A coupler circuit and a circuit board assembly

Abstract

The application provides a coupler circuit and a circuit board assembly, and belongs to the field of radio frequency technology. The coupler circuit comprises a right-handed transmission line circuit, a left-handed 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 with the first end of the right-handed transmission line circuit, and the second end of the first coupling circuit is connected with the first end of the left-handed transmission line circuit. The first end of the second coupling circuit is connected with the second end of the right-handed transmission line circuit, and the second end of the second coupling circuit is connected with the second end of the left-handed transmission line circuit. The left-handed transmission line circuit and the right-handed transmission line circuit can maintain a stable phase difference in a wide bandwidth, and the directivity of the coupler to the radio frequency signal in the wide bandwidth can be improved.

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

[0002] In a radio frequency system, the transmission power of a radio frequency signal can be monitored by a coupler (for example, a branch directional coupler). The coupling degree, isolation degree and directivity of the coupler are important indicators. At present, the directivity of the coupler for a radio frequency signal with a large bandwidth is poor. SUMMARY

[0003] Embodiments of the present application provide a coupler circuit and a circuit board assembly, which are used to improve the directivity of the coupler within the bandwidth of a radio frequency signal.

[0004] To achieve the above-mentioned purpose, embodiments of the present application adopt the following technical solutions:

[0005] In a first aspect, a coupler circuit is provided. The coupler circuit includes a right-handed transmission line circuit, a left-handed 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 end of the first coupling circuit is connected to the first end of the right-handed transmission line circuit, and the second end of the first coupling circuit is connected to the first end of the left-handed transmission line circuit. The first end of the second coupling circuit is connected to the second end of the right-handed transmission line circuit, and the second end of the second coupling circuit is connected to the second end of the left-handed transmission line circuit. The input terminal is connected to the first end of the right-handed transmission line circuit, the output terminal is connected to the second end of the right-handed transmission line circuit, the coupling terminal is connected to the first end of the left-handed transmission line circuit, and the output terminal is connected to the second end of the left-handed transmission line circuit. Alternatively, the input terminal is connected to the first end of the left-handed transmission line circuit, the output terminal is connected to the second end of the left-handed transmission line circuit, the coupling terminal is connected to the first end of the right-handed transmission line circuit, and the output terminal is connected to the second end of the right-handed transmission line circuit.

[0006] The embodiments of the present application adopt the technical solution that the right-handed transmission line circuit cooperates with the left-handed transmission line circuit. There is a significant difference between the left-handed transmission line circuit and the right-handed transmission line circuit in phase shifting of a radio frequency signal. The radio frequency signal will lag in phase after passing through the right-handed transmission line circuit, while the radio frequency signal will lead in phase after passing through the left-handed transmission line circuit. Moreover, the higher the frequency of the radio frequency signal is, the greater the phase lag amplitude of the radio frequency signal after passing through the right-handed transmission line circuit is, and the smaller the phase lead amplitude of the radio frequency signal after passing through the left-handed transmission line circuit is. The left-handed transmission line circuit and the right-handed transmission line circuit can maintain a stable phase difference within a wide bandwidth, thereby improving the directivity of the coupler for a radio frequency signal with a wide bandwidth.

[0007] In some possible implementations, the right-handed 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-handed 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-handed transmission line circuit. A second end of the first capacitor is grounded, and a second end of the second capacitor is grounded. The right-handed transmission line circuit can employ a Π-type LC circuit, and the separate arrangement of the capacitors and the inductors helps to reduce the area of the printed circuit board.

[0008] In some possible implementations, the right-handed transmission line circuit includes a second inductor, a third inductor and a third capacitor. A first end of the second inductor is connected to a first end of the right-handed transmission line circuit, a second end of the second inductor is connected to a first end of the third inductor and a first end of the third capacitor respectively, a second end of the third inductor is connected to a second end of the right-handed transmission line circuit, and a second end of the third capacitor is grounded. The right-handed transmission line circuit can employ a T-type LC circuit, and the separate arrangement of the capacitors and the inductors helps to reduce the area of the printed circuit board.

[0009] In some possible implementations, the left-handed 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-handed 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-handed transmission line circuit. A second end of the fourth inductor is grounded, and a second end of the fifth inductor is grounded. The left-handed transmission line circuit can employ a Π-type LC circuit, and the separate arrangement of the capacitors and the inductors helps to reduce the area of the printed circuit board.

[0010] In some possible implementations, the left-handed transmission line circuit includes a fifth capacitor, a sixth capacitor and a sixth inductor. A first end of the fifth capacitor is connected to a first end of the left-handed transmission line circuit, a second end of the fifth capacitor is connected to a first end of the sixth capacitor and a first end of the sixth inductor respectively, a second end of the sixth capacitor is connected to a second end of the left-handed transmission line circuit, and a second end of the sixth inductor is grounded. The left-handed transmission line circuit can employ a T-type LC circuit, and the separate arrangement of the capacitors and the inductors helps to reduce the area of the printed circuit board.

