Coupler circuit and circuit board assembly

Abstract

The invention provides a coupler circuit and a circuit board assembly, and belongs to the field of radio frequency technology. The coupler circuit comprises a right-hand transmission line circuit, a left-hand transmission line circuit, a first coupling circuit, a second coupling circuit, an input end, an output end, a coupling end and an isolation end. Wherein the first end of the first coupling circuit is connected with the first end of the right-hand transmission line circuit, and the second end of the first coupling circuit is connected with the first end of the left-hand transmission line circuit. The first end of the second coupling circuit is connected with the second end of the right-hand transmission line circuit, and the second end of the second coupling circuit is connected with the second end of the left-hand transmission line circuit. According to the embodiment of the invention, the left-hand transmission line circuit and the right-hand transmission line circuit can maintain a stable phase difference in a wide bandwidth, and can improve the directivity of the coupler to a radio frequency signal with a wide bandwidth.

Description

Technical Field

[0001] The present application relates to the field of radio frequency technology, and in particular to a coupler circuit and a circuit board assembly. Background Art

[0002] In a radio frequency system, the transmission power of a radio frequency signal can be monitored through a coupler (e.g., a branch directional coupler). The coupling degree, isolation degree, and directivity of a coupler are important indicators. Currently, the directivity of a coupler for a radio frequency signal with a large bandwidth is poor. Summary of the invention

[0003] Embodiments of the present application provide a coupler circuit and a circuit board assembly for improving the directivity of the coupler within the bandwidth of a radio frequency signal.

[0004] To achieve the above objectives, the embodiments of the present application adopt the following technical solutions: In the 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 end, an output end, a coupling end, and an isolation end. 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 input end is connected to the first end of the right-hand transmission line circuit, the output end is connected to the second end of the right-hand transmission line circuit, the coupling end is connected to the first end of the left-hand transmission line circuit, and the output end is connected to the second end of the left-hand transmission line circuit. Or, the input end is connected to the first end of the left-hand transmission line circuit, the output end is connected to the second end of the left-hand transmission line circuit, the coupling end is connected to the first end of the right-hand transmission line circuit, and the output end is connected to the second end of the right-hand transmission line circuit.

[0005] The implementation method of the present application adopts a technical solution that cooperates with a right-hand transmission line circuit and a left-hand transmission line circuit. There is a significant difference in the phase shift of the radio frequency signal between the left-hand transmission line circuit and the right-hand transmission line circuit. The radio frequency signal will experience a phase lag when passing through the right-hand transmission line circuit, while the radio frequency signal will experience a phase advance when passing through the left-hand transmission line circuit. In addition, the higher the frequency of the radio frequency signal, the greater the phase lag amplitude of the radio frequency signal passing through the right-hand transmission line circuit, and the smaller the phase advance amplitude of the radio frequency signal passing through the left-hand transmission line circuit. The implementation method of the present application can maintain a stable phase difference within a wider bandwidth through the left-hand transmission line circuit and the right-hand transmission line circuit, thereby improving the directivity of the coupler to radio frequency signals with a wider bandwidth.

[0006] In some possible implementations, the right-hand transmission line circuit includes a first inductor, a first capacitor, and a second capacitor. The first end of the first inductor and the first end of the first capacitor are both connected to the first end of the right-hand transmission line circuit, and the second end of the first inductor and the first end of the second capacitor are both connected to the second end of the right-hand transmission line circuit. The second end of the first capacitor is grounded, and the second end of the second capacitor is grounded. The right-hand transmission line circuit can adopt a Π-type LC circuit, and the discrete arrangement of the capacitor and the inductor helps to reduce the area of ​​the printed circuit board.

[0007] In some possible implementations, the right-hand transmission line circuit includes a second inductor, a third inductor, and a third capacitor. The first end of the second inductor is connected to 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 is connected to the second end of the right-hand transmission line circuit, and the second end of the third capacitor is grounded. The right-hand transmission line circuit can adopt a T-type LC circuit, and the discrete arrangement of the capacitor and the inductor helps to reduce the area of ​​the printed circuit board.

[0008] In some possible implementations, the left-hand transmission line circuit includes a fourth inductor, a fifth inductor, and a fourth capacitor. The first end of the fourth capacitor and the first end of the fourth inductor are both connected to the first end of the left-hand transmission line circuit, and the second end of the fourth capacitor and the first end of the fifth inductor are both connected to the second end of the left-hand transmission line circuit. The second end of the fourth inductor is grounded, and the second end of the fifth inductor is grounded. The left-hand transmission line circuit can adopt a Π-type LC circuit, and the discrete arrangement of the capacitor and the inductor helps to reduce the area of ​​the printed circuit board.

[0009] In some possible implementations, the left-hand transmission line circuit includes a fifth capacitor, a sixth capacitor, and a sixth inductor. The first end of the fifth capacitor is connected to 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 respectively, the second end of the sixth capacitor is connected to the second end of the left-hand transmission line circuit, and the second end of the sixth inductor is grounded. The left-hand transmission line circuit can adopt a T-type LC circuit, and the discrete arrangement of the capacitor and the inductor helps to reduce the area of ​​the printed circuit board.

[0010] In some possible implementations, the first coupling circuit includes a seventh capacitor, the first end of the seventh capacitor is connected to the first end of the first coupling circuit, and the second end of the seventh capacitor is connected to the second end of the first coupling circuit. And / or, the second coupling circuit includes an eighth capacitor, the first end of the eighth capacitor is connected to the first end of the second coupling circuit, and the second end of the eighth capacitor is connected to the second end of the second coupling circuit. The coupling circuit is implemented using a capacitor to help reduce the coupling degree of the coupler circuit, thereby reducing the impact on the output power of the output end of the coupler circuit, and also further reduce the area of ​​the printed circuit board.

