Coupler, radio frequency circuit and electronic equipment

Abstract

The invention discloses a coupler, a radio frequency circuit and electronic equipment. The coupler comprises a first transmission line layer and a second transmission line layer, wherein the first transmission line layer and the second transmission line layer respectively comprise a first transmission line and at least one second transmission line; the two ends of the first transmission line are respectively provided with a feed port. One end of each second transmission line is connected with the first transmission line, and a preset angle is formed between the extension direction of the second transmission line and the extension direction of the first transmission line; the first transmission line of the first transmission line layer and the first transmission line of the second transmission line layer are oppositely arranged, and a coupling interval is formed between the first transmission line of the first transmission line layer and the first transmission line of the second transmission line layer; the second transmission line of the first transmission line layer extends in the direction away from the second transmission line layer, and the second transmission line of the second transmission line layer extends in the direction away from the first transmission line layer.

Description

Technical Field

[0001] The present application relates to the technical field of electronic products, and in particular to a coupler, a radio frequency circuit and an electronic device. Background Art

[0002] With the development of communication technology, the RF architecture in electronic devices such as mobile phones has gradually developed from Phase 5N to Phase 7LE and Phase 8. For example, in Phase 5N, the RF architecture is composed of discrete RF devices, such as power amplifiers, filters, couplers, etc. in the RF architecture, which are all independent devices; for example, in Phase 7LE and Phase 8, the RF architecture is composed of integrated RF devices, such as power amplifiers, filters, couplers, etc., which can be integrated and packaged in one chip, where the filter only has a filtering function and the coupler only has a coupling function, that is, the filter and coupler packaged in one chip are still independent. Due to the single function of the filter and the coupler, at present, whether it is an RF architecture composed of discrete RF devices or an RF architecture composed of integrated RF devices, filters and couplers need to be configured, especially for RF architectures that require discrete power amplifiers, additional filters and couplers may need to be added, resulting in an increase in the number and cost of devices in the RF architecture, and will also increase the space occupied and layout difficulty of the RF architecture. Summary of the invention

[0003] The embodiments of the present application provide a coupler, a radio frequency circuit and an electronic device to solve the problem that the current filters and couplers have single functions, resulting in a large number of components, high cost, large space occupation and difficult layout in the radio frequency architecture.

[0004] In order to solve the above technical problems, this application is implemented as follows:

[0005] In a first aspect, an embodiment of the present application provides a coupler, comprising: a first transmission line layer and a second transmission line layer; wherein:

[0006] The first transmission line layer and the second transmission line layer respectively include: a first transmission line and at least one second transmission line; two ends of the first transmission line are respectively provided with a feeding port; one end of each of the second transmission lines is connected to the first transmission line, and the extension direction of the second transmission line is arranged at a preset angle to the extension direction of the first transmission line;

[0007] The first transmission line of the first transmission line layer and the first transmission line of the second transmission line layer are arranged opposite to each other, and a coupling interval is provided between the first transmission line of the first transmission line layer and the first transmission line of the second transmission line layer; the second transmission line of the first transmission line layer extends in a direction away from the second transmission line layer, and the second transmission line of the second transmission line layer extends in a direction away from the first transmission line layer.

[0008] In a second aspect, an embodiment of the present application further provides a radio frequency circuit, including the coupler as described above, and further including: a radio frequency transceiver, a power amplifier unit, and an antenna unit; wherein,

[0009] The transmitting port of the RF transceiver is connected to the first feeding port of the coupler through the power amplifier unit, the second feeding port of the coupler is connected to the antenna unit, the third feeding port of the coupler is connected to the coupling port of the RF transceiver, and the fourth feeding port of the coupler is connected to the load;

[0010] The first feeding port is located at the first end of the first transmission line of the first transmission line layer, the second feeding port is located at the second end of the first transmission line of the first transmission line layer, the third feeding port is located at the first end of the first transmission line of the second transmission line layer, and the fourth feeding port is located at the second end of the first transmission line of the second transmission line layer.

[0011] In a second aspect, an embodiment of the present application further provides an electronic device, comprising the radio frequency circuit as described above.

[0012] Thus, in the above scheme of the present application, the coupler composed of the first transmission line layer and the second transmission line layer, which respectively include the first transmission line and at least one second transmission line, has four feeding ports of the coupler formed by respectively arranging the feeding ports at both ends of the first transmission line in the first transmission line layer and the second transmission line layer, and by arranging the first transmission line of the first transmission line layer and the first transmission line of the second transmission line layer to be arranged relative to each other, and having a coupling interval between the first transmission line of the first transmission line layer and the first transmission line of the second transmission line layer, so that the coupler has coupling performance. Furthermore, by arranging that one end of each of the second transmission lines is connected to the first transmission line, and the extension direction of the second transmission line is arranged at a preset angle to the extension direction of the first transmission line, and the second transmission line of the first transmission line layer extends in a direction away from the second transmission line layer, and the second transmission line of the second transmission line layer extends in a direction away from the first transmission line layer, the second transmission line of the first transmission line layer and the second transmission line of the second transmission line layer are avoided as much as possible, so as to reduce the coupling between the second transmission line of the first transmission line layer and the second transmission line of the second transmission line layer, thereby reducing the new resonant frequency introduced by the coupling, and reducing the situation where the out-of-band suppression capability of the coupler is reduced when the new resonant frequency falls outside the operating frequency band of the coupler. Furthermore, an equivalent filtering network can be formed by the relative positional relationship between the first transmission line and the second transmission line arranged in the coupler to play a filtering role, that is, the coupler has both a coupling function and a filtering performance, thereby enriching the performance of the coupler. In this way, when the coupler in the embodiment of the present application is used alone in the RF architecture, the effect of the current combination of the coupler and the filter can be achieved, the number of devices in the RF architecture can be reduced, the cost can be reduced, and to a certain extent, the space occupied by the coupler and the filter in the RF architecture can be reduced, and the layout difficulty of the RF architecture can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A schematic diagram showing the structure of a coupler according to an embodiment of the present application;

