Couplers and electronic devices

Abstract

This application relates to the field of electronic technology, and provides a coupler and an electronic device. The coupler includes: a through path, a coupling path, and a first capacitor; a first terminal of the first capacitor is connected to the through path, and a second terminal of the first capacitor is connected to the coupling path; the cross-sectional area of ​​the conductor in the coupling path is smaller than a first area, where the first area is the area corresponding to the matching impedance value, and the cross-section of the conductor in the coupling path is perpendicular to the direction of the coupled signal flow in the coupling path. This coupler can ensure coupler performance while achieving module miniaturization.

Description

Technical Field

[0001] This application relates to the field of electronic technology, specifically to a coupler and an electronic device. Background Technology

[0002] With the development of electronic devices, their functions are becoming increasingly powerful. To achieve more feature-rich electronic devices, more functional hardware modules have been added, and a greater number of antennas have been introduced. Considering the portability of electronic devices, the miniaturization requirements for these modules are also increasing when dealing with the layout and wiring of more hardware modules.

[0003] Taking printed circuit boards (PCBs) in electronic devices as an example, the size of the PCB has a significant impact on the layout of the electronic device. The PCB in an electronic device can also be called the motherboard. The motherboard contains components that form the transmission and reception paths, as well as the traces between these components. Taking the transmission path as an example, couplers can be installed on the common transmission path for each frequency band to couple the transmitted signal and perform power detection or power control.

[0004] However, in order to ensure a high degree of coupling, traditional couplers require long traces, which results in a large coupler size and is not conducive to the miniaturization of electronic devices. Summary of the Invention

[0005] This application provides a coupler and an electronic device that can achieve miniaturization while ensuring the performance of the coupler.

[0006] In a first aspect, a coupler is provided, comprising: a through path, a coupling path, and a first capacitor; a first terminal of the first capacitor is connected to the through path, and a second terminal of the first capacitor is connected to the coupling path; the cross-sectional area of ​​the conductor of the coupling path is smaller than a first area, the first area being the area corresponding to the matching impedance value, and the cross-section of the conductor of the coupling path is perpendicular to the direction of the coupled signal flow in the coupling path.

[0007] The aforementioned direct path is the signal path. The coupled path is closer to the direct path and can couple the energy of the signal on the direct path, forming a coupled signal in the coupled path. The direct path includes the signal input and output terminals, while the coupled path includes the coupling terminal and the isolation terminal.

[0008] A first capacitor (i.e., a coupling capacitor) is connected between the coupling path and the through path. This first capacitor can increase the energy of the coupled signal, thereby improving the coupling degree.

[0009] Optionally, the capacitance of the first capacitor is relatively small, which can be less than or equal to 3 pF. For example, a small value such as 0.3 pF or 0.5 pF.

[0010] Optionally, the aforementioned coupling path and through path can be any of the following transmission paths: coaxial line, microstrip line, and stripline.

[0011] When the conductor material, dielectric material, conductor thickness, and dielectric thickness of the coupler are determined, the cross-sectional area of ​​the conductor in the path (i.e., the conductor's thickness) is related to the impedance. A larger conductor cross-sectional area results in lower impedance; conversely, a smaller cross-sectional area results in higher impedance. The cross-sectional area of ​​the conductor in the path must meet the impedance matching requirements to avoid losses caused by impedance discontinuities. For example, when the matching impedance is fifty ohms, the cross-sectional area of ​​the conductor in the coupler's path is calculated based on the fifty-ohm impedance matching requirements. In other words, the fifty-ohm impedance matching requirement is met when the conductor's cross-sectional area is the first specified area.

[0012] Optionally, the matching impedance value can also be other values ​​such as 75 ohms or 100 ohms, and this application embodiment does not limit this.

[0013] In this implementation, taking a matching impedance of fifty ohms as an example, if the cross-sectional area of ​​the conductor in the coupling path is less than the first area, it means that the characteristic impedance corresponding to the cross-sectional area of ​​the conductor in the coupling path is greater than fifty ohms.

[0014] In a coupler, when the cross-sectional area of ​​the conductor in the coupling path is smaller than the first area, the inductive coupling in the coupler can be increased, thereby ensuring the directionality of the coupler under the action of the first capacitor.

[0015] This coupler can ensure coupling and isolation without the need for long through-path and coupling path traces, enabling module miniaturization.

[0016] In some possible implementations, the through path and the coupling path are transmission paths in the form of microstrip lines, the first capacitor is a parallel plate capacitor, and the first capacitor includes: a first metal patch and a second metal patch, the first metal patch being the first terminal of the first capacitor, and the second metal patch being the second terminal of the first capacitor.

[0017] Microstrip line transmission paths can be applied to microstrip boards or printed circuit boards (PCBs). Taking a PCB as an example, when the through path and coupling path are microstrip line transmission paths, the first capacitor can be a parallel plate capacitor, i.e., a capacitor formed by two metal patches (a first metal patch and a second metal patch) facing each other. These two metal patches are the two terminals of the first capacitor, and a dielectric material can be filled between them. Using microstrip line transmission paths and parallel plate capacitors to implement the coupling capacitor allows for one-time forming during PCB fabrication, simplifying the process and making implementation convenient.

[0018] In some possible implementations, the first projection of the first metal patch onto the first plane and the second projection of the second metal patch onto the first plane at least partially overlap, the area of ​​the overlap between the first and second projections is positively correlated with the capacitance value of the first capacitor, and the first plane and the maximum surface of the first metal patch are parallel.

[0019] In a parallel-plate capacitor, the more the two metal contacts overlap in the direction perpendicular to the largest surface of the metal contacts, the larger the capacitance of the first capacitor; conversely, the less overlap, the smaller the capacitance. The two metal contacts can be parallel to the largest surface of the printed circuit board, for example, distributed on two layers of a multilayer circuit board.

[0020] In some possible implementations, the first metal patch and the through path are integrated in the first wiring layer (first layer or surface layer), the coupling path is located in the first wiring layer, the second metal patch is located in the second wiring layer (second layer or sub-surface layer), and the second metal patch and the coupling path are connected by metallized vias.

[0021] In some possible implementations, the second metal patch and the coupling path are integrated in the first wiring layer, the through path is located in the first wiring layer, the first metal patch is located in the second wiring layer, and the first metal patch and the through path are connected by metallized vias.

[0022] When the first capacitor is a parallel plate capacitor, one end can be located on the first wiring layer, i.e., on the same layer as the through path and coupling path; the other end can be located on the second wiring layer, on a different layer than the through path and coupling path. The metal patch located on the second wiring layer can be connected to the corresponding path through metallized vias.

[0023] This coupler does not require routing paths in the second wiring layer, thus avoiding the use of stack-up resources and saving routing resources.

[0024] In some possible implementations, the cross-sectional area of ​​the conductor in the through path is larger than the cross-sectional area of ​​the conductor in the coupling path.

[0025] In some possible implementations, the cross-sectional area of ​​the conductor in the straight-through path is the first area.

[0026] Reducing the cross-sectional area of ​​the conductor in the coupling path increases magnetic field coupling. Meanwhile, the cross-sectional area of ​​the conductor in the through path can differ from that of the conductor in the coupling path. When the cross-sectional area of ​​the conductor in the through path is smaller than a first area but larger than the cross-sectional area of ​​the conductor in the coupling path, the through path can approach the area corresponding to the matching impedance value as closely as possible. In other words, the through path can meet the impedance matching standard as closely as possible, ensuring the impedance continuity of the through path, thereby ensuring the transmission parameters of the coupler, such as guaranteeing low insertion loss.

[0027] When the cross-sectional area of ​​the conductor in the straight-through path is the first area, that is, the conductor in the straight-through path meets the impedance matching requirements, it can ensure the transmission parameters of the coupler to the greatest extent, such as ensuring the lowest insertion loss to the greatest extent in terms of conductor size.

