Multi-port connecting circuit, radio frequency front-end module, and electronic device

Abstract

The present application relates to the technical field of radio frequency circuits, and provides a multi-port connecting circuit, a radio frequency front-end module, and an electronic device. The multi-port connecting circuit comprises a first switch, a second switch, a first branch transmission line, a second branch transmission line, and a first common transmission line; the first end of the first switch and the second end of the first switch are two ends capable of being turned on; the first end of the second switch and the second end of the second switch are two ends capable of being turned on; the second end of the first switch is connected to the first end of the first branch transmission line, and the second end of the second switch is connected to the first end of the second branch transmission line; the second end of the first branch transmission line and the second end of the second branch transmission line are both directly connected to the first end of the first common transmission line. The described circuit can reduce insertion loss on a signal pathway.

Description

Multi-port connection circuit, RF front-end module and electronic equipment

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on June 16, 2023, with application number 202310724481.X and application name “Multi-port connection circuit, RF front-end module and electronic device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of radio frequency circuit technology, and in particular to a multi-port connection circuit, a radio frequency front-end module, and an electronic device. Background Art

[0003] With the development of communication technology, people's requirements for the functions and performance of terminal devices are getting higher and higher, and the specifications that terminal devices need to support are also becoming more and more advanced. For example, terminal devices need to support more frequency bands and have more antennas to adapt to more communication scenarios.

[0004] Typically, more RF channels are added to the RF front-end module (RFFEM) of a terminal device to expand the frequency band. However, due to limited space in the terminal device, the number of antennas cannot be increased indefinitely to accommodate the expansion of RF channels. Therefore, multiple RF channels often share the same antenna to reduce the number of antennas. However, with a limited number of antennas and a large number of RF channels, switching between RF channels in the RFFEM becomes complex. To address complex RF channel switching scenarios, the traditional approach is to increase the number of switches or replace them with switches with more ports to accommodate complex switching scenarios.

[0005] However, increasing the number of switches or replacing them with switches with more ports will increase the insertion loss of a single RF channel, resulting in increased power consumption of the terminal equipment.

[0006] Summary of the Invention

[0007] The present application provides a multi-port connection circuit, a radio frequency front-end module and an electronic device, which can ensure low insertion loss of the signal path, thereby reducing power consumption.

[0008] In a first aspect, a multi-port connection circuit is provided, comprising: a first switch, a second switch, a first branch transmission line, a second branch transmission line, and a first common transmission line; the first end of the first switch and the second end of the first switch are two conductive ends, and the first end of the second switch and the second end of the second switch are two conductive ends; the second end of the first switch is connected to the first end of the first branch transmission line, and the second end of the second switch is connected to the first end of the second branch transmission line; the second end of the first branch transmission line and the second end of the second branch transmission line are both directly connected to the first end of the first common transmission line; when the first end of the first switch and the second end of the first switch are conductive, and the second end of the second switch is in an off state, the first end of the first switch and the second end of the first common transmission line are in an impedance matching state in a first frequency band, and the first end of the second switch is in a high impedance state in the first frequency band.

[0009] In the above multi-port connection circuit, the second end of the first transmission line and the second end of the second branch transmission line are both directly connected to the first end of the first common transmission line. When the first end of the first switch and the second end of the first switch are turned on, and the second end of the second switch is in the off state, the first end of the first switch and the second end of the first common transmission line are in an impedance matching state in the first frequency band, so that the signal of the first frequency band can be transmitted with low loss without affecting the normal transmission of the signal of the first frequency band. At the same time, the first end of the second switch is in a high impedance state in the first frequency band, forming an open circuit characteristic for the signal of the first frequency band, so that the signal of the first frequency band cannot pass through, thereby achieving the purpose of frequency gating. In the multi-port connection circuit, there is no need to add a switch or a combiner (duplexer) for frequency gating. Instead, different branch transmission lines are directly connected to the common transmission line to directly terminate the two switches, and gating the signal of the first frequency band is achieved by controlling the port impedance. The multi-port connection circuit avoids the introduction of too many components, simplifies the circuit structure, simplifies the complexity of signal path switching, and reduces the cost; and avoids the increase in insertion loss caused by the introduction of too many components, reducing the loss on the signal path. When this multi-port connection circuit is applied in the RF front-end module, it can reduce the introduction of switches and instead adopt the method of directly terminating the transmission line, which also simplifies the complexity of antenna switching, thereby improving the specifications of TAS and CA services and improving the transmission performance in the form of cross-linking of TAS and CA services.

[0010] In one possible implementation, when the second end of the first switch is in an off state and the first end of the second switch and the second end of the second switch are turned on, the first end of the first switch is in a high-impedance state in the second frequency band, and the first end of the second switch and the second end of the first common transmission line are in an impedance matching state in the second frequency band.

[0011] When the second end of the first switch is in an off state and the first end of the second switch and the second end of the second switch are turned on, the first end of the first switch is in a high-impedance state in the second frequency band, and the first end of the second switch and the second end of the first common transmission line are in an impedance matching state in the second frequency band, so that the signal in the second frequency band can be transmitted with low loss. Without affecting the normal transmission of the signal in the second frequency band, the first end of the first switch is in a high-impedance state in the second frequency band, forming an open-circuit characteristic for the signal in the second frequency band, so that the signal in the second frequency band cannot pass through, thereby achieving the purpose of frequency gating and reducing the loss in the signal path.

[0012] In a possible implementation, the impedance matching state is a state where the port is in a fifty-ohm impedance matching state; and / or the high-impedance state is a state where the reflection coefficient of the port is greater than a preset threshold.

[0013] In one possible implementation, the first switch is a single-pole multi-throw switch, and the second end of the first switch and any one of the other ends of the first switch are two conductive ends; and / or the second switch is a single-pole multi-throw switch, and the second end of the second switch and any one of the other ends of the second switch are two conductive ends.

[0014] The port forms of the first switch and the second switch can be flexibly selected as needed to meet the requirements of different scenarios.

[0015] In one possible implementation, the second frequency band is a frequency band of a signal flowing through the first common transmission line and the second branch transmission line, and the second frequency band is higher than the first frequency band; when the second end of the first switch is in an off state and the first end of the second switch and the second end of the second switch are turned on, the difference between the sum of the electrical length of the first branch transmission line, the electrical length of the second branch transmission line, and the equivalent phase shift of the first switch and a first value is less than or equal to a first preset error threshold, and the first value is the sum of an integer multiple of a first carrier wavelength corresponding to the second frequency band and one-quarter of the first carrier wavelength; or, the difference between twice the electrical length of the first branch transmission line and the second value is less than or equal to the second preset error threshold, and the difference between the electrical length of the second branch transmission line and twice the sum of the equivalent phase shift of the first switch and the second value is less than or equal to the second preset error threshold, and the second value is an integer multiple of the first carrier wavelength.

[0016] Optionally, the first preset error threshold and the second preset error threshold may be the same or different.

[0017] The electrical length of the first branch transmission line is denoted as RouteA, and the electrical length of the second branch transmission line is denoted as RouteB. That is, when the signal is in the second frequency band with a high frequency, RouteA, RouteB, shifteroff, and the carrier wavelength λ satisfy either Formula (6) or Formula (8) below. This ensures that when the signal is transmitted at a high frequency, the signal path will not introduce additional insertion loss due to mismatch, or will introduce only a small insertion loss.

[0018] In one possible implementation, the first end of the first switch is further connected to the first end of the first phase-shifting network, and the first end of the second switch is further connected to the first end of the second phase-shifting network. When the first end of the first switch and the second end of the first switch are conductive, and the first end of the second switch and the second end of the second switch are conductive, the second end of the first phase-shifting network and the second end of the first common transmission line are in an impedance-matched state in the first frequency band, and the first phase-shifting network is used to suppress signals in the second frequency band. The second end of the second phase-shifting network and the second end of the first common transmission line are in an impedance-matched state in the second frequency band, and the second phase-shifting network is used to suppress signals in the first frequency band.

[0019] This implementation method can achieve channel selection of different frequencies without introducing switches, which simplifies the switch switching scenario while ensuring low insertion loss of the signal path and expanding the usage scenarios, making the usage scenarios richer.

[0020] In one possible implementation, the first switch is a multi-pole, multi-throw switch, the third end of the first switch and the first end of the first switch are two conductive ends, and the third end of the first switch and the fourth end of the first switch are two conductive ends; and / or, the second switch is a multi-pole, multi-throw switch, the third end of the second switch and the first end of the second switch are two conductive ends, and the third end of the second switch and the fourth end of the second switch are two conductive ends.

[0021] The port form of the first switch and the second switch can be flexibly selected as needed to meet the needs of different scenarios. When the first switch and the second switch include more ports, they can be shared with other signal channels, expanding the application scenarios.

[0022] In one possible implementation, the multi-port connection circuit further includes: a third branch transmission line, a fourth branch transmission line, and a second common transmission line; the third end of the first switch is connected to the first end of the third branch transmission line, and the third end of the second switch is connected to the first end of the fourth branch transmission line; the second end of the third branch transmission line and the second end of the fourth branch transmission line are both directly connected to the first end of the second common transmission line.

[0023] In one possible implementation, when the third end of the first switch and the fourth end of the first switch are conductive, and the third end of the second switch is in an off state, the fourth end of the first switch and the second end of the second common transmission line are in an impedance matching state in the third frequency band, and the fourth end of the second switch is in a high-impedance state in the fourth frequency band; when the third end of the first switch is in an off state, and the third end of the second switch and the fourth end of the second switch are conductive, the fourth end of the first switch is in a high-impedance state in the fourth frequency band, and the fourth end of the second switch and the second end of the second common transmission line are in an impedance matching state in the fourth frequency band.

[0024] In other words, the multi-port connection circuit can include two sets of terminated transmission lines, further simplifying the circuit, reducing insertion loss in more signal paths, further simplifying the complexity of signal path switching, and lowering costs. When applied to RF front-end modules, this multi-port connection circuit can further reduce the introduction of switches and further simplify the complexity of antenna switching, thereby improving the specifications of TAS and CA services and enhancing transmission performance when TAS and CA services are interleaved.

[0025] In one possible implementation, the fourth frequency band has a higher frequency than the third frequency band; when the first switch is in the off state and the third end of the second switch and the fourth end of the second switch are turned on, the difference between the sum of the electrical length of the third branch transmission line, the electrical length of the fourth branch transmission line, and the equivalent phase shift of the first switch and a third value is less than or equal to a third preset error threshold, and the third value is the sum of an integer multiple of the second carrier wavelength corresponding to the fourth frequency band and one-quarter of the second carrier wavelength; or, the difference between twice the electrical length of the third branch transmission line and the fourth value is less than or equal to the fourth preset error threshold, and the difference between twice the electrical length of the third branch transmission line and the sum of the equivalent phase shift of the first switch and the fourth value is less than or equal to the fourth preset error threshold, and the fourth value is an integer multiple of the second carrier wavelength.

[0026] Optionally, the third preset error threshold and the fourth preset error threshold may be the same or different; the third preset error threshold and the fourth preset error threshold may be the same or different from the first preset error threshold and the second preset error threshold mentioned above.