[0014] Figure 2A A top view showing a coupler according to an embodiment of the present application;

[0015] Figure 2B A front view showing a coupler according to an embodiment of the present application;

[0016] Figure 2C A left side view of a coupler according to an embodiment of the present application is shown;

[0017] Figure 3 One of the schematic diagrams showing the transmission line structure of a conventional coupler;

[0018] Figure 4 The second schematic diagram showing the transmission line structure of a conventional coupler;

[0019] Figure 5A Represents the traditional coupler Schematic diagram of current distribution vectors in a transmission line structure;

[0020] Figure 5B Represents the traditional coupler Scalar schematic diagram of current distribution in a transmission line structure;

[0021] Figure 6 A schematic diagram showing simulated S-parameters of a transmission line structure of a conventional coupler;

[0022] Figure 7 One of the schematic diagrams showing the structure of the transmission line of an embodiment of the present application;

[0023] Figure 8 A second schematic diagram showing the structure of a transmission line according to an embodiment of the present application;

[0024] Fig. 9A A schematic diagram showing a current distribution vector of a transmission line structure according to an embodiment of the present application;

[0025] Fig. 9B A scalar schematic diagram showing current distribution of a transmission line structure according to an embodiment of the present application;

[0026] Fig.10 A schematic diagram showing simulated S parameters of a transmission line structure according to an embodiment of the present application;

[0027] Fig.11 A schematic diagram showing an equivalent circuit of a transmission line structure used by a coupler according to an embodiment of the present application;

[0028] Fig.12 A schematic diagram showing a simulation equivalent circuit of a transmission line structure used by a coupler according to an embodiment of the present application;

[0029] Fig.13 An S-parameter schematic diagram showing a simulated equivalent circuit of a transmission line structure used in a coupler according to an embodiment of the present application;

[0030] Fig.14 Indicates the use of traditional Schematic diagram of a coupled-line coupler consisting of transmission lines;

[0031] Fig.15A One of the schematic diagrams showing the simulated S parameters of the coupler according to the embodiment of the present application;

[0032] Fig. 15B A second schematic diagram showing simulated S parameters of a coupler according to an embodiment of the present application;

[0033] Fig.16A schematic diagram showing simulated surface current distribution of a coupler according to an embodiment of the present application;

[0034] Fig.17 A block diagram showing a radio frequency circuit according to an embodiment of the present application. DETAILED DESCRIPTION

[0035] The exemplary embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present application and to fully convey the scope of the present application to those skilled in the art.

[0036] like Figure 1 and Figure 2A As shown, an embodiment of the present application provides a coupler, comprising: a first transmission line layer 11 and a second transmission line layer 12; wherein,

[0037] The first transmission line layer 11 and the second transmission line layer 12 respectively include: a first transmission line 101 and at least one second transmission line 102; both ends of the first transmission line 101 are respectively provided with a feeding port 13; one end of each of the second transmission lines 102 is connected to the first transmission line 101, and the extension direction of the second transmission line 102 is set at a preset angle to the extension direction of the first transmission line 101;

[0038] The first transmission line 101 of the first transmission line layer 11 and the first transmission line 101 of the second transmission line layer 12 are arranged opposite to each other, and a coupling interval is provided between the first transmission line 101 of the first transmission line layer 11 and the first transmission line 101 of the second transmission line layer 12; the second transmission line 102 of the first transmission line layer 11 extends in a direction away from the second transmission line layer 12, and the second transmission line 102 of the second transmission line layer 12 extends in a direction away from the first transmission line layer 11.

[0039] Optionally, the first transmission line layer 11 and the second transmission line layer 12 have the same structure, that is, the first transmission line layer 11 and the second transmission line layer 12 respectively include: a first transmission line 101 and at least one second transmission line 102 .

[0040] For example, both ends of the first transmission line 101 of the first transmission line layer 11 are provided with feeding ports 13; similarly, both ends of the first transmission line 101 of the second transmission line layer 12 are also provided with feeding ports 13. Specifically, the feeding port 13 at the first end of the first transmission line 101 of the first transmission line layer 11 can be called a first feeding port 131, the feeding port 13 at the first end of the first transmission line 101 of the first transmission line layer 11 can be called a second feeding port 132, the feeding port 13 at the first end of the first transmission line 101 of the second transmission line layer 12 can be called a third feeding port 133, and the feeding port 13 at the first end of the first transmission line 101 of the second transmission line layer 12 can be called a fourth feeding port 134. The first end and the second end are arranged opposite to each other. In this way, the coupler has four feeding ports, which can be used as the input port, the through port (or the output port), the coupling port and the isolation port of the coupler respectively.

[0041] Optionally, one end of each second transmission line 102 is connected to the first transmission line 101, for example, in the first transmission line layer 11, one end of each second transmission line 102 is connected to the middle portion of the first transmission line 101; similarly, in the second transmission line layer 12, one end of each second transmission line 102 is connected to the middle portion of the first transmission line 101. The middle portion is a portion between the first end and the second end of the first transmission line 101. For example, when there are multiple second transmission lines 102, there are intervals between different second transmission lines 102.