[0011] In some possible implementations, the first coupling circuit includes a seventh inductor, the first end of the seventh inductor is connected to the first end of the first coupling circuit, and the second end of the seventh inductor is connected to the second end of the first coupling circuit. And / or, the second coupling circuit includes an eighth inductor, the first end of the eighth inductor is connected to the first end of the second coupling circuit, and the second end of the eighth inductor is connected to the second end of the second coupling circuit. The use of an inductor to implement the coupling circuit also helps to reduce the coupling degree of the coupler circuit, thereby reducing the impact on the output power of the output end of the coupler circuit, and further reducing the area of ​​the printed circuit board.

[0012] In a second aspect, a circuit board assembly is provided, which includes a printed circuit board and the coupler circuit of any one of the first aspects, wherein the coupler circuit is disposed on the printed circuit board.

[0013] In some possible implementations, the coupler circuit is disposed on the surface of the printed circuit board, thereby making the inner layer routing of the printed circuit board more convenient.

[0014] In some possible implementations, the printed circuit board is a multi-layer printed circuit board, the left-hand transmission line circuit in the coupler circuit is arranged on the first layer of the printed circuit board, the right-hand transmission line circuit in the coupler circuit is arranged on the second layer of the printed circuit board, and the first layer and the second layer are adjacent. 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, and the seventh capacitor and the eighth capacitor are both parasitic capacitors between the first layer and the second layer.

[0015] In some possible implementations, the coupler circuit is disposed close to one side of the printed circuit board.

[0016] In a third aspect, an electronic device is provided, comprising a power amplifier, an antenna, a radio frequency chip, and a circuit board assembly according to any one of the second aspects, wherein the circuit board assembly is coupled to the power amplifier, the antenna, and the radio frequency chip, respectively.

[0017] It should be understood that the technical effects of the second and third aspects can refer to the technical effects of the first aspect and any of its embodiments, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application; Figure 2 A schematic diagram of the structure of a radio frequency transceiver provided in an embodiment of the present application; Figure 3 A schematic diagram of the connection structure of the coupler provided in the embodiment of the present application in the radio frequency transceiver device; Figure 4 A schematic diagram of the structure of a coupler provided in an embodiment of the present application; Figure 5 A schematic diagram of a transmission path from an input end to an isolation end in a coupler is provided for a radio frequency signal in an embodiment of the present application; Figure 6 A schematic diagram of a transmission path from an input end to a coupling end of a coupler is provided for a radio frequency signal in an embodiment of the present application; Figure 7 A schematic diagram of the area occupied on a printed circuit board when the coupler provided in an embodiment of the present application is implemented using a 90° phase shift line; Figure 8 A schematic diagram of the structure of the coupler provided in the embodiment of the present application when it is implemented using an inductor-capacitor network; Fig. 9 A schematic diagram of the phase-frequency characteristics of an inductor-capacitor network provided in an embodiment of the present application; Fig.10 A phase diagram of a radio frequency signal at the isolation end of a coupler provided by an embodiment of the present application when the radio frequency signal is low frequency; Fig.11 A phase diagram of a radio frequency signal at the isolation end of a coupler provided by an embodiment of the present application when the radio frequency signal is high frequency; Fig.12 A schematic diagram of the amplitude-frequency characteristics of the isolation end, coupling end and output end of the coupler provided in an embodiment of the present application; Fig.13 A schematic diagram of the structure of a coupler circuit provided in an embodiment of the present application; Fig.14 A schematic diagram of a transmission path from an input end to an isolation end in a coupler circuit is provided for a radio frequency signal in an embodiment of the present application; Fig.15 A schematic diagram of a transmission path from an input end to a coupling end in a coupler circuit is provided for a radio frequency signal in an embodiment of the present application; Fig.16A schematic diagram of phase-frequency characteristics of a right-hand transmission line circuit and a left-hand transmission line circuit provided in an embodiment of the present application; Fig.17 A phase diagram of a radio frequency signal at the isolation end of a coupler circuit provided by an embodiment of the present application when the radio frequency signal is low frequency; Fig.18 A phase diagram of a radio frequency signal at the isolation end of a coupler circuit provided in an embodiment of the present application when the radio frequency signal is high frequency; Fig.19 A schematic diagram of the structure of a first coupler circuit provided in an embodiment of the present application; Fig. 20 A schematic diagram of impedance trajectories of a right-hand transmission line circuit and a left-hand transmission line circuit provided in an embodiment of the present application on a Smith chart; Fig.21 A schematic diagram of the amplitude-frequency characteristics of a coupler circuit provided in an embodiment of the present application; Fig. 22 A schematic diagram of the structure of a second coupler circuit provided in an embodiment of the present application; Fig.23 A schematic diagram of the structure of a third coupler circuit provided in an embodiment of the present application; Fig.24 A schematic diagram of the structure of a fourth coupler circuit provided in an embodiment of the present application; Fig.25 A schematic diagram of the layout of the coupler circuit provided in an embodiment of the present application on a printed circuit board.

[0019] Figure numerals: 100, electronic device; 110, processor; 120, RF 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; 196, SIM card interface; 210, modem; 220, RF chip; 230, RF 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 DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0021] The terms "first", "second", etc. involved in the embodiments of the present application are only used to distinguish features of the same type and cannot be understood as indicating relative importance, quantity, order, etc.

[0022] The terms "exemplary" or "for example" and the like in the embodiments of the present application are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the terms "exemplary" or "for example" is intended to present the related concepts in a specific way.