[0027] In this implementation, on the basis of simplifying the circuit, it can also be ensured that during high-frequency signal transmission, the insertion loss of the signal path will not cause additional insertion loss or only introduce a small insertion loss due to mismatch.

[0028] In one possible implementation, the first transmission path of the fifth frequency band includes: a first end of the first switch, a second end of the first switch, a first branch transmission line, and a first common transmission line; the second transmission path of the fifth frequency band includes: a first end of the first switch, a third end of the first switch, a third branch transmission line, and a second common transmission line.

[0029] In this implementation, the multi-port connection circuit can meet the scenario of dual antenna switching in the transmitting state, expand the usage scenarios, and improve product specifications.

[0030] In one possible implementation, the first receiving path of the fifth frequency band includes: a first common transmission line, a second branch transmission line, the second end of the second switch, and the first end of the second switch; the second receiving path of the fifth frequency band includes: a second common transmission line, a fourth branch transmission line, the third end of the second switch, and the fourth end of the second switch.

[0031] In this implementation, the multi-port connection circuit can meet the scenario of dual antenna switching in the receiving state, expand the usage scenarios, and improve product specifications.

[0032] In one possible implementation, the circuit further includes: a third switch, a fourth switch, a fifth branch transmission line, a sixth branch transmission line, a seventh branch transmission line, an eighth branch transmission line, a third common transmission line, and a fourth common transmission line; the first end of the third switch and the second end of the third switch are conductive ends, and the first end of the fourth switch and the second end of the fourth switch are conductive ends; the second end of the third switch is connected to the first end of the fifth branch transmission line, and the second end of the fourth switch is connected to the first end of the sixth branch transmission line; the second end of the fifth branch transmission line and the second end of the sixth branch transmission line are both directly connected to the first end of the third common transmission line; the third end of the third switch and the fourth end of the third switch are conductive ends, and the third end of the fourth switch and the fourth end of the fourth switch are conductive ends; the third end of the third switch is connected to the first end of the seventh branch transmission line, and the third end of the fourth switch is connected to the first end of the eighth branch transmission line; the second end of the seventh branch transmission line and the second end of the eighth branch transmission line are both directly connected to the first end of the fourth common transmission line.

[0033] In this implementation, the multi-port connection circuit can also include four sets of terminated transmission lines, further simplifying the circuit, reducing insertion loss in more signal paths, further simplifying the complexity of signal path switching, and lowering costs. When this multi-port connection circuit is applied to RF front-end modules, it can further reduce the introduction of switches and further simplify the complexity of antenna switching, thereby improving the specifications of TAS and CA services and enhancing transmission performance when TAS and CA services are interleaved.

[0034] In one possible implementation, the first end of the first switch and the fifth end of the first switch are conductive terminals; the fifth end of the first switch is connected to the first end of the third switch. A third transmission path for the fifth frequency band includes: the first end of the first switch, the fifth end of the first switch, the first end of the third switch, the second end of the third switch, a fifth branch transmission line, and a third common transmission line. A fourth transmission path for the fifth frequency band includes: the first end of the first switch, the fifth end of the first switch, the first end of the third switch, the third end of the third switch, a seventh branch transmission line, and a fourth common transmission line.

[0035] In this implementation, the multi-port connection circuit can meet the scenario of four-antenna switching in the transmitting state, expand the usage scenarios, and improve product specifications.

[0036] In one possible implementation, the third receiving path of the fifth frequency band includes: a third common transmission line, a sixth branch transmission line, the second end of the fourth switch, and the first end of the fourth switch; the fourth receiving path of the fifth frequency band includes: a fourth common transmission line, an eighth branch transmission line, the third end of the fourth switch, and the fourth end of the fourth switch.

[0037] In this implementation, the multi-port connection circuit can meet the scenario of four-antenna switching in the receiving state, expand the usage scenarios, and improve product specifications.

[0038] In one possible implementation, the third receiving path of the fifth frequency band includes: a third common transmission line, a fifth branch transmission line, the second end of the third switch, and the fifth end of the third switch; the fourth receiving path of the fifth frequency band includes: a fourth common transmission line, a seventh branch transmission line, the third end of the third switch, and the fourth end of the third switch.

[0039] In this implementation, the multi-port connection circuit can meet the scenario of four-antenna switching in the receiving state, expand the usage scenarios, and improve product specifications.

[0040] In a second aspect, a radio frequency front-end module is provided, comprising one or more multi-port connection circuits as described in any one of the technical solutions of the first aspect.

[0041] In a third aspect, an electronic device is provided, comprising one or more multi-port connection circuits as described in any one of the technical solutions of the first aspect.

[0042] In a fourth aspect, an electronic device is provided, comprising one or more RF front-end modules as in the technical solution of the second aspect.

[0043] The implementation principles and beneficial effects of the above-mentioned RF front-end module and electronic device can be found in the previous description of the multi-port connection circuit, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] FIG1 is a schematic structural diagram of a terminal device 100 provided in an embodiment of the present application;

[0045] FIG2 is a schematic diagram of a common circuit structure including multiple signal channels;

[0046] FIG3 is a schematic structural diagram of a multi-port connection circuit provided in an embodiment of the present application;

[0047] FIG4 is a schematic structural diagram of another example of a multi-port connection circuit provided in an embodiment of the present application;

[0048] FIG5 is a simplified schematic diagram of a multi-port connection circuit according to an embodiment of the present application;

[0049] FIG6 is a simplified schematic diagram of a circuit under an ideal state provided by an embodiment of the present application;

[0050] FIG7 is an equivalent circuit diagram of a multi-port connection circuit provided in an embodiment of the present application;

[0051] FIG8 is an equivalent circuit diagram of a multi-port connection circuit provided in an embodiment of the present application;

[0052] FIG9 is a schematic structural diagram of another example of a multi-port connection circuit provided in an embodiment of the present application;

[0053] FIG10 is a schematic structural diagram of another example of a multi-port connection circuit provided in an embodiment of the present application;

[0054] FIG11 is a schematic structural diagram of another example of a multi-port connection circuit provided in an embodiment of the present application;

[0055] FIG12 is a schematic structural diagram of another example of a multi-port connection circuit provided in an embodiment of the present application;

[0056] FIG13 is a schematic structural diagram of another example of a multi-port connection circuit provided in an embodiment of the present application;

[0057] FIG14 is a structural diagram of another example of a multi-port connection circuit provided in an embodiment of the present application;

[0058] FIG15 is a simplified circuit structure diagram of the multi-port connection circuit shown in FIG14;

[0059] FIG16 is a signal flow diagram in the circuit structure shown in FIG15 ;

[0060] FIG17 is another signal flow diagram of the circuit structure shown in FIG15;

[0061] FIG18 is another signal flow diagram of the circuit structure shown in FIG15;

[0062] FIG19 is another signal flow diagram of the circuit structure shown in FIG15;

[0063] FIG20 is another signal flow diagram in the circuit structure shown in FIG15;

[0064] FIG21 is another signal flow diagram of the circuit structure shown in FIG15;

[0065] FIG22 is another signal flow diagram in the circuit structure shown in FIG15;

[0066] FIG23 is another signal flow diagram of the circuit structure shown in FIG15;

[0067] FIG24 is another signal flow diagram of the circuit structure shown in FIG15;

[0068] FIG25 is another signal flow diagram of the circuit structure shown in FIG15;

[0069] FIG26 is a schematic structural diagram of another example of a multi-port connection circuit provided in an embodiment of the present application;

[0070] FIG27 is an equivalent circuit diagram of a multi-port connection circuit provided in an embodiment of the present application;

[0071] FIG28 is a comparison diagram of an S-parameter curve of a multi-port connection circuit provided in an embodiment of the present application and an ideal state. DETAILED DESCRIPTION

[0072] The technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings in the embodiments of the present application. In the description of the embodiments of the present application, unless otherwise specified, " / " means or, for example, A / B can mean A or B; "and / or" in this article is merely a description of the association relationship of associated objects, indicating that three relationships can exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, "multiple" means two or more than two.

[0073] In the following, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the technical features indicated. Therefore, a feature specified as "first," "second," or "third" may explicitly or implicitly include one or more of the features.

[0074] The multi-port connection circuit and RF front-end module provided in the embodiments of the present application can be applied to terminal devices such as mobile phones, tablet computers, wearable devices, vehicle-mounted devices, augmented reality (AR) / virtual reality (VR) devices, laptop computers, ultra-mobile personal computers (UMPCs), netbooks, and personal digital assistants (PDAs). The embodiments of the present application do not impose any restrictions on the specific type of terminal device.

[0075] With the development of communication technology, people have higher and higher requirements for the functions and performance of terminal devices, and the specifications that terminal devices need to support are also becoming more and more advanced. Terminal devices need to support more frequency bands and have more antennas to adapt to more communication scenarios.

[0076] Typically, people add more RF channels to the RF front-end module of a terminal device to expand the frequency band. For example, for global-specification terminal devices, the frequency bands and frequency band combinations to be supported in different regions are different. Therefore, it is necessary to support more frequency bands to cover a wider area, which will result in an increase in the number of RF channels in the terminal device, and thus more switch ports are required. For example, in the non-standalone (NSA) scenario of the fifth generation mobile communication technology (5G), or in the carrier aggregation (CA) scenario, multiple RF channels need to be transmitted simultaneously. This requirement increases the complexity of the RF front-end module design and the complexity of RF channel switching. At the same time, due to the limited space of the terminal device, the number of antennas cannot be increased indefinitely to accommodate the expansion of RF channels. People often reduce the number of antennas by having multiple RF channels share the same antenna. Then, when the number of antennas is limited and the number of RF channels is large, the switching scenario of each RF channel in the RF front-end module becomes complicated. To cope with complex RF channel switching scenarios, the number of switches can be increased or replaced with switches with more ports. However, increasing the number of switches or replacing switches with more ports will increase the insertion loss of a single RF channel, resulting in increased power consumption of the terminal device.

[0077] The present application provides a multi-port connection circuit that can be used in RF front-end modules or terminal devices. By designing the port impedance of each RF channel of the multi-port connection circuit, each RF channel presents an impedance matching state for the frequency of the signal that needs to be passed directly, enabling low-loss signal transmission; and presents a high-impedance state for the signal that does not need to pass through, forming an open circuit characteristic and preventing the signal from passing through. This eliminates the need to introduce switches to enable different RF channels to select signals of different frequencies, simplifying the circuit, avoiding the increase in insertion loss caused by the introduction of switches or combiners, reducing path losses, and lowering costs.

[0078] For example, FIG1 is a schematic diagram of the structure of a terminal device 100 provided in an embodiment of the present application. The terminal device 100 may include a processor 110, an external memory interface 120, an internal memory 121, a universal serial bus (USB) interface 130, a charging management module 140, a power management module 141, a battery 142, an antenna 1, an antenna 2, a mobile communication module 150, a wireless communication module 160, an audio module 170, a speaker 170A, a receiver 170B, a microphone 170C, an earphone interface 170D, a sensor module 180, a button 190, a motor 191, an indicator 192, a camera 193, a display 194, and a subscriber identification module (SIM) card interface 195, etc. The sensor module 180 may include a pressure sensor 180A, a gyroscope sensor 180B, an air pressure sensor 180C, a magnetic sensor 180D, an acceleration sensor 180E, a distance sensor 180F, a proximity light sensor 180G, a fingerprint sensor 180H, a temperature sensor 180J, a touch sensor 180K, an ambient light sensor 180L, a bone conduction sensor 180M, etc.

