A coupler circuit and a circuit board assembly

Abstract

This application provides a coupler circuit and circuit board assembly, belonging to the field of radio frequency technology. The coupler circuit includes a right-hand transmission line circuit, a left-hand transmission line circuit, a first coupling circuit, a second coupling circuit, an input terminal, an output terminal, a coupling terminal, and an isolation terminal. The first terminal of the first coupling circuit is connected to the first terminal of the right-hand transmission line circuit, and the second terminal of the first coupling circuit is connected to the first terminal of the left-hand transmission line circuit. The first terminal of the second coupling circuit is connected to the second terminal of the right-hand transmission line circuit, and the second terminal of the second coupling circuit is connected to the second terminal of the left-hand transmission line circuit. The embodiments of this application, through the left-hand and right-hand transmission line circuits, can maintain a stable phase difference over a wide bandwidth, thereby improving the directivity of the coupler for radio frequency signals over a wider bandwidth.

Description

[0001] This application is a divisional application. The original application has the application number 202510371427.0 and the original application date is March 27, 2025. The entire contents of the original application are incorporated herein by reference. Technical Field

[0002] This application relates to the field of radio frequency technology, and more particularly to a coupler circuit and circuit board assembly. Background Technology

[0003] In radio frequency (RF) systems, the transmit power of RF signals can be monitored using couplers (e.g., branch-directed couplers). The coupling degree, isolation, and directivity of the coupler are important parameters. Currently, couplers exhibit poor directivity for RF signals with large bandwidths. Summary of the Invention

[0004] This application provides a coupler circuit and circuit board assembly for improving the directivity of the coupler within the radio frequency signal bandwidth.

[0005] To achieve the above objectives, the embodiments of this application adopt the following technical solutions:

[0006] In a first aspect, a coupler circuit is provided. The coupler circuit includes a right-hand transmission line circuit, a left-hand transmission line circuit, a first coupling circuit, a second coupling circuit, an input terminal, an output terminal, a coupling terminal, and an isolation terminal. Specifically, a first terminal of the first coupling circuit is connected to a first terminal of the right-hand transmission line circuit, and a second terminal of the first coupling circuit is connected to a first terminal of the left-hand transmission line circuit. A first terminal of the second coupling circuit is connected to a second terminal of the right-hand transmission line circuit, and a second terminal of the second coupling circuit is connected to a second terminal of the left-hand transmission line circuit. Alternatively, the input terminal is connected to a first terminal of the left-hand transmission line circuit, the output terminal is connected to a second terminal of the left-hand transmission line circuit, the coupling terminal is connected to a first terminal of the right-hand transmission line circuit, and the output terminal is connected to a second terminal of the right-hand transmission line circuit.

[0007] This application employs a technical solution combining right-hand and left-hand transmission line circuits, which exhibit significant differences in phase shifting of the radio frequency (RF) signal. The RF signal experiences phase lag after passing through the right-hand transmission line circuit, while it exhibits phase lead after passing through the left-hand transmission line circuit. Furthermore, the higher the frequency of the RF signal, the greater the phase lag after passing through the right-hand transmission line circuit, and the smaller the phase lead after passing through the left-hand transmission line circuit. This application's embodiment, through the use of left-hand and right-hand transmission line circuits, can maintain a stable phase difference over a wider bandwidth, thereby improving the directivity of the coupler for RF signals with a wider bandwidth.

[0008] In some possible implementations, the right-hand transmission line circuit includes a first inductor, a first capacitor, and a second capacitor. The first terminals of both the first inductor and the first capacitor are connected to the first terminal of the right-hand transmission line circuit, and the second terminals of both the first inductor and the second capacitor are connected to the second terminal of the right-hand transmission line circuit. The second terminal of both the first and second capacitors is grounded. The right-hand transmission line circuit can employ a Π-type LC circuit; separating the capacitor and inductor helps reduce the area of ​​the printed circuit board.

[0009] In some possible implementations, the right-hand transmission line circuit includes a second inductor, a third inductor, and a third capacitor. The first terminal of the second inductor is connected to the first terminal of the right-hand transmission line circuit. The second terminal of the second inductor is connected to both the first terminal of the third inductor and the first terminal of the third capacitor. The second terminal of the third inductor is connected to the second terminal of the right-hand transmission line circuit, and the second terminal of the third capacitor is grounded. The right-hand transmission line circuit can employ a T-type LC circuit; separating the capacitor and inductor helps reduce the area of ​​the printed circuit board.

[0010] In some possible implementations, the left-hand transmission line circuit includes a fourth inductor, a fifth inductor, and a fourth capacitor. The first terminal of the fourth capacitor and the first terminal of the fourth inductor are both connected to the first terminal of the left-hand transmission line circuit, and the second terminal of the fourth capacitor and the first terminal of the fifth inductor are both connected to the second terminal of the left-hand transmission line circuit. The second terminal of the fourth inductor is grounded, and the second terminal of the fifth inductor is also grounded. The left-hand transmission line circuit can employ a Π-type LC circuit; the separate arrangement of the capacitor and inductor helps to reduce the area of ​​the printed circuit board.

[0011] In some possible implementations, the left-hand transmission line circuit includes a fifth capacitor, a sixth capacitor, and a sixth inductor. The first terminal of the fifth capacitor is connected to the first terminal of the left-hand transmission line circuit. The second terminal of the fifth capacitor is connected to both the first terminal of the sixth capacitor and the first terminal of the sixth inductor. The second terminal of the sixth capacitor is connected to the second terminal of the left-hand transmission line circuit, and the second terminal of the sixth inductor is grounded. The left-hand transmission line circuit can employ a T-type LC circuit; the separate arrangement of the capacitors and inductors helps to reduce the area of ​​the printed circuit board.

[0012] In some possible implementations, the first coupling circuit includes a seventh capacitor, with a first terminal connected to a first terminal of the first coupling circuit and a second terminal connected to a second terminal of the first coupling circuit. And / or, the second coupling circuit includes an eighth capacitor, with a first terminal connected to a first terminal of the second coupling circuit and a second terminal connected to a second terminal of the second coupling circuit. Using capacitors in the coupling circuit helps reduce the coupling degree of the coupler circuit, thereby reducing the impact on the output power of the coupler circuit and further reducing the area of ​​the printed circuit board.

[0013] In some possible implementations, the first coupling circuit includes a seventh inductor, with a first terminal connected to a first terminal of the first coupling circuit and a second terminal connected to a second terminal of the first coupling circuit. And / or, the second coupling circuit includes an eighth inductor, with a first terminal connected to a first terminal of the second coupling circuit and a second terminal connected to a second terminal of the second coupling circuit. Using inductors in the coupling circuit also helps reduce the coupling degree of the coupler circuit, thereby reducing the impact on the output power of the coupler circuit and further reducing the area of ​​the printed circuit board.