[0028] In some possible implementations, the width of the conductor in the through path is greater than or equal to the width of the conductor in the coupling path.

[0029] When the coupler's path is a transmission line implemented using microstrip lines, the width of the conductor in the through path is proportional to the cross-sectional area. If the width of the conductor in the through path is greater than or equal to the width of the conductor in the coupled path, it means that the cross-sectional area of ​​the conductor in the through path is greater than or equal to the cross-sectional area of ​​the conductor in the coupled path.

[0030] In this implementation, the parameters of the coupler can be adjusted by adjusting the line width, and the coupler can be implemented based on mass-produced printed circuit boards, thus enabling the coupler to be implemented at low cost.

[0031] In some possible implementations, the width of the conductor in the straight-through path is a first width, which is a first preset value corresponding to a 50-ohm impedance.

[0032] For example, when the material and thickness of the printed circuit board are fixed, and the required impedance matching is 50 ohms, the width of the conductor obtained is the first width. When the width of the conductor in the straight path is the first width, the characteristic impedance is 50 ohms, which can ensure impedance continuity and thus ensure low insertion loss.

[0033] In some possible implementations, the maximum surface shape of the through path and the coupling path is a straight line, a concave shape, or a U-shape.

[0034] The shape of the maximum surface of the through path and coupling path can be flexibly set according to the application scenario to achieve miniaturization and avoid other modules, which is beneficial for layout.

[0035] In some possible implementations, a reflector is also provided at the isolation end of the coupler; the reflector is used to reflect the reflected signal flowing through the isolation end, which is the signal coupled to the isolation end by the signal reflected from the output end.

[0036] A reflector can reflect the signal coupled to the isolation end of the reflected signal to cancel the signal flowing to the coupling end, thereby avoiding inaccurate coupling caused by reflection at the output end.

[0037] In some possible implementations, the difference between the magnitude of the reflection coefficient corresponding to the reflector and the power of the signal coupled from the output terminal to the isolation terminal, and the power of the reflected signal coupled to the coupling terminal, is less than a second preset value.

[0038] In some possible implementations, the difference between the phase of the reflected signal at the output end and the phase of the reflected signal coupled to the isolation end is the first phase difference; the difference between the phase of the reflected signal at the output end and the phase at the coupling end is the second phase difference; the difference between the phase of the reflected signal coupled to the isolation end and the phase of the reflected signal after being coupled to the isolation end and then transmitted to the coupling end through the coupling path is the third phase difference; the difference between the first phase difference, the first sum of the second phase difference and the third phase difference, and 180 degrees is less than a preset threshold.

[0039] If the difference between the magnitude of the reflection coefficient corresponding to the reflector and the power of the signal coupled from the output terminal to the isolation terminal, and the power of the reflected signal coupled to the coupling terminal, is less than a second preset value, it indicates that the power of the signal coupled from the output terminal to the isolation terminal and the power of the reflected signal coupled to the coupling terminal are the same or similar, or have the same or similar amplitude.

[0040] The reflector reflects the reflected signal coupled to the isolation end, so that the secondary reflected signal and the reflected signal transmitted to the coupling end are of equal amplitude (same or similar power) and opposite in direction (180 degrees or close to 180 degrees), thus achieving cancellation.

[0041] In some possible implementations, the reflector includes a second capacitor, a first inductor, and a first resistor. The first terminal of the second capacitor is connected to an isolation terminal, the second terminal of the second capacitor is connected to the first terminal of the first inductor, the second terminal of the first inductor is connected to the first terminal of the first resistor, and the second terminal of the first resistor is grounded.

[0042] A reflector implemented using a 50-ohm L-type matching circuit can adjust the amplitude and phase of the signal to ensure signal cancellation. The reflector can also be other types of circuits, or equivalent circuits of this type; no limitation is made here.

[0043] Secondly, a motherboard is provided, which has a multi-layer circuit, including at least a first wiring layer and a second wiring layer; the motherboard includes a coupler, which includes a through path and a coupling path, which are microstrip lines disposed on the first wiring layer; the coupler also includes a first capacitor; a first end of the first capacitor is connected to the through path, and a second end of the first capacitor is connected to the coupling path; wherein, the cross-sectional area of ​​the conductor of the coupling path is smaller than a first area, the first area being a first preset value corresponding to a 50-ohm impedance, and the cross-section of the conductor of the coupling path is perpendicular to the direction of the coupled signal flow in the coupling path.

[0044] In some possible implementations, the first capacitor is a parallel-plate capacitor, comprising: a first metal patch and a second metal patch, wherein the first metal patch is a first terminal of the first capacitor and the second metal patch is a second terminal of the first capacitor; the first metal patch and the through-path are integrated in a first wiring layer, the coupling path is located in the first wiring layer, the second metal patch is located in a second wiring layer, and the second metal patch and the coupling path are connected through a metallized via; or, the second metal patch and the coupling path are integrated in a first wiring layer, the through-path is located in the first wiring layer, the first metal patch is located in the second wiring layer, and the first metal patch and the through-path are connected through a metallized via.

[0045] Thirdly, an electronic device is provided, including a coupler as described in the first aspect, or a motherboard as described in the second aspect.

[0046] The implementation principles and technical effects of the related technologies in the aforementioned motherboards and electronic devices can be found in the relevant descriptions of couplers. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the structure of a terminal device 100 provided in an embodiment of this application;

[0048] Figure 2 This is a software structure block diagram of the terminal device 100 provided in the embodiments of this application;

[0049] Figure 3 This is a schematic diagram of a circuit structure of an example radio frequency front-end provided in an embodiment of this application;

[0050] Figure 4 This is a schematic diagram of an equivalent model of a coupler provided in an embodiment of this application;

[0051] Figure 5 This is a wiring diagram of an example coupler provided in an embodiment of this application;

[0052] Figure 6 These are schematic diagrams of the structures of various couplers provided in the embodiments of this application;

[0053] Figure 7 This is a schematic diagram of the electric field coupling of an example coupler provided in an embodiment of this application;

[0054] Figure 8 This is an example of an equivalent model of a transmission line provided in an embodiment of this application;

[0055] Figure 9 This is a schematic diagram of the magnetic field distribution of an example transmission line provided in an embodiment of this application;

[0056] Figure 10 This is a schematic diagram of a microstrip line structure provided in an embodiment of this application;

[0057] Figure 11 This is a schematic diagram of the magnetic field coupling of an example coupler provided in an embodiment of this application;

[0058] Figure 12 This is a schematic diagram of the magnetic field coupling of an example coupler provided in an embodiment of this application;

[0059] Figure 13 This is a schematic diagram of the linewidths of the two couplers provided in the embodiments of this application;

[0060] Figure 14 This application provides a simulation circuit diagram and corresponding S-parameter curve of a coupler according to an embodiment.

[0061] Figure 15 This is another example of a coupler simulation circuit diagram and corresponding S-parameter curve provided in the embodiments of this application;

[0062] Figure 16 This is a schematic diagram of the structure of an example coupler provided in an embodiment of this application;

[0063] Figure 17 This is an example of an S-parameter curve of a coupler provided in an embodiment of this application;

[0064] Figure 18 This is a schematic diagram of the structure of an example coupler provided in an embodiment of this application;

[0065] Figure 19 These are schematic diagrams of the structures of various couplers provided in the embodiments of this application;

[0066] Figure 20 This is a schematic diagram of the circuit structure of an example reflector provided in an embodiment of this application;

[0067] Figure 21 This is a schematic diagram of another example of a coupler provided in the embodiments of this application;

[0068] Figure 22 This is a schematic diagram of the signal flow in an example coupler provided in an embodiment of this application;

[0069] Figure 23 This is another example of a coupler simulation circuit diagram and corresponding S-parameter curve provided in the embodiments of this application;

[0070] Figure 24 This is another example of a coupler simulation circuit diagram and corresponding S-parameter curve provided in the embodiments of this application. Detailed Implementation

[0071] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. In the description of the embodiments of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B; "and / or" in this text is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more than two.