[0011] In some possible implementation manners, the first coupling circuit includes a seventh capacitor, a first end of the seventh capacitor being connected with the first end of the first coupling circuit, and a second end of the seventh capacitor being connected with 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 being connected with the first end of the second coupling circuit, and a second end of the eighth capacitor being connected with the second end of the second coupling circuit. The coupling circuit is implemented by using the capacitor, which helps to reduce the coupling degree of the coupler circuit, thereby reducing the influence on the output power of the output end of the coupler circuit, and further reducing the area of the printed circuit board.

[0012] In some possible implementation manners, the first coupling circuit includes a seventh inductor, a first end of the seventh inductor being connected with the first end of the first coupling circuit, and a second end of the seventh inductor being connected with the second end of the first coupling circuit. And / or, the second coupling circuit includes an eighth inductor, a first end of the eighth inductor being connected with the first end of the second coupling circuit, and a second end of the eighth inductor being connected with the second end of the second coupling circuit. The coupling circuit is implemented by using the inductor, which also helps to reduce the coupling degree of the coupler circuit, thereby reducing the influence on the output power of the output end of the coupler circuit, and further reducing the area of the printed circuit board.

[0013] In the third aspect, an electronic device is provided. The electronic device includes a power amplifier, an antenna, a radio frequency chip, and the circuit board assembly of any one of the second aspect. The circuit board assembly is coupled with the power amplifier, the antenna, and the radio frequency chip, respectively.

[0014] In some possible implementation manners, the coupler circuit is arranged on the surface of the printed circuit board, so that the inner layer wiring of the printed circuit board is also more convenient.

[0015] In some possible implementation manners, the printed circuit board is a multi-layer printed circuit board, the left-handed transmission line circuit in the coupler circuit is arranged on a first layer of the printed circuit board, the right-handed 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. 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. The seventh capacitor and the eighth capacitor are both parasitic capacitances between the first layer and the second layer.

[0016] In some possible implementation manners, the coupler circuit is arranged close to one side of the printed circuit board.

[0017] In the third aspect, an electronic device is provided. The electronic device includes a power amplifier, an antenna, a radio frequency chip, and the circuit board assembly of any one of the second aspect. The circuit board assembly is coupled with the power amplifier, the antenna, and the radio frequency chip, respectively.

[0018] It should be understood that the technical effects of the second aspect and the third aspect can refer to the technical effects of the first aspect and any of the embodiments thereof, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 A structural schematic diagram of an electronic device provided by an embodiment of the present application;

[0020] Figure 2 A structural schematic diagram of a radio frequency transceiver provided by an embodiment of the present application;

[0021] Figure 3 A connection structural schematic diagram of a coupler in a radio frequency transceiver provided by an embodiment of the present application;

[0022] Figure 4 A structural schematic diagram of a coupler provided by an embodiment of the present application;

[0023] Figure 5 A path schematic diagram of a radio frequency signal from an input end to an isolation end in a coupler provided by an embodiment of the present application;

[0024] Figure 6 A path schematic diagram of a radio frequency signal from an input end to a coupling end in a coupler provided by an embodiment of the present application;

[0025] Figure 7 An occupied area schematic diagram of a coupler on a printed circuit board when the coupler is implemented by a 90° phase shift line provided by an embodiment of the present application;

[0026] Figure 8 A structural schematic diagram of a coupler implemented by an inductance-capacitance network provided by an embodiment of the present application;

[0027] Figure 9 A phase frequency characteristic schematic diagram of an inductance-capacitance network provided by an embodiment of the present application;

[0028] Figure 10 A phase schematic 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 at a low frequency;

[0029] Figure 11 A phase schematic 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 at a high frequency;

[0030] Figure 12 An amplitude frequency characteristic schematic diagram of the isolation end, the coupling end and the output end of a coupler provided by an embodiment of the present application;

[0031] Figure 13 A structural schematic diagram of a coupler circuit provided by an embodiment of the present application;

[0032] Figure 14 A schematic diagram of a path for a radio frequency signal to travel from the input end to the isolation end in a coupler circuit according to an embodiment of the application;

[0033] Figure 15 A schematic diagram of a path for a radio frequency signal to travel from the input end to the coupling end in a coupler circuit according to an embodiment of the application;

[0034] Figure 16 A schematic diagram of the phase-frequency characteristic of a right-handed transmission line circuit and a left-handed transmission line circuit according to an embodiment of the application;

[0035] Figure 17 A schematic diagram of the phase of a radio frequency signal at the isolation end of a coupler circuit according to an embodiment of the application at a low frequency;

[0036] Figure 18 A schematic diagram of the phase of a radio frequency signal at the isolation end of a coupler circuit according to an embodiment of the application at a high frequency;

