Transmission line structure and wireless communication system

Abstract

The invention provides a transmission line structure and a wireless communication system. The transmission line structure comprises a first transmission line, a plurality of second transmission lines and an impedance conversion transmission line; the first transmission line is coupled to the first port and has a first impedance and a first line width. The plurality of second transmission lines are respectively coupled with the plurality of second ports, each second transmission line has a second impedance and a second line width, and the second impedance and the second line width are respectively the same as the first impedance and the first line width; the impedance conversion transmission line is coupled between the first transmission line and the plurality of second transmission lines, and has a third impedance smaller than the first impedance and a third line width larger than the first line width. The transmission line structure can be used as a feedback network of a radio frequency front-end module, and is used for transmitting a plurality of feedback signals of a plurality of power amplifier modules to a transceiver of a wireless communication system, so that the cost of the radio frequency front-end module is reduced.

Description

Technical Field

[0001] The present invention relates to a transmission line structure and a wireless communication system, and in particular to a transmission line structure which can be used as a feedback network of a radio frequency front-end module, and a wireless communication system comprising the transmission line structure. Background Art

[0002] The RF front-end module may include a power amplifier module integrated with a multiplexer (PAMiD), and with the improvement of wireless communication technology, the number of power amplifier modules in the RF front-end module may increase to achieve signal transmission and reception at different frequencies. In addition, multiple feedback signals of multiple power amplifier modules can be transmitted to the transceiver of the wireless communication system through the feedback network of the RF front-end module. However, the prior art mainly uses switches such as single-pole multi-throw (SPMT) as the feedback network of the RF front-end module, thereby increasing the cost of the RF front-end module.

[0003] Therefore, it is necessary to provide a transmission line structure and a wireless communication system to solve the above problems. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a transmission line structure and a wireless communication system to address the deficiencies of the prior art. The transmission line structure can be used as a feedback network of a radio frequency front-end module to transmit multiple feedback signals of multiple power amplifier modules to a transceiver of a wireless communication system, so as to reduce the cost of the radio frequency front-end module.

[0005] In order to solve the above technical problems, one of the technical solutions adopted by the present invention is to provide a transmission line structure. The transmission line structure includes a first transmission line, a plurality of second transmission lines and an impedance conversion transmission line. The first transmission line is coupled to the first port and has a first impedance and a first line width. The plurality of second transmission lines are respectively coupled to the plurality of second ports, and each second transmission line has a second impedance and a second line width. The second impedance and the second line width are respectively the same as the first impedance and the first line width. The impedance conversion transmission line is coupled between the first transmission line and the plurality of second transmission lines, and has a third impedance less than the first impedance and a third line width greater than the first line width.

[0006] In order to solve the above technical problems, another technical solution adopted by the present invention is to provide a wireless communication system. The wireless communication system includes a transceiver and a radio frequency front-end module, and the radio frequency front-end module includes a plurality of power amplifier modules coupled to the transceiver and a transmission line structure. The transmission line structure is used as a feedback network of the radio frequency front-end module to transmit a plurality of feedback signals of the plurality of power amplifier modules to the transceiver, and includes a first transmission line, a plurality of second transmission lines and an impedance conversion transmission line. The first transmission line is coupled to the transceiver and has a first impedance and a first line width. The plurality of second transmission lines are respectively coupled to the plurality of power amplifier modules, and each second transmission line has a second impedance and a second line width. The second impedance and the second line width are respectively the same as the first impedance and the first line width. The impedance conversion transmission line is coupled between the first transmission line and the plurality of second transmission lines, and has a third impedance less than the first impedance and a third line width greater than the first line width.

[0007] To further understand the features and technical contents of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are only for reference and description and are not intended to limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 FIG. 1 is a schematic diagram of a transmission line structure according to a first embodiment of the present invention.

[0009] Figure 2 It is a functional block diagram of a wireless communication system according to a first embodiment of the present invention.

[0010] Figure 3A FIG. 1 is a schematic diagram showing that the first transmission line of the first embodiment of the present invention is arranged in the form of a strip line.

[0011] Figure 3B FIG. 4 is a schematic diagram showing that the second transmission line of the first embodiment of the present invention is arranged in the form of a strip line.