[0072] Hereinafter, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature.

[0073] The coupler provided in this application embodiment can be applied to terminal devices such as mobile phones, tablets, wearable devices, in-vehicle devices, augmented reality (AR) / virtual reality (VR) devices, laptops, ultra-mobile personal computers (UMPCs), netbooks, and personal digital assistants (PDAs). This application embodiment does not impose any restrictions on the specific type of terminal device.

[0074] For example, Figure 1This is a schematic diagram of the structure of a terminal device 100 provided in an embodiment of this application. The terminal device 100 may include a processor 110, an external memory interface 120, an internal memory 121, a universal serial bus (USB) interface 130, a charging management module 140, a power management module 141, a battery 142, an antenna 1, an antenna 2, a mobile communication module 150, a wireless communication module 160, an audio module 170, a speaker 170A, a receiver 170B, a microphone 170C, a headphone jack 170D, a sensor module 180, buttons 190, a motor 191, an indicator 192, a camera 193, a display screen 194, and a subscriber identification module (SIM) card interface 195, etc. The sensor module 180 may include a pressure sensor 180A, a gyroscope sensor 180B, a barometric pressure sensor 180C, a magnetic sensor 180D, an accelerometer sensor 180E, a distance sensor 180F, a proximity sensor 180G, a fingerprint sensor 180H, a temperature sensor 180J, a touch sensor 180K, an ambient light sensor 180L, a bone conduction sensor 180M, etc.

[0075] It is understood that the structures illustrated in the embodiments of this application do not constitute a specific limitation on the terminal device 100. In other embodiments of this application, the terminal device 100 may include more or fewer components than illustrated, or combine some components, or split some components, or have different component arrangements. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0076] Processor 110 may include one or more processing units, such as: application processor (AP), modem processor, graphics processing unit (GPU), image signal processor (ISP), controller, memory, video codec, digital signal processor (DSP), baseband processor, and / or neural network processing unit (NPU), etc. Different processing units may be independent devices or integrated into one or more processors.

[0077] The controller can serve as the central nervous system and command center of the terminal device 100. The controller can generate operation control signals based on the instruction opcode and timing signals to control the fetching and execution of instructions.

[0078] The processor 110 may also include a memory for storing instructions and data. In some embodiments, the memory in the processor 110 is a cache memory. This memory can store instructions or data that the processor 110 has just used or that are used repeatedly. If the processor 110 needs to use the instruction or data again, it can retrieve it directly from the memory. This avoids repeated accesses, reduces the waiting time of the processor 110, and thus improves the efficiency of the system.

[0079] In some embodiments, the processor 110 may include one or more interfaces. Interfaces may include an inter-integrated circuit (I2C) interface, an inter-integrated circuit sound (I2S) interface, a pulse code modulation (PCM) interface, a universal asynchronous receiver / transmitter (UART) interface, a mobile industry processor interface (MIPI), a general-purpose input / output (GPIO) interface, a subscriber identity module (SIM) interface, and / or a universal serial bus (USB) interface, etc.

[0080] It is understood that the interface connection relationships between the modules illustrated in the embodiments of this application are merely illustrative and do not constitute a structural limitation on the terminal device 100. In other embodiments of this application, the terminal device 100 may also adopt different interface connection methods or a combination of multiple interface connection methods as described in the above embodiments.

[0081] The wireless communication function of the terminal device 100 can be implemented through antenna 1, antenna 2, mobile communication module 150, wireless communication module 160, modem processor and baseband processor, etc.

[0082] Antenna 1 and antenna 2 are used to transmit and receive electromagnetic wave signals. Figure 1 The structures of antennas 1 and 2 shown are merely one example. Each antenna in terminal device 100 can be used to cover one or more communication frequency bands. Different antennas can also be reused to improve antenna utilization. For example, antenna 1 can be reused as a diversity antenna for a wireless local area network. In some other embodiments, the antennas can be used in conjunction with tuning switches.

[0083] The mobile communication module 150 can provide solutions for wireless communication, including 2G / 3G / 4G / 5G, applied to the terminal device 100. The mobile communication module 150 may include at least one filter, switch, power amplifier, low noise amplifier (LNA), etc. The mobile communication module 150 can receive electromagnetic waves via antenna 1, and perform filtering, amplification, and other processing on the received electromagnetic waves before transmitting them to a modem processor for demodulation. The mobile communication module 150 can also amplify the signal modulated by the modem processor and convert it into electromagnetic waves for radiation via antenna 1. In some embodiments, at least some functional modules of the mobile communication module 150 may be housed in the processor 110. In some embodiments, at least some functional modules of the mobile communication module 150 and at least some modules of the processor 110 may be housed in the same device.

[0084] The modem processor may include a modulator and a demodulator. The modulator modulates the low-frequency baseband signal to be transmitted into a mid-to-high frequency signal. The demodulator demodulates the received electromagnetic wave signal into a low-frequency baseband signal. The demodulator then transmits the demodulated low-frequency baseband signal to the baseband processor for processing. After processing by the baseband processor, the low-frequency baseband signal is transmitted to the application processor. The application processor outputs sound signals through audio devices (not limited to speaker 170A, receiver 170B, etc.) or displays images or videos through the display screen 194. In some embodiments, the modem processor may be a separate device. In other embodiments, the modem processor may be independent of the processor 110 and may be housed in the same device as the mobile communication module 150 or other functional modules.

[0085] The wireless communication module 160 can provide solutions for wireless communication applications on the terminal device 100, including wireless local area networks (WLAN) (such as wireless fidelity (Wi-Fi) networks), Bluetooth (BT), global navigation satellite system (GNSS), frequency modulation (FM), near field communication (NFC), and infrared (IR) technologies. The wireless communication module 160 can be one or more devices integrating at least one communication processing module. The wireless communication module 160 receives electromagnetic waves via antenna 2, performs frequency modulation and filtering of the electromagnetic wave signals, and sends the processed signal to processor 110. The wireless communication module 160 can also receive signals to be transmitted from processor 110, perform frequency modulation and amplification, and convert them into electromagnetic waves for radiation via antenna 2.

[0086] In some embodiments, antenna 1 of terminal device 100 is coupled to mobile communication module 150, and antenna 2 is coupled to wireless communication module 160, enabling terminal device 100 to communicate with networks and other devices via wireless communication technology. The wireless communication technology may include Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), Code Division Multiple Access (CDMA), Wideband Code Division Multiple Access (WCDMA), Time Division Code Division Multiple Access (TD-CDMA), Long Term Evolution (LTE), BT, GNSS, WLAN, NFC, FM, and / or IR technologies, etc. The GNSS may include the Global Positioning System (GPS), the Global Navigation Satellite System (GLONASS), the BeiDou Navigation Satellite System (BDS), the Quasi-Zenith Satellite System (QZSS), and / or satellite-based augmentation systems (SBAS).

[0087] Terminal device 100 implements display functions through a GPU, display screen 194, and application processor. The GPU is a microprocessor for image processing, connected to the display screen 194 and the application processor. The GPU is used to perform mathematical and geometric calculations and for graphics rendering. Processor 110 may include one or more GPUs, which execute program instructions to generate or modify display information.

[0088] The software system of terminal device 100 can adopt a layered architecture, event-driven architecture, microkernel architecture, microservice architecture, or cloud architecture. This application embodiment uses the layered architecture Android system as an example to exemplify the software structure of terminal device 100.

[0089] Figure 2This is a software structure block diagram of the terminal device 100 according to an embodiment of this application. The layered architecture divides the software into several layers, each with a clear role and division of labor. Layers communicate with each other through software interfaces. In some embodiments, the Android system is divided into four layers, from top to bottom: the application layer, the application framework layer, the Android runtime and system libraries, and the kernel layer. The application layer may include a series of application packages.