[0079] It should be understood that the structures illustrated in the embodiments of the present application do not constitute a specific limitation on the terminal device 100. In other embodiments of the present application, the terminal device 100 may include more or fewer components than shown, or may combine or separate certain components, or arrange the components differently. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0080] The processor 110 may include one or more processing units. For example, the processor 110 may include an application processor (AP), a modem processor, a graphics processing unit (GPU), an image signal processor (ISP), a controller, a memory, a video codec, a digital signal processor (DSP), a baseband processor, and / or a neural-network processing unit (NPU). The different processing units may be independent devices or integrated into one or more processors.

[0081] The controller may be the nerve center and command center of the terminal device 100. The controller may generate an operation control signal according to the instruction operation code and the timing signal to complete the control of fetching and executing instructions.

[0082] The wireless communication function of the terminal device 100 can be implemented through the antenna 1, the antenna 2, the mobile communication module 150, the wireless communication module 160, the modem processor and the baseband processor.

[0083] Antenna 1 and Antenna 2 are used to transmit and receive electromagnetic wave signals. The structures of Antenna 1 and Antenna 2 in Figure 1 are only examples. Each antenna in terminal device 100 can be used to cover a single or multiple communication frequency bands. Different antennas can also be reused to improve antenna utilization. For example, Antenna 1 can be reused as a diversity antenna for a wireless local area network. In other embodiments, the antennas can be used in conjunction with a tuning switch.

[0084] The mobile communication module 150 can provide solutions for wireless communications including 2G / 3G / 4G / 5G applied to the terminal device 100. The mobile communication module 150 may include at least one filter, a switch, a power amplifier, a low noise amplifier (LNA), etc. The mobile communication module 150 can receive electromagnetic waves from the antenna 1, and filter, amplify, and process the received electromagnetic waves, and transmit them to the modulation and demodulation processor for demodulation. The mobile communication module 150 can also amplify the signal modulated by the modulation and demodulation processor, and convert it into electromagnetic waves for radiation through the antenna 1. In some embodiments, at least some of the functional modules of the mobile communication module 150 can be set in the processor 110. In some embodiments, at least some of the functional modules of the mobile communication module 150 can be set in the same device as at least some of the modules of the processor 110.

[0085] The modem processor 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. The demodulator then transmits the demodulated low-frequency baseband signal to the baseband processor for processing. After being processed by the baseband processor, the low-frequency baseband signal is passed to the application processor. The application processor outputs a sound signal through an audio device (not limited to the speaker 170A, the receiver 170B, etc.) or displays an image or video through the display screen 194. In some embodiments, the modem processor may be an independent device. In other embodiments, the modem processor may be independent of the processor 110 and be set in the same device as the mobile communication module 150 or other functional modules.

[0086] The wireless communication module 160 can provide wireless communication solutions including wireless local area networks (WLAN) (such as wireless fidelity (Wi-Fi) networks), Bluetooth (BT), global navigation satellite system (GNSS), frequency modulation (FM), near field communication (NFC), infrared (IR), etc. applied to the terminal device 100. The wireless communication module 160 can be one or more devices integrating at least one communication processing module. The wireless communication module 160 receives electromagnetic waves via the antenna 2, frequency modulates and filters the electromagnetic wave signals, and sends the processed signals to the processor 110. The wireless communication module 160 can also receive the signal to be sent from the processor 110, frequency modulate it, amplify it, and convert it into electromagnetic waves for radiation through the antenna 2.

[0087] In some embodiments, the antenna 1 of the terminal device 100 is coupled to the mobile communication module 150, and the antenna 2 is coupled to the wireless communication module 160, so that the terminal device 100 can communicate with the network and other devices through wireless communication technology. The wireless communication technology may include global system for mobile communications (GSM), general packet radio service (GPRS), code division multiple access (CDMA), wideband code division multiple access (WCDMA), time-division code division multiple access (TD-CDMA), long term evolution (LTE), BT, GNSS, WLAN, NFC, FM, and / or IR technology. The GNSS may include a global positioning system (GPS), a global navigation satellite system (GLONASS), a Beidou navigation satellite system (BDS), a quasi-zenith satellite system (QZSS) and / or a satellite based augmentation system (SBAS).

[0088] In the terminal device shown in FIG1 above, the mobile communication module 150 and / or the wireless communication module 160 can be shown in the form of a radio frequency front-end module. For ease of understanding, the following embodiments of the present application will take the terminal device having the structure shown in FIG1 as an example, and specifically describe the multi-port connection circuit provided in the embodiment of the present application in combination with the accompanying drawings and application scenarios. It should be noted that, in the radio frequency front-end module, the scenario of switching the radio frequency channel (signal path) by a switch can adopt the multi-port connection circuit shown in the embodiment of the present application to simplify the circuit structure. Of course, the multi-port connection circuit provided in the embodiment of the present application is not limited to use in the radio frequency front-end module, and can also be used in other scenarios of selecting signals, which is not limited in the embodiment of the present application. Next, an exemplary description is given of the scenario in which the multi-port connection circuit is used in the radio frequency front-end module.

[0089] Figure 2(a) shows a schematic diagram of a portion of an RF channel in a common example of multiple cascaded switches in an RF front-end module. As shown in Figure 2(a), for single-channel high-frequency and single-channel intermediate-frequency signals, a double-pole double-throw (DPDT) or double-pole four-throw (DPFFT) switch must pass through two switches to reach antenna 1 (ANT1) or antenna 2 (ANT2). High-frequency or intermediate-frequency signals in carrier aggregation (CA) or dual-link (DC) mode must pass through two switches and a combiner (also called a duplexer) to reach antenna 1 (ANT1) or antenna 2 (ANT2). Figure 2(b) shows another common schematic diagram of a portion of an RF channel in a common example of multiple cascaded switches in an RF front-end module. As shown in Figure 2(b), signals from B34, B39, and B40, as well as the GSM high-frequency transmit signal (GSM_HB_TX), also need to pass through two switches to reach antenna 1 (ANT1) or antenna 2 (ANT2).

[0090] For the scenario shown in FIG2 above where RF channels need to be switched, an embodiment of the present application provides a multi-port connection circuit, as shown in FIG4 , including: a first switch, a second switch, a first branch transmission line, a second branch transmission line, and a first common transmission line. The first end of the first switch and the second end of the first switch are two ends that can be turned on, and the first end of the second switch and the second end of the second switch are two ends that can be turned on. That is, the first end of the first switch and the second end of the first switch can be turned on or off under the action of a control signal, and the first end of the second switch and the second end of the second switch can be turned on or off under the action of a control signal.

[0091] Optionally, the first switch can be a single-pole double-throw switch, the second end of the first switch can be the common end of the switch, and the first end of the first switch can be any one of the two discrete ends. Optionally, the first switch can also be a single-pole three-throw switch, a single-pole four-throw switch, or other single-pole multi-throw switch. The second end of the first switch can be the common end of the first switch, and the first end of the first switch can be any one of multiple discrete ends. In Figure 3, the first switch is an single-pole four-throw switch, and the first end of the first switch is discrete end 1. Optionally, the first switch can also be a multi-pole multi-throw switch, such as a double-pole three-throw switch, a double-pole double-throw switch, a double-pole four-throw switch, a double-pole five-throw switch, a three-pole three-throw switch, a three-pole four-throw switch, etc., which is not limited in the embodiments of the present application.

[0092] Optionally, the second switch may be a single-pole double-throw switch, the second end of the second switch may be the common end of the second switch, and the first end of the second switch may be any one of the two discrete ends. Optionally, the second switch may also be a single-pole three-throw, single-pole four-throw, or other single-pole multi-throw switch. The second end of the second switch may be the common end of the second switch, and the first end of the second switch may be any one of multiple discrete ends. FIG3 illustrates an example in which the second switch is a single-pole four-throw switch and the first end of the second switch is discrete end 1. Optionally, the second switch may also be a multi-pole multi-throw switch, such as a double-pole three-throw switch, a double-pole double-throw switch, a double-pole four-throw switch, a double-pole five-throw switch, a three-pole three-throw switch, a three-pole four-throw switch, etc., which is not limited in the embodiments of the present application.

[0093] The first switch and the second switch can be the same switch or different switches, which is not limited in the present embodiment. As long as the first switch includes a first end and a second end that can be turned on and off, and the second switch includes a first end and a second end that can be turned on and off, it can be sufficient.

[0094] Specifically, the second end of the first switch is connected to the first end of the first branch transmission line, the second end of the second switch is connected to the first end of the second branch transmission line, and the second end of the first transmission line and the second end of the second branch transmission line are both directly connected to the first end of the first common transmission line. In FIG3 , the first end is labeled with a number "1" and the second end is labeled with a number "2".

[0095] For the entire multi-port connection circuit shown in Figure 3, the external ports include: Port 1, Port 2, and Port 3. When the first switch is in the on state, the first end of the first switch and the second end of the first switch are conductive, and the second end of the second switch is in the off state, the first end of the first switch and the second end of the first common transmission line are in an impedance matching state in the first frequency band, and the first end of the second switch is in a high-impedance state in the first frequency band.

[0096] It should be noted that, in the embodiments of the present application, when a certain end of a switch is in an off state, it means that the port in the off state and any other port of the switch are not conductive, for example, the port may be in a floating state. Specifically, the off state of a certain end of a switch can be a situation where the port and other ports of the switch are not conductive, but other ports may be conductive; or it can be a situation where none of the ports of the switch are conductive, that is, the entire switch is in an off state (also called an off state). In addition, it is expected that the impedance of the port in the off state is close to an infinite high impedance state.

[0097] That is, when a signal in the first frequency band flows into the multi-port connection circuit from port 1, because the first end of the first switch and the second end of the first common transmission line are in an impedance-matched state in the first frequency band, the signal in the first frequency band can be transmitted to port 2 with minimal insertion loss. In other words, the transmission coefficient (S12) between ports 1 and 2 is large, exhibiting a low-loss, direct-through transmission characteristic. Furthermore, for the first frequency band, because the first end of the second switch is in a high-impedance state in the first frequency band, equivalent to an open circuit, the signal in the first frequency band flowing from port 1 cannot pass through the second switch to port 3.

[0098] When a signal in the first frequency band flows from port 2 into the multi-port connection circuit, because the first end of the first switch and the second end of the first common transmission line are in an impedance-matched state within the first frequency band, the signal in the first frequency band can be transmitted to port 1 with minimal insertion loss. In other words, the transmission coefficient (S21) between port 2 and port 1 is large, resulting in a low-loss, direct-through transmission characteristic. Furthermore, for the first frequency band, because the first end of the second switch is in a high-impedance state within the first frequency band, equivalent to an open circuit, the signal in the first frequency band flowing from port 2 cannot pass through the second switch to port 3.

