Directional coupler

Abstract

A directional coupler includes a main path, a coupling path, a first port, and a second port. The main path is used for transmitting a first radio frequency signal. The coupling path at least partially overlaps the main path. The coupling path includes a first end, a second end, and at least one wire routed between the first end and the second end. The first port is coupled to the first end of the coupling path. The second port is coupled to the second end of the coupling path, wherein at least one of the first port and the second port is located at the inner side of the at least one winding.

Description

Technical Field

[0001] The present invention relates to a radio frequency (RF) circuit, and more specifically, to a directional coupler. Background Art

[0002] A directional coupler is a passive device that can be used to couple part of the electromagnetic power on a signal path to another path, thereby generating a new signal that can be used for power detection or control. A directional coupler usually contains two paths, a transmission path and a coupling path, which are placed close enough to each other to transfer power on one path to another, for example, from a transmission path to a coupling path.

[0003] When designing a directional coupler, compact layout and reduced insertion loss may be key considerations. For example, a compact layout may require small areas for the transmission path and the coupling path, which may result in insufficient areas for the two paths, which in turn may result in insufficient coupling factor.

[0004] The coupling factor, also known as the coupling coefficient, is measured in decibels (dB) and is used to indicate the strong or weak coupling between the two paths of the coupler, and can be determined by the amount of power from one path to the other. The coupling factor may be significantly affected by at least one of the following: the size and / or shape of the transmission path, the size and / or shape of the coupling path, and the appropriate proximity of the two paths. In other words, the coupling factor may be determined by the electromagnetic interaction between the two paths. In the case of a compact layout, there may not be enough area for the transmission path, resulting in a shortened transmission path or a reduced number of turns in the transmission path, which may be detrimental to improving the coupling factor. For example, the transmission path may be designed as a straight line without turns.

[0005] A shorter transmission path or a reduced number of turns in the transmission path may weaken the interaction between the transmission path and the coupling path, resulting in a lower coupling factor. This is because the magnetic field generated may be weaker, so the coupled induced current or induced voltage is lower. Therefore, careful consideration is required when designing a directional coupler. Summary of the invention

[0006] One embodiment of the present invention provides a directional coupler, which includes a main path, a coupling path, a first port and a second port. The main path is used to transmit a first radio frequency signal. The coupling path at least partially overlaps with the main path. The coupling path includes a first end, a second end and at least one winding wired between the first end and the second end. The first port is coupled to the first end of the coupling path. The second port is coupled to the second end of the coupling path, wherein at least one of the first port and the second port is located on the inner side of at least one winding wire.

[0007] Another embodiment of the present invention provides a directional coupler, which includes a main path, a coupling path, a first port, a second port and at least one passive element. The main path is used to transmit a first radio frequency signal. The coupling path at least partially overlaps with the main path. The coupling path includes a first end, a second end and at least one winding wired between the first end and the second end. The at least one winding includes an innermost winding, and the innermost winding includes a first portion and a second portion. The first portion is closer to the main path than the second portion, and the first portion may be parallel to the main path. The first port is coupled to the first end of the coupling path. The second port is coupled to the second end of the coupling path. At least one passive element may be located at the first portion of the innermost winding. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 FIG. 4 is a top view of a layout of a directional coupler according to an embodiment of the present invention.

[0009] Figure 2 yes Figure 1 A cross-sectional view of the directional coupler along dashed line 2-2'.

[0010] Figure 3 yes Figure 1 A cross-sectional view of the directional coupler along dashed line 3-3'.

[0011] Figure 4 FIG. 4 is a top view of a layout of a directional coupler according to another embodiment of the present invention.

[0012] Figure 5 FIG. 4 is a top view of a layout of a directional coupler according to another embodiment of the present invention.