[0037] Figure 19 A schematic diagram of the structure of a first coupler circuit according to an embodiment of the application;

[0038] Figure 20 A schematic diagram of the impedance locus of a right-handed transmission line circuit and a left-handed transmission line circuit according to an embodiment of the application on a Smith chart;

[0039] Figure 21 A schematic diagram of the amplitude-frequency characteristic of a coupler circuit according to an embodiment of the application;

[0040] Figure 22 A schematic diagram of the structure of a second coupler circuit according to an embodiment of the application;

[0041] Figure 23 A schematic diagram of the structure of a third coupler circuit according to an embodiment of the application;

[0042] Figure 24 A schematic diagram of the structure of a fourth coupler circuit according to an embodiment of the application;

[0043] Figure 25 A schematic diagram of the layout of a coupler circuit according to an embodiment of the application on a printed circuit board.

[0044] 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

[0045] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0046] 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.

[0047] The terms "exemplary" or "for example" in the embodiments of this application are used to indicate examples, illustrations, or descriptions. Any embodiment or design described in this application as "exemplary" or "for example" should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0048] The terms "coupling" and "connection" involved in the embodiments of this application should be understood in a broad sense. For example, they may 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.

[0049] Embodiments of the present application provide an electronic device, which can be fixed or mobile. In addition, the electronic device can 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 apparatus, etc. For example, the electronic device can be a mobile phone, a pad, a desktop computer, a notebook computer, an all-in-one machine, 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 smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in 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 land mobile network (PLMN), etc.

[0050] Taking the electronic device as a mobile phone as an example, Figure 1A possible structure of an electronic device is shown. The electronic device 100 can include a processor 110, an external memory interface 130, an internal memory 140, a universal serial bus (USB) interface (hereinafter referred to as a 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 key 191, a motor 192, an indicator 193, a camera 194, a display 195, and a subscriber identification module (SIM) card interface (hereinafter referred to as a SIM card interface 196), etc.

[0051] Among them, the sensor module 180 can include a pressure sensor, a gyroscope sensor, a barometric 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, etc.

[0052] It can be understood that the interface connection relationship between the modules shown in the embodiments of the present application is only illustrative and does not constitute a specific limitation on the electronic device 100. In some other embodiments of the present application, the electronic device 100 can include more or fewer components than shown, or combine certain components, or split certain components, or different component arrangements. The components shown can be implemented in hardware, software, or a combination of software and hardware.

[0053] In some examples, the processor 110 can include one or more processing units; where the processing units can 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, a neural-network processing unit (NPU), etc. In some examples, different processing units can be independent devices; for example, the processor 110 can be a baseband processor. In some examples, the processor 110 can also be a system on chip (SoC) integrated with multiple processing units.

[0054] The memory in the processor 110 can also be configured to store computer instructions and data. In some embodiments, the memory in the processor 110 is a cache. The memory can store computer instructions or data that the processor 110 has just used or repeatedly used. If the processor 110 needs to use the computer instructions or data again, it can directly call from the memory. This avoids repeated access and reduces the waiting time of the processor 110, thereby improving the efficiency of the system.

[0055] The external memory interface 130 can be used to connect an external storage card, such as a micro SanDisk (Micro SD) card, to expand the storage capacity of the electronic device 100. The external storage card communicates with the processor 110 through the external memory interface 130 to realize the data storage function. For example, music, video, and other files are saved in the external storage card.

[0056] The internal memory 140 can be used to store computer executable program codes including computer instructions. The processor 110 performs various functional applications of the electronic device 100 and data processing by executing the computer instructions stored in the internal memory 140. In addition, the internal memory 140 can include a high-speed random access memory, and can further include a non-volatile memory such as at least one of a magnetic disk storage device, a flash memory device, a universal flash storage (UFS), etc.

[0057] The memory to which embodiments of the present application are directed can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories. Among them, the non-volatile memory can be a read-only memory (ROM), a programmable ROM (PROM), an erasable PROM (EPROM), an electrically EPROM (EEPROM), or a flash memory. The volatile memory can be a random access memory (RAM) used as an external cache. By way of example and not limitation, many forms of RAM can be used, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synch link DRAM (SLDRAM), and direct ram bus RAM (DR RAM). It should be noted that the memory of the system and method described herein is intended to include, but not be limited to, these and any other suitable types of memory.

[0058] The audio module 170 can include a speaker, a receiver, a microphone, and a headphone interface, and the electronic device 100 can implement audio functions through the audio module 170 and the processor 110, etc. For example, music playback, recording, etc.