[0099] Optionally, the impedance matching state can be that the port impedance is 50 ohms (ohm) or close to 50 ohms, such as 49 ohms, 48 ​​ohms, 45 ohms, or 51 ohms, 52 ohms or 55 ohms, etc., as long as the difference from 0 ohms is relatively small, for example, less than 5 ohms, 3 ohms and other relatively small impedance differences, the loss of transmission energy can be within an acceptable range, and the port is in an impedance matching state.

[0100] Optionally, the impedance matching state can be achieved by adjusting the line width or material of the first common transmission line and / or the first branch transmission line to adjust the port impedance, or by adding a matching network to the first common transmission line and / or the first branch transmission line and debugging the electrical performance parameters of the matching network to adjust the port impedance. Optionally, the matching network can be a T-type, L-type, or Π-type network composed of lumped parameter elements, and the specific values ​​of the capacitors or inductors at each matching position in the matching network are not limited. Optionally, the matching network can also be a network formed by distributed parameter elements, such as copper foils of different sizes or shapes.

[0101] Optionally, the high-impedance state can be achieved by adjusting the line width or material of the first common transmission line and / or the second branch transmission line to adjust the impedance. Alternatively, the high-impedance state can be achieved by adding a matching network to the first common transmission line and / or the second branch transmission line and adjusting the electrical performance parameters of the matching network. For details on the implementation of the matching network, please refer to the description of the impedance matching state above.

[0102] Alternatively, the high-impedance state may be a state in which the port impedance is relatively large, such as 1000 ohms, less than but close to 1000 ohms, or greater than 1000 ohms, such as 900 ohms, 950 ohms, 1050 ohms, or 1100 ohms or greater. Generally, in the high-impedance state, the reflection state of the port is preferably total reflection. Taking port 3 as an example, the reflection coefficient S33 is targeted to be close to 0, with a larger value being preferred, such as greater than -0.5 dB.

[0103] Therefore, both impedance matching and high impedance can be achieved by adjusting the matching network in the signal path. Figure 4 shows an example of a T-type matching network composed of lumped parameter elements. In Figure 4, each matching position in the matching network can be a capacitor or an inductor. The specific capacitance and inductance values ​​are based on achieving the required impedance matching state.

[0104] To clearly illustrate the port impedance when the first end of the first switch and the second end of the first switch are conductive and the second end of the second switch is off, the circuit shown in FIG3 or FIG4 can be simplified into the model shown in FIG5. In FIG5, the port impedances of ports 1 and 2 are 50 ohms or close to 50 ohms, and the port impedance of port 3 is in a high-impedance state, for example, 1000 ohms.

[0105] In the multi-port connection circuit shown in FIG3 , the second end of the first transmission line and the second end of the second branch transmission line are both directly connected to the first end of the first common transmission line. When the first end of the first switch and the second end of the first switch are turned on, and the second end of the second switch is in the off state, the first end of the first switch and the second end of the first common transmission line are in an impedance matching state in the first frequency band, so that the signal of the first frequency band can be transmitted with low loss without affecting the normal transmission of the signal of the first frequency band. At the same time, the first end of the second switch is in a high impedance state in the first frequency band, forming an open circuit characteristic for the signal of the first frequency band, so that the signal of the first frequency band cannot pass through, thereby achieving the purpose of frequency gating. In the multi-port connection circuit shown in FIG3 , there is no need to add a switch or a combiner (duplexer) for frequency gating. Instead, different branch transmission lines are directly connected to the common transmission line to directly terminate the two switches, and the gating of the signal of the first frequency band is achieved by controlling the port impedance. This multi-port connection circuit avoids the introduction of excessive components, simplifies the circuit structure, and reduces the complexity of signal path switching, while also reducing costs. It also avoids the increased insertion loss caused by the introduction of too many components, reducing signal path losses. When applied to RF front-end modules, this multi-port connection circuit reduces the introduction of switches and instead directly terminates the transmission line, simplifying antenna switching complexity. This improves the specifications of TAS and CA services, and enhances transmission performance when TAS and CA services are interleaved.

[0106] Optionally, in the multi-port circuit shown in FIG3 , the channels of port 1 and port 3 can also be used to gate signals in the second frequency band. When the second end of the first switch is in an off state and the first end of the second switch and the second end of the second switch are in a conducting state, the first end of the first switch is in a high-impedance state in the second frequency band, and the first end of the second switch and the second end of the first common transmission line are in an impedance matching state in the second frequency band, enabling signals in the second frequency band to be transmitted with low loss. Without affecting the normal transmission of signals in the second frequency band, the first end of the first switch is in a high-impedance state in the second frequency band, forming an open-circuit characteristic for signals in the second frequency band, preventing them from passing through. This achieves the purpose of frequency gating and simultaneously reduces losses in the signal path.

[0107] The first branch transmission line, the second branch transmission line and the first common transmission line can be regarded as a group of terminated transmission lines, which do not require the introduction of components such as switches and combiners, and can achieve frequency selection and ensure low insertion loss in the signal path.

[0108] To clearly illustrate the implementation principle of the embodiment shown in FIG3 , the factors affecting the insertion loss in the signal path are described here. Taking the multi-port connection circuit shown in FIG3 as an example, the insertion loss composition from port 2 to port 1 in the first frequency band may include the following:

[0109] 1. Insertion loss of the first common transmission line, denoted as ILcommon;

[0110] 2. Insertion loss of the first branch transmission line, denoted as ILA;

[0111] 3. The device insertion loss of the first switch when it is in the on state, denoted as IL1;

[0112] 4. The return loss introduced by the second branch transmission line and the insertion loss introduced by the impedance mismatch state are recorded as ILB;

[0113] 5. The return loss introduced by the impedance failure of the port of the second switch in the off state and the insertion loss introduced by the impedance mismatch state are recorded as ILoff.

[0114] Therefore, when the signal of the first frequency band flows from port 2 to port 1, the insertion loss ILtotle of the entire signal path is: ILtotle= ILcommon + ILA + IL1+ ILB + ILoff Formula (1)

[0115] When the first common transmission line and the components in the multi-port connection circuit are fixed, the ideal insertion loss ILideal from port 2 to port 1 is: ILideal= ILcommon + IL1 Formula (2)

[0116] FIG6 shows an equivalent circuit diagram of a multi-port connection circuit under ideal insertion loss conditions. The insertion loss of the signal path from port 2 to port 1 in the first frequency band is ILcommon + IL1. ILcommon and IL1 are fixed insertion losses and cannot be avoided.

[0117] Then, by subtracting the above formula (1) from formula (2), the additional insertion loss is ILtotle-ILideal, which can be expressed as the following relationship: ILtotle-ILideal= ILA+ ILB+ILoff Formula (3)

[0118] The three items on the right side of formula (3): ILA, ILB, and ILoff are adjustable indicators that affect insertion loss.

[0119] It can be understood that the carrier wavelength is the ratio of the speed of light to its frequency, satisfying the relationship v = λ × f. The speed of light in air, v, can be approximated to the speed of light in a vacuum, 3 × 108 m / s. For the communication frequency f range of 450 MHz to 7200 MHz used in mobile communications, the corresponding carrier wavelength λ range is: 0.04 meters (m) (for 7200 MHz) ≤ λ ≤ 0.67 m (for 450 MHz).

[0120] For common, relatively low communication frequencies, the carrier wavelength is relatively long. For example, a frequency of 2000MHz corresponds to a carrier wavelength of 0.15m, or 15 centimeters (cm). The length of the transmission line in the signal path is usually as short as possible, for example, 5 millimeters (mm). Therefore, the length of the transmission line is much shorter than the carrier wavelength, which means that the length of the transmission line is incomparable to the carrier wavelength. In this case, after the signal passes through the transmission line, the phase change is very small, and the impact caused by the phase change can be ignored. Only the port impedance needs to be considered to meet the signal transmission requirements. In other words, for relatively low communication frequencies, only factors affecting impedance matching such as materials, line width, and matching networks need to be considered.

[0121] However, at higher communication frequencies, the carrier wavelength is relatively short. For example, the carrier wavelength corresponding to 7200MHz is 0.04m, or 4cm. Therefore, a transmission line length of approximately 5mm in the signal path is comparable to a 4cm carrier wavelength. This means that when the transmission line length approaches the carrier wavelength, phase shifts during signal transmission become a concern.

[0122] Specifically, taking a high-frequency signal with a relatively high transmission frequency as an example, the electrical length of the first branch transmission line is recorded as RouteA, and the electrical length of the second branch transmission line is recorded as RouteB. Then RouteA, RouteB and the carrier wavelength λ need to satisfy either the following formula (4) or formula (5) to ensure low insertion loss: RouteA+RouteB=αλ+kλ / 4, Formula (4) 2×RouteA=2×RouteB=αλ+kλ Formula (5)

[0123] Wherein, α is an integer, and the values ​​of α in formula (4) and formula (5) can be the same or different. Optionally, the ideal value of k is 1. However, in actual circuits, k can be a value close to 1 between 0.5 and 1.5, such as 1.01, 1.1, 0.9, 0.8, etc., and the values ​​of k in formula (4) and formula (5) can be different. When k takes a value close to 1, the above formula (4) and formula (5) are approximately valid, that is, when k takes a value of 1, the equal sign in formula (4) and formula (5) can be approximately equal (≈). Regardless of whether k takes a value close to 1, or k takes a value equal to 1 and the equal sign is changed to an approximately equal sign, RouteA, RouteB and the carrier wavelength can be said to satisfy formula (4) or formula (5).

[0124] Taking the circuit structure shown in Figure 3 as an example, if RouteA, RouteB, and the carrier wavelength λ satisfy formula (4), then for ports 2 and 3, the phase difference between the transmitted signal (also called the carrier phase) and the reflected signal is 90 degrees or close to 90 degrees, which can reduce the increase in insertion loss caused by impedance mismatch. The view from port 2 to port 3 is an open circuit, and the view from port 3 to port 2 is also an open circuit. In other words, for a port, the other branch transmission line and switch have no effect on the insertion loss of the signal path corresponding to this port. Taking port 2 as an example, if RouteA, RouteB, and the carrier wavelength λ satisfy formula (4), the additional insertion loss ILB and ILoff in the signal path between port 1 and port 2 due to the presence of the second branch transmission line and the second switch can be avoided or reduced, thereby ensuring lower insertion loss in the signal path.

[0125] If RouteA, RouteB, and the carrier wavelength λ satisfy formula (5), then when the signal is transmitted from port 2 to port 3 and then returned from port 3 to port 2, the phase undergoes a change of approximately an integer multiple of half a wavelength, which is the same as the original phase at port 2, equivalent to no phase change. In other words, the phase of the signal reflected from port 3 is the same as the phase on the original signal path (also called the carrier phase), so there is no loss to the signal. Taking the signal path from port 1 to port 2 as an example, this is equivalent to not introducing or reducing additional insertion loss ILB and ILoff, thereby ensuring that the insertion loss of the signal path is lower.