[0042] Optionally, the extension direction of the second transmission line 102 is set at a preset angle with the extension direction of the first transmission line 101, for example, the extension direction of the second transmission line 102 is perpendicular to the extension direction of the first transmission line 101, that is, the extension direction of the second transmission line 102 is 90 degrees to the extension direction of the first transmission line 101, or it can be 90±σ degrees (σ can represent a processing error or a value that satisfies the filtering performance of the working frequency of the coupler, etc.), or it can be other preset angles that can satisfy the filtering performance of the working frequency of the coupler, etc., and the embodiments of the present application are not limited to this.

[0043] Optionally, the number of second transmission lines 102 set in the first transmission line layer 11 and the second transmission line layer 12 can be one or more, for example, 1, 2, 3, or more than 3 second transmission lines 102 can be set in the first transmission line layer 11 and the second transmission line layer 12, etc., which can be specifically set according to the filtering requirements of the coupler, and is not specifically limited in the embodiment of the present application.

[0044] In this embodiment, a coupler consisting of a first transmission line layer 11 and a second transmission line layer 12, each including a first transmission line 101 and at least one second transmission line 102, is configured by feeding ports 13 respectively arranged at both ends of the first transmission line 101 in the first transmission line layer 11 and the second transmission line layer 12, thereby forming four feeding ports of the coupler, and the first transmission line 101 of the first transmission line layer 11 and the first transmission line 101 of the second transmission line layer 12 are arranged opposite to each other, and a coupling interval is provided between the first transmission line 101 of the first transmission line layer 11 and the first transmission line 101 of the second transmission line layer 12, so that the coupler has coupling performance. Furthermore, by setting one end of each second transmission line 102 to be connected to the first transmission line 101, and the extension direction of the second transmission line 102 is set at a preset angle to the extension direction of the first transmission line 101, and the second transmission line 102 of the first transmission line layer 11 extends in a direction away from the second transmission line layer 12, and the second transmission line 102 of the second transmission line layer 12 extends in a direction away from the first transmission line layer 11, so that the second transmission line 102 of the first transmission line layer 11 and the second transmission line 102 of the second transmission line layer 12 are avoided as much as possible, so as to reduce the coupling between the second transmission line 102 of the first transmission line layer 11 and the second transmission line 102 of the second transmission line layer 12, thereby reducing the new resonant frequency introduced by the coupling, and reducing the situation where the out-of-band suppression capability of the coupler is reduced when the new resonant frequency falls outside the working frequency band of the coupler. And through the relative position relationship between the first transmission line and the second transmission line set in the coupler, an equivalent filtering network can be formed to play a filtering role. That is, the coupler has both power coupling function and filtering characteristics, thereby enriching the performance of the coupler. In this way, when the coupler in the embodiment of the present application is used alone in the RF architecture, the effect of the current combination of coupler and filter can be achieved, and the number of devices in the RF architecture can be reduced, the cost can be reduced, and to a certain extent, the space occupied by the coupler and filter in the RF architecture can be reduced, and the difficulty of layout of the RF architecture can be reduced.

[0045] It should be noted that in the embodiment of the present application, a structure with filtering characteristics is designed on a device with a power coupling function, so that the device has both a power coupling function and a filtering characteristic. It can be called a coupler, or a coupler with filtering characteristics, or a filter with a coupling function, or other names other than these (such as a radio frequency device with power coupling and filtering characteristics, etc.), and the embodiment of the present application is not limited to this.

[0046] Optionally, the first end of the first transmission line 101 of the first transmission line layer 11 is aligned with the first end of the first transmission line 101 of the second transmission line layer 12; the second end of the first transmission line 101 of the first transmission line layer 11 is aligned with the second end of the first transmission line 101 of the second transmission line layer 12; and the at least one second transmission line 102 of the first transmission line layer 11 is arranged in a one-to-one correspondence with the at least one second transmission line 102 of the second transmission line layer 12.

[0047] For example: See Figure 2A In the top view of the coupler shown in the figure, the first transmission line 101 of the first transmission line layer 11 is arranged opposite to the first transmission line 101 of the second transmission line layer 12, and the first end of the first transmission line 101 of the first transmission line layer 11 is aligned with the first end of the first transmission line 101 of the second transmission line layer 12; the second end of the first transmission line 101 of the first transmission line layer 11 is aligned with the second end of the first transmission line 101 of the second transmission line layer 12, so as to ensure that the coupler in the embodiment of the present application has better coupling performance. Considering that in the embodiment of the present application, the first transmission line layer 11 and the second transmission line layer 12 have the same structure, and the first transmission line layer 11 and the second transmission line layer 12 have different layout directions in the coupler, that is, at least one second transmission line 102 of the first transmission line layer 11 and at least one second transmission line 102 of the second transmission line layer 12 are arranged in a one-to-one correspondence, or it can also be said that at least one second transmission line 102 of the first transmission line layer 11 and at least one second transmission line 102 of the second transmission line layer 12 are symmetrically arranged relative to the first transmission line 101 of the first transmission line layer 11 and the first transmission line 101 of the second transmission line layer 12, so as to ensure that the coupler in the embodiment of the present application has better coupling performance and filtering characteristics.

[0048] Alternatively, if Figure 2B and Figure 2C As shown, the coupler further includes: a reference ground layer 14 and a dielectric substrate 15 ; wherein the first transmission line layer 11 , the second transmission line layer 12 and the reference ground layer 14 are sequentially arranged on different layers of the dielectric substrate 15 .