[0023] The terms "coupling" and "connection" involved in the embodiments of the present application should be understood in a broad sense. For example, they may refer to a direct physical connection, or an indirect connection achieved through electronic devices, such as a connection achieved through resistors, inductors, capacitors or other electronic devices.

[0024] The embodiment of the present application provides an electronic device, which can be fixed or mobile. In addition, the electronic device can also be called user equipment (UE), terminal, terminal equipment, mobile station (MS), mobile terminal (MT), access terminal equipment, vehicle-mounted terminal equipment, industrial control terminal equipment, mobile station, remote station, remote terminal equipment, mobile device, wireless communication equipment, terminal agent or terminal device, etc. Exemplarily, the electronic device may be a mobile phone, a tablet computer (pad), a desktop computer, a laptop computer, an all-in-one computer, a vehicle-mounted terminal, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control, a wireless terminal in self driving, a wireless terminal in remote medical surgery, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless communication function, a computing device or other processing device connected to a wireless modem, a wearable device, a terminal device in a future mobile communication network, or a terminal device in a future evolved public mobile land network (PLMN), etc.

[0025] Taking a mobile phone as an example, Figure 11 shows a possible structure of 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, a button 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).

[0026] Among them, the sensor module 180 may include a pressure sensor, a gyroscope sensor, an air pressure sensor, a magnetic sensor, an acceleration sensor, a distance sensor, a proximity light sensor, a fingerprint sensor, a temperature sensor, a touch sensor, an ambient light sensor, a bone conduction sensor, and the like.

[0027] It is to be understood that the interface connection relationship between the modules illustrated in the embodiment of the present application is only a schematic illustration and does not constitute a specific limitation on the electronic device 100. In other embodiments of the present application, the electronic device 100 may include more or fewer components than shown in the figure, or combine some components, or split some components, or arrange the components differently. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0028] In some examples, the processor 110 may include one or more processing units; wherein the processing unit may include a field programmable gate array (FPGA), a central processing unit (CPU), an application processor (AP), a network processor (NP), a digital signal processor (DSP), a microcontroller unit (MCU), a programmable logic device (PLD), a graphics processing unit (GPU), an image signal processor (ISP), a controller, a video codec, a baseband processor, and a neural-network processing unit (NPU). In some examples, different processing units may be independent devices; for example, the processor 110 may be a baseband processor. In some examples, the processor 110 may also be a system on chip (SoC) integrated with multiple processing units.

[0029] The processor 110 may also be provided with a memory for storing computer instructions and data. In some embodiments, the memory in the processor 110 is a cache memory. The memory may store computer instructions or data that the processor 110 has just used or cyclically used. If the processor 110 needs to use the computer instructions or data again, it may be directly called from the memory. This avoids repeated access, reduces the waiting time of the processor 110, and thus improves the efficiency of the system.

[0030] The external memory 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 memory interface 130 to implement a data storage function. For example, files such as music and videos can be stored in the external memory card.

[0031] The internal memory 140 may be used to store computer executable program codes, which include computer instructions. The processor 110 executes various functional applications and data processing of the electronic device 100 by running the computer instructions stored in the internal memory 140. In addition, the internal memory 140 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, a universal flash storage (UFS), etc.

[0032] The memory involved in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), and direct RAM bus RAM (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0033] The audio module 170 may include a speaker, a receiver, a microphone and an earphone interface. The electronic device 100 may implement audio functions such as music playing and recording through the audio module 170 and the processor 110 .

[0034] The audio module 170 is used to convert digital audio information into analog audio signal output, and is also used to convert analog audio input into digital audio signals. In some embodiments, the audio module 170 can be arranged in the processor 110, or some functional modules of the audio module 170 can be arranged in the processor 110. The speaker, also known as the "speaker", is used to convert audio electrical signals into sound signals. The receiver, also known as the "earpiece", is used to convert audio electrical signals into sound signals. The microphone, also known as the "microphone" or "microphone", is used to convert sound signals into electrical signals. The electronic device 100 can be provided with at least one microphone. The headphone jack is used to connect wired headphones. The headphone jack can be a USB interface 150, or it can be a 3.5mm open mobile terminal platform (OMTP) standard interface, or a cellular telecommunications industry association of the USA (CTIA) standard interface.

[0035] The button 191 includes a power button, a volume button, etc. The button 191 may be a mechanical button 191. It may also be a touch button 191. The electronic device 100 may receive input from the button 191 and generate key signal input related to the user settings and function control of the electronic device 100. The motor 192 may generate a vibration prompt. The motor 192 may be used for incoming call vibration prompts or for touch vibration feedback. The indicator 193 may be an indicator light, which may be used to indicate the charging status, power changes, messages, missed calls, notifications, etc. The SIM card interface 196 is used to connect the SIM card. The SIM card may be inserted into the SIM card interface 196 or pulled out from the SIM card interface 196 to achieve contact and separation with the electronic device 100. The electronic device 100 may support 1 or N SIM card interfaces 196, where N is a positive integer greater than 1. The SIM card interface 196 may support Nano SIM cards, Micro SIM cards, SIM cards, etc. In some embodiments, the electronic device 100 uses an embedded SIM (eSIM) card. The eSIM card can be embedded in the electronic device 100 and cannot be separated from the electronic device 100 .

[0036] The electronic device 100 can implement a shooting function through an ISP, a camera 194, a video codec, a GPU, a display screen 195, and a 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 a static image or a video. In some embodiments, the electronic device 100 can include 1 or N cameras 194, where N is a positive integer greater than 1.