[0014] In a second aspect, a circuit board assembly is provided. The circuit board assembly includes a printed circuit board and a coupler circuit as described in any of the first aspects above, the coupler circuit being disposed on the printed circuit board.

[0015] In some possible implementations, the coupler circuit is disposed on the surface of the printed circuit board, thereby making it easier to route the inner layers of the printed circuit board.

[0016] In some possible implementations, the printed circuit board is a multilayer printed circuit board. The left-hand transmission line circuit in the coupler circuit is disposed on the first layer of the printed circuit board, and the right-hand transmission line circuit in the coupler circuit is disposed on the second layer of the printed circuit board, with the first and second layers adjacent to each other. The first coupling circuit in the coupler circuit includes a seventh capacitor, and the second coupling circuit in the coupler circuit includes an eighth capacitor. Both the seventh and eighth capacitors are parasitic capacitances between the first and second layers.

[0017] In some possible implementations, the coupler circuit is positioned closer to the side of the printed circuit board.

[0018] Thirdly, an electronic device is provided. This electronic device includes a power amplifier, an antenna, a radio frequency chip, and a circuit board assembly according to any one of the second aspects described above, the circuit board assembly being coupled to the power amplifier, the antenna, and the radio frequency chip, respectively.

[0019] It should be understood that the technical effects of the second and third aspects can be referred to the technical effects of the first aspect and any of its embodiments, and will not be repeated here. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application;

[0021] Figure 2 This is a schematic diagram of the structure of a radio frequency transceiver provided in an embodiment of this application;

[0022] Figure 3 This is a schematic diagram of the connection structure of the coupler in the radio frequency transceiver device provided in the embodiments of this application;

[0023] Figure 4 This is a schematic diagram of the structure of a coupler provided in an embodiment of this application;

[0024] Figure 5 A schematic diagram of the path for the transmission of radio frequency signals from the input end to the isolation end in a coupler is provided in this embodiment of the application;

[0025] Figure 6 A schematic diagram of the path for the transmission of radio frequency signals from the input end to the coupling end in a coupler is provided in this embodiment of the application;

[0026] Figure 7 A schematic diagram showing the area occupied on a printed circuit board when the coupler provided in the embodiment of this application is implemented using a 90° phase shift line;

[0027] Figure 8 This is a schematic diagram of the structure of the coupler implemented using an inductor-capacitor network, as provided in the embodiments of this application.

[0028] Figure 9 This is a schematic diagram of the phase frequency characteristics of an inductor-capacitor network provided in an embodiment of this application;

[0029] Figure 10 This is a phase diagram of the radio frequency signal at the isolation terminal of the coupler provided in this application embodiment when the radio frequency signal is at a low frequency.

[0030] Figure 11This is a phase diagram of the radio frequency signal at the isolation terminal of the coupler provided in the embodiments of this application when the radio frequency signal is at a relatively high frequency;

[0031] Figure 12 A schematic diagram of the amplitude-frequency characteristics of the isolation terminal, coupling terminal, and output terminal of the coupler provided in the embodiments of this application;

[0032] Figure 13 This is a schematic diagram of a coupler circuit provided in an embodiment of this application;

[0033] Figure 14 A schematic diagram of the path for the transmission of radio frequency signals from the input terminal to the isolation terminal in the coupler circuit is provided in this embodiment of the application.

[0034] Figure 15 A schematic diagram of the path for the transmission of radio frequency signals from the input end to the coupling end in the coupler circuit is provided in the embodiments of this application.

[0035] Figure 16 A schematic diagram of the phase frequency characteristics of the right-hand transmission line circuit and the left-hand transmission line circuit provided in the embodiments of this application;

[0036] Figure 17 This is a schematic diagram of the phase of the radio frequency signal at the isolation terminal of the coupler circuit provided in the embodiments of this application when the radio frequency signal is at a low frequency.

[0037] Figure 18 This is a schematic diagram of the phase of the radio frequency signal at the isolation terminal of the coupler circuit provided in the embodiments of this application when the radio frequency signal is at a relatively high frequency.

[0038] Figure 19 This is a schematic diagram of the structure of a first type of coupler circuit provided in an embodiment of this application;

[0039] Figure 20 A schematic diagram of the impedance trajectories of the right-hand transmission line circuit and the left-hand transmission line circuit provided in the embodiments of this application on the Smith chart;

[0040] Figure 21 A schematic diagram of the amplitude-frequency characteristics of the coupler circuit provided in the embodiments of this application;

[0041] Figure 22 This is a schematic diagram of the structure of a second coupler circuit provided in an embodiment of this application;

[0042] Figure 23 This is a schematic diagram of the structure of the third coupler circuit provided in the embodiments of this application;

[0043] Figure 24 This is a schematic diagram of the structure of the fourth coupler circuit provided in the embodiments of this application;

[0044] Figure 25This is a schematic diagram of the layout of the coupler circuit on a printed circuit board provided in an embodiment of this application.

[0045] Reference numerals: 100, electronic device; 110, processor; 120, radio frequency transceiver; 130, external memory interface; 140, internal memory; 150, USB interface; 160, power management module; 161, battery; 162, wireless charging coil; 170, audio module; 180, sensor module; 191, button; 192, motor; 193, indicator; 194, camera; 195, display screen; 196, SIM card interface; 210, modem; 220, radio frequency chip; 230, radio frequency front-end module; 240, antenna; 300, coupler circuit; 310, right-hand transmission line circuit; 320, left-hand transmission line circuit; 330, first coupling circuit; 340, second coupling circuit. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0047] The terms "first" and "second" used in the embodiments of this application are only used to distinguish features of the same type and should not be construed as indicating relative importance, quantity, order, etc.

[0048] The terms "exemplary" or "for example" used in the embodiments of this application are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0049] The terms "coupling" and "connection" used in the embodiments of this application should be interpreted broadly. For example, they can refer to a physical direct connection or an indirect connection achieved through electronic devices, such as a connection achieved through resistors, inductors, capacitors or other electronic devices.

[0050] This application provides an electronic device, which can be fixed or mobile. Additionally, this electronic device may also be referred to as user equipment (UE), terminal, terminal device, mobile station (MS), mobile terminal (MT), access terminal device, vehicle-mounted terminal device, industrial control terminal device, mobile station, remote station, remote terminal device, mobile device, wireless communication device, terminal agent, or terminal device, etc. For example, the electronic device may be a mobile phone, tablet, desktop computer, laptop computer, all-in-one computer, vehicle terminal, virtual reality (VR) terminal device, augmented reality (AR) terminal device, wireless terminal in industrial control, wireless terminal in self-driving, wireless terminal in remote medical surgery, wireless terminal in smart grid, wireless terminal in transportation safety, wireless terminal in smart city, wireless terminal in smart home, cellular phone, cordless phone, session initiation protocol (SIP) phone, wireless local loop (WLL) station, personal digital assistant (PDA), handheld device with wireless communication capabilities, computing device or other processing device connected to a wireless modem, wearable device, terminal device in future mobile communication networks, or terminal device in future evolved public land mobile network (PLMN), etc.