[0059] The audio module 170 is configured to convert digital audio information into an analog audio signal output, and to convert an analog audio input into a digital audio signal. In some embodiments, the audio module 170 can be disposed in the processor 110, or some functional modules of the audio module 170 can be disposed in the processor 110. A speaker, also referred to as a "loudspeaker", is configured to convert an audio electrical signal into a sound signal. A receiver, also referred to as a "earpiece", is configured to convert an audio electrical signal into a sound signal. A microphone, also referred to as a "microphone", "microphone", is configured to convert a sound signal into an electrical signal. The electronic device 100 can be provided with at least one microphone. An earphone interface is configured to connect a wired earphone. The earphone interface can be a USB interface 150, or a 3.5mm open mobile terminal platform (OMTP) standard interface, a cellular telecommunications industry association of the USA (CTIA) standard interface.

[0060] The keys 191 include a power key, a volume key, and the like. The keys 191 can be mechanical keys 191. Alternatively, the keys 191 can be touch keys. The electronic device 100 can receive a key 191 input, and generate a key signal input related to user settings and function control of the electronic device 100. The motor 192 can generate a vibration prompt. The motor 192 can be used for incoming call vibration prompts, and can also be used for touch vibration feedback. The indicator 193 can be an indicator light, and can be used to indicate a charging state, a power change, and can also be used to indicate a message, a missed call, a notification, and the like. The SIM card interface 196 is configured 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, N being a positive integer greater than 1. The SIM card interface 196 can support a Nano SIM card, a Micro SIM card, a SIM card, and the like. In some embodiments, the electronic device 100 uses an embedded SIM (eSIM) card, which can be embedded in the electronic device 100 and cannot be separated from the electronic device 100.

[0061] The electronic device 100 can implement a photographing function through an ISP, a camera 194, a video codec, a GPU, a display screen 195, and a processor 110, and the like. The ISP is configured to process data fed back by the camera 194. In some embodiments, the ISP can be disposed in the camera 194. The camera 194 is configured to capture a still image or a video. In some embodiments, the electronic device 100 can include one or N cameras 194, N being a positive integer greater than 1.

[0062] The electronic device 100 can implement a display function through a GPU, a display screen 195, and a processor 110, etc. The GPU is a microprocessor 110 for image processing, connecting the display screen 195 and the processor 110. The GPU is used to perform mathematical and geometric calculations for graphics rendering. The processor 110 can include one or more GPUs that execute computer instructions to generate or change display information.

[0063] 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 can include 1 or more display screens 195. In other embodiments, the touch screen in the display screen 195 can be a folding screen.

[0064] The battery 161 can include one or more battery cells, and the plurality of battery cells can be connected in series, in parallel, etc. to supply power to the load.

[0065] The power management module 160 is used to receive charging input from a charger. The charger can be a wireless charger, such as a wireless charging base, other electronic devices with reverse wireless charging function, etc. The power management module 160 can receive wireless charging input through 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 the wired charger through the USB interface 150.

[0066] The processor 110 is coupled with 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 can 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.

[0067] Figure 2 A structural schematic diagram of a radio frequency transceiver is shown. As shown in the figure, Figure 2 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 with the RFIC 220, the RFIC 220 is coupled with the RFFE 230, and the RFFE 230 is coupled with the antenna 240.

[0068] The modem 210 is configured to encode and decode user data (e.g., voice data, text data, and video data) or control information for transmission and reception by the radio transceiver 120. In some embodiments, the modem 210 can include a modulator and a demodulator. The modulator is configured to modulate a low-frequency baseband signal to be transmitted into a medium-high frequency signal. The demodulator is configured to demodulate a received electromagnetic wave signal into a low-frequency baseband signal and send the demodulated low-frequency baseband signal to the baseband processor 110.

[0069] The radio chip 220 (also referred to as a receiver, a transmitter, or a transceiver) can include a transport (TX) and a radio receive (RX). In some embodiments, the radio chip 220 can receive a baseband signal from the modem 210, process the baseband signal (e.g., up-convert and digital-to-analog conversion) to obtain a radio frequency signal, and send the radio frequency signal to the radio front-end module 230 through the radio frequency transmission end, which can send the radio frequency signal to the antenna 240 to realize the transmission of the radio frequency signal. In some embodiments, the radio frequency receiving end of the radio chip 220 can receive a radio frequency signal received by the antenna 240 through the radio front-end module 230, and the radio chip 220 can process the received radio frequency signal (e.g., down-convert and analog-to-digital conversion) to obtain a baseband signal, and send the baseband signal to the modem 210 to realize the reception of the radio frequency signal.

[0070] The antenna 240 is configured to transmit and receive electromagnetic wave signals. The antenna 240 can be a single antenna 240, or an antenna array composed of multiple antennas 240. Each antenna 240 can be used to cover a single or multiple frequency bands, and different antennas 240 can be multiplexed to improve the utilization of the antenna 240.

[0071] The radio front-end module 230 can include a power amplifier (PA), a low noise amplifier (LNA), and a filter, and other radio frequency processing devices for amplifying and / or filtering the radio frequency signal. The radio frequency transmission end and the radio frequency receiving end of the radio chip 220 can be coupled to the antenna 240 through one or more radio frequency processing devices in the radio front-end module 230.