[0037] The electronic device 100 can realize the display function through a GPU, a display screen 195, and a processor 110. The GPU is a microprocessor 110 for image processing, which connects 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 change display information.

[0038] 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 touch screen in the display screen 195 may be a folding screen.

[0039] The battery 161 may include one or more battery cells, and the multiple battery cells may be connected in series, in parallel, or the like to supply power to the load.

[0040] The power management module 160 is used to receive charging input from a charger. The charger may be a wireless charger, such as a wireless charging base, other electronic devices with reverse wireless charging function, etc. The power management module 160 may receive wireless charging input via a wireless charging coil 162 of the electronic device 100. The charger may also be a wired charger, for example, the power management module 160 may receive charging input from a wired charger via the USB interface 150.

[0041] The processor 110 is coupled to the radio frequency transceiver 120 to implement 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 technology (IR), near field communication (NFC), etc.

[0042] Figure 2 FIG. 1 shows a schematic diagram of the structure of a radio frequency transceiver. Figure 2 As shown, the RF transceiver 120 includes a modem 210, a radio frequency integrated circuit (RFIC) 220, a radio frequency front-end module (RFFE) 230 and an antenna (ANT) 240; wherein the modem 210 is coupled to the RF chip 220, the RF chip 220 is coupled to the RF front-end module 230, and the RF front-end module 230 is coupled to the antenna 240.

[0043] The modem 210 is used to encode and decode user data (e.g., voice data, text data, and video data) or control information so as to transmit and receive through the RF transceiver 120. In some embodiments, the modem 210 may include a modulator and a demodulator. The modulator is used to modulate the low-frequency baseband signal to be transmitted into a medium-high frequency signal. The demodulator is used to demodulate the received electromagnetic wave signal into a low-frequency baseband signal and send the demodulated low-frequency baseband signal to the baseband processor 110.

[0044] The RF chip 220 (which may also be referred to as a receiver, transmitter, or transceiver) may include a transmitter (transport, TX) and a RF receiver (receive, RX). In some embodiments, the RF chip 220 may receive a baseband signal from the modem 210, process the baseband signal (e.g., up-conversion and digital-to-analog conversion) to obtain a RF signal, and send the RF signal to the RF front-end module 230 through the RF transmitter. The RF front-end module 230 may send the RF signal to the antenna 240 to achieve transmission of the RF signal. In some embodiments, the RF receiver of the RF chip 220 may receive the RF signal received from the antenna 240 through the RF front-end module 230. The RF chip 220 may process the received RF signal (e.g., down-conversion and analog-to-digital conversion) to obtain a baseband signal, and send the baseband signal to the modem 210 to achieve reception of the RF signal.

[0045] The antenna 240 is used to transmit and receive electromagnetic wave signals. The antenna 240 may be a single antenna 240 or an antenna array composed of multiple antennas 240. Each antenna 240 may be used to cover a single or multiple frequency bands, and different antennas 240 may be reused to improve the utilization of the antenna 240.

[0046] The RF front-end module 230 may include a plurality of RF processing devices such as a power amplifier (PA), a low noise amplifier (LNA), and a filter for amplifying and / or filtering RF signals. The RF transmitter and the RF receiver of the RF chip 220 may be coupled to the antenna 240 through one or more RF processing devices in the RF front-end module 230.

[0047] In some embodiments, the radio frequency transceiver device further includes a coupler, which generally includes an input terminal (input, IN), an output terminal (output, OUT), a coupling terminal (couple, CPL) and an isolation terminal (isolated, ISO). Figure 3 As shown, the RF transmitting end of the RF chip 220 is coupled to the input end of the power amplifier, the output end of the power amplifier is coupled to the input end of the coupler, the output end of the coupler is coupled to the antenna, the coupling end of the coupler is coupled to the detection end (detection, DET) of the RF chip 220, and the isolation end of the coupler is grounded.

[0048] Figure 4 A schematic diagram of the structure of a coupler 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 end 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 end 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 end of the coupler, and the second end of the second phase shift structure and the second end of the second coupling channel are both coupled to the coupling end of the coupler.

[0049] The first phase shift structure and the second phase shift structure can perform a -90° phase shift on the RF signal (i.e., a phase lag of 90°). In some examples, when the RF signal is input from the first end of the first phase shift structure (i.e., the input end of the coupler), it is phase 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 end of the coupler).

[0050] like Figure 5 As shown, in some examples, the first coupling channel and the second coupling channel can perform a φ° phase shift (i.e., a phase lag of φ°) on the RF signal. When the RF signal is input from the first end of the first phase shift structure (i.e., the input end of the coupler), the RF signal sequentially passes through the first phase shift structure, the second coupling channel, and the second phase shift structure (which can be referred to as path one) after being phase shifted by -180°+φ° (-90°+φ°-90°), and then passes through the first coupling channel (which can be referred to as path two) after being phase shifted by φ°. The RF signal passing through path one has an opposite phase to the RF signal passing through path two, and is canceled out at the first end of the second phase shift structure, so there is no output at one end of the second phase shift structure (the isolation end of the coupler).

[0051] like Figure 6As shown, in some examples, the first coupling channel and the second coupling channel can perform a φ° phase shift on the RF signal. When the RF signal is input from the first end of the first phase shift structure (i.e., the input end of the coupler), the RF signal is phase-shifted by -90°+φ° through the first phase shift structure and the second coupling channel (which can be called path three) in sequence, and is phase-shifted by φ°-90° through the first coupling channel and the second phase shift structure (which can be called path four) in sequence, and is coupled to the two 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 is superimposed at the second end of the second phase shift structure, so a small portion of the power of the RF signal can be coupled out at the two ends of the second phase shift structure (the coupling ends of the coupler).