[0012] Figure 3C FIG. 1 is a schematic diagram showing that the impedance conversion transmission line according to the first embodiment of the present invention is arranged in the form of a strip line.

[0013] Figure 4 is a schematic diagram of a transmission line structure according to a second embodiment of the present invention.

[0014] Figure 5 It is a functional block diagram of a wireless communication system according to a second embodiment of the present invention.

[0015] Main component symbols:

[0016] 1 Transmission line structure

[0017] 11. First Transmission Line

[0018] 12a, 12b, 12c, 12d second transmission line

[0019] 13 Impedance Transformation Transmission Line

[0020] P1 Input Port

[0021] P2a, P2b, P2c, P2d output ports

[0022] Z1 First impedance

[0023] W1 First line width

[0024] Z2 Second impedance

[0025] W2 Second line width

[0026] Z3 Third impedance

[0027] W3 Third line width

[0028] 2 Wireless Communication Systems

[0029] 21 Transceiver

[0030] 22 RF front-end module

[0031] 22a, 22b, 22c, 22d Power amplifier modules

[0032] f1, f2, f3, f4 feedback signals

[0033] C1 First conductive plane

[0034] C2 Second conductive plane

[0035] D Dielectric

[0036] H, H1 Height

[0037] T Thickness

[0038] S1 First line distance

[0039] S2 Second line distance

[0040] S3 Third line distance

[0041] V1 First through hole

[0042] V2a, V2b, V2c, V2d Second through hole

[0043] 111 First Sub-Transmission Line

[0044] 121a, 121b, 121c, 121d second sub-transmission line

[0045] 221a, 221b, 221c, 221d Logic switches DETAILED DESCRIPTION

[0046] The following is an explanation of the implementation of the present invention through specific embodiments. Those skilled in the art can understand the advantages and effects of the present invention from the content provided in this specification. The present invention can be implemented or applied through other different specific embodiments, and the details in this specification can also be modified and changed in various ways based on different viewpoints and applications without departing from the concept of the present invention. In addition, the drawings of the present invention are only simple schematic illustrations and are not depicted according to actual dimensions. It is stated in advance. The following implementations will further explain the relevant technical content of the present invention in detail, but the content provided is not intended to limit the scope of protection of the present invention.

[0047] Please also read Figure 1 and Figure 2 , Figure 1 is a schematic diagram of a transmission line structure according to a first embodiment of the present invention, Figure 2 FIG. 1 is a functional block diagram of a wireless communication system according to a first embodiment of the present invention. Figure 1 As shown, the transmission line structure 1 may include a first transmission line 11, a plurality of second transmission lines and an impedance conversion transmission line 13. For the convenience of the following description, the plurality of second transmission lines in the first embodiment of the present invention take two second transmission lines 12a and 12b as an example, but the present invention does not limit the specific number of second transmission lines.

[0048] The first transmission line 11 is coupled to the first port, and has a first impedance Z1 and a first line width W1. The second transmission lines 12a and 12b are respectively coupled to a plurality of second ports, and each second transmission line has a second impedance Z2 and a second line width W2. It should be noted that the second impedance Z2 and the second line width W2 may be respectively the same as the first impedance Z1 and the first line width W1. In addition, the impedance conversion transmission line 13 is coupled between the first transmission line 11 and the second transmission lines 12a and 12b, and has a third impedance Z3 less than the first impedance Z1 and a third line width W3 greater than the first line width W1.

[0049] On the other hand, the embodiment of the present invention also provides a wireless communication system 2 including a transceiver 21 and a radio frequency front-end module 22, and the transmission line structure 1 can replace a switch such as an SPMT as a feedback network of the radio frequency front-end module 22 to reduce the cost of the radio frequency front-end module 22. Figure 2 As shown, the RF front-end module 22 includes a plurality of power amplifier modules coupled to the transceiver 21 and a transmission line structure 1. For the convenience of the following description, the plurality of power amplifier modules of the first embodiment of the present invention takes two power amplifier modules 22a and 22b as an example, but the present invention does not limit the specific number of power amplifier modules.