[0051] Taking mobile phones as an example, Figure 1This diagram illustrates a possible structure for an electronic device. The electronic device 100 may include a processor 110, an external memory interface 130, an internal memory 140, a universal serial bus (USB) interface (hereinafter referred to as USB interface 150), a power management module 160, a battery 161, a wireless charging coil 162, a radio frequency transceiver 120, an audio module 170, a sensor module 180, buttons 191, a motor 192, an indicator 193, a camera 194, a display screen 195, and a subscriber identification module (SIM) card interface (hereinafter referred to as SIM card interface 196), etc.

[0052] The sensor module 180 may include pressure sensors, gyroscope sensors, barometric pressure sensors, magnetic sensors, accelerometers, distance sensors, proximity sensors, fingerprint sensors, temperature sensors, touch sensors, ambient light sensors, bone conduction sensors, etc.

[0053] 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 specific limitation on the electronic device 100. In other embodiments of this application, the electronic 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.

[0054] In some examples, processor 110 may include one or more processing units; wherein, processing units may include field-programmable gate arrays (FPGAs), central processing units (CPUs), application processors (APs), network processors (NPs), digital signal processors (DSPs), microcontroller units (MCUs), programmable logic devices (PLDs), graphics processing units (GPUs), image signal processors (ISPs), controllers, video codecs, baseband processors, and neural-network processing units (NPUs), etc. In some examples, different processing units may be independent devices; for example, processor 110 may be a baseband processor. In some examples, processor 110 may also be a system-on-a-chip (SoC) integrating multiple processing units.

[0055] The processor 110 may also include a memory for storing computer instructions and data. In some embodiments, the memory in the processor 110 is a cache. This memory can store computer instructions or data that the processor 110 has just used or that are used repeatedly. If the processor 110 needs to use the same computer instructions or data again, it can retrieve them directly from the memory. This avoids repeated accesses, reduces the waiting time of the processor 110, and thus improves the efficiency of the system.

[0056] The external storage interface 130 can be used to connect an external memory card, such as a micro SanDisk (Micro SD) card, to expand the storage capacity of the electronic device 100. The external memory card communicates with the processor 110 through the external storage interface 130 to perform data storage functions. For example, music, video, and other files can be saved on the external memory card.

[0057] Internal memory 140 can be used to store computer executable program code, which includes computer instructions. Processor 110 executes various functional applications and data processing of electronic device 100 by running the computer instructions stored in internal memory 140. In addition, internal memory 140 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device, flash memory device, universal flash storage (UFS), etc.

[0058] The memory involved in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct memory bus RAM (DR RAM). It should be noted that the memory used in the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0059] The audio module 170 may include a speaker, receiver, microphone, and headphone jack. The electronic device 100 can implement audio functions, such as music playback and recording, through the audio module 170 and processor 110.

[0060] Audio module 170 is used to convert digital audio information into analog audio signal output, and also to convert analog audio input into digital audio signal. In some embodiments, audio module 170 may be located in processor 110, or some functional modules of audio module 170 may be located in processor 110. A speaker, also called a "loudspeaker," is used to convert audio electrical signals into sound signals. A receiver, also called a "handpiece," is used to convert audio electrical signals into sound signals. A microphone, also called a "microphone" or "voice transducer," is used to convert sound signals into electrical signals. Electronic device 100 may be equipped with at least one microphone. A headphone jack is used to connect wired headphones. The headphone jack may be a USB interface 150, or a 3.5mm Open Mobile Terminal Platform (OMTP) standard interface, or a Cellular Telecommunications Industry Association of the USA (CTIA) standard interface.

[0061] Buttons 191 include a power button, volume buttons, etc. Buttons 191 can be mechanical buttons or touch-sensitive buttons. The electronic device 100 can receive input from buttons 191 and generate key signal inputs related to user settings and function control. Motor 192 can generate vibration alerts. Motor 192 can be used for incoming call vibration alerts or for touch vibration feedback. Indicator 193 can be an indicator light, used to indicate charging status, battery level changes, messages, missed calls, notifications, etc. SIM card interface 196 is used to connect a SIM card. The SIM card can be inserted into or removed from the SIM card interface 196 to achieve contact and separation with the electronic device 100. The electronic device 100 can support one or N SIM card interfaces 196, where N is a positive integer greater than 1. SIM card interfaces 196 can support Nano SIM cards, Micro SIM cards, SIM cards, etc. In some embodiments, the electronic device 100 employs an embedded SIM (eSIM) card, which can be embedded in the electronic device 100 and cannot be separated from the electronic device 100.

[0062] Electronic device 100 can perform shooting functions through an ISP, camera 194, video codec, GPU, display 195, and processor 110. The ISP is used to process data fed back by the camera 194. In some embodiments, the ISP can be set in the camera 194. The camera 194 is used to capture still images or videos. In some embodiments, electronic device 100 may include one or N cameras 194, where N is a positive integer greater than 1.

[0063] Electronic device 100 can implement display functions through a GPU, a display screen 195, and a processor 110. The GPU is a microprocessor 110 for image processing, connected to the display screen 195 and the processor 110. The GPU is used to perform mathematical and geometric calculations for graphics rendering. The processor 110 may include one or more GPUs, which execute computer instructions to generate or modify display information.

[0064] The display screen 195 is used to display images, videos, etc. The display screen 195 includes a display panel. In some embodiments, the electronic device 100 may include one or more display screens 195. In other embodiments, the touchscreen in the display screen 195 may be a foldable screen.

[0065] Battery 161 may include one or more cells, and multiple cells may be connected in series, parallel or other ways to supply power to the load.

[0066] The power management module 160 receives charging input from a charger. The charger can be a wireless charger, such as a wireless charging dock or other electronic devices with reverse wireless charging capabilities. The power management module 160 can receive wireless charging input via the wireless charging coil 162 of the electronic device 100. The charger can also be a wired charger; for example, the power management module 160 can receive charging input from a wired charger via a USB interface 150.

[0067] The processor 110 is coupled to the radio frequency transceiver 120 to realize the 2G / 3G / 4G / 5G mobile communication and wireless communication functions of the electronic device 100. The wireless communication 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-SCDMA), Long Term Evolution (LTE), Wireless Local Area Networks (WLAN), Bluetooth (BT), Global Navigation Satellite System (GNSS), Frequency Modulation (FM), Infrared (IR), Near Field Communication (NFC), etc.