[0013] Explanation of symbols:

[0014] 1, 4, 5: Directional coupler

[0015] 2-2', 3-3': dotted line

[0016] 10: Main Path

[0017] 20, 40, 50: coupling paths

[0018] 31, 32, 33, 34: Winding

[0019] 50: Resistance

[0020] 60: Capacitor

[0021] 70, 90: Port

[0022] L1, L3: Layer

[0023] L2: Insulation layer

[0024] RF1: First radio frequency signal

[0025] RF2: Second radio frequency signal

[0026] S11, S12, S13, S14: Part 1

[0027] S21, S22, S23, S24: Part 2

[0028] S31: Part 3

[0029] S41: Part 4

[0030] T1: First End

[0031] T2: Second end

[0032] W1, W2, W3, W4, W5, W6: Width DETAILED DESCRIPTION

[0033] The present invention can be understood by referring to the following detailed description in conjunction with the accompanying drawings. It should be noted that in order to facilitate the understanding of the readers and the simplicity of the drawings, the multiple drawings in the present invention only depict a portion of the electronic device, and the specific elements in the drawings are not drawn according to the actual scale. In addition, the number and size of each element in the figure are only for illustration and are not intended to limit the scope of the present invention. Elements marked with the same symbol in the drawings have the same or similar properties or functions in the context.

[0034] Certain words are used throughout the specification and the appended claims to refer to specific components. It should be understood by those skilled in the art that electronic equipment manufacturers may refer to the same components with different names. This document does not intend to distinguish between components with the same function but different names.

[0035] In the following description and each claim, words such as "include", "contain", "have" and the like are open-ended words, and therefore should be interpreted as "including but not limited to..." Therefore, when the terms "include", "contain" and / or "have" are used in the description of the present invention, they specify the existence of corresponding features, regions, steps, operations and / or components, but do not exclude the existence of one or more corresponding features, regions, steps, operations and / or components.

[0036] The directional terms mentioned herein, such as "inside", "outside", "up", "down", "front", "back", "left", "right", etc., are only references to the directions of the drawings. Therefore, the directional terms used are for illustration and not for limiting the present invention. In the drawings, each figure illustrates the general characteristics of the methods, structures and / or materials used in a particular embodiment. However, these drawings should not be interpreted as defining or limiting the scope or nature covered by these embodiments. For example, for clarity, the relative size, thickness and position of each film layer, region and / or structure may be reduced or enlarged.

[0037] It should be noted that the following embodiments can replace, reorganize, or mix features in several different embodiments to complete other embodiments without departing from the spirit of the present invention. The features between the embodiments can be mixed and matched as long as they do not violate the spirit of the invention or conflict with each other.

[0038] Please refer to Figure 1 . Figure 1 1 is a top view of the layout of a directional coupler 1 according to an embodiment of the present invention. In some embodiments, the directional coupler 1 can be disposed between an amplifier and an antenna, and can be used to monitor and measure the power of a radio frequency signal, and can adjust the output power of the radio frequency signal according to the measurement result. Furthermore, the directional coupler 1 can be further coupled to a power detector, and the power detector can receive a coupling signal from the directional coupler 1 and output a detection signal accordingly.

[0039] In some embodiments, Figure 1 As shown, the directional coupler 1 may include a main path 10 , a coupling path 20 , and at least one port. For example, the at least one port includes a port 70 and a port 90 .

[0040] The main path 10 may be configured to transfer (e.g., transmit and / or receive) a first radio frequency (RF) signal RF1. For example, the first radio frequency signal RF1 may be a signal transferred from an output terminal of an amplifier (not shown) to an antenna (not shown). Further, the main path 10 may be disposed between two ports, such as an input port and an output port (not shown). In this case, the input port of the main path 10 may be coupled to the output terminal of the amplifier, the output port of the main path 10 may be coupled to the antenna, and thus the first radio frequency signal RF1 from the amplifier may be transferred from the input port of the main path 10 to the output port, and further transferred to the antenna.

[0041] The coupling path 20 may be configured to generate the second RF signal RF2 by electromagnetic coupling with the main path 10, for example, by coupling a certain amount of power from the first RF signal RF1 with a coupling factor, thereby generating the second RF signal RF2. In some embodiments, in a top view of the directional coupler 1, that is, viewed from the top direction of the directional coupler 1, the coupling path 20 may at least partially overlap with the main path 10. Figure 1 As shown, the coupling path 20 includes a first end T1, a second end T2 and at least one winding, and the at least one winding is wired between the first end T1 and the second end T2. In detail, the at least one winding may include four windings 31, 32, 33 and 34. The winding 31 may be the innermost winding, and the winding 34 may be the outermost winding. However, the present invention is not limited thereto. In other embodiments, the number of windings may be two, three or five, etc.