[0090] like Figure 2 As shown, the application package may include applications such as camera, gallery, calendar, call, map, navigation, WLAN, Bluetooth, music, video, and SMS.

[0091] The application framework layer provides application programming interfaces (APIs) and a programming framework for applications in the application layer. The application framework layer includes some predefined functions.

[0092] like Figure 2 As shown, the application framework layer may include a window manager, content provider, view system, phone manager, resource manager, notification manager, etc.

[0093] The application layer and application framework layer run in a virtual machine. The virtual machine executes the Java files of the application layer and application framework layer as binary files. The virtual machine is used to perform functions such as object lifecycle management, stack management, thread management, security and exception management, and garbage collection.

[0094] System libraries can include multiple functional modules. For example: surface manager, media libraries, 3D graphics processing libraries (e.g., OpenGL ES), 2D graphics engines (e.g., SGL), etc.

[0095] The kernel layer is the layer between hardware and software. The kernel layer contains at least the display driver, camera driver, audio driver, and sensor driver.

[0096] For ease of understanding, the following embodiments of this application will be described using the following methods: Figure 1 and Figure 2 Taking the terminal device with the structure shown as an example, the coupler provided in the embodiments of this application will be specifically described in conjunction with the accompanying drawings and application scenarios.

[0097] Couplers are widely used in various circuits to couple signals from the signal path to achieve functions such as signal splitting, power detection, and closed-loop optimization of digital pre-distortion (DPD) algorithms.

[0098] Taking a power detection function as an example, a coupler can be installed on the transmission path in the terminal device to couple the transmitted signal. The coupled signal is then input to the power detection module for power detection. For example, see [link to relevant documentation]. Figure 3 As shown, the transmitted signal is output by the RF chip, processed by the RF front-end module, and then output to the antenna for transmission through the direct path of the coupler. Figure 3 Only some components are shown, along with one transmission path and the direction of the transmitted signal on that path. The directions of the transmitted and received signals on other paths, as well as other components included in the circuit, are not shown here. The coupler enables the transmitted signal to pass through with low loss and couples to obtain a coupled signal with a certain amount of energy. The coupled signal can then enter the power detection circuit for power detection. With a fixed coupling degree of the coupler, when the power of the coupled signal is high and the converted level of the coupled signal is greater than the reference level, it indicates that the transmitted signal power is high. In this case, the detection signal output by the power detection module can be high, and the detection result indicates that the transmitted signal power is normal. When the power of the coupled signal is very low and the converted level is less than the reference level, it indicates that the transmitted signal power is too low or there is no transmitted signal. In this case, the detection signal output by the power detection module can be low, and the detection result indicates that the transmitted signal power is abnormal.

[0099] Figure 4 This is a schematic diagram of a coupler. The coupler includes an input terminal (1), an output terminal (2), a coupling terminal (3), and an isolation terminal (4).

[0100] Specifically, in Figure 4 In the coupler shown, the signal flow direction can be seen from the arrows. When a signal passes through the coupler, it enters from the input terminal and exits from the output terminal. The coupling terminal is used to output the coupled signal on the coupling path, and the isolation terminal can be grounded through a 50-ohm impedance. Figure 4 (Not shown in the image).

[0101] The performance of a coupler can be described by the following parameters: insertion loss, coupling, isolation, and directivity.

[0102] Insertion loss: The ratio of the output signal power to the input signal power. Lower insertion loss indicates less signal loss along the pass-through path. Insertion loss should be below 0.5 dB; for example, 0.1 dB or 0.2 dB is acceptable.

[0103] Coupling degree: The ratio of the signal power input to the input terminal to the signal power output to the coupling terminal. Too low a coupling degree will result in insufficient coupled signal energy at the output, indicating poor coupler effectiveness and inability to perform normal power detection. The coupling degree should be greater than 10dB, for example, 12dB or 15dB. The coupling degree corresponds to the S-parameters of the coupling terminal. Figure 4 Taking the coupler shown as an example, the coupling degree is the opposite of S31. When S31 is -15dB, the coupling degree is 15dB.

[0104] Isolation: The ratio of the signal power input to the isolation terminal to the signal power output to the isolation terminal. Higher isolation indicates effective isolation between ports and less signal loss. Isolation is typically required to be higher than 35dB, for example, 40dB, 50dB, or even higher. Isolation corresponds to the S-parameters of the isolation terminal. Figure 4 Taking the coupler shown as an example, the isolation is the opposite of S41. When S41 is -45dB, the isolation is 45dB.

[0105] Directivity: The difference between isolation and coupling. The stronger the directivity, the more the signal flows towards the desired coupling end, and the more effective the coupler is.

[0106] In current electronic devices, couplers are mounted on printed circuit boards (PCBs), and their circuit structure and function are implemented using PCB traces. PCBs can have multiple metal layers, each used for routing circuit traces. Dielectric material fills the spaces between the metal layers. Electrical connections between different metal layers can also be achieved through metallized vias. When couplers are used in electronic devices for power detection or closed-loop optimization of DPD algorithms, more stringent requirements are placed on the coupler's coupling degree and directionality. In such cases, a two-layer trace configuration is often used to ensure that the coupling degree meets the system's dynamic range. Figure 5 This is an example of a coupler set up on a printed circuit board. Figure 5 Image (a) shows a schematic diagram of the coupler's surface layer routing on the printed circuit board. Figure 5 In (a) of the diagram, the black-filled portion is a through path, using surface layer routing; the white-filled portion is a coupling path, using sub-surface layer routing. The two ends of the coupling path in the sub-surface layer are connected to the coupling and isolation ends of the surface layer through metallized vias. Figure 5 (b) in the diagram is a schematic diagram of the sub-surface layer traces in this printed circuit board. Figure 5 In (b), the black-filled part is the coupling path of the sub-surface trace, and the white-filled part is the straight-through path of the surface trace.

[0107] Optionally, in a printed circuit board, in addition to the top and second-to-top layers, the third layer can be a ground layer, and the fourth layer can be a power layer or other signal trace layer. Optionally, a printed circuit board may also include more layers for arranging other signal traces, and for setting power layers and more ground layers to prevent signal crosstalk.

[0108] Figure 5 The coupler implementation shown is problematic for electronic devices with limited routing resources (small area for circuit routing), especially small terminal devices. Because it occupies two layers of routing resources, it prevents other signal lines from being placed in the corresponding area of ​​the sub-surface layer, thus wasting stack-up resources.

[0109] This application provides a coupler that uses surface traces to establish a through path and a coupling path. By placing a coupling capacitor between the through path and the coupling path, the coupling degree of the electric field is increased, thereby improving the coupling strength. It also adaptively increases the coupling degree of the magnetic field, ensuring high isolation and guaranteeing the coupler's directionality. This coupler, while maintaining performance, does not require occupying sub-surface trace resources, saving trace resources and avoiding the need to increase trace length to improve coupling strength, thus preventing an increase in coupler size and facilitating module miniaturization.

[0110] To clearly describe the technical solution of this application, the technical solution of the embodiments of this application will be explained below in conjunction with the structure and principle of the coupler.

[0111] Figure 6 This is a schematic diagram of a coupler disposed on a printed circuit board, as provided in an embodiment of this application. The coupler shown is a microstrip line coupler. Figure 6 As shown in (a), the coupler includes a through path and a coupling path in the form of a microstrip line. The two ends of the through path are the input and the output, respectively.

[0112] Specifically, when a signal flows through the coupler, it is input at the input terminal, transmitted through the through-path, and output at the output terminal. The coupling path and the through-path can be located on the surface layer (first layer) of the printed circuit board, and the two paths are arranged parallel or nearly parallel. The coupling path includes a coupling terminal and an isolation terminal. The coupling path is used to couple the signal flowing through the through-path to obtain a coupled signal, which is then output through the coupling terminal. The coupling terminal can be located in the same direction as the input terminal, and the isolation terminal can be located in the same direction as the output terminal.