[0049] For example, the first transmission line layer 11, the second transmission line layer 12 and the reference ground layer 14 are sequentially arranged in different layers of the dielectric substrate 15, that is, the second transmission line layer 12 is located between the first transmission line layer 11 and the reference ground layer 14, and there is a gap between the second transmission line layer 12 and the first transmission line layer 11, and there is a gap between the second transmission line layer 12 and the reference ground layer 14, and the gap is filled by the dielectric substrate 15.

[0050] For example: See Figure 2B In the front view of the coupler shown, the distance between the first transmission line layer 11 and the second transmission line layer 12 is H2, and the distance between the second transmission line layer 12 and the reference ground layer 14 is H3. By adjusting the distance between the first transmission line layer 11 and the second transmission line layer 12 to H2, the coupling coefficient of the coupler can be adjusted. Of course, in addition to this, the coupler can also be adjusted to retain its required operating frequency point and filter out other resonance points by adjusting the distribution position of one or more second transmission lines 102 on the first transmission line 101, or adjusting the distance between multiple second transmission lines 102, or adjusting the width of one or more second transmission lines 102, or adjusting the length of one or more second transmission lines 102, etc. The embodiment of the present application is not limited to this.

[0051] For example, see Figure 2C The left side view of the coupler shown in FIG. 1 shows a diagram of a coupler in which the first transmission line layer 11 and the second transmission line layer 12 are spaced apart from each other. Figure 2A In the top view of the coupler shown, the first transmission line 101 of the first transmission line layer 11 overlaps with the first transmission line 101 of the second transmission line layer 12 to ensure that the first transmission line 101 of the first transmission line layer 11 and the first transmission line 101 of the second transmission line layer 12 can be coupled, that is, the first transmission line 101 of the first transmission line layer 11 and the first transmission line 101 of the second transmission line layer 12 are not in contact with each other, and the two interact with each other through the spatial electromagnetic field at a relatively close distance. Figure 2C From the left view of the coupler shown, the second transmission line 102 of the first transmission line layer 11 and the second transmission line 102 of the second transmission line layer 12 extend in opposite directions, so that the second transmission line 102 of the first transmission line layer 11 and the second transmission line 102 of the second transmission line layer 12 avoid each other as much as possible, so as to reduce the coupling between the second transmission line 102 of the first transmission line layer 11 and the second transmission line 102 of the second transmission line layer 12, and better achieve the filtering effect.

[0052] Optionally, the first transmission line layer 11 is disposed on a first surface of the dielectric substrate 15 , or the first transmission line layer 11 is disposed inside the dielectric substrate 15 .

[0053] and / or,

[0054] The reference ground layer 14 is arranged on the second surface of the dielectric substrate 15, or the reference ground layer 14 is arranged inside the dielectric substrate 15;

[0055] Wherein, the first surface and the second surface are arranged opposite to each other.

[0056] For example, the second transmission line layer 12 is located between the first transmission line layer 11 and the reference ground layer 14, for example: the first transmission line layer 11 can be arranged on the first surface of the dielectric substrate 15, the second transmission line layer 12 is arranged in the dielectric substrate 15, and the reference ground layer 14 is arranged on the second surface of the dielectric substrate 15. Alternatively, the first transmission line layer 11 can be arranged on the first surface of the dielectric substrate 15, the second transmission line layer 12 is arranged in the dielectric substrate 15, and the reference ground layer 14 is arranged in the dielectric substrate 15. Alternatively, the first transmission line layer 11 is arranged in the dielectric substrate 15, the second transmission line layer 12 is arranged in the dielectric substrate 15, and the reference ground layer 14 is arranged on the second surface of the dielectric substrate 15. Alternatively, the first transmission line layer 11, the second transmission line layer 12 and the reference ground layer 14 are all arranged in the dielectric substrate 15, etc., and the embodiments of the present application are not limited thereto.

[0057] Optionally, the length of the first transmission line 101 satisfies: Wherein, L is the length of the first transmission line 101, and λ is the wavelength corresponding to the resonant frequency of the working coupler.

[0058] For example, the length of the first transmission line 101 can be determined according to the resonant frequency of the coupler. For example, when the resonant frequency of the coupler is f1, the corresponding wavelength λ1 can be determined. For example, the length of the first transmission line 101 satisfies: When the resonant frequency of the coupler is f1, the length of the first transmission line 101 is

[0059] It should be noted that the actual length L of the first transmission line 101 can be based on Determine, where σ represents an error, such as an error in actual processing technology, or considering the actual length L of the first transmission line 101 When it is close to, the resonant frequency of the coupler can be reached, then σ can also represent the error value that satisfies the resonant frequency of the coupler, etc. The value of σ can be an integer or zero, and the embodiments of the present application are not limited to this.

[0060] Optionally, the first transmission line layer 11 and the second transmission line layer 12 further include: a third transmission line 103 and a fourth transmission line 104 , respectively.

[0061] The first end of the third transmission line 103 is connected to the first end of the first transmission line 101, and the extension direction of the third transmission line 103 is set at a preset angle with the extension direction of the first transmission line 101; the first end of the fourth transmission line 104 is connected to the second end of the first transmission line 101, and the extension direction of the fourth transmission line 104 is set at a preset angle with the extension direction of the first transmission line 101; the second end of the third transmission line 103 and the second end of the fourth transmission line 104 are respectively provided with the feeding port 13; wherein the first end and the second end are arranged opposite to each other.