[0042] It is worth noting that the winding described herein may include multiple parts, wherein there is an angle between at least two parts, that is, the angle between the tangents of the at least two parts is an acute angle, an obtuse angle, or a right angle. In other words, the winding includes at least two parts, and the angle between the tangents of the two parts is non-zero or 180 degrees.

[0043] Furthermore, the coupling path 20 may be disposed between two ports, such as port 70 and port 90. In this embodiment, the port 70 may be coupled to the first end T1 of the coupling path 20, and the port 90 may be coupled to the second end T2 of the coupling path 20.

[0044] In one embodiment of the present invention, at least one of the port 70 and the port 90 may be located on the inner side of the windings of the coupling path 20. For example, the port 70 may be located on the inner side of at least one winding, and specifically, the port 70 may be located on the inner side of the innermost winding 31. Therefore, the port 70 may be referred to as an inner port. In other words, the windings 31 to 34 of the coupling path 20 surround the port 70. The port 90 may be located on the outer side of at least one winding, and specifically, the port 90 may be located on the outer side of the outermost winding 34. Therefore, the port 90 may be referred to as an outer port. In this embodiment, the first end T1 of the coupling path 20 coupled to the port 70 may be located on the inner side of the winding, and the second end T2 coupled to the port 90 may be located on the outer side of the winding.

[0045] In one embodiment of the present invention, at least one winding of the coupling path 20 may have a substantially rectangular profile. Figure 1 As shown, the port 90 is shown to be located at the upper left corner outside the rectangle, but the present invention is not limited thereto. In other embodiments, the port 90 may be located at other positions outside the rectangle, such as the upper right corner. In some embodiments, the port 90 may be directly coupled to the second portion S24 of the outermost winding 34. That is, the port 90 may be located at the second portion S24 of the outermost winding 34.

[0046] In the present embodiment, the profile of the coupling path 20 may have a first dimension of approximately 237 μm and a second dimension of approximately 180 μm.

[0047] like Figure 1 As shown, the port 70 is shown to be located substantially at the center of the rectangle, but the present invention is not limited thereto. In other embodiments, the port 70 may be located at other positions of the rectangle, such as the left position or the right position. The first end T1 of the coupling path 20 is shown as the end of the first portion S11 of the innermost winding 31. Figure 1 It is shown in the figure that the first end T1 is located at the left side of the rectangle, but the present invention is not limited thereto. In other embodiments, the first end T1 may be located at other positions of the rectangle, such as the center or the right side.

[0048] For example, port 70 or port 90 may be a coupled port or an isolated port. In one embodiment of the present invention, port 90 may be used as a coupled port to output a second radio frequency signal RF2. Port 70 may be used as an isolation port, for example, it may be grounded. Therefore, port 70 may also be referred to as a ground port. Desirably, no signal is output at port 70, that is, the power of the signal is zero. However, in actual applications, due to a certain degree of mismatch in the circuit, there may be a low-power signal at port 70. Furthermore, port 70 may be further coupled to other circuits (e.g., resistors) to adjust the degree of mismatch in the circuit.

[0049] It is worth noting that the functions of the various ports described above are only for illustration and description, and do not limit their uses. That is to say, for example, port 90 of directional coupler 1 can also be used as an isolation port, and port 70 can also be used as a coupling port. A coupled port can also be called a detection port. For example, port 70 and / or port 90 may include a pad, a through-wafer via, or a through silicon via. In addition, port 70 and / or port 90 may be further coupled to a bonding wire, a bump, or a ground terminal.