[0068] Figure 2 A schematic diagram of a radio frequency transceiver is shown. Figure 2 As shown, the radio frequency transceiver 120 includes a modem 210, a radio frequency integrated circuit (RFIC) 220, a radio frequency front-end (RFFE) 230, and an antenna (ANT) 240; wherein the modem 210 is coupled to the RFIC 220, the RFIC 220 is coupled to the RFFE 230, and the RFFE 230 is coupled to the antenna 240.

[0069] Modem 210 is used to encode and decode user data (e.g., voice data, text data, and video data) or control information for transmission and reception via radio frequency transceiver 120. In some embodiments, modem 210 may include a modulator and a demodulator. The modulator modulates a 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 and transmits the demodulated low-frequency baseband signal to baseband processor 110.

[0070] The radio frequency (RF) chip 220 (also referred to as a receiver, transmitter, or transceiver) may include a transmitter (TX) and an RF receiver (RX). In some embodiments, the RF chip 220 can receive baseband signals from the modem 210, process the baseband signals (e.g., up-conversion and digital-to-analog conversion) to obtain RF signals, and transmit the RF signals to the RF front-end module 230 via the RF transmitter. The RF front-end module 230 can transmit the RF signals via the antenna 240, thereby realizing the transmission of RF signals. In some embodiments, the RF receiver of the RF chip 220 can receive RF signals received from the antenna 240 through the RF front-end module 230. The RF chip 220 can process the received RF signals (e.g., down-conversion and analog-to-digital conversion) to obtain baseband signals, and transmit the baseband signals to the modem 210, thereby realizing the reception of RF signals.

[0071] Antenna 240 is used to transmit and receive electromagnetic wave signals. Antenna 240 can be a single antenna or an antenna array composed of multiple antennas 240. Each antenna 240 can cover one or more frequency bands, and different antennas 240 can be reused to improve the utilization rate of the antennas 240.

[0072] The RF front-end module 230 may include multiple RF processing devices such as a power amplifier (PA), a low noise amplifier (LNA), and filters for amplifying and / or filtering RF signals. The RF transmitter and receiver of the RF chip 220 can be coupled to the antenna 240 through one or more RF processing devices in the RF front-end module 230.

[0073] In some implementations, the radio frequency transceiver also includes a coupler, which typically includes an input (IN), an output (OUT), a coupling terminal (CPL), and an isolation terminal (ISO). For example... Figure 3 As shown, the RF transmitter of the RF chip 220 is coupled to the input of the power amplifier, the output of the power amplifier is coupled to the input of the coupler, the output of the coupler is coupled to the antenna, the coupling end of the coupler is coupled to the detection end (DET) of the RF chip 220, and the isolation end of the coupler is grounded.

[0074] Figure 4 A schematic diagram of a coupler structure is shown, such as... Figure 4 As shown, the coupler includes a first phase shift structure, a second phase shift structure, a first coupling channel, and a second coupling channel. The first end of the first phase shift structure and the first end of the first coupling channel are both coupled to the input terminal of the coupler. The second end of the first phase shift structure and the first end of the second coupling channel are both coupled to the output terminal of the coupler. The first end of the second phase shift structure and the second end of the first coupling channel are both coupled to the isolation terminal of the coupler. The second end of the second phase shift structure and the second end of the second coupling channel are both coupled to the coupling terminal of the coupler.

[0075] The first and second phase shift structures can perform a -90° phase shift (i.e., a 90° phase lag) on ​​the radio frequency signal. In some examples, when the radio frequency signal is input from the first end of the first phase shift structure (i.e., the input of the coupler), it is shifted by -90° by the first phase shift structure and then output from the second end of the first phase shift structure (i.e., the output of the coupler).

[0076] like Figure 5 As shown, in some examples, the first coupling channel and the second coupling channel are capable of coupling radio frequency signals. Phase shift (i.e., phase lag) When the radio frequency signal is input from the first end of the first phase shift structure (i.e., the input end of the coupler), the radio frequency signal sequentially passes through the first phase shift structure, the second coupling channel, and the second phase shift structure (which can be called path one) for phase shifting. Afterwards, and after phase shifting through the first coupling channel (which can be called path two). Afterwards, the RF signal passing through path one has an opposite phase to the RF signal passing through path two, and they cancel each other out at the first end of the second phase shift structure. Therefore, there is no output at one end of the second phase shift structure (the isolation end of the coupler).

[0077] like Figure 6 As shown, in some examples, the first coupling channel and the second coupling channel are capable of coupling radio frequency signals. Phase shifting. When the radio frequency signal is input from the first end of the first phase shift structure (i.e., the input end of the coupler), the radio frequency signal undergoes phase shifting sequentially through the first phase shift structure and the second coupling channel (which can be called path three). Then, it undergoes phase shifting sequentially through the first coupling channel and the second phase shift structure (which can be called path four). Then, it is coupled to both ends of the second phase shift structure. The RF signal passing through path three has the same phase as the RF signal passing through path four, and they are superimposed at the second end of the second phase shift structure. Therefore, a small portion of the power of the output RF signal can be coupled at both ends of the second phase shift structure (the coupling ends of the coupler).

[0078] When an RF signal is input to the coupler, a portion of the power is output directly from the output, while another portion is coupled to the coupling terminal for output, and the isolation terminal remains unconnected. A small fraction of the RF signal power, for example -20dB to -30dB (i.e., one-hundredth to one-thousandth), is extracted by the coupler and fed into the RF chip. This ensures complete RF signal transmission and allows for RF signal monitoring and power measurement. This is extremely useful for performance monitoring and troubleshooting of RF transceivers.

[0079] like Figure 7 As shown, in some embodiments, the first and second phase shift structures can employ 90° phase shift lines, resulting in a 90° phase lag after the RF signal passes through either the first or second phase shift structure. However, for lower frequency RF signals, such as those in the B20 or B28 bands, the 90° phase shift line is relatively long (typically 3 mm), requiring the coupler to occupy a larger printed circuit board (PCB) area.

[0080] like Figure 8 As shown, in some other embodiments, the first phase shift structure and the second phase shift structure can be implemented using an inductor-capacitor network. Since the impedance of capacitors and inductors to AC signals varies with frequency, the inductor-capacitor network has different responses to radio frequency signals of different frequencies. Figure 9 The phase-frequency response diagram of the inductor-capacitor network is shown. It can be seen that the higher the frequency of the radio frequency signal, the greater the phase lag after passing through the inductor-capacitor network.

[0081] For example, such as Figure 10 As shown, when the radio frequency signal is low-frequency within its frequency band, the phase shift amplitude of the RF signal caused by the inductor-capacitor network may be -80° (i.e., phase lag of 80°), resulting in a phase shift in the RF signal as it passes through the path. After path two phase shift The RF signal passing through path one and the RF signal passing through path two are 160° out of phase, so they cannot be completely canceled out at the first end of the second phase shift structure. As a result, the isolation end of the coupler will couple part of the power of the RF signal.