[0050] Specifically, when the transmission line structure 1 is used as the feedback network of the RF front-end module 22, the transmission line structure 1 is used to transmit the feedback signal f1 of the power amplifier module 22a and the feedback signal f2 of the power amplifier module 22b to the transceiver 21. Therefore, the first port can be the input port P1 of the transceiver 21, and the plurality of second ports can be the output port P2a of the power amplifier module 22a and the output port P2b of the power amplifier module 22b. In other words, the number of second transmission lines of the transmission line structure 1 can be determined according to the number of power amplifier modules of the RF front-end module 22.

[0051] Furthermore, the transceiver 21 and the power amplifier modules 22a and 22b can be arranged in a printed circuit board having a plurality of metal layers stacked on each other. Therefore, the first transmission line 11, the second transmission lines 12a and 12b and the impedance conversion transmission line 13 can be arranged in the aforementioned printed circuit board in the form of striplines, thereby reducing the design size of the printed circuit board. Figures 3A to 3C , Figures 3A to 3C Schematic diagrams of the first transmission line, the second transmission line and the impedance conversion transmission line of the first embodiment of the present invention being arranged in the form of strip lines.

[0052] like Figures 3A to 3C As shown, the first transmission line 11, the second transmission lines 12a, 12b and the impedance conversion transmission line 13 can be arranged in the dielectric D between the first conductive plane C1 and the second conductive plane C2. Therefore, the embodiment of the present invention can use the two metal layers in the aforementioned printed circuit board to form the first conductive plane C1 and the second conductive plane C2 respectively, and use another metal layer between the two metal layers as a routing layer to lay out the first transmission line 11, the second transmission lines 12a, 12b and the impedance conversion transmission line 13.

[0053] Specifically, before the first transmission line 11, the second transmission lines 12a, 12b, and the impedance conversion transmission line 13 are arranged, the embodiment of the present invention can determine the first reference metal layer and the second reference metal layer used to form the first conductive plane C1 and the second conductive plane C2 in the printed circuit board according to the laminated structure data of the printed circuit board, and determine the third reference metal layer as a routing layer between the first reference metal layer and the second reference metal layer. In other words, the first reference metal layer and the second reference metal layer of the printed circuit board can form the first conductive plane C1 and the second conductive plane C2 respectively, and the first transmission line 11, the second transmission lines 12a, 12b, and the impedance conversion transmission line 13 are arranged in the third reference metal layer between the first reference metal layer and the second reference metal layer.

[0054] In addition, before laying out the first transmission line 11, the second transmission lines 12a, 12b and the impedance conversion transmission line 13, the embodiment of the present invention can also calculate the line width and line spacing of the matching transmission line impedance according to the laminated structure data of the printed circuit board. Please refer to Table 1, which is the laminated structure data of the printed circuit board provided by the embodiment of the present invention. As shown in Table 1, the printed circuit board of the embodiment of the present invention can have six metal layers stacked on each other, and an insulating material as a dielectric D can also be provided between two adjacent metal layers, such as a prepreg (PP) commonly used for printed circuit boards.

[0055] [Table 1]

[0056]

[0057]

[0058] Further, assuming that the embodiment of the present invention uses the metal layer L3 as the routing layer (ie, the third reference metal layer), the first reference metal layer and the second reference metal layer can be the metal layer L2 and the metal layer L4, respectively, but the present invention is not limited thereto. Figures 3A to 3C Before laying out the first transmission line 11, the second transmission lines 12a, 12b and the impedance conversion transmission line 13, the embodiment of the present invention can obtain, based on the laminated structure data of the printed circuit board, that the height H between the first conductive plane C1 and the second conductive plane C2 is 149 microns, the height H1 between each transmission line and the second conductive plane C2 is 67 microns, and the thickness T of each transmission line is 15 microns.

[0059] It should be noted that the first conductive plane C1 and the second conductive plane C2 are ground planes on the upper and lower sides of the transmission line. In addition, the stripline form of the embodiment of the present invention can also refer to a coplanar stripline form. Figures 3A to 3C As shown, in the embodiment of the present invention, ground planes can also be formed on the left and right sides of the transmission line. That is, in addition to the transmission line, a ground plane can also be formed on the third reference metal layer, and the so-called line spacing refers to the gap distance between the transmission line and the ground plane on the same metal layer.