[0052] When the RF signal is input from the input end of the coupler, part of the power is directly output from the output end, the other part of the power is coupled to the coupled end output, and the isolation end remains without output. A small part of the power of the RF signal is extracted through the coupler; for example, -20dB to -30dB (that is, one hundredth to one thousandth) and sent to the RF chip. This can not only ensure the complete transmission of the RF signal, but also monitor the RF signal and measure the signal power. This is very useful for performance monitoring and troubleshooting of RF transceivers.

[0053] like Figure 7 As shown, in some embodiments, the first phase shift structure and the second phase shift structure may use a 90° phase shift line, and the phase of the RF signal lags by 90° after passing through the first phase shift structure or the second phase shift structure. However, for RF signals with lower frequency bands, such as RF signals in the B20 or B28 frequency bands, the length of the 90° phase shift line is relatively long (usually 3 mm), resulting in the coupler needing to occupy a larger printed circuit board (PCB) area.

[0054] like Figure 8 As shown, in some other embodiments, the first phase shift structure and the second phase shift structure can be implemented by an inductor-capacitor network. Since the impedance of the capacitor and the inductor to the AC signal varies with the frequency, the inductor-capacitor network has different responses to RF signals of different frequencies. Fig. 9 The phase-frequency characteristic diagram of the inductor-capacitor network is shown in FIG. It can be seen that the higher the frequency of the RF signal, the greater the phase lag amplitude through the inductor-capacitor network.

[0055] For example, Fig.10As shown in the figure, when the RF signal is low frequency within its frequency band, the phase shift amplitude of the RF signal by the inductor-capacitor network may be -80° (i.e., the phase lags by 80°), resulting in a phase shift of -160°+φ° (-80°+φ°-80°) when passing through path 1 and a phase shift of φ° when passing through path 2. The phase difference between the RF signal passing through path 1 and the RF signal passing through path 2 is 160°, so they cannot be completely offset at the first end of the second phase shift structure, resulting in partial power of the RF signal being coupled to the isolation end of the coupler.

[0056] For example, Fig.11 As shown in the figure, when the RF signal is high frequency within its frequency band, the phase shift amplitude of the RF signal by the inductor and capacitor network may be -100° (i.e., the phase lags by 100°), resulting in the RF signal being phase shifted by -200°+φ° (-100°+φ°-100°) when passing through path 1 and φ° when passing through path 2. The phase difference between the RF signal passing through path 1 and the RF signal passing through path 2 is 200°, so they cannot be completely offset at the first end of the second phase shift structure, resulting in the coupling of part of the power of the RF signal at the isolation end of the coupler.

[0057] Fig.12 The schematic diagram of the amplitude-frequency characteristics of the coupler when the first phase shift structure and the second phase shift structure adopt an inductor-capacitor network is shown. Among them, when the frequency of the RF signal input from the input end of the coupler is 700MHz~760MHz (bandwidth 60MHz), the amplitude gain of the output end of the coupler to the RF signal is -0.02dB~-0.04dB, and the input RF signal can be output almost losslessly. The amplitude gain of the coupling end of the coupler to the RF signal is -25.91dB~-24.42dB, that is, the output power is approximately one-three-hundredth of the power of the input RF signal. The amplitude gain of the isolation end of the coupler to the RF signal is -45.02dB~-53.98dB, that is, the output power is approximately one-thirtieth to one-two-hundredth of the power of the input RF signal. However, when the frequency of the RF signal input from the input end of the coupler is less than 700MHz, or greater than 760MHz, the directivity of the coupler is less than 20dB; the directivity is the ratio of the output power of the coupling end to the output power of the isolation end. In other words, the coupler has good directivity only within a narrow bandwidth. For RF signals with a wider bandwidth (for example, the B28 band with a bandwidth of 90MHz), the coupler has poor directivity.

[0058] The embodiments of the present application provide a coupler circuit for improving the directivity of the coupler to radio frequency signals with a wider bandwidth. Fig.13 An exemplary schematic diagram of a coupler circuit is provided. Fig.13As 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. 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.

[0059] Although not shown in the drawings of the present application, those skilled in the art should understand that the coupler circuit 300 provided in the embodiment of the present application can also be 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.

[0060] There is a significant difference in the phase shift of the RF signal between the left-hand transmission line circuit 320 and the right-hand transmission line circuit 310. The RF signal will have a phase lag when passing through the right-hand transmission line circuit 310, while the RF signal will have a phase advance when passing through the left-hand transmission line circuit 320.

[0061] like Fig.14 As shown, in some examples, the first coupling circuit 330 and the second coupling circuit 340 can perform a φ° phase shift on the RF signal. Thus, when the RF signal is input from the first end of the right-hand transmission line circuit 310 (i.e., the input end of the coupler circuit 300), the RF signal is phase-shifted by -90°+φ° by the right-hand transmission line circuit 310 and the second coupling circuit 340 in sequence, and is phase-shifted by φ°+90° by the first coupling circuit 330 and the left-hand transmission line circuit 320 in sequence, and is coupled to the second end of the left-hand transmission line circuit 320 (i.e., the isolated end of the coupler circuit 300) after being phase-shifted by φ°+90°. The phase difference between the two RF signals coupled to the isolated end of the coupler circuit 300 is 180° (i.e., the phases are opposite), so they are canceled at the isolated end of the coupler circuit 300, so there is no output at the isolated end of the coupler circuit 300 (i.e., the second end of the left-hand transmission line circuit 320).