[0082] For example, such as Figure 11As shown, when the radio frequency signal is at a relatively high frequency within its frequency band, the phase shift amplitude of the radio frequency signal caused by the inductor-capacitor network may be -100° (i.e., phase lag of 100°), resulting in a phase shift in the radio frequency signal as it passes through the path. After path two phase shift The RF signal passing through path one and the RF signal passing through path two are 200° out of phase, so they cannot be completely canceled out at the first end of the second phase shift structure, resulting in the isolation end of the coupler coupling part of the RF signal power.

[0083] Figure 12 The diagram illustrates the amplitude-frequency characteristics of the coupler when the first and second phase-shift structures employ an inductor-capacitor network. When the frequency of the RF signal input to the coupler is 700MHz to 760MHz (bandwidth 60MHz), the amplitude gain at the coupler's output is -0.02dB to -0.04dB, allowing for almost lossless output of the input RF signal. The amplitude gain at the coupling end is -25.91dB to -24.42dB, meaning the output power is approximately one-three-hundredth of the input RF signal power. The amplitude gain at the isolation end is -45.02dB to -53.98dB, meaning the output power is approximately one-thirty-thousandth to one-two-hundred-thousandth of the input RF signal power. However, when the frequency of the RF signal input to the coupler is less than 700MHz or greater than 760MHz, the coupler's directivity is less than 20dB; here, directivity is the ratio of the output power at the coupling end to the output power at the isolation end. In other words, the coupler only has good directivity within a narrow bandwidth; for RF signals with a wider bandwidth (e.g., the B28 band with a 90MHz bandwidth), the coupler's directivity is poor.

[0084] This application provides a coupler circuit for improving the directivity of the coupler for radio frequency signals with a wider bandwidth. Figure 13 An exemplary schematic diagram of a coupler circuit is provided. For example... Figure 13 As shown, the coupler circuit 300 includes a right-hand transmission line circuit 310, a left-hand transmission line circuit 320, a first coupling circuit 330, a second coupling circuit 340, an input terminal, an output terminal, a coupling terminal, and an isolation terminal. Specifically, the first terminal of the first coupling circuit 330 and the first terminal of the right-hand transmission line circuit 310 are both connected to the input terminal; the second terminal of the first coupling circuit 330 and the first terminal of the left-hand transmission line circuit 320 are both connected to the coupling terminal; the first terminal of the second coupling circuit 340 and the second terminal of the right-hand transmission line circuit 310 are both connected to the output terminal; and the second terminal of the second coupling circuit 340 and the second terminal of the left-hand transmission line circuit 320 are both connected to the isolation terminal.

[0085] Although not shown in the accompanying drawings, those skilled in the art should understand that the coupler circuit 300 provided in the embodiments of this application can also have other structures. For example, the second end of the first coupling circuit 330 and the first end of the left-hand transmission line circuit 320 are both connected to the input end, the first end of the first coupling circuit 330 and the first end of the right-hand transmission line circuit 310 are both connected to the coupling end, the second end of the second coupling circuit 340 and the second end of the left-hand transmission line circuit 320 are both connected to the output end, and the first end of the second coupling circuit 340 and the second end of the right-hand transmission line circuit 310 are both connected to the isolation end.

[0086] The left-hand transmission line circuit 320 and the right-hand transmission line circuit 310 exhibit significant differences in phase shifting of the radio frequency (RF) signal. The RF signal will experience phase lag after passing through the right-hand transmission line circuit 310, while the RF signal will experience phase lead after passing through the left-hand transmission line circuit 320.

[0087] like Figure 14 As shown, in some examples, the first coupling circuit 330 and the second coupling circuit 340 are capable of coupling radio frequency signals. Phase shifting. Thus, when the radio frequency signal is input from the first terminal of the right-hand transmission line circuit 310 (i.e., the input terminal of the coupler circuit 300), the radio frequency signal undergoes phase shifting sequentially through the right-hand transmission line circuit 310 and the second coupling circuit 340. Then, the phase shifts sequentially through the first coupling circuit 330 and the left-hand transmission line circuit 320. Then, it is coupled to the second end of the left-hand transmission line circuit 320 (i.e., the isolation end of the coupler circuit 300). The phase difference between the two RF signals coupled to the isolation end of the coupler circuit 300 is 180° (i.e., they are out of phase), so they cancel each other out at the isolation end of the coupler circuit 300. Therefore, there is no output at the isolation end of the coupler circuit 300 (i.e., the second end of the left-hand transmission line circuit 320).

[0088] like Figure 15 As shown, in some examples, the first coupling circuit 330 and the second coupling circuit 340 are capable of coupling radio frequency signals. Phase shifting. Thus, when the radio frequency signal is input from the first terminal of the right-hand transmission line circuit 310 (i.e., the input terminal of the coupler circuit 300), the radio frequency signal undergoes phase shifting sequentially through the right-hand transmission line circuit 310, the second coupling circuit 340, and the left-hand transmission line circuit 320. Then, and sequentially through the first coupling circuit 330 phase shift. Then, it is coupled to the first end of the left-hand transmission line circuit 320 (i.e., the coupling end of the coupler circuit 300). The phase difference between the two RF signals coupled to the coupling end of the coupler circuit 300 is 0° (i.e., they are in the same phase), so they are superimposed at the coupling end of the coupler circuit 300. Therefore, the coupling end of the coupler circuit 300 (i.e., the first end of the left-hand transmission line circuit 320) can couple a small portion of the power of the output RF signal.

[0089] Figure 16 A schematic diagram of the phase frequency characteristics of the left-hand transmission line circuit 320 and the right-hand transmission line circuit 310 is shown. Figure 16 As shown, the higher the frequency of the radio frequency signal, the greater the phase lag of the radio frequency signal passing through the right-hand transmission line circuit 310, and the smaller the phase lead of the radio frequency signal passing through the left-hand transmission line circuit 320. The left-hand transmission line circuit 320 and the right-hand transmission line circuit 310 can maintain a stable phase difference over a wide bandwidth. The embodiments of this application, through the technical solution of the right-hand transmission line circuit 310 and the left-hand transmission line circuit 320 working together, can improve the directivity of the coupler for radio frequency signals over a wide bandwidth.

[0090] For example, such as Figure 16 and Figure 17 As shown, when the radio frequency (RF) signal is at a lower frequency within its frequency band, the phase shift amplitude of the right-hand transmission line circuit 310 is -80° (i.e., phase lag of 80°), while the phase shift amplitude of the left-hand transmission line circuit 320 is +100° (i.e., phase lead of 100°). Therefore, when the RF signal is input from the first terminal of the right-hand transmission line circuit 310 (i.e., the input terminal of the coupler circuit 300), the RF signal undergoes phase shifting sequentially through the right-hand transmission line circuit 310 and the second coupling circuit 340. Then, the phase shifts sequentially through the first coupling circuit 330 and the left-hand transmission line circuit 320. Then, it is coupled to the second end of the left-hand transmission line circuit 320 (i.e., the isolation end of the coupler circuit 300). The phase difference between the two RF signals coupled to the isolation end of the coupler circuit 300 is 180° (i.e., they are out of phase), so they cancel each other out at the isolation end of the coupler circuit 300. Therefore, there is no output at the isolation end of the coupler circuit 300 (i.e., the second end of the left-hand transmission line circuit 320).