[0050] like Figure 1 As shown, in the top view of the directional coupler 1, taking the innermost winding 31 as an example, it may include a first portion S11, a second portion S21, and other portions connected therebetween (e.g., a third portion S31 and a fourth portion S41). The first portion S11 and the second portion S21 may be parallel to the main path 10, and the first portion S11 may be closer to the main path 10 than the second portion S21. The third portion S31 and the fourth portion S41 may be perpendicular to the main path 10. Further, the first portion S11 may overlap with the main path 10, and the second portion S21 may not overlap with the main path 10.

[0051] In a further embodiment, the first portion S11 may have a width W1, the second portion S21 may have a width W2, and the width W1 may not be equal to the width W2. Preferably, the width W1 may be greater than the width W2. In this embodiment, with respect to the innermost winding 31, electromagnetic coupling may substantially occur between the main path 10 and the first portion S11.

[0052] Similarly, winding 32 may include a first portion S12, a second portion S22 and other portions (not labeled) connected therebetween, winding 33 may include a first portion S13, a second portion S23 and other portions (not labeled) connected therebetween, and the outermost winding 34 may include a first portion S14, a second portion S24 and other portions (not labeled) connected therebetween.

[0053] In one embodiment of the present invention, the main path 10 may be formed in a first layer L1 , and the coupling path 20 may be formed in a second layer L2 , and the second layer L2 is different from the first layer L1 .

[0054] Please refer to Figure 2 and Figure 3 . Figure 2 yes Figure 1 A cross-sectional view of the directional coupler 1 along the dashed line 2 - 2 ′. Figure 3 yes Figure 1A cross-sectional view of the directional coupler 1 along the dashed line 3-3'.

[0055] like Figure 2 As shown, the main path 10 may be formed in the first layer L1. For example, the main path 10 may be a conductive path located in the first layer L1. Figure 2 , shown as the first portion S14 of the outermost winding 34) may be formed in the second layer L2, for example, the coupling path 20 may be a conductive path positioned in the second layer L2. In addition, the insulating layer L3 may be formed between the layers L1 and L2. For example, the conductive material of the main path 10 or the coupling path 20 may include, but is not limited to, aluminum, copper, gold, silver, and combinations or alloys thereof. The material of the insulating layer L2 may include, but is not limited to, silicon dioxide (SiO2), silicon nitride (SiNx), hafnium oxide (HfO2), zirconium oxide (ZrO2), and / or tantalum pentoxide (Ta2O5).

[0056] like Figure 3 As shown, the first portion S11 of the innermost winding 31, the first portion S12 of the winding 32, the first portion S13 of the winding 33, and the first portion S14 of the outermost winding 34 all overlap with the main path 10. However, the present invention is not limited thereto, and in other embodiments, for example, the first portion S11 of the innermost winding 31 or the first portion S14 of the outermost winding 34 may not overlap with the main path 10. Furthermore, the second portion S21 of the innermost winding 31, the second portion S22 of the winding 32, the second portion S23 of the winding 33, and the second portion S24 of the outermost winding 34 do not overlap with the main path 10. However, the present invention is not limited thereto, and in other embodiments, for example, the second portion S21 of the innermost winding 31 may overlap with the main path 10.

[0057] In the illustrated embodiment, the first portions S11, S12, S13, and S14 have the same width, such as width W1, and the second portions S21, S22, S23, and S24 have the same width, such as width W2. However, in other embodiments, the first portions S11, S12, S13, and S14 may have different widths, and / or the second portions S21, S22, S23, and S24 may have different widths.

[0058] Conventionally, the coupling port and the isolation port of the coupler may all be located outside the winding, so a crossing wiring is required to connect the inner end (e.g., the first end) of the winding to the port located outside the winding. In this case, undesirable electromagnetic coupling may occur between the crossing wiring and the winding of the coupling path. In at least one embodiment of the present invention, at least one of the port 70 and the port 90 may be located inside the winding of the coupling path 20. For example, the port 70 used as the isolation port may be located inside the winding, thereby avoiding crossing wiring, thereby weakening or avoiding undesirable electromagnetic coupling. Furthermore, the directional coupler according to at least one embodiment of the present invention can more effectively utilize the layout area, thereby achieving a compact layout configuration.

[0059] In at least one embodiment of the present invention, for example, the coupling factor may be determined or adjusted by the overlap area between the coupling path 20 and the main path 10 .