[0062] like Fig.15As shown, in some examples, the first coupling circuit 330 and the second coupling circuit 340 can perform a φ° phase shift on the RF signal. Thus, when the RF signal is input from the first end of the right-hand transmission line circuit 310 (i.e., the input end of the coupler circuit 300), the RF signal is phase-shifted by φ° (-90°+φ°+90°) by the right-hand transmission line circuit 310, the second coupling circuit 340, and the left-hand transmission line circuit 320 in sequence, and then phase-shifted by φ° by the first coupling circuit 330 in sequence, and then 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., the phases are the same), so they are superimposed at the coupling end of the coupler circuit 300, so that the coupling end of the coupler circuit 300 (i.e., the first end of the left-hand transmission line circuit 320) can couple out a small portion of the power of the RF signal.

[0063] Fig.16 FIG. 3 shows a schematic diagram of the phase-frequency characteristics of the left-hand transmission line circuit 320 and the right-hand transmission line circuit 310. Fig.16 As shown, the higher the frequency of the RF signal, the greater the phase lag amplitude of the RF signal passing through the right-hand transmission line circuit 310, and the smaller the phase advance amplitude of the RF 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 within a wider bandwidth. The embodiment of the present application uses the technical solution of matching the right-hand transmission line circuit 310 with the left-hand transmission line circuit 320, thereby improving the directivity of the coupler to the RF signal with a wider bandwidth.

[0064] For example, Fig.16 and Fig.17 As shown, when the RF signal is low frequency within its frequency band, the phase shift amplitude of the right-hand transmission line circuit 310 to the RF signal is -80° (i.e., the phase lags by 80°), while the phase shift amplitude of the left-hand transmission line circuit 320 to the RF signal is +100° (i.e., the phase leads by 100°). Therefore, when the RF signal is input from the first end of the right-hand transmission line circuit 310 (i.e., the input end of the coupler circuit 300), the RF signal is phase-shifted by -80°+φ° by the right-hand transmission line circuit 310 and the second coupling circuit 340 in sequence, and is phase-shifted by φ°+100° by the first coupling circuit 330 and the left-hand transmission line circuit 320 in sequence, and then 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 isolated end of the coupler circuit 300 is 180° (i.e., opposite phases), and thus they are canceled out at the isolated end of the coupler circuit 300. Therefore, the isolated end of the coupler circuit 300 (i.e., the second end of the left-hand transmission line circuit 320) has no output.

[0065] For example, Fig.16 and Fig.18 As shown, when the RF signal is biased towards high frequency within its frequency band, the phase shift amplitude of the right-hand transmission line circuit 310 to the RF signal is -100° (i.e., the phase lags by 100°), while the phase shift amplitude of the left-hand transmission line circuit 320 to the RF signal is +80° (i.e., the phase leads by 80°). Therefore, when the RF signal is input from the first end of the right-hand transmission line circuit 310 (i.e., the input end of the coupler circuit 300), the RF signal is phase-shifted by -100°+φ° by the right-hand transmission line circuit 310 and the second coupling circuit 340 in sequence, and is phase-shifted by φ°+80° by the first coupling circuit 330 and the left-hand transmission line circuit 320 in sequence, and then 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 isolated end of the coupler circuit 300 is also 180° (i.e., opposite phases), and thus they are canceled out at the isolated end of the coupler circuit 300. Therefore, the isolated end of the coupler circuit 300 (i.e., the second end of the left-hand transmission line circuit 320) has no output.

[0066] like Fig.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 end of the first inductor L1 and the first end of the first capacitor C1 are both connected to the first end of the right-hand transmission line circuit 310, and the second end of the first inductor L1 and the first end of the second capacitor C2 are both connected to the second end of the right-hand transmission line circuit 310. The second end of the first capacitor C1 is grounded, and the second end of the second capacitor C2 is grounded. In other words, 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.

[0067] The left-hand transmission line circuit 320 includes a fourth inductor L4, a fifth inductor L5, and a fourth capacitor C4. The first end of the fourth capacitor C4 and the first end of the fourth inductor L4 are both connected to the first end of the left-hand transmission line circuit 320, and the second end of the fourth capacitor C4 and the first end of the fifth inductor L5 are both connected to the second end of the left-hand transmission line circuit 320. The second end of the fourth inductor L4 is grounded, and the second end of the fifth inductor L5 is grounded. That is, 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.

[0068] 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=10.5nH), and the capacitance values ​​of the first capacitor C1, the second capacitor C2, and the fourth capacitor C4 are all 4.3 pF (i.e., C1=C2=C4=4.3pF). Thus, 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 : .

[0069] Fig. 20 The schematic diagram of the trajectory of the right-hand transmission line circuit 310 and the left-hand transmission line circuit 320 on the Smith chart shows that when the frequency of the RF signal is 750 MHz, the complex impedance of the right-hand transmission line circuit 310 is Z0 (0.980 + j0.001), and the imaginary part of the complex impedance is almost zero, which is 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), and the imaginary part of the complex impedance is almost zero, which is also located at the center point of the Smith chart. Among them, Z0 is the matching resistance. In other words, the right-hand transmission line circuit 310 and the left-hand transmission line circuit 320 present the characteristics of pure resistance to the RF signal with a frequency of 750 MHz.

[0070] Fig.21 The schematic diagram of the amplitude-frequency characteristics of the coupler circuit 300 provided in the embodiment of the present application is shown. Among them, when the frequency of the RF signal input from the input end of the coupler circuit 300 is 700MHz~800MHz (bandwidth 100MHz), the amplitude gain of the output end of the coupler circuit 300 to the RF signal is 0.68dB~-0.66dB. The amplitude gain of the coupling end of the coupler circuit 300 to the RF signal is -24.68dB~-24.52dB, that is, the output power is approximately one three hundredth of the power of the input RF signal. The amplitude gain of the isolation end of the coupler circuit 300 to the RF signal is -47.81dB~-64.19dB, that is, the output power is approximately one fifty-thousandth to one two-and-a-half millionth of the power of the input RF signal. The directivity of the coupler circuit 300 within a bandwidth of 100MHz is greater than 20dB. That is to say, the coupler circuit 300 provided in the embodiment of the present application has good directivity within a wider bandwidth.