[0091] For example, such as Figure 16 and Figure 18As shown, when the radio frequency signal is at a higher frequency within its frequency band, the phase shift amplitude of the right-hand transmission line circuit 310 on the radio frequency signal is -100° (i.e., phase lag of 100°), while the phase shift amplitude of the left-hand transmission line circuit 320 on the radio frequency signal is +80° (i.e., phase lead of 80°). Therefore, when the radio frequency signal is input from the first terminal of the right-hand transmission line circuit 310 (i.e., the input terminal of the coupler circuit 300), the radio frequency signal undergoes phase shifting sequentially through the right-hand transmission line circuit 310 and the second coupling circuit 340. Then, the phase shifts sequentially through the first coupling circuit 330 and the left-hand transmission line circuit 320. Then, it is coupled to the second end of the left-hand transmission line circuit 320 (i.e., the isolation end of the coupler circuit 300). The phase difference between the two RF signals coupled to the isolation end of the coupler circuit 300 is also 180° (i.e., they are out of phase), so they cancel each other out at the isolation end of the coupler circuit 300. Therefore, there is no output at the isolation end of the coupler circuit 300 (i.e., the second end of the left-hand transmission line circuit 320).

[0092] like Figure 19 As shown, in some embodiments, the right-hand transmission line circuit 310 includes a first inductor L1, a first capacitor C1, and a second capacitor C2. The first terminals of both the first inductor L1 and the first capacitor C1 are connected to the first terminal of the right-hand transmission line circuit 310, and the second terminals of both the first inductor L1 and the second capacitor C2 are connected to the second terminal of the right-hand transmission line circuit 310. The second terminal of the first capacitor C1 is grounded, and the second terminal of the second capacitor C2 is also grounded. That is, the right-hand transmission line circuit 310 can be a Π-type inductor-capacitor (LC) circuit composed of the first inductor L1, the first capacitor C1, and the second capacitor C2.

[0093] The left-hand transmission line circuit 320 includes a fourth inductor L4, a fifth inductor L5, and a fourth capacitor C4. The first terminal of the fourth capacitor C4 and the first terminal of the fourth inductor L4 are both connected to the first terminal of the left-hand transmission line circuit 320, and the second terminal of the fourth capacitor C4 and the first terminal of the fifth inductor L5 are both connected to the second terminal of the left-hand transmission line circuit 320. The second terminal of the fourth inductor L4 is grounded, and the second terminal of the fifth inductor L5 is grounded. That is to say, the left-hand transmission line circuit 320 can be a Π-type LC circuit composed of the fourth inductor L4, the fifth inductor L5, and the fourth capacitor C4.

[0094] In some examples, the inductance values ​​of the first inductor L1, the fourth inductor L4, and the fifth inductor L5 are all 10.5 nanohenries (i.e., L1 = L4 = L5 = 10.5 nH), and the capacitance values ​​of the first capacitor C1, the second capacitor C2, and the fourth capacitor C4 are all 4.3 picofarads (i.e., C1 = C2 = C4 = 4.3 pF). Therefore, the resonant frequency f of the right-hand transmission line circuit 310 can be calculated. r1 And the resonant frequency f of the left-hand transmission line circuit 320. r2 :

[0095]

[0096] Figure 20 The diagram shows the traces of the right-hand transmission line circuit 310 and the left-hand transmission line circuit 320 on a Smith chart. When the frequency of the radio frequency signal is 750MHz, the complex impedance of the right-hand transmission line circuit 310 is Z0(0.980+j0.001), with an imaginary part that is almost zero, located at the center point of the Smith chart (i.e., the impedance matching point). The complex impedance of the left-hand transmission line circuit 320 is Z0(0.975+j0.002), with an imaginary part that is almost zero, also located at the center point of the Smith chart. Here, Z0 is the matching resistor. That is to say, the right-hand transmission line circuit 310 and the left-hand transmission line circuit 320 exhibit purely resistive characteristics for a 750MHz radio frequency signal.

[0097] Figure 21 A schematic diagram of the amplitude-frequency characteristics of the coupler circuit 300 provided in this embodiment is shown. When the frequency of the radio frequency signal input from the input terminal of the coupler circuit 300 is 700MHz to 800MHz (bandwidth 100MHz), the amplitude gain of the output terminal of the coupler circuit 300 relative to the radio frequency signal is 0.68dB to -0.66dB. The amplitude gain of the coupling terminal of the coupler circuit 300 relative to the radio frequency signal is -24.68dB to -24.52dB, meaning the output power is approximately one three-hundredth of the power of the input radio frequency signal. The amplitude gain of the isolation terminal of the coupler circuit 300 relative to the radio frequency signal is -47.81dB to -64.19dB, meaning the output power is approximately one fifty-thousandth to one two-hundred-and-five-thousandth of the power of the input radio frequency signal. The directivity of the coupler circuit 300 is greater than 20dB within a 100MHz bandwidth. In other words, the coupler circuit 300 provided in this application embodiment has good directivity over a wide bandwidth.

[0098] like Figure 22As shown, in some embodiments, the right-hand transmission line circuit 310 includes a second inductor L2, a third inductor L3, and a third capacitor C3. The first terminal of the second inductor L2 is connected to the first terminal of the right-hand transmission line circuit 310. The second terminal of the second inductor L2 is connected to both the first terminal of the third inductor L3 and the first terminal of the third capacitor C3. The second terminal of the third inductor L3 is connected to the second terminal of the right-hand transmission line circuit 310, and the second terminal of the third capacitor C3 is grounded. That is, the right-hand transmission line circuit 310 can be a T-type LC circuit composed of the second inductor L2, the third inductor L3, and the third capacitor C3.

[0099] The left-hand transmission line circuit 320 includes a fifth capacitor C5, a sixth capacitor C6, and a sixth inductor L6. The first terminal of the fifth capacitor C5 is connected to the first terminal of the left-hand transmission line circuit 320. The second terminal of the fifth capacitor C5 is connected to both the first terminals of the sixth capacitor C6 and the sixth inductor L6. The second terminal of the sixth capacitor C6 is connected to the second terminal of the left-hand transmission line circuit 320, and the second terminal of the sixth inductor L6 is grounded. In other words, the left-hand transmission line circuit 320 can be a T-type LC circuit composed of the fifth capacitor C5, the sixth capacitor C6, and the sixth inductor L6.