[0072] In some embodiments, the radio transceiver further includes a coupler, which generally includes an input (IN), an output (OUT), a coupling end (CPL), and an isolated end (ISO). As shown in FIG. 1, the coupler can be coupled to the radio chip 220 and the baseband processor 110.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.

[0073] Figure 4 A schematic diagram of the structure of a coupler is shown. Figure 4 As shown, the coupler includes a first phase-shifting structure, a second phase-shifting structure, a first coupling channel, and a second coupling channel. The first end of the first phase-shifting 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-shifting 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-shifting 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-shifting structure and the second end of the second coupling channel are both coupled to the coupling end of the coupler.

[0074] The first and second phase-shifting structures can perform a -90° phase shift on the RF signal (i.e., a 90° phase lag). In some examples, when the RF signal is input through the first end of the first phase-shifting structure (i.e., the input end of the coupler), it undergoes a -90° phase shift by the first phase-shifting structure and is then output through the second end of the first phase-shifting structure (i.e., the output end of the coupler).

[0075] 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 an RF signal is input from the first end of the first phase-shifting structure (i.e., the input end of the coupler), the RF signal sequentially passes through the first phase-shifting structure, the second coupling channel, and the second phase-shifting 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 and path two have opposite phases and cancel each other out at the first end of the second phase-shifting structure. Consequently, no output is generated at one end of the second phase-shifting structure (the isolation end of the coupler).

[0076] 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-shifting structure (i.e., the input end of the coupler), the RF signal is phase-shifted by -90°+φ° through the first phase-shifting structure and the second coupling channel (which can be referred to as path three), and then by φ°-90° through the first coupling channel and the second phase-shifting structure (which can be referred to as path four), before being coupled to the two ends of the second phase-shifting structure. The RF signal passing through path three and path four have the same phase and are superimposed at the second end of the second phase-shifting structure. As a result, a small portion of the RF signal's power can be coupled out of the two ends of the second phase-shifting structure (the coupling end of the coupler).

[0077] When an RF signal is input to the coupler's input, a portion of the power is directly output from the output, while another portion is coupled to the coupled output. The isolator remains idle. The coupler extracts a small portion of the RF signal's power—for example, -20dB to -30dB (1 / 100 to 1 / 1000)—and feeds it to the RF chip. This ensures complete RF signal transmission and allows for signal monitoring and power measurement. This is extremely useful for performance monitoring and troubleshooting of RF transceivers.

[0078] like Figure 7 As shown, in some embodiments, the first and second phase-shift structures can utilize 90° phase-shift lines. The RF signal lags in phase by 90° after passing through the first or second phase-shift structures. However, for lower-frequency RF signals, such as those in the B20 or B28 bands, the 90° phase-shift lines are relatively long (typically 3 mm), resulting in the coupler requiring a larger printed circuit board (PCB) area.

[0079] like Figure 8 As shown, in 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 the capacitor and the inductor to the AC signal changes with the frequency, the inductor-capacitor network has different responses to RF signals of different frequencies. Figure 9 The phase-frequency characteristic diagram of the LC network is shown in Figure 1. It can be seen that the higher the frequency of the RF signal, the greater the phase lag amplitude after passing through the LC network.

[0080] For example, Figure 10As shown in the figure, when the RF signal is at a low frequency within its frequency band, the inductor-capacitor network may shift the RF signal by -80° (i.e., a phase lag of 80°). This results in a phase shift of -160°+φ° (-80°+φ°-80°) along path one and a phase shift of φ° along path two. The RF signal along path one and along path two have a 160° phase difference, so they cannot be completely canceled out at the first end of the second phase-shifting structure. Consequently, some of the RF signal's power will be coupled to the coupler's isolation end.

[0081] For example, Figure 11 As shown in the figure, when the RF signal is high within its frequency band, the inductor-capacitor network may shift the RF signal by -100° (i.e., a 100° phase lag). This results in a phase shift of -200°+φ° (-100°+φ°-100°) along path one and a φ° phase shift along path two. The RF signal along path one and along path two have a 200° phase difference, so they cannot be completely canceled out at the first end of the second phase-shifting structure. Consequently, some of the RF signal's power will be coupled to the coupler's isolated end.

[0082] Figure 12 A schematic diagram shows 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 inputted from the coupler's input is between 700MHz and 760MHz (60MHz bandwidth), the coupler's output has an amplitude gain of -0.02dB to -0.04dB, allowing it to output the input RF signal almost losslessly. The amplitude gain of the coupled end of the coupler ranges from -25.91dB to -24.42dB, meaning the output power is approximately one-three-hundredth of the input RF signal's power. The amplitude gain of the isolated end of the coupler ranges from -45.02dB to -53.98dB, meaning the output power is approximately one-thirtieth to one-two-hundredth of the input RF signal's power. However, when the frequency of the RF signal inputted from the coupler's input is less than 700MHz or greater than 760MHz, the coupler's directivity is less than 20dB. Directivity is the ratio of the output power at the coupled end to the output power at the isolated end. This means that a coupler only has good directivity within a narrow bandwidth. For RF signals with a wider bandwidth (for example, the 90MHz B28 band), the coupler's directivity is poor.