[0062] For example, the extension direction of the third transmission line 103 is set at a preset angle with the extension direction of the first transmission line 101, such as the extension direction of the third transmission line 103 is perpendicular to the extension direction of the first transmission line 101, that is, the extension direction of the third transmission line 103 is 90 degrees to the extension direction of the first transmission line 101, or it can be 90±σ degrees (σ can represent a processing error or a value that satisfies the filtering performance of the working frequency of the coupler, etc.), or it can be other preset angles that can satisfy the filtering performance of the working frequency of the coupler, etc., and the embodiments of the present application are not limited to this.

[0063] Similarly, the extension direction of the fourth transmission line 104 is arranged at a preset angle with the extension direction of the first transmission line 101, for example, the extension direction of the fourth transmission line 104 is perpendicular to the extension direction of the first transmission line 101, that is, the extension direction of the fourth transmission line 104 is 90 degrees to the extension direction of the first transmission line 101, or it can be 90±σ degrees (σ can represent a processing error or a value that satisfies the filtering performance of the working frequency of the coupler, etc.), or it can be other preset angles that can satisfy the filtering performance of the working frequency of the coupler, etc., and the embodiments of the present application are not limited thereto.

[0064] Optionally, the feeding port 13 located at the second end of the third transmission line 103 of the first transmission line layer 11 can be called a first feeding port 131, and the first feeding port 131 can be used as a signal input port of the coupler; the feeding port 13 located at the second end of the fourth transmission line 104 of the first transmission line layer 11 can be called a second feeding port 132, and the second feeding port 132 can be used as a through port (or a signal output port) of the coupler; the feeding port 13 located at the second end of the third transmission line 103 of the second transmission line layer 12 can be called a third feeding port 133, and the third feeding port 133 can be used as a coupling port of the coupler; the feeding port 13 located at the second end of the fourth transmission line 104 of the second transmission line layer 12 can be called a fourth feeding port 134, and the fourth feeding port 134 can be used as an isolation port of the coupler.

[0065] Alternatively, considering that the first transmission line layer 11 and the second transmission line layer 12 have the same structure but are laid out in different directions, the functions of the first feeding port 131 and the third feeding port 133 can be interchanged, and the functions of the second feeding port 132 and the fourth feeding port 134 can also be interchanged, such as the third feeding port 133 serving as the signal input port of the coupler, the first feeding port 131 serving as the coupling port of the coupler, the fourth feeding port 134 serving as the through port (or signal output port) of the coupler, and the second feeding port 132 serving as the isolation port of the coupler. Alternatively, the functions of the first feeding port 131 and the second feeding port 132 are interchanged, and the functions of the third feeding port 133 and the fourth feeding port 134 are interchanged, such as the second feeding port 132 serving as the signal input port of the coupler, the first feeding port 131 serving as the through port (or signal output port) of the coupler, the fourth feeding port 134 serving as the coupling port of the coupler, and the third feeding port 133 serving as the isolation port of the coupler, etc. The embodiments of the present application are not limited thereto.

[0066] Optionally, the first feeding port 131 has two connection ends, one of which is connected to the second end of the third transmission line 103 of the first transmission line layer 11, and the other connection end is connected to the reference ground 14; the second feeding port 132 has two connection ends, one of which is connected to the second end of the fourth transmission line 104 of the first transmission line layer 11, and the other connection end is connected to the reference ground 14; the third feeding port 133 has two connection ends, one of which is connected to the second end of the third transmission line 103 of the second transmission line layer 12, and the other connection end is connected to the reference ground 14; the fourth feeding port 134 has two connection ends, one of which is connected to the second end of the fourth transmission line 104 of the second transmission line layer 12, and the other connection end is connected to the reference ground 14.

[0067] Optionally, when there are multiple second transmission lines 102 , the multiple second transmission lines 102 are symmetrically distributed on the first transmission line layer 11 ; and / or the third transmission line 103 and the fourth transmission line 104 are symmetrically arranged on the first transmission line 101 .

[0068] In this embodiment, by arranging the first transmission line layer 11 and the second transmission line layer 12 in the coupler to have a symmetrical structure, the coupler can have better power coupling function and filtering characteristics.

[0069] Considering that the first transmission line layer 11 and the second transmission line layer 12 in the embodiment of the present application adopt the same structure, the embodiment of the present application combines the transmission line structure constituting the coupler to explain its working principle and the technical effect achieved compared with the transmission line structure adopted by the traditional coupler:

[0070] like Figure 3 and Figure 4 As shown, the conventional coupler The transmission line structure is composed of transmission lines TL1, TL2, TL1′ and feeding ports P1 and P2. Among them, the transmission line TL2 is a standard The transmission lines TL1 and TL1′ are transmission lines whose characteristic impedance is the same as the impedance of the feeding ports P1 and P2. Here, λ is the wavelength corresponding to the center frequency of the operating frequency band of the transmission line.