[0126] That is, if RouteA, RouteB, and the carrier wavelength λ satisfy either Formula (4) or Formula (5), it can be ensured that during high-frequency signal transmission, the signal path's insertion loss will not be introduced due to mismatch, or only a small insertion loss will be introduced. Of course, if RouteA, RouteB, and the carrier wavelength λ do not satisfy either Formula (4) or Formula (5), it means that during high-frequency signal transmission, the signal path's insertion loss will be introduced due to mismatch, resulting in a large additional insertion loss, which will increase the signal path's insertion loss and affect transmission performance.

[0127] However, since a switch is usually not physically disconnected in the strict sense when it is in the off state, that is, it cannot reach an infinite high-impedance state, the off-state switch or the switch port will still produce return loss for the transmitted signal, affecting the insertion loss in the signal path, that is, ILoff. However, the magnitude of ILoff depends on the characteristics of the switch itself. If the return loss of the switch port is large, that is, the reflection coefficient is relatively small, for example, less than -0.5dB, then the switch will have a large ILoff even in the off state. In this case, a phase shift network can be added to the path to change the phase of the signal and offset the phase change caused by the return loss. In this case, the phase change caused by the return loss can be regarded as the equivalent phase shift of the switch, recorded as shifteroff. Then RouteA, RouteB, shifteroff, and carrier wavelength λ need to satisfy either the following formula (6) or formula (7) to ensure low insertion loss: RouteA+RouteB+shifteroff=αλ+kλ / 4, Formula (6) 2×RouteA=2×(RouteB+shifteroff)=αλ+kλ Formula (7)

[0128] Wherein, α is an integer, and the values ​​of α in formula (6) and formula (7) can be the same or different. Optionally, the ideal value of k is 1. However, in actual circuits, k can be a value close to 1 between 0.5 and 1.5, such as 1.01, 1.1, 0.9, 0.8, etc., and the values ​​of k in formula (6) and formula (7) can be different. When k takes a value close to 1, the above formulas (4) and (5) are approximately true, that is, when k takes a value of 1, the equal signs in formula (6) and (7) can be approximately equal (≈). Whether k takes a value close to 1, or k takes a value equal to 1 and the equal sign is changed to an approximately equal sign, RouteA, RouteB, shifteroff and carrier wavelength can be said to satisfy formula (6) or formula (7).

[0129] Taking the circuit structure shown in Figure 3 as an example, if RouteA, RouteB, shifteroff, and carrier wavelength λ satisfy formula (6), then for ports 2 and 3, the phase difference between the transmitted signal (also called the carrier phase) and the reflected signal is 90 degrees or close to 90 degrees, which can reduce the increase in insertion loss caused by impedance mismatch. In this case, the view from port 2 to port 3 is an open circuit, and the view from port 3 to port 2 is also an open circuit. In other words, for a port, the other branch transmission line and switch have no effect on the insertion loss of the signal path corresponding to this port. Taking port 2 as an example, the additional insertion loss ILB and ILoff in the signal path between port 1 and port 2 caused by the introduction of the second branch transmission line and the second switch can be avoided or reduced, thereby ensuring lower insertion loss in the signal path.

[0130] If RouteA, RouteB, and the carrier wavelength λ satisfy formula (7), then when the signal is transmitted from port 2 to port 3 and then returned from port 3 to port 2, the phase undergoes a change of approximately an integer multiple of half a wavelength, which is the same as the original phase at port 2, equivalent to no phase change. In other words, the phase of the signal reflected from port 3 is the same as the phase on the original signal path (also called the carrier phase), so there is no loss to the signal. Taking the signal path from port 1 to port 2 as an example, if RouteA, RouteB, shifteroff, and the carrier wavelength λ satisfy formula (6), it is equivalent to not introducing or reducing additional insertion loss ILB and ILoff, thus ensuring that the insertion loss of the signal path is lower.

[0131] That is, if RouteA, RouteB, and the carrier wavelength λ satisfy either Formula (6) or Formula (7), it can be ensured that during high-frequency signal transmission, the signal path insertion loss will not introduce additional insertion loss due to mismatch or will only introduce a small insertion loss. Of course, if RouteA, RouteB, shifteroff, and the carrier wavelength λ do not satisfy either Formula (6) or Formula (7), it means that during high-frequency signal transmission, the signal path insertion loss will introduce a large additional insertion loss due to mismatch, for example, ILB and ILoff are relatively large, resulting in an increase in the signal path insertion loss and affecting transmission performance.

[0132] Based on the above description of the characteristics during high-frequency signal transmission, an embodiment of the present application also provides a multi-port connection circuit, the specific structure of which can be seen in Figure 3 or Figure 4. The first frequency band is a relatively low frequency, and the length of the transmission line is much smaller than the carrier wavelength of the first frequency band, and is incomparable to the carrier wavelength of the first frequency band; while the second frequency band is a relatively high frequency, and the length of the transmission line is close to the carrier wavelength corresponding to the second frequency band, and is comparable to the carrier wavelength.

[0133] When the first end of the first switch and the second end of the first switch are conductive, and the second end of the second switch is off, when a signal in the first frequency band passes through, the first end of the first switch and the second end of the first common transmission line are in an impedance matching state within the first frequency band, and the first end of the second switch is in a high-impedance state within the first frequency band. In this case, the signal in the first frequency band can pass through the signal path from port 1 to port 2 with low loss.

[0134] When the second end of the first switch is in the off state and the first end of the second switch and the second end of the second switch are in conduction, the sum of the electrical length of the first branch transmission line, the electrical length of the second branch transmission line, and the equivalent phase shift of the first switch can be less than or equal to the first preset error threshold value with a first value, the first value being the sum of an integer multiple (αλ) of the first carrier wavelength corresponding to one-quarter of the second frequency band and one-quarter of the first carrier wavelength (kλ / 4), where k is 1. That is, the electrical length of the first branch transmission line, the electrical length of the second branch transmission line, and the equivalent phase shift of the first switch satisfy the relationship of the above formula (6). At this time, since the switch in the off state of the port is the first switch and the signal path is from port 1 to port 3, the shifteroff in formula (6) represents the equivalent phase shift corresponding to the second end of the first switch when it is off. Then, for the signal path between port 1 and port 3, the additional insertion loss ILA and ILoff caused by the introduction of the first branch transmission line and the first switch can be avoided or reduced, and the insertion loss of the signal path between port 1 and port 3 can be ensured to be low.

[0135] Optionally, when the second end of the first switch is in the off state and the first end of the second switch and the second end of the second switch are in conduction, the difference between twice the electrical length of the first branch transmission line and the second value is less than or equal to the second preset error threshold, and the difference between twice the sum of the electrical length of the second branch transmission line and the equivalent phase shift of the first switch corresponding to the second frequency band and the second value is less than or equal to the second preset error threshold, and the second value is an integer multiple of the first carrier wavelength corresponding to the second frequency band. That is, the electrical length of the first branch transmission line, the electrical length of the second branch transmission line, and the equivalent phase shift of the first switch satisfy the relationship evolved from the above formula (7). The above-mentioned first preset error threshold and the second preset error threshold can be the same or different. Both can be smaller values, such as ±0.5, ±0.1, ±0.01, ±0.05, etc. The embodiment of the present application does not limit the specific values ​​of the first preset error threshold and the second preset error threshold. At this time, since the switch in the off-state of the port is the first switch and the signal path is from port 1 to port 3, shifteroff in formula (7) represents the equivalent phase shift corresponding to the second end of the first switch when it is off, and the adaptive evolution of formula (7) is formula (8): 2×RouteB=2×(RouteA+shifteroff)=αλ+kλ Formula (8)

[0136] Wherein, α is an integer. Optionally, the ideal value of k is 1. However, in actual circuits, k can be a value close to 1 between 0.5 and 1.5, such as 1.01, 1.1, 0.9, 0.8, etc. When k takes a value close to 1, the above formula (85) is approximately true, that is, when k takes a value equal to 1, the equal sign in formula (8) can be an approximately equal sign (≈). Regardless of whether k takes a value close to 1, or k takes a value equal to 1 and the equal sign is changed to an approximately equal sign, RouteA, RouteB, shifteroff, and carrier wavelength can be said to satisfy formula (8).

[0137] In addition, in the above formulas (5), (7), and (8), if α is a value close to an integer, such as 5.1, 4.9, which are close to the integer 5, or 3.95, 4.02, which are close to the integer 4, then k can be 0, and the right sides of formulas (5), (7), and (8) can be simplified to αλ.

[0138] Based on the same principle as the above formula (7), for the signal path between port 1 and port 3, the additional insertion losses ILA and ILoff caused by the introduction of the first branch transmission line and the first switch can be avoided or reduced, ensuring that the signal path between port 1 and port 3 has a low insertion loss characteristic.

[0139] It should be noted that, in the embodiments of the present application, when it is said that some parameters satisfy a certain formula, it is necessary for these parameters to satisfy the relationship of the formula. It may be that the relationship between these parameters makes the equation of the formula valid or makes the variant of the formula valid; it may also be that the equal sign in the formula is replaced by an approximately equal sign (≈), that is, as long as the values ​​on both sides of the formula are close, they do not necessarily have to be completely equal. For example, the difference between the values ​​on both sides of the formula is less than or equal to a preset error threshold. The preset error threshold is a smaller value, such as ±0.5, ±0.1, ±0.01, ±0.05, etc. The embodiments of the present application do not limit the specific value of the preset error threshold.

[0140] It should be noted that the carrier wavelength corresponding to the frequency band described above can be the carrier wavelength corresponding to the center frequency of the frequency band, or the carrier wavelength corresponding to a frequency point within the frequency band. When the input signal has a fixed frequency, the carrier wavelength is the wavelength corresponding to the fixed frequency. If the input signal has a frequency point that varies within a frequency band, the carrier wavelength can be the wavelength corresponding to the center frequency of the frequency band, to maximize compatibility with the characteristics of the entire frequency band.

[0141] Regardless of whether the size of the transmission line in the multi-port connection circuit is comparable to the carrier wavelength corresponding to the second frequency band, that is, the signal frequency of the first frequency band is relatively low, when the signal of the first frequency band needs to be selected, the first end of the first switch and the second end of the first switch are turned on, and the second end of the second switch is turned off. At this time, port 1 and port 2 are in an impedance matching state, and the signal path between port 1 and port 2 can transmit the signal of the first frequency band with low insertion loss. Then the structural diagram of the multi-port connection circuit shown in Figure 3 can be equivalent to the equivalent circuit diagram shown in Figure 7. The path corresponding to the second switch in Figure 7 (including the second switch and the second branch transmission line) is equivalent to non-existent.

[0142] When it is necessary to select the signal of the second frequency band, the first end of the second switch and the second end of the second switch are turned on, and the first end of the first switch is turned off. At this time, if the size of the transmission line in the multi-port connection circuit is not comparable to the carrier wavelength corresponding to the second frequency band, that is, the signal frequency of the second frequency band is relatively low, port 1 and port 3 are in an impedance matching state, and the signal path between port 1 and port 3 can transmit the signal of the second frequency band with low insertion loss. If the size of the transmission line in the multi-port connection circuit is comparable to the carrier wavelength corresponding to the second frequency band, the size of the transmission line satisfies formula (6) or formula (8), and the signal of the second frequency band is transmitted on the signal path between port 1 and port 3 with low insertion loss, then the structural schematic diagram of the multi-port connection circuit shown in Figure 3 can be seen in Figure 8. The path corresponding to the first switch in Figure 8 (including the first switch and the first branch transmission line) is equivalent to not existing.