[0071] like Fig. 22As shown, in other embodiments, the right-hand transmission line circuit 310 includes a second inductor L2, a third inductor L3 and a third capacitor C3. The first end of the second inductor L2 is connected to the first end of the right-hand transmission line circuit 310, the second end of the second inductor L2 is connected to the first end of the third inductor L3 and the first end of the third capacitor C3 respectively, the second end of the third inductor L3 is connected to the second end of the right-hand transmission line circuit 310, and the second end of the third capacitor C3 is grounded. In other words, 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.

[0072] The left-hand transmission line circuit 320 includes a fifth capacitor C5, a sixth capacitor C6, and a sixth inductor L6. The first end of the fifth capacitor C5 is connected to the first end of the left-hand transmission line circuit 320, the second end of the fifth capacitor C5 is connected to the first end of the sixth capacitor C6 and the first end of the sixth inductor L6, respectively, the second end of the sixth capacitor C6 is connected to the second end of the left-hand transmission line circuit 320, and the second end of the sixth inductor L6 is grounded. That is, 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.

[0073] like Fig.23 As shown, in 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. The embodiment of the present 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.

[0074] Please continue to refer to Fig.19 In some implementations, the first coupling circuit 330 includes a seventh capacitor C7, a first end of the seventh capacitor C7 is connected to the first end of the first coupling circuit 330, and a second end of the seventh capacitor C7 is connected to the second end of the first coupling circuit 330. And / or, the second coupling circuit 340 includes an eighth capacitor C8, a first end of the eighth capacitor C8 is connected to the first end of the second coupling circuit 340, and a second end of the eighth capacitor C8 is connected to the second end of the second coupling circuit 340.

[0075] In some embodiments, the capacitance value of the seventh capacitor C7 is equal to the capacitance value of the eighth capacitor C8. In order to reduce the coupling degree of the coupler circuit 300, the capacitance values ​​of the seventh capacitor C7 and the eighth capacitor C8 can 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).

[0076] Please continue to refer to Fig.24 In some embodiments, the first coupling circuit 330 includes a seventh inductor L7, a first end of the seventh inductor L7 is connected to the first end of the first coupling circuit 330, and a second end of the seventh inductor L7 is connected to the second end of the first coupling circuit 330. And / or, the second coupling circuit 340 includes an eighth inductor L8, a first end of the eighth inductor L8 is connected to the first end of the second coupling circuit 340, and a second end of the eighth inductor L8 is connected to the second end of the second coupling circuit 340.

[0077] In some embodiments, the inductance of the seventh inductor L7 is equal to the inductance of the eighth inductor L8. In order to reduce the coupling degree of the coupler circuit 300, the inductance of the seventh inductor L7 and the eighth inductor L8 can be greater than the inductance of the first inductor L1; for example, the inductance of the seventh inductor L7 and the eighth inductor L8 is 100 nanohenry (ie, L7=L8=100nH).

[0078] In a second aspect, a circuit board assembly is provided. The circuit board assembly includes a printed circuit board (not shown) and Fig.19 and Figure 22 to Figure 24 In any of the coupler circuits 300 shown in FIG, the coupler circuit 300 is disposed on a printed circuit board. The coupler circuit 300 provided in the embodiment of the present application is composed of discrete structures such as an inductor and a capacitor.

[0079] In some embodiments, the inductor is a 01005 size chip inductor, the capacitor is a 01005 size chip capacitor, and the size of the 01005 size chip capacitor and the 01005 size chip inductor are both 0.4 mm×0.2 mm. The various components in the coupler circuit 300 can be arranged on the surface of a printed circuit board; for example, Fig.19 The first capacitor C1, the second capacitor C2, the fourth capacitor C4, the seventh capacitor C7, the eighth capacitor C8, the first inductor L1, the fourth inductor L4 and the fifth inductor L5 in the coupler circuit 300 can be configured as follows: Fig.25The layout shown is arranged on the surface of the printed circuit board on one side close to the printed circuit board. In addition to the gaps between the components, the coupler circuit 300 provided in the embodiment of the present application occupies approximately 1.5 mm×1.5 mm of the printed circuit board area, thereby reducing the printed circuit board area by 50% and only occupying the surface layer of the printed circuit board, making the inner layer routing of the printed circuit board more convenient.

[0080] In one embodiment, the printed circuit board is a multi-layer printed circuit board, the left-hand transmission line circuit 320 in the coupler circuit 300 is arranged on the first layer of the printed circuit board, and the right-hand transmission line circuit 310 in the coupler circuit 300 is arranged on the second layer of the printed circuit board, and 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, and the seventh capacitor C7 and the eighth capacitor C8 are both parasitic capacitors between the first layer and the second layer. Thereby, the area of ​​the printed circuit board can be further reduced.

[0081] The present application also provides an electronic device, which includes a power amplifier, an antenna, a radio frequency chip and Fig.25 The circuit board assembly shown is coupled to the power amplifier, the antenna and the radio frequency chip respectively.

