, and the fourth coupling connection through hole is connected to the second coupling connection through hole.

2. The laminated microstrip coupler according to claim 1, characterized in that: The four layers of the PCB substrate are all penetrated by metal through holes.

3. The laminated microstrip coupler according to claim 2, characterized in that: The metal through holes are arranged at both ends of the signal transmission line, and the metal through holes three-dimensionally surround the ground.

4. The laminated microstrip coupler according to claim 1, characterized in that: The signal transmission line is a copper foil laid on the first layer of PCB board, and the coupling line is a copper foil laid on the second layer of PCB board.

5. The laminated microstrip coupler according to claim 1, characterized in that: The coupling line is located directly below the signal transmission line.

6. The laminated microstrip coupler according to claim 5, characterized in that: The two ends of the coupling line are output through a 90-degree corner, and a 45-degree cut is made at the 90-degree corner.

7. The laminated microstrip coupler according to claim 1, characterized in that: The first metal through hole on the signal transmission line is used to connect the signal input port of the chip.

8. The laminated microstrip coupler according to claim 7, characterized in that: The second metal through hole on the signal transmission line is used to connect a load resistor and to be grounded.

9. The laminated microstrip coupler according to claim 1, characterized in that: The two grounding layers are arranged in parallel, and through-layer via stumps are formed between the metal through holes connecting the two grounding layers.

10. An electronic device, characterized in that: The electronic device comprises the stacked microstrip coupler according to any one of claims 1 to 9.

Images