[0113] Figure 6In the coupler shown in (a), the coupling capacitor is a parallel-plate capacitor (also called a planar capacitor). The two terminals of the parallel-plate capacitor are two metal plates. These two metal plates are arranged on two different layers of the printed circuit board, such as the top layer and the second layer. The two metal plates located on the top and second layers are positioned opposite each other to form the parallel-plate capacitor. Optionally, the two metal plates are attached to different dielectric layers of the printed circuit board, and their projections on the plane containing the largest surface of the printed circuit board partially or completely overlap. Under otherwise unchanged conditions, the larger the overlapping area of ​​the two metal plates, the larger the capacitance of the parallel-plate capacitor. The largest surface of the printed circuit board is the area on which the two metal plates overlap. Figure 6 The XOY plane shown in (a) is parallel to the plane. The largest surfaces of the two metal patches are parallel to the XOY plane. Figure 6 The third layer of the printed circuit board is also shown in (a), while other metal layers are not shown.

[0114] Alternatively, the specific form of a parallel plate capacitor can be found in [reference needed]. Figure 6 The structure within the dashed box in (b) is shown. It can be seen that the first metal patch is connected to the through-path; for example, the first metal patch and the conductor portion of the microstrip line serving as the through-path can be integrally formed. The second metal patch is located on the sub-surface layer and is connected to the conductor of the microstrip line serving as the coupling path via a metallized via. The second metal patch is a metal patch structure in the sub-surface layer independent of other network structures. Optionally, when the sub-surface layer is a ground layer or other routing layer, gaps are etched between the second metal patch and the ground layer of the sub-surface layer, as well as other signal lines.

[0115] Optionally, the second metal patch can also be integrated with the conductor portion of the microstrip line serving as a coupling path; the first metal patch is located in the subsurface layer and is connected to the conductor of the microstrip line serving as a through path via a metallized via. The first metal patch is a metal patch structure in the subsurface layer independent of other network structures; see [link to relevant documentation] for details. Figure 6 As shown in (c) in the figure.

[0116] Optionally, the maximum surface of the metal patch of the above-mentioned coupling capacitor is exemplified as a rectangle. The maximum surface of the metal patch can also be other shapes, such as square, circle, ellipse, rhombus or other irregular shapes. This application embodiment does not limit this.

[0117] Optionally, the coupling capacitor described above can also be in the form of a surface-mount capacitor, which can be a lumped-parameter element. The first terminal of the surface-mount capacitor is electrically connected to the through-path, and the second terminal is electrically connected to the coupling path. Optionally, this electrical connection can be achieved by soldering or by bonding with conductive materials, as long as a method that enables electrical connection is used.

[0118] In order to clearly illustrate the principle of the technical solution of this application, Figure 6 The coupler shown can be simplified as follows: Figure 7 The coupler model shown illustrates the current flow direction under the influence of electric field coupling and magnetic field coupling in the coupler. Figure 7 The diagram shows the direction of current flow caused by electric field coupling between the through path and the coupled path.

[0119] It is understandable that adding a coupling capacitor enhances electric field coupling, resulting in larger currents flowing towards the coupling end and isolation end in the coupling path. Increased current towards the coupling end improves coupling; increased current towards the isolation end reduces isolation. Furthermore, a larger capacitance value results in stronger electric field coupling, and consequently, larger currents flowing towards the coupling end and isolation end in the coupling path.

[0120] When the coupling strength increases while the isolation decreases, the directivity of the coupler decreases. To avoid affecting the directivity of the coupler, magnetic field coupling can be increased simultaneously. In this embodiment, the strength of magnetic field coupling can be increased by reducing the width (linewidth) of the transmission line of the microstrip line coupler. When the linewidth is narrowed, for example, to less than the theoretical linewidth for a 50-ohm match, the inductance is enhanced compared to the theoretical linewidth for a 50-ohm match, thereby increasing the magnetic field coupling.

[0121] Figure 8 Figure (a) shows two transmission lines. These two transmission lines can be parallel microstrip lines or twisted pairs. One transmission line is the signal path, and the other is the reflection path. Both transmission lines exhibit both inductive and capacitive properties. The inductive property can be represented by an equivalent inductance in series, and the capacitive property can be represented by an equivalent capacitance in parallel. Figure 8 (b) shows the equivalent models of the two transmission lines. It can be seen that the longer the length of these two transmission lines, the larger the inductance of the equivalent inductor connected in series in the equivalent model, and the larger the capacitance of the equivalent capacitor connected in parallel.

[0122] It is understandable that, assuming other conditions remain unchanged for the two transmission lines, when the line width becomes narrower, the inductance increases, which is equivalent to a larger inductance value of the equivalent inductance.

[0123] To clearly illustrate the effect of transmission line width on equivalent inductance, we will first combine this with... Figure 9 The model of the coaxial transmission line shown is used for illustration.

[0124] Figure 9The model of a coaxial transmission line and the distribution of the magnetic field are shown. According to Ampere's circuital law, the magnetic field strength is inversely proportional to the area of ​​a closed loop. Therefore, with the distance between the two transmission lines remaining constant, the thinner the transmission line, the stronger the magnetic field induced in the adjacent transmission line, and the larger the equivalent inductance; the thicker the transmission line, the weaker the magnetic field induced in the adjacent transmission line, and the smaller the equivalent inductance.

[0125] Therefore, with the distance between the two transmission lines remaining constant, the smaller the cross-sectional area of ​​the conductor, the stronger the magnetic field; the larger the cross-sectional area of ​​the conductor, the weaker the magnetic field.

[0126] Figure 9 A schematic diagram of the magnetic field distribution at the locations of two adjacent coaxial transmission lines is shown. (For example...) Figure 9 As shown, when a signal is transmitted in one of the transmission paths (i.e., the signal path), an induced current will be generated in the adjacent reflection path due to magnetic field coupling. The larger the conductor radius of the coaxial transmission line, that is, the larger the cross-sectional area of ​​the conductor, the weaker the magnetic field in the reflection path, and the smaller the induced current in the reflection path. Conversely, the smaller the conductor radius of the coaxial transmission line, that is, the smaller the cross-sectional area of ​​the conductor, the stronger the magnetic field in the reflection path, and the larger the induced current in the reflection path.

[0127] When the transmission line is in the form of a microstrip line, you can refer to... Figure 10 The structure shown. Figure 10 A schematic diagram of a transmission line in the form of a microstrip line is shown. Figure 10 As shown, a microstrip transmission line is composed of a metal conductor attached to a dielectric. Based on Figure 9 The principles revealed by the illustrated embodiments and related descriptions indicate that the magnitude of the equivalent inductance of the transmission line is negatively correlated with the cross-sectional area of ​​the transmission line. Figure 10 In this context, the dielectric constant of the medium is denoted as □r, and the thickness of the medium is denoted as d (i.e., the distance between the conductor and the substrate). The cross-section of a metallic conductor is rectangular. With the thickness t of the metallic conductor remaining constant, the wider the linewidth w, the larger the cross-sectional area S; conversely, the narrower the linewidth w, the smaller the cross-sectional area S. Specifically, the equivalent inductance L (in Henry H) of a transmission line satisfies the following formula (1):

[0128] L(H)∝(μdl) / w Formula (1)

[0129] Where u represents the permeability of the medium, which is related to the material type of the medium; l represents the length of the metallic conductor. It can be seen that the equivalent inductance L is directly proportional to u, d, and l, and inversely proportional to the linewidth w.