[0083] An embodiment of the present application provides a coupler circuit for improving the directivity of the coupler to radio frequency signals with a wider bandwidth. Figure 13 An exemplary structural diagram of a coupler circuit is provided. Figure 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.

[0084] Although not shown in the drawings of this application, those skilled in the art will appreciate that the coupler circuit 300 provided in the embodiments of this application may 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.

[0085] 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 experience a phase lag when passing through the right-hand transmission line circuit 310, while the RF signal will experience a phase advance when passing through the left-hand transmission line circuit 320.

[0086] like Figure 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 an 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 undergoes a phase shift of -90° to +φ° by the right-hand transmission line circuit 310 and the second coupling circuit 340, and then undergoes a phase shift of φ° to +90° by the first coupling circuit 330 and the left-hand transmission line circuit 320 before being coupled to the second end of the left-hand transmission line circuit 320 (i.e., the isolated end of the coupler circuit 300). The two RF signals coupled to the isolated end of the coupler circuit 300 have a phase difference of 180° (i.e., opposite phases), and thus cancel each other out at the isolated end of the coupler circuit 300. Consequently, no output is generated from the isolated end of the coupler circuit 300 (i.e., the second end of the left-hand transmission line circuit 320).

[0087] like Figure 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 an 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 undergoes a φ° phase shift (-90° + φ° + 90°) through the right-hand transmission line circuit 310, the second coupling circuit 340, and the left-hand transmission line circuit 320, and then undergoes a φ° phase shift through the first coupling circuit 330 before being coupled to the first end of the left-hand transmission line circuit 320 (i.e., the coupled end of the coupler circuit 300). The two RF signals coupled to the coupled end of the coupler circuit 300 have a phase difference of 0° (i.e., the same phase), and thus are superimposed at the coupled end of the coupler circuit 300. Consequently, the coupled 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 RF signal's power.

[0088] Figure 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. Figure 16 As shown, the higher the frequency of the RF signal, the greater the phase lag of the RF signal passing through the right-hand transmission line circuit 310, while the phase advance of the RF signal passing through the left-hand transmission line circuit 320 is smaller. The left-hand transmission line circuit 320 and the right-hand transmission line circuit 310 can maintain a stable phase difference within a wide bandwidth. The embodiments of the present application utilize the technical solution of cooperating with the right-hand transmission line circuit 310 and the left-hand transmission line circuit 320 to improve the directivity of the coupler for RF signals with a wide bandwidth.

[0089] For example, Figure 16 and Figure 17 As shown, when the RF signal is at a low frequency within its frequency band, the right-hand transmission line circuit 310 applies a phase shift of -80° (i.e., a phase lag of 80°), while the left-hand transmission line circuit 320 applies a phase shift of +100° (i.e., a phase advance of 100°). Therefore, when an 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 undergoes a phase shift of -80°+φ° through the right-hand transmission line circuit 310 and the second coupling circuit 340, and then a phase shift of φ°+100° through the first coupling circuit 330 and the left-hand transmission line circuit 320 before being coupled to the second end of the left-hand transmission line circuit 320 (i.e., the isolation end of the coupler circuit 300). The two RF signals coupled to the isolated end of the coupler circuit 300 have a phase difference of 180° (i.e., opposite phases), and thus cancel each other out at the isolated end of the coupler circuit 300. Consequently, there is no output from the isolated end of the coupler circuit 300 (i.e., the second end of the left-hand transmission line circuit 320).

[0090] For example,Figure 16 and Figure 18 As shown, when the RF signal is higher in its frequency band, the right-hand transmission line circuit 310 applies a phase shift of -100° (i.e., a phase lag of 100°), while the left-hand transmission line circuit 320 applies a phase shift of +80° (i.e., a phase advance of 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 undergoes a phase shift of -100°+φ° through the right-hand transmission line circuit 310 and the second coupling circuit 340, and then undergoes a phase shift of φ°+80° through the first coupling circuit 330 and the left-hand transmission line circuit 320 before being coupled to the second end of the left-hand transmission line circuit 320 (i.e., the isolation end of the coupler circuit 300). The two RF signals coupled to the isolated end of the coupler circuit 300 also have a phase difference of 180° (i.e., opposite phases), and thus cancel each other out at the isolated end of the coupler circuit 300. Consequently, the isolated end of the coupler circuit 300 (i.e., the second end of the left-hand transmission line circuit 320) has no output.