[0143] Based on the embodiment shown in FIG3 above, a first phase-shift network can be added to the first port of the first switch. The first phase-shift network can be a filter or a notch filter. It should be noted that both the filter and the notch filter can be implemented by connecting capacitors and inductors in series and / or in parallel. The network form can be a T-type, L-type, or π-type network, or a combination or cascade of these three network forms. As long as it can pass the desired first frequency band signal and suppress the unwanted second frequency band signal, it can achieve the desired impedance matching state while gating the frequency. Optionally, a second phase-shift network can be added to the first port of the second switch. The structure of the second phase-shift network can refer to the description of the first phase-shift network, except that the specific parameters of the various components in the second phase-shift network are different from those of the first phase-shift network. The second phase-shift network can pass the desired second frequency band signal and suppress the unwanted first frequency band signal, while gating the frequency and achieving the desired impedance matching state. For details, see FIG9 , where the first and second phase-shift networks in FIG9 are both shown in the form of π-type networks. Optionally, the first phase-shift network and the second phase-shift network can be composed of lumped parameter components as shown in Figure 9, or modular components, such as surface acoustic wave filters (SAWs) or modular notches. The specific form of the phase-shift network is not limited in this embodiment of the application. Optionally, the first phase-shift network and the second phase-shift network can exist simultaneously or separately, as long as they can meet the impedance state of each port at the required frequency selection.

[0144] The multi-port connection circuit shown in FIG9 can also be used in a state where both the first switch and the second switch are turned on. Specifically, when the first end of the first switch and the second end of the first switch are turned on, and when the first end of the second switch and the second end of the second switch are turned on, the second end of the first phase shift network (i.e., port 2) and the second end of the first common transmission line (i.e., port 1) are in an impedance matching state in the first frequency band. The first phase shift network can be a filter or a notch filter whose passband includes the first frequency band and whose stopband includes the second frequency band. When the signal of the first frequency band flows through the signal path from port 1 to port 2, the insertion loss is small, while the signal of the second frequency band is suppressed and cannot pass through. The second end of the second phase shift network (port 3) and the second end of the first common transmission line (i.e., port 1) are in an impedance matching state in the second frequency band. The second phase shift network can be a filter or a notch filter whose passband includes the second frequency band and whose stopband includes the first frequency band. When the signal of the second frequency band flows through the signal path from port 1 to port 3, the insertion loss is small, while the signal of the first frequency band is suppressed and cannot pass through. In the embodiment shown in Figure 9, frequency gating is achieved when both switches are on by adding phase-shift networks corresponding to the frequencies in the two channels. This approach can be applied to scenarios where two signals are running concurrently, such as non-standalone (NSA) and carrier aggregation (CA). This approach also enables channel gating at different frequencies without requiring switches, simplifying the switching scenario while ensuring low insertion loss in the signal path and expanding the range of possible applications.

[0145] In the above embodiments, the first switch and the second switch are described as single-pole multi-throw switches. In the above embodiments, the first end is not limited to the pin marked "1" above, but can also be other pins, as long as it can be connected to the pin of the second end. When the multi-port connection circuit is used in a radio frequency front-end module or other transceiver system, after the switch selects the first end, the other unconnected ends can be left floating or connected to other signal paths. This is not limited in the embodiments of the present application. It can be understood that if the other unconnected ends are connected to other signal paths, then for the frequency selected by the signal path, the impedance matching state of the port described in the above embodiments can be used to select signals of different frequencies and ensure that the insertion loss of the signal path is low. The corresponding phase shift network can also be set in the path where the corresponding end is located according to the needs of the path selection frequency, which will not be repeated here.

[0146] In some scenarios, the first switch and / or the second switch may also be a multi-pole, multi-throw (MPMT) switch, such as a double-pole, double-pole, triple-throw (DPDT), double-pole, four-throw (DPTT), triple-pole, triple-throw (TPTT), or three-pole, four-throw (TPFT) switch, each with multiple terminals and multiple channels. The first switch and the second switch may be the same or different. FIG10 illustrates an example in which the first switch is a TPTT switch and the second switch is a DP4T switch. As shown in FIG10 , the third terminal of the first switch (the terminal marked "3") and the first terminal of the first switch are conductive terminals, and the third terminal of the first switch and the fourth terminal of the first switch (the terminal marked "4") are conductive terminals. Optionally, the third terminal of the second switch (the terminal marked "3") and the first terminal of the second switch are conductive terminals, and the third terminal of the second switch and the fourth terminal of the second switch (the terminal marked "4") are conductive terminals. Optionally, the unconnected terminals of the first and second switches can be connected to other signal paths to achieve multi-channel switching.

[0147] When the first switch and / or the second switch is a multi-pole multi-throw switch, the multi-port connection circuit can also be shown in Figure 11, including: a third branch transmission line, a fourth branch transmission line, and a second common transmission line. Figure 11 is an example based on Figure 10, in which a group of terminated transmission lines including a third branch transmission line, a fourth branch transmission line, and a second common transmission line are added. Specifically, the third end of the first switch is connected to the first end of the third branch transmission line, and the third end of the second switch is connected to the first end of the fourth branch transmission line; the second end of the third branch transmission line and the second end of the fourth branch transmission line are both directly connected to the first end of the second common transmission line. The detailed description of the third branch transmission line, the fourth branch transmission line, and the second common transmission line and the way they interact can be found in the description of the first branch transmission line, the second branch transmission line, and the first common transmission line in the various embodiments above, and will not be repeated here. Figure 11 illustrates an example in which the signal path of the third branch transmission line corresponds to the fourth port of the first switch, i.e., port 5 in Figure 11; the signal path of the fourth branch transmission line corresponds to the fourth port of the second switch, i.e., port 6 in Figure 11; and the second end of the second branch transmission line corresponds to port 4 in Figure 11. In practice, since the third end of the first switch can also be conductively connected to the first end, the third end of the second switch can also be conductively connected to the first end, as long as the corresponding port impedance states meet the requirements of the gating frequency and low insertion loss.

[0148] In the multi-port connection circuit shown in FIG11 , when the third end of the first switch and the fourth end of the first switch are conductive, and the third end of the second switch is in the OFF state, the fourth end of the first switch and the second end of the second common transmission line are in an impedance matching state in the third frequency band, and the fourth end of the second switch is in a high-impedance state in the fourth frequency band. When the third end of the first switch is in the OFF state, and the third end of the second switch and the fourth end of the second switch are conductive, if the fourth frequency band is a frequency band where the carrier wavelength and the transmission line size are not comparable, then the fourth end of the first switch is in a high-impedance state in the fourth frequency band, and the fourth end of the second switch and the second end of the second common transmission line are in an impedance matching state in the fourth frequency band, thereby ensuring the gating and low insertion loss characteristics of the transmission of signals in the fourth frequency band. The specific implementation principles and beneficial effects can be found in the description of the set of terminated transmission lines included in FIG3 to FIG9 above. Optionally, the third frequency band can be the same as or different from the first frequency band, and the fourth frequency band can be the same as or different from the second frequency band. This description will not be repeated here.

[0149] In the embodiment shown in FIG11 , when the third end of the first switch is in an off state and the third end of the second switch and the fourth end of the second switch are on, if the fourth frequency band is a frequency band in which the carrier wavelength and the transmission line size are comparable, then the difference between the sum of the electrical length of the third branch transmission line, the electrical length of the fourth branch transmission line, and the equivalent phase shift of the first switch and a third value is less than or equal to a third preset error threshold, where the third value is the sum of an integer multiple of the carrier wavelength corresponding to the fourth frequency band and one-quarter of the carrier wavelength; or, the difference between twice the electrical length of the third branch transmission line and the fourth value is less than or equal to the fourth preset error threshold, and the difference between the electrical length of the fourth branch transmission line and twice the sum of the equivalent phase shift of the first switch and the fourth value is less than or equal to the fourth preset error threshold, where the fourth value is a positive integer multiple of the second carrier wavelength corresponding to the fourth frequency band. That is to say, the electrical length of the third branch transmission line, the electric field of the fourth branch transmission line, and the carrier wavelength of the fourth frequency band can satisfy any of the relationships in the aforementioned formulas (6) and (8). Adaptively, the electrical length of the first branch transmission line can be replaced with the electrical length of the third branch transmission line, the electrical length of the second branch transmission line can be replaced with the electrical length of the fourth branch transmission line, and the carrier wavelength corresponding to the second frequency band can be replaced with the carrier wavelength corresponding to the fourth frequency band, thereby satisfying the gating and low insertion loss of the high-frequency signal in the fourth frequency band. The specific implementation principle and beneficial effects can be found in the specific description of formulas (6) and (8) above, which will not be repeated here.

[0150] The third and fourth preset error thresholds can be the same or different. Both can be relatively small values, such as ±0.5, ±0.1, ±0.01, ±0.05, and the like. The present embodiment of the application does not limit the specific values ​​of the third and fourth preset error thresholds. Furthermore, the third and fourth preset error thresholds can be the same or different from the first and second preset error thresholds described above, and the present embodiment of the application does not limit these values.

[0151] In some embodiments, the structure shown in FIG11 can also be used in dual-antenna switching scenarios, such as TAS or MIMO scenarios, so that the application scenarios of the multi-port connection circuit are richer. Specifically, the fifth frequency band can include two transmission paths under the dual-antenna TAS service. Among them, the first transmission path includes: the first end of the first switch, the second end of the first switch, the first branch transmission line and the first common transmission line. That is, the transmission signal of the fifth frequency band can flow from the first end of the first switch through the second end of the first switch, through the first branch transmission line and the first common transmission line, and then reach the antenna or other switches. The second transmission path may include: the first end of the first switch, the third end of the first switch, the third branch transmission line and the second common transmission line. That is, the transmission signal of the fifth frequency band can also flow from the first end of the first switch through the third end of the first switch, through the third branch transmission line and the second common transmission line, and then reach another antenna.

[0152] If the fifth frequency band is in a MIMO reception state, it may also include two reception paths. The first reception path includes: a first common transmission line, a second branch transmission line, the second end of the second switch, and the first end of the second switch. That is, the reception signal of the fifth frequency band can be received by a single antenna and sequentially pass through the first common transmission line, the second branch transmission line, the second end of the second switch, and the first end of the first switch. Furthermore, the second reception path includes: a second common transmission line, a fourth branch transmission line, the third end of the second switch, and the fourth end of the second switch. That is, the reception signal of the fifth frequency band can also be received by another antenna and sequentially pass through the second common transmission line, the fourth branch transmission line, the third end of the second switch, and the fourth end of the second switch.

[0153] Optionally, the fifth frequency band may be the same as or different from any of the first, second, third, or fourth frequency bands, and this embodiment of the present application does not limit this. The first and fourth ends of the first switch in the two transmit paths of the fifth frequency band are not limited to the first and fourth ends, but may also be ports of the first switch that can be connected to the second and third ends, respectively. The specific configuration can be adjusted based on the overall circuit design and this embodiment does not limit this.