[0130] It should be noted that the magnetic field coupling between two transmission lines can also be equivalent to... Figure 11The model shown. The directions of the current in the transmission path and the reflection path can be found in [reference needed]. Figure 11 The direction indicated by the arrow in the image. Figure 12 The diagram shows the direction of current flow caused by magnetic field coupling between two transmission lines. Figure 12 As indicated by the white arrows in the image, Il3 and Il4). Figure 12 It can be seen that, along the coupling path from the coupling capacitor to the isolation terminal, the electric field coupling current Ic2 (black arrow) and the magnetic field coupling current Il4 (white arrow) are in opposite directions and can cancel each other out to a certain extent. The higher the degree of cancellation, the higher the isolation.

[0131] When a coupling capacitor is introduced into the coupler, currents Ic1 and Ic2 increase. Correspondingly reducing the linewidth enhances magnetic field coupling, leading to a corresponding increase in current Ic4. When current Ic4 also increases, it can more effectively offset current Ic2, resulting in a smaller current through the isolation terminal. This ensures that the isolation is not degraded by the introduction of the coupling capacitor, thus guaranteeing the coupler's directivity. In other words, by simultaneously increasing the coupling capacitor and reducing the transmission line width, a coupler can be implemented in a smaller size while maintaining both coupling and isolation.

[0132] Optionally, reducing the linewidth can involve simultaneously reducing the linewidth of both the through-path and the coupling path. For example, based on a metal conductor and dielectric of fixed thickness and material, the calculated linewidth of the microstrip line corresponding to a 50-ohm impedance matching state is W-1. In this embodiment, however, the linewidths of both the through-path and the coupling path are reduced, for example, both to W-2. See [link to documentation] for details. Figure 13 As shown in (a) above, when the linewidths of both the through path and the coupling path are reduced, it is possible to ensure that the isolation does not decrease, thereby ensuring the directivity of the coupler.

[0133] Furthermore, when the linewidth of the coupling path is reduced to less than the linewidth W-2 of the microstrip line corresponding to a 50-ohm impedance, the corresponding impedance calculated based on the reduced linewidth W-2 is greater than 50 ohms, for example, it might be 75 ohms, 100 ohms, etc. When the coupling path is connected to traces of other linewidths outside the coupler, considering the impedance discontinuity caused by the change in linewidth, impedance mismatch is theoretically likely to occur, which will increase signal loss.

[0134] Based on this, the impedance after the actual reduction in line width is explained as follows. For details, please refer to the input impedance relationship shown in formula (2):

[0135]

[0136] Where Zin is the input impedance of the input port, Z0 is the characteristic impedance, and Zl is the load impedance of the port. l represents the length of the transmission line, and λ represents the wavelength of the signal. It can be understood that, due to the small size of the coupler itself, l in formula (2) is very small, therefore... The represented electrical dimension is very small, close to 0. Therefore, the imaginary parts in the numerator and denominator of formula (2) can be ignored. Based on this, the input impedance Z in Basically close to Z L .

[0137] In other words, even if the linewidth becomes narrower, the input impedance Zin of the port does not change much for small-sized couplers. The reduced linewidth will not cause impedance mismatch and will not increase signal loss.

[0138] Alternatively, the linewidth can be reduced to W-2 for the coupling path, while the linewidth for the straight-through path remains W-1, corresponding to a 50-ohm impedance matching. See [link to documentation] for details. Figure 13 As shown in (b) above, reducing the linewidth of the coupling path while keeping the linewidth of the through path unchanged ensures that the directivity requirements are met while maintaining a 50-ohm impedance match in the through path, thus preventing a deterioration in transmission performance.

[0139] Figure 14 A simulation circuit diagram of an example coupler and the corresponding S-parameter graph are shown. Figure 14 In the coupler, S21 represents transmission loss; the lower the transmission loss, the less signal is lost as it passes through the coupler. S31 corresponds to coupling degree, and S41 corresponds to isolation degree. Figure 14 and Figure 15 In this design, the dielectric thickness H is 35 μm (d, as mentioned earlier); the dielectric constant Er is 4; the permeability Mur is 1 (u, as mentioned earlier); the conductor conductivity Cond is infinite, for example, 1.0E+50; the package height Hu is 3.93701+34 mil; the conductor thickness T is 20 μm; and the roughness Rcough is 0 mil.

[0140] exist Figure 14 In (a) of the coupler, the linewidth of both the through path and the coupling path is set to 0.015 mm, and the length is 3 mm (the dimensions on both sides of the coupling capacitor are 1.5 mm each); the line spacing between the through path and the coupling path is 0.06 mm; and the coupling capacitor is 0.05 pF. The characteristic impedance of the four ports of the coupler—input, output, coupling, and isolation—is 50 ohms.

[0141] Within the frequency range of a start frequency of 0.5 GHz and a stop frequency of 5 GHz, the S-parameters can be found in [reference needed]. Figure 14As shown in (b) of the diagram. Taking a frequency of 842.7MHz as an example, S21 is very small, at -0.002dB; S31 is -34.722; S41 is -60.872; S32 and S41 are equal. It can be concluded that the directivity of this coupler is 26.15dB (the difference between 60.872 and 34.722), which meets the usage requirements. Optionally, the directivity specification can be set to 15dB or a larger value. When the directivity of the coupler meets 15dB, the coupler can be used normally.

[0142] Figure 15 A simulation circuit diagram and graph of another coupler are shown. Figure 15 In (a) of the middle, compared to Figure 14 As shown in (a), the coupling capacitance increases to 0.1 pF. With other conditions remaining constant, the increased capacitance indicates stronger electric field coupling. Consequently, the linewidth decreases to 0.015 mm.

[0143] Within the frequency range of Start = 0.5 GHz and Stop = 5 GHz. S-parameters can be found in [reference needed]. Figure 15 As shown in (b) of the diagram. Taking a frequency of 842.7MHz as an example, S21 is very small, at -0.007dB; S31 is -39.863dB; S41 is -61.951dB; S32 and S41 are equal. It can be concluded that the directivity of this coupler is 22.088dB (the difference between 61.951dB and 39.863dB), which meets the usage requirements.

[0144] Depend on Figure 14 and Figure 15 It can be seen that by increasing the coupling capacitance and using a narrower linewidth, the coupling and isolation of the coupler can be ensured within a smaller size. Furthermore, as the coupling capacitance increases, the linewidth needs to be further reduced to maintain the coupler's directivity.

[0145] Figure 16 A simulation diagram of a coupler is shown. Figure 16 (a) and (b) in the figure are the side view and top view of the simulated structure of the coupler, respectively. Figure 16 In the coupler shown, the coupling capacitance is 0.03pF; the length of the coupler (i.e., the length of the through path and / or the coupling path) is 3 mm; the line width is 0.065 mm; and the line spacing between the through path and the coupling path is 0.06 mm. Figure 16 In the coupler shown, the material and Figure 14 and Figure 15 Same. That is to say Figure 16 Other parameters such as the thickness of the medium, dielectric constant, conductor type, and conductor thickness can be found in [reference needed]. Figure 14 and Figure 15The relevant descriptions in the document will not be repeated here.

[0146] in addition, Figure 17 for Figure 16 The graph shows the S-parameters of the coupler. For the frequency range of Start = 0.5 GHz and Stop = 5 GHz, the S-parameters can be found in [reference needed]. Figure 17 As shown. Taking a frequency of 891.5MHz as an example, S21 is very small, at -0.03dB; S31 is -34.649; S41 is -57.173; S32 and S41 are equal. It can be concluded that the directivity of this coupler is 22.624dB (the difference between 57.173 and 34.649), which meets the usage requirements.

[0147] Optionally, the coupling capacitor described above can also be a surface-mount capacitor. The two terminals of this surface-mount capacitor are electrically connected to the through path and the coupling path, respectively; see [link to documentation] for details. Figure 18 As shown. Figure 18 The example circuit uses pads 1 and 2, which connect the two stages of the coupling capacitor, as separate structures. In actual circuits, the pads and the connected paths are integrated. Furthermore, the size of the pads is designed to be as close as possible to the width of the path to ensure the continuity of the path impedance, while ensuring safe soldering or bonding.