[0091] 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 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 Pi-type inductor-capacitor (LC) circuit consisting of the first inductor L1, the first capacitor C1, and the second capacitor C2.

[0092] 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. In other words, the left-hand transmission line circuit 320 can be a Pi-type LC circuit consisting of the fourth inductor L4, the fifth inductor L5, and the fourth capacitor C4.

[0093] In some examples, the inductance values of the first inductor L1, the fourth inductor L4 and the fifth inductor L5 are all 10.5 nanohenry (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 picofarad (i.e., C1=C2=C4=4.3 pF). Thus, the resonant frequency f r1 of the right-handed transmission line circuit 310 and the resonant frequency f r2 of the left-handed transmission line circuit 320 can be calculated as follows:

[0094] .

[0095] Figure 20 The trajectory diagrams of the right-handed transmission line circuit 310 and the left-handed transmission line circuit 320 on the Smith chart are shown in FIG. 6. When the frequency of the radio frequency signal is 750 MHz, the complex impedance of the right-handed 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-handed transmission line circuit 320 is Z0(0.975+j0.002), and the imaginary part of the complex impedance is also almost zero, which is also located at the center point of the Smith chart. Here, Z0is the matching resistance. That is to say, the right-handed transmission line circuit 310 and the left-handed transmission line circuit 320 exhibit a pure resistance characteristic to the radio frequency signal with a frequency of 750 MHz.

[0096] Figure 21 The amplitude-frequency characteristic diagram of the coupler circuit 300 provided by the embodiment of the present application is shown in FIG. 7. When the frequency of the radio frequency signal input from the input end of the coupler circuit 300 is 700 MHz-800 MHz (bandwidth 100 MHz), the amplitude gain of the radio frequency signal at the output end of the coupler circuit 300 is 0.68 dB-0.66 dB. The amplitude gain of the radio frequency signal at the coupling end of the coupler circuit 300 is -24.68 dB-24.52 dB, that is, the output power is about one three-hundredth of the input power of the radio frequency signal. The amplitude gain of the radio frequency signal at the isolation end of the coupler circuit 300 is -47.81 dB-64.19 dB, that is, the output power is about one fifty-thousandth to one two-hundred-fifty-millionth of the input power of the radio frequency signal. The directivity of the coupler circuit 300 within the 100 MHz bandwidth is greater than 20 dB. That is to say, the coupler circuit 300 provided by the embodiment of the present application has good directivity within a wider bandwidth.

[0097] As Figure 22As shown, in some 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 consisting of the second inductor L2, the third inductor L3, and the third capacitor C3.

[0098] 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. The second end of the sixth inductor L6 is grounded. In other words, the left-hand transmission line circuit 320 may be a T-type LC circuit consisting of the fifth capacitor C5, the sixth capacitor C6, and the sixth inductor L6.

[0099] like Figure 23 As shown, in other embodiments, the right-hand transmission line circuit 310 in the coupler circuit 300 can be a Pi-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 embodiments of the present application do not impose any restrictions on the combination of the left-hand transmission line circuit 320 and the right-hand transmission line circuit 310.

[0100] Please continue to refer to Figure 19 In some embodiments, 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.

[0101] In some embodiments, the capacitance value of the seventh capacitor C7 and the capacitance value of the eighth capacitor C8 are equal. In order to reduce the coupling degree of the coupler circuit 300, the capacitance value of the seventh capacitor C7 and the eighth capacitor C8 can be smaller than the capacitance value of the first capacitor C1; for example, the capacitance value of the seventh capacitor C7 and the eighth capacitor C8 are both 0.25 pico farad (i.e., C7=C8=0.25 pF).

[0102] Please continue to refer to Figure 24 In some embodiments, the first coupling circuit 330 includes a seventh inductor L7, a first end of the seventh inductor L7 is connected with the first end of the first coupling circuit 330, and a second end of the seventh inductor L7 is connected with 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 with the first end of the second coupling circuit 340, and a second end of the eighth inductor L8 is connected with the second end of the second coupling circuit 340.

[0103] In some embodiments, the inductance value of the seventh inductor L7 and the inductance value of the eighth inductor L8 are equal. In order to reduce the coupling degree of the coupler circuit 300, the inductance value 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 value of the seventh inductor L7 and the eighth inductor L8 are both 100 nano henry (i.e., L7=L8=100 nH).

[0104] In a second aspect, a circuit board assembly is provided. The circuit board assembly includes a printed circuit board (not shown) and Figure 19 and Figure 22 to Figure 24 The coupler circuit 300 shown in any of the above is arranged on the printed circuit board. The coupler circuit 300 provided by the embodiments of the present application is composed of discrete structures such as inductors and capacitors.