[0154] Next, the application of the multi-port connection circuit provided in the embodiment of the present application in the actual circuit is described. Specifically, taking the circuit shown in Figure a in Figure 2 as an example, after the multi-port connection circuit is introduced, the structure of the original circuit has changed, as shown in Figure a in Figure 12. Compared with Figure a in Figure 2, the combiner is reduced. In other words, if the high-frequency signal or the carrier aggregation state (CA) signal or the dual-link state (DC) of the intermediate frequency signal reaches antenna 1 (ANT1) or antenna 2 (ANT2), it needs to pass through a two-stage switch without passing through a combiner. When the port impedance state meets the requirements, different signal paths can realize the gating of high-frequency signals and intermediate frequency signals while achieving low insertion loss, simplifying the circuit and reducing costs. For another example, taking the circuit shown in Figure b in Figure 2 as an example, after the multi-port connection circuit is introduced, the structure of the original circuit has changed, as shown in Figure b in Figure 12. In diagram b of Figure 12, the GSM high-frequency transmission signal (GSM_HB_TX) and signals in the B34, B39, and B40 frequency bands only need to pass through one switch to connect to the antenna. Compared with diagram b of Figure 2, one switch is reduced in the path of the GSM high-frequency transmission signal and signals in the B34, B39, and B40 frequency bands. When the port impedance state meets the requirements, different signal paths can be used to select high-frequency signals and intermediate-frequency signals, while achieving low insertion loss and simplifying the circuit.

[0155] Based on the embodiment shown in Figure a of FIG12 above, the signal paths for a single-channel high-frequency signal and a single-channel intermediate-frequency signal can also be implemented using a set of terminated transmission lines, as shown in FIG13 . In FIG13 , ports 2 and 5 are shown as corresponding terminals of the same switch, while ports 3 and 6 are shown as corresponding terminals of the same switch. As shown in FIG13 , due to the introduction of a set of terminated transmission lines, the original double-pole four-throw switch-2 can be replaced with a double-pole three-throw switch. It should be noted that, when the design and process of the switches themselves are the same, generally speaking, the more switch ports there are, the greater the insertion loss, while the fewer switch ports there are, the lower the insertion loss. In the circuit shown in FIG13 , the introduction of an additional set of terminated transmission lines reduces the number of switch ports, thereby reducing the insertion loss of the entire signal path.

[0156] When the above-mentioned multi-port connection circuit is applied to the RF front-end module, the circuit diagram of the relevant parts can be found in Figure 14. First, the functions and marked identifiers of the various components appearing in Figure 14 are explained. Generally, the filter appearing on the signal path of the RF signal can filter the signal that needs to pass through the signal path, that is, filter out the signal of unnecessary frequency and retain the signal of required frequency; the notch filter can suppress the signal that needs to be suppressed and pass other required frequency signals; the coupler can be used to couple the signal on the main path and perform power detection on the coupled signal to achieve the purpose of power detection (PD detection) of the signal on the main path. Generally, couplers on multiple different signal paths can also be connected to each other and share a power detection port. In Figure 14, TX represents the transmit path, RX represents the receive path, PRX represents the main receive path, DRX represents the diversity receive path, M represents the Multiple-Input Multiple-Output (MIMO) path, B represents the frequency band (BAND), MB represents the intermediate frequency signal (Middle Band), HB represents the high frequency signal (High Band), GSM represents the signal path of the Global System for Mobile Communication (GMS) standard, DIV represents the diversity signal path, MHBLDiFEM represents the medium and high frequency diversity module, the two separate ends of the duplexer can select two different frequency signals, and the common end can pass signals of different frequencies; the four separate ends of the quadplexer can respectively select four different frequency signals, and the common end can pass signals of different frequencies. Transmit antenna selection (TAS) represents the signal path used in the scenario of smart antenna selection. In the diagram shown in Figure 14, the transmission line shown by the black thick line is the terminated transmission line in the multi-port connection circuit described in this application, and Figure 14 shows four groups of terminated transmission lines. Originally, each set of terminated transmission lines used a single-pole double-throw switch to achieve frequency gating or path gating, or multiple sets of terminated transmission lines could achieve frequency gating or path gating through multi-pole multi-throw switches. By adopting the technical solution of this application, there is no need to use multiple single-pole double-throw switches or multi-pole multi-throw switches, reducing the number of switching components. Next, the signal flow of the circuit shown in Figure 14 in different operating states is described to illustrate that Figure 14 reduces path insertion loss without reducing the specifications of the original circuit.

[0157] To clearly illustrate the signal flow under the TAS service, the irrelevant components and connecting lines in Figure 14 can be simplified. The simplified circuit structure diagram can be seen in Figure 15. Figure 15 can be considered to include two groups of multi-port connection circuits as shown in Figure 11. For example, a second group of multi-port connection circuits can be added to the multi-port connection circuit shown in Figure 11.

[0158] The second multi-port connection circuit includes: a third switch (the first switch-2 in FIG. 15 ), a fourth switch (the second switch-2 in FIG. 15 ), a fifth branch transmission line, a sixth branch transmission line, a seventh branch transmission line, an eighth branch transmission line, a third common transmission line, and a fourth common transmission line. The first end of the third switch and the second end of the third switch are conductive terminals, and the first end of the fourth switch and the second end of the fourth switch are conductive terminals. The second end of the third switch is connected to the first end of the fifth branch transmission line, and the second end of the fourth switch is connected to the first end of the sixth branch transmission line. The second end of the fifth branch transmission line and the second end of the sixth branch transmission line are both directly connected to the first end of the third common transmission line. The third end of the third switch and the fourth end of the third switch are conductive terminals, and the third end of the fourth switch and the fourth end of the fourth switch are both conductive terminals. The third end of the third switch is connected to the first end of the seventh branch transmission line, and the third end of the fourth switch is connected to the first end of the eighth branch transmission line. The second end of the seventh branch transmission line and the second end of the eighth branch transmission line are both directly connected to the first end of the fourth common transmission line.

[0159] In Figure 15 above, the two groups of multi-port connection circuits can respectively realize dual-antenna switching. For details, please refer to the description of Figure 11 when working in the fifth frequency band, which will not be repeated here. The two groups of multi-port connection circuits in Figure 15 can also be combined into an overall multi-port connection circuit to realize four-antenna switching, such as four-antenna TAS services and four-antenna MIMO scenarios. Specifically, the first switch also has a fifth end, and the first end of the first switch and the fifth end of the first switch are two conductive ends. The fifth end of the first switch is connected to the first end of the third switch.

[0160] In Figure 15 , the first transmit path (n41_TX_TAS2) and the second transmit path (n41_TX_TAS1) for the fifth frequency band can be seen in Figures 17 and 16 . A third transmit path (n41_TX_TAS4) can also be added for the fifth frequency band, comprising: the first end of the first switch, the fifth end of the first switch, the first end of the third switch, the second end of the third switch, a fifth branch transmission line, and a third common transmission line. At the same time, a fourth transmit path (n41_TX_TAS4) can also be added for the fifth frequency band, comprising: the first end of the first switch, the fifth end of the first switch, the first end of the third switch, the third end of the third switch, a seventh branch transmission line, and a fourth common transmission line. For details, see Figures 19 and 18 .

[0161] In Figure 15 , the first receiving path (n41_RX1) and the second receiving path (n41_RX2) for the fifth frequency band can be shown in Figure 20 . A third receiving path can also be added for the fifth frequency band, comprising: a third common transmission line, a sixth branch transmission line, the second end of the fourth switch, and the first end of the fourth switch. Furthermore, the fourth receiving path for the fifth frequency band comprises: a fourth common transmission line, an eighth branch transmission line, the third end of the fourth switch, and the fourth end of the fourth switch. It should be noted that the first end of the fourth switch and the fourth end of the fourth switch can also be other ports of the fourth switch, as long as they can be electrically connected to the second end and the third end of the fourth switch, respectively.

[0162] Optionally, the third receiving path for the fifth frequency band may further include: a third common transmission line, a fifth branch transmission line, the second end of a third switch, and the fifth end of the third switch. The fourth receiving path for the fifth frequency band may include: a fourth common transmission line, a seventh branch transmission line, the third end of the third switch, and the fourth end of the third switch. It should be noted that the fourth end and the fifth end of the third switch herein may alternatively be other ports of the third switch, as long as they can be electrically connected to the second end and the third end of the third switch, respectively.

[0163] In the multi-port connection circuit shown in Figure 15 above, taking the fifth frequency band as n41 as an example, it is also compatible with the four-antenna TAS service and four-antenna MIMO scenario in the sixth frequency band. Next, based on the circuit schematic shown in Figure 15, taking the sixth frequency band as B1 or B3 (expressed as B1 / B3) as an example, the signal direction of the multi-antenna switching scenario of n41 and B1 / B3 is described.

[0164] In Figure 15, the n41 frequency band can implement four-antenna TAS services. The four transmit paths can be seen as the paths indicated by arrows in Figures 16, 17, 18, and 19, respectively. As shown in Figure 16, in the first n41 signal path indicated by n41_TX_TAS1, the transmit signal in the n41 frequency band reaches antenna 4 (ANT4) after passing through the multi-port connection circuit, and the n41 frequency band signal is transmitted through ANT4. As shown in Figure 17, in the second n41 signal path indicated by n41_TX_TAS2, the transmit signal in the n41 frequency band reaches antenna 3 (ANT3) after passing through the multi-port connection circuit, and the n41 frequency band signal is transmitted through ANT3. As shown in Figure 18, in the third n41 signal path indicated by n41_TX_TAS3, the transmit signal in the n41 frequency band reaches antenna 2 (ANT2) after passing through the multi-port connection circuit, and the n41 frequency band signal is transmitted through ANT2. As shown in FIG19 , in the fourth n41 signal path indicated by n41_TX_TAS4, the transmission signal of the n41 frequency band reaches antenna 1 (ANT1) after passing through the multi-port connection circuit, and the signal of the n41 frequency band is transmitted through ANT1.

[0165] Figure 20 shows the four receive paths of the n41 in a MIMO scenario. The four receive paths are represented by n41_RX1, n41_RX2, n41_RX3, and n41_RX4.

[0166] Figures 16 through 20 demonstrate that the introduction of multi-port connection circuitry into the RF front-end module does not affect the path switching function for TAS and MIMO services on the n41. By eliminating the need for switches, antenna switching complexity is simplified, improving transmission performance for TAS and MIMO services while reducing signal path losses.