[0071] like Figure 5A and Figure 5B The traditional coupler Schematic diagram of current distribution in transmission line structure; Figure 6 The traditional coupler The simulation S parameter diagram of the transmission line structure shows that its fundamental operating frequency ① is around 4 GHz, but due to The transmission line is periodic, and it also works near the multiple frequencies of frequency points ②, ③, ④, etc. (where frequency point ① and frequency point ①′ are the same frequency point, frequency point ② and frequency point ②′ are the same frequency point, frequency point ③ and frequency point ③′ are the same frequency point, and frequency point ④ and frequency point ④′ are the same frequency point). The periodicity of the transmission line is not conducive to the transmission of RF signals. Because the coupler is usually connected to the back end of the power amplifier, and the power amplifier, a nonlinear device, will generate a large number of nonlinear products (such as harmonics, stray signals, etc.) when working. If these harmonics and stray signals fall into the receiving (RX) band of other frequency bands (Band), it will affect its receiving sensitivity, or if these harmonics and stray signals fall into the transmitting (TX) band of other bands, it will affect its transmission-related indicators. Therefore, a filter is usually added between the power amplifier and the coupler to prevent other signals from passing through, that is, to filter out other signals except the main frequency. Therefore, when using Figure 3 and Figure 4 This When a coupler is composed of transmission lines, a filter needs to be added at the front end.

[0072] like Figure 7 and Figure 8 FIG. 1 shows a schematic diagram of a transmission line structure used by a coupler of an embodiment of the present application. Taking the transmission line structure including three second transmission lines as an example, the transmission line structure of the embodiment of the present application is also composed of transmission lines TL1, TL2, TL1′, and feeding ports P1 and P2, which is different from the conventional coupler. The difference in the transmission line structure is that in the transmission line structure adopted by the coupler in the embodiment of the present application, the transmission line TL2 is composed of four parts: transmission lines TL2_1, TL2_2, TL2_3, and TL2_4.

[0073] like Fig. 9A and Fig. 9B As shown, it is a schematic diagram of the current distribution of the transmission line structure of the coupler of the embodiment of the present application; Fig.10 FIG. 1 is a schematic diagram of the simulated S parameters of the transmission line structure of the coupler of the embodiment of the present application. Fig.10 As can be seen from the curve of the S11 parameter shown in FIG. 1 , the transmission line structure adopted by the coupler of the embodiment of the present application has an operating frequency point ① near 4 GHz, but it does not work at Figure 6 The frequency points ②, ③, ④ and other multiples are shown near the frequency points (wherein, frequency point ① and frequency point ①′ are the same frequency point, frequency point ② and frequency point ②′ are the same frequency point, frequency point ③ and frequency point ③′ are the same frequency point, and frequency point ④ and frequency point ④′ are the same frequency point). And from Fig.10 It can be seen from the curve graph of the S21 parameter that most of the energy of the transmission line structure adopted by the coupler in the embodiment of the present application is only propagated near the frequency point ①′, which is similar to a bandpass network and has a bandpass filter characteristic.

[0074] For the convenience of description Fig.10 The effects shown, such as Fig.11As shown, a schematic diagram of the equivalent circuit of the transmission line structure used by the coupler of the embodiment of the present application is given, wherein C1 is the equivalent coupling capacitor between the transmission line TL2_2 and the floor GND, C2 is the equivalent coupling capacitor between the transmission line TL2_3 and the floor GND, and C3 is the equivalent coupling capacitor between the transmission line TL2_4 and the floor GND. C4 is the equivalent coupling capacitor between the transmission lines TL2_2 and TL2_3, and C5 is the equivalent coupling capacitor between the transmission lines TL2_4 and TL2_3. L1 is the equivalent inductance from the transmission line TL1 to the transmission line TL2_2 on the transmission line TL2_1; L2 is the equivalent inductance from the transmission line TL2_2 to the transmission line TL2_3 on the transmission line TL2_1; L3 is the equivalent inductance from the transmission line TL2_3 to the transmission line TL2_4 on the transmission line TL2_1; L4 is the equivalent inductance from the transmission line TL2_4 to the transmission line TL1′ on the transmission line TL2_1. L5 is the equivalent inductance of the transmission line TL2_2, L6 is the equivalent inductance of the transmission line TL2_3, and L7 is the equivalent inductance of the transmission line TL2_4. Fig.11 The circuit shown forms a bandpass network that functions as a bandpass filter, thereby allowing signals to be transmitted only within a specific frequency range.

[0075] based on Fig.11 The equivalent circuit shown in the figure is simulated in ADS. After optimizing the values ​​of capacitors and inductors, L1, L2, L3, L4, L5, and L7 are set to 0.1nH, L6 is set to 5.1nH, C1 and C3 are set to 6.5pF, C2 is set to 7pF, and C4 and C5 are set to 1pF. Fig.12 Based on Fig.12 The simulation equivalent circuit shown in the figure obtains the S parameters of ADS simulation, as shown in Fig.13 As shown. It can be seen that the equivalent circuit has the characteristics of a bandpass filter and operates around 4 GHz.

[0076] It should be noted that Fig.12In the simulation equivalent circuit shown, the inductance and capacitance values ​​are not unique, and one set of values ​​is presented here. C1, C2, and C3 are the equivalent coupling capacitances between the transmission lines TL2_2, TL2_3, and TL2_4 and the floor GND, respectively. Since the equivalent capacitance of the parallel plate capacitor is related to the parallel plate spacing and width, the capacitance values ​​of C1, C2, and C3 can be adjusted by adjusting the spacing between the transmission lines TL2_2, TL2_3, and TL2_4 and the floor GND, and adjusting the width of the transmission lines TL2_2, TL2_3, and TL2_4. Similarly, the capacitance values ​​of C4 and C5 can be adjusted by adjusting the spacing between the transmission lines TL2_2 and TL2_4 and TL2_3, respectively. Since the inductance of the transmission line (or straight wire) is related to its length, the inductance values ​​of the inductors L5, L6, and L7 can be adjusted by adjusting the lengths of the transmission lines TL2_2, TL2_3, and TL2_4. In this way, by optimizing the capacitance values ​​of C1, C2, C3, C4, and C5, and the inductance values ​​of L5, L6, and L7, the passband of the transmission line structure can operate within the required frequency range, so that the entire path has a bandpass filter characteristic.