[0060] Secondly, according to the above parameters, the embodiment of the present invention can calculate the line width and line spacing that match the transmission line impedance. For example, when the first impedance Z1 of the first transmission line 11 is 50 ohms, the embodiment of the present invention can calculate the line width and line spacing that match 50 ohms by calculation software according to the above parameters to be 52 microns and 125 microns respectively. Therefore, the first line width W1 and the first line spacing S1 of the first transmission line 11 can be 52 microns and 125 microns respectively. Similarly, the second line width W2 and the second line spacing S2 of the second transmission line 12a or 12b can also be 52 microns and 125 microns respectively.

[0061] In addition, according to the impedance conversion principle, the third impedance Z3 of the impedance conversion transmission line 13 will be half of the first impedance Z1. Therefore, when the third impedance Z3 of the impedance conversion transmission line 13 is 25 ohms, the embodiment of the present invention can also calculate the line width and line spacing matching 25 ohms to be 180 microns and 180 microns respectively through calculation software according to the above parameters. In other words, the third line width W3 and the third line spacing S3 of the impedance conversion transmission line 13 can be 180 microns and 180 microns respectively. Then, according to the above line width and line spacing, the embodiment of the present invention can arrange the first transmission line 11, the second transmission lines 12a, 12b and the impedance conversion transmission line 13 in the metal layer L3.

[0062] It should be noted that if the calculated line width is too thin to be laid out, the embodiment of the present invention can also re-determine the first, second and / or third reference metal layers (for example, the first reference metal layer, the second reference metal layer and the third reference metal layer can also be metal layer L2, metal layer L5 and metal layer L3, respectively) to obtain the above-mentioned new parameters, and calculate the new line width and new line spacing that match the transmission line impedance based on the above-mentioned new parameters. It can be seen that the first transmission line 11, the second transmission line 12a, 12b and the impedance conversion transmission line 13 can be laid out inside the printed circuit board without occupying the surface area of ​​the printed circuit board. In addition, since the feedback network of the RF front-end module 22 does not have high power requirements, the length of the transmission line can also be as short as possible to further reduce the design size of the printed circuit board.

[0063] On the other hand, the transceiver 21 and the power amplifier modules 22a, 22b may also be arranged in different metal layers of the printed circuit board. Figure 2As shown, when the transceiver 21 is not disposed on the third reference metal layer, the first transmission line 11 can be coupled to the input port P1 of the transceiver 21 through the first through hole V1 and the first sub-transmission line 111. Similarly, when the power amplifier modules 22a and 22b are not disposed on the third reference metal layer, the second transmission line 12a can be coupled to the output port P2a of the power amplifier module 22a through the second through hole V2a and the second sub-transmission line 121a, and the second transmission line 12b can be coupled to the output port P2b of the power amplifier module 22b through the second through hole V2b and the second sub-transmission line 121b.

[0064] That is to say, the first sub-transmission line 111 is a transmission line in which the transceiver 21 and the transmission line structure 1 change layers through the first through hole V1, the second sub-transmission line 121a is a transmission line in which the power amplifier module 22a and the transmission line structure 1 change layers through the second through hole V2a, and the second sub-transmission line 121b is a transmission line in which the power amplifier module 22b and the transmission line structure 1 change layers through the second through hole V2b, thereby enabling the transceiver 21 and the power amplifier modules 22a, 22b on different metal layers to be connected to each other.

[0065] Furthermore, if Figure 2 As shown, the power amplifier modules 22a and 22b may have logic switches 221a and 221b, respectively, and are coupled to the second transmission lines 12a and 12b through the logic switches 221a and 221b, respectively, and in response to one of the power amplifier modules being in operation, the logic switches of the other power amplifier modules are configured to be open circuits to ensure that at this time only one feedback signal of the power amplifier module can be transmitted to the transceiver 21 through the transmission line structure 1.

[0066] For example, when the power amplifier module 22a is working, the logic switch 221b of the power amplifier module 22b is configured to be open circuited to ensure that only the feedback signal f1 of the power amplifier module 22a can be transmitted to the transceiver 21 through the transmission line structure 1. Conversely, when the power amplifier module 22b is working, the logic switch 221a of the power amplifier module 22a is configured to be open circuited to ensure that only the feedback signal f2 of the power amplifier module 22b can be transmitted to the transceiver 21 through the transmission line structure 1.