[0148] In the above embodiments, the shapes of the through path and coupling path of the coupler are exemplified by a straight line (or linear shape). Alternatively, the shapes of the through path and coupling path can also be other shapes, such as... Figure 19 The "U" shape shown in (a) and Figure 19 The U-shape shown in (b) is an example. This shape can further shorten the length of the coupler, which is beneficial for module miniaturization.

[0149] Alternatively, the shapes of the through path and the coupling path can also be other irregular shapes, such as irregular shapes formed to avoid other elements according to layout requirements.

[0150] Optionally, the coupling capacitor and the through-path can be connected at the middle or near the middle of the through-path; or they can be located near the input terminal, for example... Figure 19 As shown in (c); it can also be located near the output terminal, for example... Figure 19 As shown in (d) in the diagram; it can also be positioned to avoid other components according to layout requirements. The specific location of the coupling capacitor is not limited in the embodiments of this application.

[0151] For couplers, reducing the spacing between the two paths can improve coupling. However, due to manufacturing limitations, coupling cannot be increased by indefinitely reducing the spacing. When the minimum spacing is 60 micrometers, coupling can be improved by adding coupling capacitance as mentioned above. On the other hand, due to manufacturing limitations, the minimum linewidth of a microstrip line is 50 micrometers. If reducing the linewidth is insufficient to increase the strength of the magnetic field coupling, a reflector can be added to the isolation end of the coupler to reflect the signal transmitted to the isolation end, thus ensuring both isolation and coupling, and consequently, the directivity of the coupler.

[0152] The circuit structure of the reflector and its working principle in the coupler will be described in detail below with reference to the accompanying drawings.

[0153] In some embodiments, the reflector's circuit structure consists of a matching circuit and a 50-ohm load, where the matching can be any of L-type, T-type, or π-type. Alternatively, the reflector's circuit structure can be found in... Figure 20 As shown, it includes one or more combinations of parallel capacitors, series inductors, and parallel resistors (i.e., an L-type +50 ohm load). The specific parameters of each component in the reflector are not limited in the embodiments of this application. Figure 20 An example is given with a parallel capacitor of 1.0pF, a series inductor of 1.0nH, and a parallel resistor of 50 ohms.

[0154] Optionally, the circuit structure of the reflector can also be other circuit structures, such as any one or more combinations of series capacitors, parallel inductors, and series resistors; furthermore, the circuit structure of the reflector can also be... Figure 20 Based on the structure shown, any combination of one or more of the following can be added: parallel capacitors, series capacitors, parallel inductors, series inductors, parallel resistors, and series resistors. Optionally, the parameters of these RC components can be adjusted according to the frequency used in the actual circuit and the specific circuit. As long as the characteristic impedance, viewed from the input terminal of the reflector, meets the circuit requirements, it is acceptable.

[0155] Next, we will explain the working principle of the reflector and the requirements for its characteristic impedance, taking into account the signal flow direction. Figure 21 A schematic diagram of a circuit structure including a reflector coupler is shown.

[0156] Figure 22Figure (a) shows the flow of the input signal in the coupler. Path 1 represents the transmission path of the input signal, indicating the path from the input terminal to the output terminal along the direct path. Path 2 represents the coupling path of the input signal, indicating the path from the input terminal to the coupling terminal along the direct path, the coupling capacitor, and the coupling path in sequence.

[0157] Figure 22 Figure (a) shows the path of the input signal in the coupler. In reality, when the input signal transmitted along path 1 flows through the output terminal, there will be a certain degree of reflection due to impedance discontinuity. The degree of reflection can be described by the parameter S22: the larger S22 is, the stronger the reflected signal; the smaller S22 is, the weaker the reflected signal.

[0158] For reflected signals, the coupler remains a coupler, but the function of the ports changes compared to the input signal. The original output becomes the input of the reflected signal, the original input becomes the output of the reflected signal, the original isolation terminal becomes the coupling terminal of the transmitted signal, and the original coupling terminal becomes the isolation terminal of the reflected signal. The transmission path of the reflected signal can be found in [reference needed]. Figure 22 In (b), path 3 represents the transmission path of the reflected signal, indicating the path from the input terminal (port 2) of the reflected signal to the output terminal (port 1) of the reflected signal along the straight-through path. Path 4 represents the coupling path of the reflected signal, indicating the path from the input terminal of the reflected signal to the coupling terminal (port 4) of the reflected signal sequentially along the straight-through path, the coupling capacitor, and the coupling path. This signal is denoted as the coupled reflected signal. Path 5 represents the leakage path of the reflected signal, indicating the path from the input terminal (port 2) of the reflected signal to the isolation terminal (port 3) of the reflected signal sequentially along the straight-through path, the coupling capacitor, and the coupling path.

[0159] For couplers, the coupled reflected signal will be superimposed on the coupled signal of the input signal, thus affecting the accuracy of the coupling degree.

[0160] For the reflected signal, the reflector is located at the coupling end. The power of the signal (coupled reflected signal) at the coupling end (port 4) corresponding to the reflected signal is much greater than the power of the signal at the isolation end (port 3) corresponding to the reflected signal. Therefore, when the reflector reflects the signal flowing through port 4 (i.e., the coupled signal of the reflected signal), this reflected signal is denoted as the secondary reflected signal. At the isolation end (port 3) corresponding to the reflected signal, the secondary reflected signal can cancel out or weaken the strength of the coupled reflected signal, thereby minimizing the impact of the coupled reflected signal on the coupling degree and ensuring that the coupling degree is not affected by the reflection at the output end.

[0161] In order for the above reflector to meet the usage requirements, the reflector can adjust the amplitude and phase of the reflected signal flowing through it and reflect it, so that the amplitude of the secondary reflected signal and the amplitude of the coupled reflected signal are as close as possible, and the phases are as opposite as possible or nearly opposite, so as to cancel each other out.

[0162] For the input port of the reflector, the input impedance is denoted as X+jY. Here, Y affects the phase change of the signal reflected by the reflector. For example, 50+j10 indicates a phase adjustment of 10 degrees.

[0163] Furthermore, for the port connected to the reflector, the reflection coefficient Γ is adjusted so that the product of the magnitude of the reflection coefficient Γ|Γ| and the power (or amplitude) of the secondary reflected signal at that port is equal to or approximately equal to the power (or amplitude) of the coupled reflected signal at port 3. The reflection coefficient is the ratio of the difference between the input impedance and the characteristic impedance to the sum of the input impedance and the characteristic impedance. The reflection coefficient can be determined by adjusting the parameters of the reflector's resistive, capacitive, and inductive elements.

[0164] Furthermore, the phase difference between the reflected signal at port 2 and the phase of the reflected signal coupled to port 3 is denoted as Φ1; the phase difference between the reflected signal at port 2 and the phase of the secondary reflected signal after reflection at port 3 is denoted as Φ2; the phase difference of the secondary reflected signal transmitted to port 3 through the coupling path is denoted as Φ3. Φ1 is the opposite phase or nearly opposite phase to the sum of Φ2 and Φ3, i.e., a phase difference of 180 degrees or nearly 180 degrees.

[0165] Figure 23 and Figure 24 The simulation circuit diagram and S-parameter graphs before and after adding the reflector are shown.

[0166] exist Figure 23 In (a) of the coupler, no reflector is provided at the isolation end, and the characteristic impedance of the isolation end is 50 ohms.

[0167] Within the frequency range of a start frequency of 0.5 GHz and a stop frequency of 5 GHz, the S-parameters can be found in [reference needed]. Figure 23 As shown in (b) of the diagram. Taking a frequency of 846.5MHz as an example, S21 is very small, at -0.050dB; S31 is -24.209; S32 is -27.742; S32 and S41 are equal. It can be concluded that the directivity of this coupler is 3.535dB (the difference between 27.742 and 24.209), which does not meet the usage requirements.