[0077] It should also be noted that the transmission line TL2_1 is Figure 7 and Figure 8 The length of the main transmission line of the transmission line structure shown in FIG. 1 determines the resonant frequency of the transmission line structure (for example, its length can be set to ), so after the resonant frequency (operating frequency) of the transmission line structure is determined, it is not appropriate to adjust the size of the transmission line TL2_1. Considering L1, L2, L3, and L4 as the distributed inductance of the transmission line TL2_1, after the resonant frequency of the transmission line structure is determined, the inductance values ​​of L1, L2, L3, and L4 are fixed accordingly. The subsequent operation can be mainly carried out by optimizing the capacitance values ​​of C1, C2, C3, C4, and C5, and the inductance values ​​of L5, L6, and L7, so that the passband of the transmission line structure can work within the required frequency range. When using Figure 7 and Figure 8 When the coupled line coupler is constructed by the transmission line structure shown in FIG. 1 , the above limitations also need to be noted. That is, the transmission line TL2_1 is The transmission line itself has multiple resonance points. The function of the transmission lines TL2_2, TL2_3, and TL2_4 is to form a filtering network to filter out the remaining resonance points and only retain the required operating frequency points.

[0078] like Fig.14 As shown, given by Figure 3 The tradition shown Schematic diagram (top view) of a coupled line coupler composed of transmission lines, which consists of transmission lines TL1, TL2, TL1′, TL2′, feeding ports P1, P2, P3, P4, and reference ground GND. Among them, transmission lines TL2 and TL2′ are standard The transmission line is arranged to ensure that its coupling coefficient is the largest and its coupling port can output the maximum power; the transmission lines TL1 and TL1′ are transmission lines with characteristic impedances that are the same as the impedances of the feeding ports P1, P2, P3, and P4. H1 is the spacing between the transmission line TL2 and the transmission line TL2′. By adjusting H1, the coupling coefficient of the coupled line coupler can be controlled.

[0079] The coupler formed by the transmission line structure of the embodiment of the present application can be further referred to Figure 1 As shown. Fig.15A and Fig. 15B As shown in FIG. 1 , a schematic diagram of the simulated S parameters of a coupler formed by the transmission line structure of an embodiment of the present application is given. Fig.15A From the curve of the S11 parameter, we can see that it works in the N77 frequency band (3800MHz~4200MHz) and there is no obvious resonance near the double frequency. Fig. 15B From the curve of the S21 parameter, it can be seen that most of the signal energy is transmitted in the N77 frequency band, and less energy is transmitted near the double frequency, which has obvious bandpass filter characteristics. Fig. 15B From the curve of the S21 parameter, we can see that within the passband, its insertion loss is -0.65db, which meets the requirements of low insertion loss of devices in RF applications of electronic devices such as mobile phones. Fig. 15B From the curve of the S31 parameter, we can see that its value is -9.23, which means that the coupler is a 9.23db coupler and its coupling coefficient is 9.23. Fig. 15B It can be seen that S41 is less than -25db, indicating that its isolation effect is good.

[0080] Fig.16 As shown, the simulated surface current distribution (scalar) of the coupler formed by the transmission line structure of the embodiment of the present application is given. Fig.16 It can be seen that after the signal flows into the first feeding port 131 (signal input port), most of the energy flows out from the second feeding port 132 (through port) and the third feeding port 133 (coupling port), and a small amount of energy flows out from the fourth feeding port 134 (isolation port).

[0081] It should be noted that in the design Figure 7When the transmission line structure with filtering characteristics is shown, in addition to having filtering characteristics, the insertion loss should be as small as possible within its transmission bandwidth, that is, the S21 modulus value should be small. S21 (insertion loss) is also an important feature for measuring couplers, especially in mobile phone electronic devices. Couplers are generally located at the back end of the power amplifier. Larger insertion loss will reduce the power flowing from the RF end to the antenna end, thereby affecting the user experience. Figure 1 What needs to be reflected in the coupler shown is that the insertion loss between the input port and the through port should be small, for example, the insertion loss can be reduced by selecting a low-loss material for the dielectric substrate. In addition, Figure 7 The transmission lines TL2_2, TL2_3, and TL2_4 shown not only play a filtering role, but also, as open-circuit short-circuit lines, can be used for impedance matching, and play a role in optimizing impedance in the coupler, so that its S11 is smaller, that is, the reflection is smaller.

[0082] like Fig.17 As shown, an embodiment of the present application provides a radio frequency circuit, including the coupler 10 as described above, and also including: a radio frequency transceiver 20, a power amplifier unit 30, and an antenna unit 40; wherein,

[0083] The transmitting port of the RF transceiver 20 is connected to the first feeding port 131 of the coupler through the power amplifier unit 30, the second feeding port 132 of the coupler is connected to the antenna unit 40, the third feeding port 133 of the coupler is connected to the coupling port of the RF transceiver 20, and the fourth feeding port 134 of the coupler is connected to the load;

[0084] Among them, the first feeding port 131 is located at the first end of the first transmission line 101 of the first transmission line layer 11, the second feeding port 132 is located at the second end of the first transmission line 101 of the first transmission line layer 11, the third feeding port 133 is located at the first end of the first transmission line 101 of the second transmission line layer 12, and the fourth feeding port 134 is located at the second end of the first transmission line 101 of the second transmission line layer 12.