[0060] In one embodiment, the coupling factor can be adjusted by changing the degree of overlap between the first portion of at least one winding and the main path. For example, the first portion S11 of the innermost winding 31 can completely overlap, partially overlap, or not overlap with the main path 10, thereby achieving different coupling factors. For example, in the case where the first portion S11 completely overlaps with the main path 10, a larger coupling factor is achieved, and in the case where the first portion S11 does not overlap with the main path 10, a smaller coupling factor is achieved. Similarly, the first portion S14 of the outermost winding 34 can completely overlap, partially overlap, or not overlap with the main path 10, thereby achieving different coupling factors.

[0061] In another embodiment, the coupling factor can be adjusted by changing the width of the first portion of at least one winding, for example, the first portion S11 of the innermost winding 31 can be widened to achieve a larger coupling factor.

[0062] In yet another embodiment, the coupling factor can be adjusted by changing the number of at least one winding, for example, more windings can achieve a larger coupling factor.

[0063] According to at least one embodiment of the present invention, a directional coupler 1 can still achieve a larger coupling factor when the available layout area is limited. For example, when the main path 10 is a single path with a shorter length, a desired coupling factor can be achieved. Therefore, at least one embodiment of the present invention can provide a directional coupler with a desired coupling factor, a smaller insertion loss, and / or a compact layout.

[0064] Back to Figure 1In some embodiments, the directional coupler 1 may further include at least one passive element, which may be coupled between the coupling path 20 and the inner port 70. The at least one passive element may include a resistor 50 and / or a capacitor 60. In detail, the first end of the resistor 50 may be directly coupled to the first portion S11 of the innermost winding 31 of the coupling path 20, that is, located at the first portion S11 of the innermost winding 31. The second end of the resistor 50 may be coupled to the inner port 70. Similarly, the first end of the capacitor 60 may be directly coupled to the first portion S11 of the innermost winding 31, that is, located at the first portion S11 of the innermost winding 31. The second end of the capacitor 60 may be coupled to the inner port 70. In this embodiment, the resistor 50 and the capacitor 60 may be coupled in parallel and may be located at different positions of the first portion S11 of the innermost winding 31.

[0065] In this embodiment, the resistor 50 and the capacitor 60 can be used to form a resistor-capacitor (RC) circuit. The RC circuit can achieve impedance matching between the directional coupler 1 and the circuit it is coupled to, so as to reduce reflection, thereby achieving ideal isolation between the ports and improving the performance of the directional coupler 1. In addition, the RC circuit can be used to filter out unwanted signals (such as noise or interference). This can help improve the quality of the signal (such as the second radio frequency signal RF2) coupled to the port 90 of the directional coupler 1.

[0066] In other embodiments of the present invention, the coupling path 20 of the directional coupler 1 may have other polygonal profiles.

[0067] In one example, see Figure 4 , Figure 4 is a top view of the layout of a directional coupler 4 according to another embodiment of the present invention. The directional coupler 4 includes a main path 10, a coupling path 40, a port 70, and a port 90. The difference between the directional coupler 4 and the directional coupler 1 is that the profiles of the coupling path 40 and the coupling path 20 are different, wherein the coupling path 40 has an octagonal profile. In detail, the coupling path 40 includes a first end T1 coupled to the port 70, a second end T2 coupled to the port 90, and at least one winding wired between the first end T1 and the second end T2. Similarly, taking the innermost winding 31 as an example, the first portion S11 may have a width W3, the second portion S21 may have a width W4, and the width W3 may not be equal to the width W4.

[0068] In another example, see Figure 5 , Figure 5is a top view of the layout of a directional coupler 5 according to another embodiment of the present invention. The directional coupler 5 includes a main path 10, a coupling path 50, a port 70, and a port 90. The difference between the directional coupler 5 and the directional coupler 1 is that the profiles of the coupling path 50 and the coupling path 20 are different, wherein the coupling path 50 has the profile of an athletic field runway. In detail, the coupling path 50 includes a first end T1 coupled to the port 70, a second end T2 coupled to the port 90, and at least one winding wired between the first end T1 and the second end T2. Similarly, taking the innermost winding 31 as an example, the first portion S11 may have a width W5, the second portion S21 may have a width W6, and the width W5 may not be equal to the width W6.