[0100] like Figure 23 As shown, in some other embodiments, the right-hand transmission line circuit 310 in the coupler circuit 300 can be a Π-type LC circuit composed of a first inductor L1, a first capacitor C1, and a second capacitor C2, and the left-hand transmission line circuit 320 can be a T-type LC circuit composed of a fifth capacitor C5, a sixth capacitor C6, and a sixth inductor L6. This application does not impose any restrictions on the combination of the left-hand transmission line circuit 320 and the right-hand transmission line circuit 310.

[0101] Please continue to refer to Figure 19 In some embodiments, the first coupling circuit 330 includes a seventh capacitor C7, the first end of which is connected to the first end of the first coupling circuit 330, and the second end of which is connected to the second end of the first coupling circuit 330. And / or, the second coupling circuit 340 includes an eighth capacitor C8, the first end of which is connected to the first end of the second coupling circuit 340, and the second end of which is connected to the second end of the second coupling circuit 340.

[0102] In some implementations, the capacitance of the seventh capacitor C7 is equal to that of the eighth capacitor C8. To reduce the coupling of the coupler circuit 300, the capacitance values ​​of the seventh capacitor C7 and the eighth capacitor C8 may be less than the capacitance value of the first capacitor C1; for example, the capacitance values ​​of the seventh capacitor C7 and the eighth capacitor C8 are both 0.25 pF (i.e., C7 = C8 = 0.25 pF).

[0103] Please continue to refer to Figure 24 In some embodiments, the first coupling circuit 330 includes a seventh inductor L7, with a first terminal of the seventh inductor L7 connected to a first terminal of the first coupling circuit 330, and a second terminal of the seventh inductor L7 connected to a second terminal of the first coupling circuit 330. And / or, the second coupling circuit 340 includes an eighth inductor L8, with a first terminal of the eighth inductor L8 connected to a first terminal of the second coupling circuit 340, and a second terminal of the eighth inductor L8 connected to a second terminal of the second coupling circuit 340.

[0104] In some implementations, the inductance value of the seventh inductor L7 is equal to the inductance value of the eighth inductor L8. To reduce the coupling of the coupler circuit 300, the inductance values ​​of the seventh inductor L7 and the eighth inductor L8 can be greater than the inductance value of the first inductor L1; for example, the inductance values ​​of the seventh inductor L7 and the eighth inductor L8 are both 100 nanohenries (i.e., L7 = L8 = 100 nH).

[0105] Secondly, a circuit board assembly is provided. The circuit board assembly includes a printed circuit board (not shown) and... Figure 19 and Figures 22 to 24 The coupler circuit 300 shown in any of the embodiments is disposed on a printed circuit board. The coupler circuit 300 provided in this application embodiment is composed of discrete structures such as inductors and capacitors.

[0106] In some embodiments, the inductor is a 01005-size surface mount inductor, and the capacitor is a 01005-size surface mount capacitor. Both the 01005-size surface mount capacitor and the 01005-size surface mount inductor have dimensions of 0.4mm × 0.2mm. The components in the coupler circuit 300 can be disposed on the surface of a printed circuit board; for example, Figure 19 The first capacitor C1, second capacitor C2, fourth capacitor C4, seventh capacitor C7, eighth capacitor C8, first inductor L1, fourth inductor L4, and fifth inductor L5 in the coupler circuit 300 shown can be arranged as follows: Figure 25The layout shown is positioned on the surface of the printed circuit board (PCB) on the side closest to the PCB. Including the gaps between components, the coupler circuit 300 provided in this embodiment occupies approximately 1.5mm × 1.5mm of PCB area, thereby reducing the PCB area by 50%. Furthermore, it only occupies the surface layer of the PCB, making internal layer routing on the PCB more convenient.

[0107] In one embodiment, the printed circuit board is a multilayer printed circuit board. The left-hand transmission line circuit 320 in the coupler circuit 300 is disposed on the first layer of the printed circuit board, and the right-hand transmission line circuit 310 in the coupler circuit 300 is disposed on the second layer of the printed circuit board. The first layer and the second layer are adjacent. The first coupling circuit 330 in the coupler circuit 300 includes a seventh capacitor C7, and the second coupling circuit 340 in the coupler circuit 300 includes an eighth capacitor C8. Both the seventh capacitor C7 and the eighth capacitor C8 are parasitic capacitances between the first layer and the second layer. This can further reduce the area of ​​the printed circuit board.

[0108] This application also provides an electronic device, which includes a power amplifier, an antenna, a radio frequency chip, and... Figure 25 The circuit board assembly shown is coupled to the power amplifier, antenna, and RF chip, respectively.

[0109] This application provides a coupler circuit and circuit board assembly. The coupler circuit employs a combination of right-hand and left-hand transmission line circuits, which exhibit significant differences in phase shifting of radio frequency (RF) signals. The RF signal experiences phase lag after passing through the right-hand transmission line circuit, while it exhibits phase lead after passing through the left-hand transmission line circuit. Furthermore, the higher the frequency of the RF signal, the greater the phase lag after passing through the right-hand transmission line circuit, and the smaller the phase lead after passing through the left-hand transmission line circuit. This application's embodiment maintains a stable phase difference over a wide bandwidth through the left-hand and right-hand transmission line circuits, thereby improving the coupler's directivity for RF signals with a wider bandwidth.

[0110] In the several embodiments provided in this application, it should be understood that the disclosed coupler circuits, circuit board assemblies, and electronic devices can be implemented in other ways. For example, the device embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or modules may be electrical, mechanical, or other forms.

[0111] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; that is, they may be located on one device or distributed across multiple devices. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0112] In addition, the functional modules in the various embodiments of this application can be integrated into one device, or each module can exist physically separately, or two or more modules can be integrated into one device.

[0113] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented using software programs, implementation can be, in whole or in part, in the form of a computer program product.

[0114] 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 circuit, characterized in that, It includes a right-hand transmission line circuit, a left-hand transmission line circuit, a first coupling circuit, and a second coupling circuit; wherein, the right-hand transmission line circuit is used to perform phase lag shifting on the signal, and the higher the frequency of the signal, the greater the phase lag shifting amplitude of the right-hand transmission line circuit; the left-hand transmission line circuit is used to perform phase lead shifting on the signal, and the higher the frequency of the signal, the smaller the phase lead shifting amplitude of the left-hand transmission line circuit. The first end of the first coupling circuit is connected to the first end of the right-hand transmission line circuit, and the second end of the first coupling circuit is connected to the first end of the left-hand transmission line circuit. The first end of the second coupling circuit is connected to the second end of the right-hand transmission line circuit, and the second end of the second coupling circuit is connected to the second end of the left-hand transmission line circuit. The first end of the right-hand transmission line circuit serves as the input end of the coupler circuit, the second end of the right-hand transmission line circuit serves as the output end of the coupler circuit, the first end of the left-hand transmission line circuit serves as the coupling end of the coupler circuit, and the second end of the left-hand transmission line circuit serves as the isolation end of the coupler circuit; or, the first end of the left-hand transmission line circuit serves as the input end of the coupler circuit, the second end of the left-hand transmission line circuit serves as the output end of the coupler circuit, the first end of the right-hand transmission line circuit serves as the coupling end of the coupler circuit, and the second end of the right-hand transmission line circuit serves as the isolation end of the coupler circuit.