[0067] In addition, when the number of power amplifier modules increases to four, please also refer to Figure 4 and Figure 5 . Figure 4 is a schematic diagram of a transmission line structure according to a second embodiment of the present invention, and Figure 5 FIG. 1 is a functional block diagram of a wireless communication system according to a second embodiment of the present invention. Figure 5As shown, the RF front-end module 22 may also include power amplifier modules 22a, 22b, 22c, 22d coupled to the transceiver 21 and the transmission line structure 1. Therefore, the plurality of second transmission lines of the transmission line structure 1 may also include second transmission lines 12a, 12b, 12c and 12d respectively coupled to the power amplifier modules 22a, 22b, 22c and 22d.

[0068] Specifically, the second transmission lines 12a, 12b, 12c and 12d are respectively coupled to the output ports P2a, P2b, P2c and P2d of the power amplifier modules 22a, 22b, 22c and 22d. Figure 4 and Figure 5 As shown, the impedance conversion transmission line 13 of the second embodiment of the present invention can be a T-type transmission line. The first end of the T-type transmission line is coupled to the first transmission line 11, the second end of the T-type transmission line is coupled to the second transmission lines 12a and 12b, and the third end of the T-type transmission line is coupled to the second transmission lines 12c and 12d. Therefore, when the transmission line structure 1 is used as Figure 5 When the feedback network of the RF front-end module 22 is formed, the transmission line structure 1 is used to transmit the feedback signal f1 of the power amplifier module 22a, the feedback signal f2 of the power amplifier module 22b, the feedback signal f3 of the power amplifier module 22c and the feedback signal f4 of the power amplifier module 22d to the transceiver 21.

[0069] Further, as mentioned above, when the power amplifier modules 22c and 22d are not arranged on the third reference metal layer, the second transmission line 12c can be coupled to the output port P2c of the power amplifier module 22c through the second through hole V2c and the second sub-transmission line 121c, and the second transmission line 12d can be coupled to the output port P2d of the power amplifier module 22d through the second through hole V2d and the second sub-transmission line 121d. In addition, the power amplifier modules 22a, 22b, 22c, and 22d can have logic switches 221a, 221b, 221c, and 221d, respectively, and are coupled to the second transmission lines 12a, 12b, 12c, and 12d through the logic switches 221a, 221b, 221c, and 221d, respectively, and in response to one of the power amplifier modules being in operation, the logic switches of the other power amplifier modules are configured to be open circuits to ensure that at this time, only one feedback signal of the power amplifier module can be transmitted to the transceiver 21 through the transmission line structure 1.

[0070] Since the details of the second embodiment of the present invention are similar to the previous contents, they will not be described in detail here. In addition, in the case where the transmission line structure 1 of the first embodiment is used as the basic model, the present invention can also couple a basic model after any second transmission line of the second embodiment to form a feedback network for five power amplifier modules. Similarly, the present invention can also couple two, three or four basic models after two, three or four second transmission lines of the second embodiment to form a feedback network for six, seven or eight power amplifier modules. Since the relevant details are similar to the previous contents, they will not be described in detail here.

[0071] In summary, one of the beneficial effects of the present invention is that the transmission line structure and wireless communication system provided by the present invention can be used as a feedback network of the RF front-end module through the first transmission line, multiple second transmission lines and impedance conversion transmission line, which are used to transmit multiple feedback signals of multiple power amplifier modules to the transceiver of the wireless communication system to reduce the cost of the RF front-end module. In addition, the first transmission line, the second transmission line and the impedance conversion transmission line can also be arranged in the printed circuit board in the form of strip lines to reduce the design size of the printed circuit board. It should be noted that in other embodiments, the first transmission line, the second transmission line and the impedance conversion transmission line can also be arranged on the surface of the printed circuit board in the form of microstrip lines to reduce the complexity of calculating the line width and line spacing. However, since the details of the arrangement in the form of microstrip lines are similar to the previous content, they will not be repeated here.

[0072] The contents provided above are only preferred feasible embodiments of the present invention, and are not intended to limit the scope of the claims of the present invention. Therefore, all equivalent technical changes made using the contents of the present invention description and drawings are included in the scope of the claims of the present invention.