[0069] In other examples, the coupling path of the directional coupler may have other profiles, such as an elliptical profile.

[0070] Through the directional couplers in the above embodiments, the layout area can be reduced and used more effectively, thereby realizing a compact layout configuration of the directional coupler. The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made according to the claims of the present invention should fall within the scope of the present invention.

Claims

1. A directional coupler, characterized in that: include: A main path for transmitting a first radio frequency signal; a coupling path at least partially overlapping the main path, wherein the coupling path includes a first end, a second end, and at least one winding wire routed between the first end and the second end; a first port coupled to the first end of the coupling path; and A second port is coupled to the second end of the coupling path, wherein at least one of the first port and the second port is located inside the at least one winding.

2. The directional coupler according to claim 1, characterized in that The first port is located inside the at least one winding, and the second port is located outside the at least one winding.

3. The directional coupler according to claim 1, characterized in that The first port or the second port is at least one of the following: a bonding pad, a through wafer via, or a through silicon via.

4. The directional coupler according to claim 1, characterized in that: The first port or the second port is further coupled to at least one of the following: a welding wire, a bump or a ground terminal.

5. The directional coupler according to claim 1, characterized in that: The at least one winding includes an innermost winding, the innermost winding includes a first portion and a second portion, and the first portion is closer to the main path than the second portion.

6. The directional coupler according to claim 5, characterized in that: The first portion has a first width, the second portion has a second width, and the first width is greater than the second width.

7. The directional coupler according to claim 5, characterized in that: The first portion of the innermost winding is parallel to the main path.

8. The directional coupler according to claim 7, characterized in that: The directional coupler further includes at least one passive element located at the first portion of the innermost winding and coupled between the coupling path and the first port.

9. The directional coupler according to claim 8, characterized in that The at least one passive component includes a resistor, a first end of the resistor is located at the first portion of the innermost winding, and a second end of the resistor is coupled to the first port.

10. The directional coupler according to claim 9, characterized in that The at least one passive component further includes a capacitor, a first end of the capacitor is located at the first portion of the innermost winding, and a second end of the capacitor is coupled to the first port.

11. The directional coupler according to claim 5, characterized in that In a top view of the directional coupler, the first portion of the innermost winding overlaps the main path, and the second portion of the innermost winding does not overlap the main path.

12. The directional coupler according to claim 1, characterized in that The at least one winding includes an outermost winding, the outermost winding includes a first portion and a second portion, and the first portion is closer to the main path than the second portion.

13. The directional coupler according to claim 12, characterized in that The first portion of the outermost winding is parallel to the main path.

14. The directional coupler according to claim 13, characterized in that The second port is located at the second portion of the outermost winding.

15. The directional coupler according to claim 12, characterized in that In a top view of the directional coupler, the first portion of the outermost winding overlaps the main path, while the second portion of the outermost winding does not overlap the main path.

16. The directional coupler according to claim 1, characterized in that The main path is formed in a first layer, and the coupling path is formed in a second layer, and the second layer is different from the first layer.

17. The directional coupler according to claim 16, characterized in that An insulating layer is formed between the first layer and the second layer.

18. The directional coupler according to claim 1, characterized in that The coupling path has a polygonal profile.

19. A directional coupler comprising: A main path for transmitting a first radio frequency signal; a coupling path at least partially overlapping the main path, wherein the coupling path includes a first end, a second end, and at least one winding wire routed between the first end and the second end, the at least one winding wire includes an innermost winding wire, the innermost winding wire includes a first portion and a second portion, the first portion is closer to the main path than the second portion, and the first portion of the innermost winding wire is parallel to the main path; a first port coupled to the first end of the coupling path; a second port coupled to the second end of the coupling path; as well as At least one passive component is located at the first portion of the innermost winding.

20. The directional coupler according to claim 19, characterized in that The first port is located inside at least one winding of the coupling path, and the second port is located outside the at least one winding of the coupling path.

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