[0085] Optionally, the second feeding port 132 of the coupler may be connected to the antenna unit 40 via a switch 50 .

[0086] Specifically, in the RF circuit, the signal flows out from the RF transceiver 20, passes through the RF front-end devices such as the power amplifier unit 30, the coupler 10, and the switch 50, and finally reaches the antenna unit 40. Among them, the coupler 10 in the RF circuit can filter and filter out other signals except the main frequency signal, and can also perform power distribution, and couple part of the signal output by the power amplifier unit 30 to the RF transceiver 20 for power detection. After the internal algorithm calculation, the power can be accurately controlled so that the signal power reaching the antenna unit 40 meets the expectations.

[0087] It should be noted that the RF circuit in the embodiment of the present application uses a coupler with coupling function and filtering characteristics, which can reduce the number of devices in the RF circuit and reduce costs, and to a certain extent can also reduce the space occupied by the RF circuit coupler and filter, and reduce the difficulty of layout of the RF architecture.

[0088] An embodiment of the present application also provides an electronic device, comprising the radio frequency circuit as described above.

[0089] Optionally, the electronic device in the embodiment of the present application may include but is not limited to: a mobile phone, a tablet computer, a wearable device or other electronic device with a radio frequency function, etc., and the embodiment of the present application is not limited thereto.

[0090] It should be noted that the electronic device in the embodiment of the present application can implement the various embodiments of the above-mentioned radio frequency circuit and can achieve the same technical effect. To avoid repetition, it will not be described here.

[0091] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0092] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present application.

[0093] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

[0094] The above is a preferred embodiment of the present application. It should be pointed out that for ordinary personnel in this technical field, several improvements and modifications can be made without departing from the principles described in the present application. These improvements and modifications are also within the scope of protection of the present application.

Claims

1. A coupler, characterized in that: include: A first transmission line layer and a second transmission line layer; wherein, The first transmission line layer and the second transmission line layer respectively include: a first transmission line and at least one second transmission line; two ends of the first transmission line are respectively provided with a feeding port; one end of each of the second transmission lines is connected to the first transmission line, and the extension direction of the second transmission line is arranged at a preset angle to the extension direction of the first transmission line; The first transmission line of the first transmission line layer and the first transmission line of the second transmission line layer are arranged opposite to each other, and a coupling interval is provided between the first transmission line of the first transmission line layer and the first transmission line of the second transmission line layer; the second transmission line of the first transmission line layer extends in a direction away from the second transmission line layer, and the second transmission line of the second transmission line layer extends in a direction away from the first transmission line layer.

2. The coupler according to claim 1, characterized in that The first end of the first transmission line of the first transmission line layer is aligned with the first end of the first transmission line of the second transmission line layer; the second end of the first transmission line of the first transmission line layer is aligned with the second end of the first transmission line of the second transmission line layer; The at least one second transmission line of the first transmission line layer is arranged in a one-to-one correspondence with the at least one second transmission line of the second transmission line layer.

3. The coupler according to claim 1 or 2, characterized in that: The length of the first transmission line satisfies: Wherein, L is the length of the first transmission line, and λ is the wavelength corresponding to the resonant frequency at which the coupler operates.

4. The coupler according to claim 1 or 2, characterized in that: In the case that there are plural second transmission lines, the plurality of second transmission lines are symmetrically distributed on the first transmission line layer.

5. The coupler according to claim 1, characterized in that: The first transmission line layer and the second transmission line layer further include: a third transmission line and a fourth transmission line respectively; wherein, The first end of the third transmission line is connected to the first end of the first transmission line, and the extension direction of the third transmission line is arranged at a preset angle with the extension direction of the first transmission line; The first end of the fourth transmission line is connected to the second end of the first transmission line, and the extension direction of the fourth transmission line is arranged at a preset angle with the extension direction of the first transmission line; The second end of the third transmission line and the second end of the fourth transmission line are respectively provided with the feeding port; Wherein, the first end and the second end are arranged opposite to each other.

6. The coupler according to claim 5, characterized in that The third transmission line and the fourth transmission line are symmetrically arranged on the first transmission line.

7. The coupler according to claim 1, characterized in that: Also includes: Reference strata and dielectric substrates; wherein, The first transmission line layer, the second transmission line layer and the reference ground layer are sequentially arranged on different layers of the dielectric substrate.

8. The coupler according to claim 7, characterized in that The first transmission line layer is arranged on the first surface of the dielectric substrate, or the first transmission line layer is arranged in the dielectric substrate; and / or, The reference ground layer is arranged on the second surface of the dielectric substrate, or the reference ground layer is arranged inside the dielectric substrate; Wherein, the first surface and the second surface are arranged opposite to each other.

9. A radio frequency circuit, characterized in that: The coupler according to any one of claims 1 to 8 further comprises: a radio frequency transceiver, a power amplifier unit, and an antenna unit; wherein: The transmitting port of the RF transceiver is connected to the first feeding port of the coupler through the power amplifier unit, the second feeding port of the coupler is connected to the antenna unit, the third feeding port of the coupler is connected to the coupling port of the RF transceiver, and the fourth feeding port of the coupler is connected to the load; The first feeding port is located at the first end of the first transmission line of the first transmission line layer, the second feeding port is located at the second end of the first transmission line of the first transmission line layer, the third feeding port is located at the first end of the first transmission line of the second transmission line layer, and the fourth feeding port is located at the second end of the first transmission line of the second transmission line layer.

10. An electronic device, characterized in that: Comprising the radio frequency circuit as claimed in claim 9.

Images