[0082] In an embodiment of the present application, a coupler circuit and a circuit board assembly are provided. The coupler circuit adopts a technical solution of cooperating a right-hand transmission line circuit with a left-hand transmission line circuit, and there is a significant difference in the phase shift of the radio frequency signal between the left-hand transmission line circuit and the right-hand transmission line circuit. The radio frequency signal will have a phase lag when passing through the right-hand transmission line circuit, and the radio frequency signal will have a phase advance when passing through the left-hand transmission line circuit. In addition, the higher the frequency of the radio frequency signal, the greater the phase lag amplitude of the radio frequency signal passing through the right-hand transmission line circuit, and the smaller the phase advance amplitude of the radio frequency signal passing through the left-hand transmission line circuit. In an embodiment of the present application, a stable phase difference can be maintained within a wider bandwidth through the left-hand transmission line circuit and the right-hand transmission line circuit, thereby improving the directivity of the coupler to radio frequency signals with a wider bandwidth.

[0083] In the several embodiments provided in the present 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 only schematic. For example, the division of the modules is only a logical function division. There may be other division methods in actual implementation, such as multiple modules or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0084] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical modules, that is, they may be located in one device or distributed on multiple devices. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present embodiment.

[0085] In addition, each functional module in each embodiment of the present application may be integrated into one device, or each module may exist physically separately, or two or more modules may be integrated into one device.

[0086] In the above embodiments, all or part of the embodiments may be implemented by software, hardware, firmware or any combination thereof. When implemented by software programs, all or part of the embodiments may be implemented in the form of computer program products.

[0087] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection 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, a second coupling circuit, an input terminal, an output terminal, a coupling terminal and an isolation terminal; A first end of the first coupling circuit is connected to a first end of the right-hand transmission line circuit, and a second end of the first coupling circuit is connected to a first end of the left-hand transmission line circuit; A first end of the second coupling circuit is connected to a second end of the right-hand transmission line circuit, and a second end of the second coupling circuit is connected to a second end of the left-hand transmission line circuit; The input terminal is connected to the first terminal of the right-hand transmission line circuit, the output terminal is connected to the second terminal of the right-hand transmission line circuit, the coupling terminal is connected to the first terminal of the left-hand transmission line circuit, and the output terminal is connected to the second terminal of the left-hand transmission line circuit; or, 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.

2. The coupler circuit according to claim 1, characterized in that The right-hand transmission line circuit includes a first inductor, a first capacitor and a second capacitor; A first end of the first inductor and a first end of the first capacitor are both connected to a first end of the right-hand transmission line circuit, and a second end of the first inductor and a first end of the second capacitor are both connected to a second end of the right-hand transmission line circuit; A second terminal of the first capacitor is grounded, and a second terminal of the second capacitor is grounded.

3. The coupler circuit according to claim 1, 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 is connected to the first end of the right-hand transmission line circuit, the second end of the second inductor is respectively connected to the first end of the third inductor and the first end of the third capacitor, the second end of the third inductor is connected to the second end of the right-hand transmission line circuit, and the second end of the third capacitor is grounded.

4. The coupler circuit according to any one of claims 1 to 3, characterized in that: The left-hand transmission line circuit includes a fourth inductor, a fifth inductor and a fourth capacitor; A first end of the fourth capacitor and a first end of the fourth inductor are both connected to a first end of the left-hand transmission line circuit, and a second end of the fourth capacitor and a first end of the fifth inductor are both connected to a second end of the left-hand transmission line circuit; A second end of the fourth inductor is grounded, and a second end of the fifth inductor is grounded.

5. The coupler circuit according to any one of claims 1 to 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 is connected to the first end of the left-hand transmission line circuit, the second end of the fifth capacitor is respectively connected to the first end of the sixth capacitor and the first end of the sixth inductor, the second end of the sixth capacitor is connected to the second end of the left-hand transmission line circuit, and the second end of the sixth inductor is grounded.

6. The coupler circuit according to claim 1, characterized in that The first coupling circuit comprises a seventh capacitor, a first end of the seventh capacitor is connected to the first end of the first coupling circuit, and a second end of the seventh capacitor is connected to the second end of the first coupling circuit; and / or, The second coupling circuit includes an eighth capacitor, a first end of the eighth capacitor is connected to the first end of the second coupling circuit, and a second end of the eighth capacitor is connected to the second end of the second coupling circuit.

7. The coupler circuit according to claim 1, characterized in that The first coupling circuit comprises a seventh inductor, a first end of the seventh inductor is connected to a first end of the first coupling circuit, and a second end of the seventh inductor is connected to a second end of the first coupling circuit; and / or, The second coupling circuit includes an eighth inductor, a first end of the eighth inductor is connected to the first end of the second coupling circuit, and a second end of the eighth inductor is connected to the second end of the second coupling circuit.

8. A circuit board assembly, characterized in that: It comprises a printed circuit board and the coupler circuit according to any one of claims 1 to 7, wherein the coupler circuit is arranged on the printed circuit board.

9. The circuit board assembly according to claim 8, characterized in that: The coupler circuit is disposed on a surface of the printed circuit board.

10. The circuit board assembly according to claim 8, characterized in that: The printed circuit board is a multi-layer printed circuit board, the left-hand transmission line circuit in the coupler circuit is arranged on a first layer of the printed circuit board, and the right-hand transmission line circuit in the coupler circuit is arranged on a second layer of the printed circuit board, and the first layer and the second layer are adjacent; A first coupling circuit of the coupler circuits includes a seventh capacitor, and a second coupling circuit of the coupler circuits includes an eighth capacitor; The seventh capacitor and the eighth capacitor are both parasitic capacitors between the first layer and the second layer.

11. The circuit board assembly according to any one of claims 8 to 10, characterized in that: The coupler circuit is disposed adjacent to one side of the printed circuit board.

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