Claims

1. A transmission line structure, comprising: a first transmission line, the first transmission line is coupled to a first port and has a first impedance and a first line width; a plurality of second transmission lines, the plurality of second transmission lines are respectively coupled to the plurality of second ports, wherein each of the second transmission lines has a second impedance and a second line width, and the second impedance and the second line width are respectively the same as the first impedance and the first line width; and An impedance conversion transmission line is coupled between the first transmission line and the second transmission lines, and has a third impedance and a third line width, wherein the third impedance is smaller than the first impedance, and the third line width is larger than the first line width.

2. The transmission line structure as described in claim 1, wherein the first transmission line, the second transmission lines and the impedance conversion transmission line are arranged in a dielectric between a first conductive plane and a second conductive plane, and when the transmission line structure is used as a feedback network of a radio frequency front-end module, the transmission line structure is used to transmit multiple feedback signals of multiple power amplifier modules of the radio frequency front-end module to a transceiver.

3. The transmission line structure as described in claim 2, wherein a first reference metal layer and a second reference metal layer of a printed circuit board form the first conductive plane and the second conductive plane respectively, and the first transmission line, the second transmission lines and the impedance conversion transmission line are arranged in a third reference metal layer between the first reference metal layer and the second reference metal layer.

4. The transmission line structure as described in claim 3, wherein the first port is an input port of the transceiver, and when the transceiver is not set on the third reference metal layer, the first transmission line is coupled to the input port of the transceiver through a first through hole and a first sub-transmission line.

5. The transmission line structure as described in claim 4, wherein the second ports are respectively multiple output ports of the power amplifier modules, and when the power amplifier modules are not arranged on the third reference metal layer, the second transmission lines are respectively coupled to the output ports of the power amplifier modules through multiple second through holes and multiple second sub-transmission lines.

6. The transmission line structure as claimed in claim 1, wherein the second transmission lines include four second transmission lines, the impedance conversion transmission line is a T-type transmission line, a first end of the T-type transmission line is coupled to the first transmission line, and a second end and a third end of the T-type transmission line are respectively coupled to two of the second transmission lines and another two of the second transmission lines.

7. A wireless communication system, comprising: a transceiver; as well as A radio frequency front-end module, the radio frequency front-end module comprising: a plurality of power amplifier modules, the plurality of power amplifier modules being coupled to the transceiver; and a transmission line structure, the transmission line structure serving as a feedback network of the RF front-end module, for transmitting a plurality of feedback signals of the power amplifier modules to the transceiver; The transmission line structure includes: a first transmission line, the first transmission line is coupled to the transceiver and has a first impedance and a first line width; a plurality of second transmission lines, the plurality of second transmission lines are respectively coupled to the power amplifier modules, wherein each of the second transmission lines has a second impedance and a second line width, and the second impedance and the second line width are respectively the same as the first impedance and the first line width; and An impedance conversion transmission line is coupled between the first transmission line and the second transmission lines, and has a third impedance and a third line width, wherein the third impedance is smaller than the first impedance, and the third line width is larger than the first line width. 8 . The wireless communication system as claimed in claim 7 , wherein the first transmission line, the second transmission lines and the impedance conversion transmission line are disposed in a dielectric between a first conductive plane and a second conductive plane.

9. The wireless communication system as described in claim 8, wherein a first reference metal layer and a second reference metal layer of a printed circuit board form the first conductive plane and the second conductive plane respectively, and the first transmission line, the second transmission lines and the impedance conversion transmission line are arranged in a third reference metal layer between the first reference metal layer and the second reference metal layer.

10. The wireless communication system as described in claim 9, wherein when the transceiver is not arranged on the third reference metal layer, the first transmission line is coupled to the transceiver through a first through hole and a first sub-transmission line, and when the power amplifier modules are not arranged on the third reference metal layer, the second transmission lines are coupled to the power amplifier modules through a plurality of second through holes and a plurality of second sub-transmission lines, respectively.

11. The wireless communication system as claimed in claim 7, wherein the power amplifier modules respectively have a plurality of logic switches and are respectively coupled to the second transmission lines through the logic switches, and in response to one of the power amplifier modules being in operation, the logic switches of the other power amplifier modules are configured to be open.

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