[0168] exist Figure 24 In (a) of the coupler, a reflector is set at the isolation end, and the characteristic impedance of the isolation end is 50+j5.

[0169] Within the frequency range of a start frequency of 0.5 GHz and a stop frequency of 5 GHz, the S-parameters can be found in [reference needed]. Figure 24 As shown in (b) of the diagram. Taking a frequency of 846.5MHz as an example, S21 is -0.036dB; S31 is -29.232; S32 is -71.665; S32 and S41 are equal. It can be concluded that the directivity of this coupler is 42.433dB (71.665 minus the difference of 29.232), and the isolation and directivity are greatly improved.

[0170] The above Figure 23 and Figure 24 The example illustrates that introducing a reflector to adjust the amplitude (or power) and phase of the signal can improve the directivity of the coupler.

[0171] This application also provides a transmitting module, including the above-described coupler.

[0172] This application also provides a radio frequency front-end module, including the above-mentioned coupler.

[0173] This application also provides an alternative printed circuit board, including the coupler described above.

[0174] This application also provides an electronic device, including the aforementioned coupler. The electronic device provided in this embodiment can be... Figure 1 The terminal device 100 shown is an example. When using integrated units, the terminal device may include a processing module, a storage module, and a communication module. The processing module can be used to control and manage the actions of the terminal device; for example, it can support the terminal device in executing steps performed by the display unit, detection unit, and processing unit. The storage module can support the terminal device in executing stored program code and data. The communication module can support communication between the terminal device and other devices.

[0175] The processing module can be a processor or a controller. It can implement or execute various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this application. The processor can also be a combination of functions that implement computing capabilities, such as a combination of one or more microprocessors, a digital signal processor (DSP), and a microprocessor, etc. The storage module can be a memory. The communication module can specifically be a radio frequency circuit, a Bluetooth chip, a Wi-Fi chip, or other devices that interact with other terminal devices.

[0176] In one embodiment, when the processing module is a processor and the storage module is a memory, the terminal device involved in this embodiment can be a device having... Figure 1 The device with the structure shown.

[0177] In this embodiment, the beneficial effects that can be achieved by including the above-mentioned coupler in the electronic device, circuit board and various modules can be referred to in the beneficial effects of the corresponding coupler provided above, and will not be repeated here.

[0178] In the several embodiments provided in this application, it should be understood that the disclosed apparatus can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces, indirect coupling or communication connection between devices or units. The replaced units may or may not be physically separate. The component shown as a unit may be one physical unit or multiple physical units, that is, it may be located in one place or distributed in multiple different places. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0179] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0180] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A coupler, characterized in that, include: Straight-through path, coupling path, and first capacitor; The first terminal of the first capacitor is connected to the through path, and the second terminal of the first capacitor is connected to the coupling path. The cross-sectional area of ​​the conductor in the coupling path is smaller than the first area, which is the area corresponding to the matching impedance value. The cross-section of the conductor in the coupling path is perpendicular to the direction of the coupled signal in the coupling path.

2. The coupler according to claim 1, characterized in that, The through path and the coupling path are transmission paths in the form of microstrip lines. The first capacitor is a parallel plate capacitor. The first capacitor includes a first metal patch and a second metal patch. The first metal patch is the first terminal of the first capacitor, and the second metal patch is the second terminal of the first capacitor.

3. The coupler according to claim 2, characterized in that, The first projection of the first metal patch on the first plane and the second projection of the second metal patch on the first plane at least partially overlap, the area of ​​the overlap between the first projection and the second projection is positively correlated with the capacitance value of the first capacitor, and the first plane and the maximum surface of the first metal patch are parallel.

4. The coupler according to claim 3, characterized in that, The first metal patch and the through path are integrally disposed in the first wiring layer, the coupling path is located in the first wiring layer, the second metal patch is located in the second wiring layer, and the second metal patch and the coupling path are connected by metallized vias.

5. The coupler according to claim 3, characterized in that, The second metal patch and the coupling path are integrally disposed in the first wiring layer, the through path is located in the first wiring layer, the first metal patch is located in the second wiring layer, and the first metal patch and the through path are connected by metallized vias.

6. The coupler according to claim 4 or 5, characterized in that, The cross-sectional area of ​​the conductor in the straight-through path is greater than the cross-sectional area of ​​the conductor in the coupling path.

7. The coupler according to claim 6, characterized in that, The cross-sectional area of ​​the conductor in the straight-through path is the first area.

8. The coupler according to claim 6, characterized in that, The width of the conductor in the straight-through path is greater than or equal to the width of the conductor in the coupling path.

9. The coupler according to claim 8, characterized in that, The width of the conductor in the straight-through path is a first width, which is a first preset value corresponding to a 50-ohm impedance.

10. The coupler according to claim 2, characterized in that, The shape of the largest surface of the straight passage and the coupling passage is a straight line, a concave shape, or a U-shape.

11. The coupler according to any one of claims 2 to 10, characterized in that, The isolation end of the coupler is also provided with a reflector; The reflector is used to reflect the reflected signal flowing through the isolation end, and the reflected signal is the signal reflected by the output end of the coupler and coupled to the isolation end.

12. The coupler according to claim 11, characterized in that, The difference between the magnitude of the reflection coefficient corresponding to the reflector and the power of the signal coupled to the isolation terminal by the signal reflected from the output terminal and the power of the signal coupled to the coupling terminal of the coupler is less than a second preset value. And / or, The phase difference between the phase of the reflected signal at the output terminal and the phase of the reflected signal coupled to the isolation terminal is the first phase difference; The difference between the phase of the reflected signal at the output end and the phase at the coupling end is the second phase difference; The difference between the phase of the reflected signal coupled to the isolation terminal and the phase of the reflected signal after being coupled to the isolation terminal and then transmitted to the coupling terminal through the coupling path is the third phase difference; The difference between the first phase difference, the first sum of the second phase difference and the third phase difference, and 180 degrees is less than a preset threshold.

13. The coupler according to claim 11 or 12, characterized in that, The reflector includes a second capacitor, a first inductor, and a first resistor. The first terminal of the second capacitor is connected to the isolation terminal, the second terminal of the second capacitor is connected to the first terminal of the first inductor, the second terminal of the first inductor is connected to the first terminal of the first resistor, and the second terminal of the first resistor is grounded.

14. The coupler according to any one of claims 1 to 13, characterized in that, The capacitance of the first capacitor is less than or equal to 3 picofarads.

15. An electronic device, characterized in that, include: A motherboard, wherein the motherboard is provided with multi-layer circuitry, the multi-layer circuitry including at least: a first wiring layer and a second wiring layer; The motherboard includes a coupler, which includes a through path and a coupling path, wherein the through path and the coupling path are microstrip lines disposed on the first wiring layer; The coupler further includes: a first capacitor; The first terminal of the first capacitor is connected to the through path, and the second terminal of the first capacitor is connected to the coupling path. Wherein, the cross-sectional area of ​​the conductor of the coupling path is smaller than the first area, the first area being a first preset value corresponding to a 50-ohm impedance, and the cross-section of the conductor of the coupling path is perpendicular to the flow direction of the coupled signal in the coupling path.

16. The electronic device according to claim 15, characterized in that, The first capacitor is a parallel plate capacitor, which includes a first metal patch and a second metal patch. The first metal patch is the first terminal of the first capacitor, and the second metal patch is the second terminal of the first capacitor. The first metal patch and the through-path are integrally disposed in the first wiring layer, the coupling path is located in the first wiring layer, the second metal patch is located in the second wiring layer, and the second metal patch and the coupling path are connected through a metallized via; or... The second metal patch and the coupling path are integrally disposed in the first wiring layer, the through path is located in the first wiring layer, the first metal patch is located in the second wiring layer, and the first metal patch and the through path are connected by metallized vias.

17. An electronic device, characterized in that, Includes the coupler as described in any one of claims 1 to 14.

Images