2. The coupler circuit according to claim 1, characterized in that, When the first end of the right-hand transmission line circuit serves as the input terminal of the coupler circuit, the second end of the right-hand transmission line circuit serves as the output terminal of the coupler circuit, the first end of the left-hand transmission line circuit serves as the coupling terminal of the coupler circuit, and the second end of the left-hand transmission line circuit serves as the isolation terminal of the coupler circuit, The right-hand transmission line circuit is configured to: phase-shift the signal input from the input terminal of the coupler circuit, and transmit the phase-shifted signal to the output terminal of the coupler circuit; The first coupling circuit is configured to: phase-shift a signal input from the input terminal of the coupler circuit, and transmit the phase-shifted signal to the coupling terminal of the coupler circuit; The second coupling circuit is configured to: phase-shift the signal transmitted to the output terminal of the coupler circuit and transmit the phase-shifted signal to the isolation terminal of the coupler circuit; or, phase-shift the signal transmitted to the isolation terminal of the coupler circuit and transmit the phase-shifted signal to the output terminal of the coupler circuit. The left-hand transmission line circuit is configured to: phase-shift the signal transmitted to the coupling end of the coupler circuit and transmit the phase-shifted signal to the isolation end of the coupler circuit; or, phase-shift the signal transmitted to the isolation end of the coupler circuit and transmit the phase-shifted signal to the coupling end of the coupler circuit.

3. The coupler circuit according to claim 1, characterized in that, When the first end of the left-hand transmission line circuit serves as the input terminal of the coupler circuit, the second end of the left-hand transmission line circuit serves as the output terminal of the coupler circuit, the first end of the right-hand transmission line circuit serves as the coupling terminal of the coupler circuit, and the second end of the right-hand transmission line circuit serves as the isolation terminal of the coupler circuit, The left-hand transmission line circuit is configured to: phase-shift the signal input from the input terminal of the coupler circuit, and transmit the phase-shifted signal to the output terminal of the coupler circuit; The first coupling circuit is configured to: phase-shift a signal input from the input terminal of the coupler circuit, and transmit the phase-shifted signal to the coupling terminal of the coupler circuit; The second coupling circuit is configured to: phase-shift the signal transmitted to the output terminal of the coupler circuit and transmit the phase-shifted signal to the isolation terminal of the coupler circuit; or, phase-shift the signal transmitted to the isolation terminal of the coupler circuit and transmit the phase-shifted signal to the output terminal of the coupler circuit. The right-hand transmission line circuit is configured to: phase-shift the signal transmitted to the coupling end of the coupler circuit and transmit the phase-shifted signal to the isolation end of the coupler circuit; or, phase-shift the signal transmitted to the isolation end of the coupler circuit and transmit the phase-shifted signal to the coupling end of the coupler circuit.

4. The coupler circuit according to any one of claims 1-3, characterized in that, The right-hand transmission line circuit includes a first inductor, a first capacitor, and a second capacitor; The first end of the first inductor is connected to the first end of the first capacitor, and the connection node between the first inductor and the first capacitor serves as the first end of the right-hand transmission line circuit. The second end of the first inductor is connected to the first end of the second capacitor, and the connection node between the first inductor and the second capacitor serves as the second end of the right-hand transmission line circuit. The second terminal of the first capacitor is grounded, and the second terminal of the second capacitor is also grounded.

5. The coupler circuit according to any one of claims 1-3, characterized in that, The right-hand transmission line circuit includes a second inductor, a third inductor, and a third capacitor; The first end of the second inductor serves as the first end of the right-hand transmission line circuit. The second end of the second inductor is connected to the first end of the third inductor and the first end of the third capacitor, respectively. The second end of the third inductor serves as the second end of the right-hand transmission line circuit, and the second end of the third capacitor is grounded.

6. The coupler circuit according to any one of claims 1-3, characterized in that, The left-hand transmission line circuit includes a fourth inductor, a fifth inductor, and a fourth capacitor; The first end of the fourth capacitor is connected to the first end of the fourth inductor, and the connection node between the fourth capacitor and the fourth inductor serves as the first end of the left-hand transmission line circuit. The second end of the fourth capacitor is connected to the first end of the fifth inductor, and the connection node between the fourth capacitor and the fifth inductor serves as the second end of the left-hand transmission line circuit. The second terminal of the fourth inductor is grounded, and the second terminal of the fifth inductor is grounded.

7. The coupler circuit according to any one of claims 1-3, characterized in that, The left-hand transmission line circuit includes a fifth capacitor, a sixth capacitor, and a sixth inductor; The first end of the fifth capacitor serves as the first end of the left-hand transmission line circuit. The second end of the fifth capacitor is connected to the first end of the sixth capacitor and the first end of the sixth inductor. The second end of the sixth capacitor serves as the second end of the left-hand transmission line circuit. The second end of the sixth inductor is grounded.

8. The coupler circuit according to any one of claims 1-3, characterized in that, The first coupling circuit includes a seventh capacitor, wherein a first end of the seventh capacitor serves as a first end of the first coupling circuit, and a second end of the seventh capacitor serves as a second end of the first coupling circuit. or, The first coupling circuit includes a seventh inductor, the first end of which serves as the first end of the first coupling circuit, and the second end of which serves as the second end of the first coupling circuit.

9. The coupler circuit according to any one of claims 1-3, characterized in that, The second coupling circuit includes an eighth capacitor, the first end of which serves as the first end of the second coupling circuit, and the second end of which serves as the second end of the second coupling circuit. or, The second coupling circuit includes an eighth inductor, the first end of which serves as the first end of the second coupling circuit, and the second end of which serves as the second end of the second coupling circuit.

10. A circuit board assembly, characterized in that, It includes a printed circuit board and a coupler circuit as described in any one of claims 1-9, wherein the coupler circuit is disposed on the printed circuit board.

11. The circuit board assembly according to claim 10, characterized in that, The printed circuit board is a multilayer printed circuit board. The left-hand transmission line circuit in the coupler circuit is located on the first layer of the printed circuit board, and the right-hand transmission line circuit in the coupler circuit is located on the second layer of the printed circuit board. The first layer and the second layer are adjacent to each other. The first coupling circuit in the coupler circuit includes a seventh capacitor, and the second coupling circuit in the coupler circuit includes an eighth capacitor. Both the seventh capacitor and the eighth capacitor are parasitic capacitances between the first layer and the second layer.

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