[0105] In some embodiments, the inductor is a 01005 size patch inductor, and the capacitor is a 01005 size patch capacitor. The size of the 01005 size patch capacitor and the 01005 size patch inductor is both 0.4 mm x 0.2 mm. Each element in the coupler circuit 300 can be arranged on the surface of the printed circuit board; for example, Figure 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 shown above can be arranged according to the following schematic diagram: Figure 25The layout shown is arranged on the surface of the printed circuit board close to one side of the printed circuit board. Adding the gap between the elements, the coupler circuit 300 provided by the embodiment of the application occupies about 1.5 mm x 1.5 mm of the area of the printed circuit board, thereby reducing the printed circuit board area by 50%, and only occupying the surface layer of the printed circuit board, so that the inner layer wiring of the printed circuit board is also more convenient.

[0106] In an embodiment, the printed circuit board is a multi-layer printed circuit board, the left-handed transmission line circuit 320 in the coupler circuit 300 is arranged on a first layer of the printed circuit board, the right-handed transmission line circuit 310 in the coupler circuit 300 is arranged on a 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 capacitances between the first layer and the second layer. Thus, the area of the printed circuit board can be further reduced.

[0107] The embodiment of the 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 with the power amplifier, the antenna and the radio frequency chip, respectively.

[0108] The coupler circuit and the circuit board assembly provided in the embodiment of the application adopt the technical scheme that the right-handed transmission line circuit cooperates with the left-handed transmission line circuit, and the left-handed transmission line circuit and the right-handed transmission line circuit have significant differences in phase shift of the radio frequency signal. The radio frequency signal will lag in phase after passing through the right-handed transmission line circuit, and the radio frequency signal will lead in phase after passing through the left-handed transmission line circuit. Moreover, the higher the frequency of the radio frequency signal is, the greater the phase lag of the radio frequency signal after passing through the right-handed transmission line circuit is, and the smaller the phase lead of the radio frequency signal after passing through the left-handed transmission line circuit is. The left-handed transmission line circuit and the right-handed transmission line circuit can maintain a stable phase difference in a wide bandwidth, thereby improving the directivity of the coupler to the radio frequency signal in a wide bandwidth.

[0109] In several embodiments provided in the present application, it should be understood that the disclosed coupler circuit, circuit board assembly and electronic device can be implemented in other manners. For example, the embodiments of the device described above are merely schematic; for example, the division of the modules is merely a logical function division; an actual division can be another division manner during actual implementation; for example, a plurality of modules or components can be combined or integrated into another device, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the modules shown or discussed can be indirect coupling or communication connection through some interface, device or module, and can be electrical, mechanical or in other forms.

[0110] The modules described as separated components can or can not be physically separated, and the components shown as modules can or can not be physical modules, i.e., can be located in one device or distributed on a plurality of devices. Some or all of the modules can be selected according to actual needs to achieve the purpose of the embodiments.

[0111] In addition, each functional module in each embodiment of the present application can be integrated in one device, or each module can be physically present alone, or two or more modules can be integrated in one device.

[0112] In the above embodiments, all or part of the embodiments can be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or part of the embodiments can be implemented in the form of a computer program product.

[0113] The above description is merely specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A coupler circuit, characterized in that: The invention comprises 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; wherein the right-hand transmission line circuit is used to perform a phase lag phase shift on a signal, and the higher the frequency of the signal, the greater the phase lag phase shift amplitude of the right-hand transmission line circuit on the signal; the left-hand transmission line circuit is used to perform a phase advance phase shift on the signal, and the higher the frequency of the signal, the smaller the phase advance phase shift amplitude of the left-hand transmission line circuit on the signal; 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 the second end of the right-hand transmission line circuit, and a second end of the second coupling circuit is connected to the 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 the first terminal of the left-hand transmission line circuit, the output terminal is connected to the second terminal of the left-hand transmission line circuit, the coupling terminal is connected to the first terminal of the right-hand transmission line circuit, and the output terminal is connected to the second terminal of the right-hand transmission line circuit.

2. The coupler circuit according to claim 1, wherein: 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, wherein: The right-hand transmission line circuit includes a second inductor, a third inductor, and a third capacitor; A first end of the second inductor is connected to a first end of the right-hand transmission line circuit, a second end of the second inductor is connected to a first end of the third inductor and a first end of the third capacitor respectively, a second end of the third inductor is connected to a second end of the right-hand transmission line circuit, and a 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; 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; 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 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.

6. The coupler circuit according to claim 1, wherein: The first coupling circuit includes 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, wherein: The first coupling circuit includes a seventh inductor, a first end of the seventh inductor is connected to the first end of the first coupling circuit, and a 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, 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: The device 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, wherein: The coupler circuit is disposed on a surface of the printed circuit board.

10. The circuit board assembly according to claim 8, wherein: 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 to each other; A first coupling circuit in the coupler circuits includes a seventh capacitor, and a second coupling circuit in 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 arranged close to one side of the printed circuit board.

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