[0167] In the circuits shown in Figures 14 and 15 above, the B1 and B3 frequency bands can also implement four-antenna TAS services. The four transmit paths can be seen as the paths indicated by the arrows in Figures 21, 22, 23, and 24, respectively. As shown in Figure 21, in the first B1 / B3 (representing B1 or B3) signal path indicated by B1 / B3_TX_TAS1, the transmit signal in the B1 / B3 frequency band reaches ANT1 after passing through the multi-port connection circuit, and the signal in the B1 / B3 frequency band is transmitted through ANT1. As shown in Figure 22, in the second B1 / B3 signal path indicated by B1 / B3_TX_TAS2, the transmit signal in the B1 / B3 frequency band reaches ANT2 after passing through the multi-port connection circuit, and the signal in the B1 / B3 frequency band is transmitted through ANT2. As shown in Figure 23, in the third B1 / B3 signal path indicated by B1 / B3_TX_TAS3, the B1 / B3 frequency band transmit signal reaches ANT3 after passing through the multi-port connection circuit, and the B1 / B3 frequency band signal is transmitted through ANT3. As shown in Figure 24, in the fourth B1 / B3 signal path indicated by B1 / B3_TX_TAS4, the B1 / B3 frequency band transmit signal reaches ANT4 after passing through the multi-port connection circuit, and the B1 / B3 frequency band signal is transmitted through ANT4.

[0168] Figure 25 shows the four receive paths of B1 / B3 in a MIMO scenario. These paths are represented by B1 / B3_RX1, B1 / B3_RX2, B1 / B3_RX3, and B1 / B3_RX4. The received signals from B1 / B3 can be selected by the quadplexer shown in Figure 14, which is not described here.

[0169] Figures 21 through 25 above demonstrate that the introduction of multi-port connection circuitry into the RF front-end module does not affect the path switching function for TAS and MIMO services on B1 / B3. By eliminating the need for switches, antenna switching complexity is simplified, improving transmission performance for TAS and MIMO services while reducing signal path losses.

[0170] Figure 26 is a schematic diagram of a partial circuit structure of a multi-port connection circuit provided in an embodiment of the present application and applied to a radio frequency front-end module. It should be noted that the meaning of the icons and annotations of the various components in Figure 26 can be found in the description of Figure 14 and will not be repeated here. In Figure 26, ANT3 can be used as an antenna for MIMO scenarios of intermediate frequency signals (B1\B3 and other frequency bands); ANT4 can be used as an antenna for intermediate frequency signals (B1\B3 and other frequency bands), high frequency signals (B7 and other frequency bands) and 5G communication frequency bands (such as n41); ANT1 can be used as the main antenna for intermediate frequency signals (B1\B3 and other frequency bands) and high frequency signals (B7 and other frequency bands), and can also be used as an antenna for the n78 frequency band; ANT2 can be used as a diversity antenna for intermediate frequency signals (B1\B3 and other frequency bands) and high frequency signals (B7 and other frequency bands).

[0171] In some circuits of the RF front-end module shown in FIG26 , the introduction of a multi-port connection circuit does not affect the path switching function in various scenarios, but can also simplify the circuit and reduce path loss.

[0172] FIG27 is an equivalent circuit diagram of a multi-port connection circuit provided in an embodiment of the present application.

[0173] The foregoing article describes in detail the structure of the multi-port connection circuit of the embodiment of the present application and its application in the RF front-end module. Next, combined with simulation parameters, a quantitative description is given of how the multi-port connection circuit can reduce insertion loss.

[0174] For details, please refer to the equivalent circuit diagram of the multi-port connection circuit shown in Figure 27. Figure a in Figure 27 is a schematic diagram of the structure of the actual multi-port connection circuit. When the signal of the first frequency band is transmitted from port 1 to port 2, Figure a in Figure 27 can be equivalent to the circuit diagram shown in Figure 27 b under ideal conditions. In order to clearly compare the S parameters, the original port 1 in the equivalent circuit diagram can be changed to port 4, and the original port 2 can be changed to port 5. Through simulation, the curve diagram of the S parameters is obtained, which can be seen in Figure 28. As can be seen from Figure 28, the actual circuit shown in Figure 27 has a smaller increase in insertion loss than the circuit under ideal conditions. The specific values ​​can be explained by the readings of the marked points. The specific values ​​of the marked points at each frequency point of the S parameters can be organized into the parameters in Table 1.

[0175] Table 1

[0176] Referring to Figure 28, in Table 1, S21 represents the insertion loss of the signal path from port 1 to port 2 at different frequencies. At 1710 MHz, 1810 MHz, 2170 MHz, 2500 MHz, and 2690 MHz, the values ​​are 1.5 dB, 1.6 dB, 1.8 dB, 2.3 dB, and 2.5 dB, respectively. S54 represents the insertion loss of the signal path from port 5 to port 4 at different frequencies. At 1710 MHz, 1810 MHz, 2170 MHz, 2500 MHz, and 2690 MHz, the values ​​are 1.3 dB, 1.4 dB, 1.6 dB, 1.8 dB, and 1.9 dB, respectively. Common switches have insertion losses greater than 0.3 dB in frequencies below 2170 MHz and often approach 1 dB in frequencies above 2500 MHz. It can be seen that for frequencies below 2170 MHz, increasing the insertion loss on the common transmission line by 0.2 dB can avoid the larger insertion loss of more than 0.3 dB caused by the introduction of a switch. For frequencies above 2500 MHz, increasing the insertion loss on the common transmission line by 0.5 dB or 0.6 dB can avoid the larger insertion loss of nearly 1 dB caused by the introduction of a switch. The technical solution of the embodiment of the present application has significant benefits.

[0177] Similarly, if signals are transmitted through the signal paths of ports 1 and 3, refer to the data for S31. It can be seen that increasing the insertion loss of the common transmission line by 0.2dB can significantly reduce the large insertion loss caused by the switch, achieving a significant benefit and enabling the selection of signals of different frequencies while reducing insertion loss.

[0178] An embodiment of the present application also provides a radio frequency front-end module, comprising one or more multi-port connection circuits described in any of the above embodiments.

[0179] An embodiment of the present application further provides an electronic device, comprising one or more multi-port connection circuits described in any of the above embodiments.

[0180] An embodiment of the present application also provides an electronic device, comprising the RF front-end module described in any of the above embodiments.

[0181] Among them, in the RF front-end module and electronic device provided in this embodiment, the relevant implementation principles and technical effects can be found in the aforementioned description of the multi-port connection circuit, and will not be repeated here.

[0182] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic, for example, the division of modules or units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units 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 units, the replaced units may or may not be physically separated, and the components displayed as units may be one physical unit or multiple physical units, that is, they may be located in one place, or they may be distributed in multiple different places. Some or all of the units can be selected according to actual needs to achieve the purpose of the scheme of this embodiment.

[0183] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0184] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solution of the embodiment of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for enabling a device (which can be a single-chip microcomputer, chip, etc.) or a processor (processor) to execute all or part of the steps of the various embodiments of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0185] The above content is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A multi-port connection circuit, characterized in that: include: A first switch, a second switch, a first branch transmission line, a second branch transmission line, and a first common transmission line; The first end of the first switch and the second end of the first switch are two ends that can be conducted, and the first end of the second switch and the second end of the second switch are two ends that can be conducted; The second end of the first switch is connected to the first end of the first branch transmission line, and the second end of the second switch is connected to the first end of the second branch transmission line; The second end of the first branch transmission line and the second end of the second branch transmission line are both directly connected to the first end of the first common transmission line; When the first end of the first switch and the second end of the first switch are turned on, and the second end of the second switch is in an off state, the first end of the first switch and the second end of the first common transmission line are in an impedance matching state in a first frequency band, and the first end of the second switch is in a high impedance state in the first frequency band.

2. The multi-port connection circuit according to claim 1, characterized in that: When the second end of the first switch is in an off state and the first end of the second switch and the second end of the second switch are turned on, the first end of the first switch is in a high impedance state in the second frequency band, and the first end of the second switch and the second end of the first common transmission line are in an impedance matching state in the second frequency band.

3. The multi-port connection circuit according to claim 1 or 2, characterized in that: The impedance matching state is a state where the port is in a fifty-ohm impedance matching state; and / or, The high impedance state is a state in which the reflection coefficient of the port is greater than a preset threshold.

4. The multi-port connection circuit according to any one of claims 1 to 3, characterized in that: The first switch is a single-pole multi-throw switch, and the second end of the first switch and any one of the other ends of the first switch are two conductive ends; and / or, The second switch is a single-pole multi-throw switch, and the second end of the second switch and any one of the other ends of the second switch are two conductive ends.

5. The multi-port connection circuit according to any one of claims 1 to 4, characterized in that: The second frequency band is a frequency band of signals flowing through the first common transmission line and the second branch transmission line, and the second frequency band has a higher frequency than the first frequency band; When the second end of the first switch is in an off state, and the first end of the second switch and the second end of the second switch are turned on, the sum of the electrical length of the first branch transmission line, the electrical length of the second branch transmission line, and the equivalent phase shift of the first switch differs from a first value less than or equal to a first preset error threshold, and the first value is a sum of an integer multiple of a first carrier wavelength corresponding to the second frequency band and one quarter of the first carrier wavelength; or, The difference between twice the electrical length of the first branch transmission line and a second value is less than or equal to a second preset error threshold, and the difference between twice the sum of the electrical length of the second branch transmission line and an equivalent phase shift of the first switch and the second value is less than or equal to the second preset error threshold, and the second value is an integer multiple of the first carrier wavelength.

6. The multi-port connection circuit according to any one of claims 1 to 5, characterized in that: The first end of the first switch is also connected to the first end of the first phase shift network, and the first end of the second switch is also connected to the first end of the second phase shift network; When the first end of the first switch and the second end of the first switch are turned on, and the first end of the second switch and the second end of the second switch are turned on, the second end of the first phase shift network and the second end of the first common transmission line are in an impedance matching state in the first frequency band, and the first phase shift network is used to suppress signals in the second frequency band; The second end of the second phase shift network and the second end of the first common transmission line are in an impedance matching state in the second frequency band, and the second phase shift network is used to suppress signals in the first frequency band.

7. The multi-port connection circuit according to claim 1, characterized in that: The first switch is a multi-pole multi-throw switch, the third end of the first switch and the first end of the first switch are two conductive ends, and the third end of the first switch and the fourth end of the first switch are two conductive ends; and / or, The second switch is a multi-pole multi-throw switch, the third end of the second switch and the first end of the second switch are two conductive ends, and the third end of the second switch and the fourth end of the second switch are two conductive ends.

8. The multi-port connection circuit according to claim 7, characterized in that: The multi-port connection circuit further includes: a third branch transmission line, a fourth branch transmission line and a second common transmission line; The third end of the first switch is connected to the first end of the third branch transmission line, and the third end of the second switch is connected to the first end of the fourth branch transmission line; The second end of the third branch transmission line and the second end of the fourth branch transmission line are both directly connected to the first end of the second common transmission line.

9. The multi-port connection circuit according to claim 8, characterized in that: When the third end of the first switch and the fourth end of the first switch are turned on, and the third end of the second switch is in an off state, the fourth end of the first switch and the second end of the second common transmission line are in an impedance matching state in a third frequency band, and the fourth end of the second switch is in a high impedance state in the fourth frequency band; When the third end of the first switch is in an off state, and the third end of the second switch and the fourth end of the second switch are turned on, the fourth end of the first switch is in a high-impedance state in the fourth frequency band, and the fourth end of the second switch and the second end of the second common transmission line are in an impedance matching state in the fourth frequency band.

10. The multi-port connection circuit according to claim 9, characterized in that: The fourth frequency band has a higher frequency than the third frequency band; When the third end of the first switch is in an off state, and the third end of the second switch and the fourth end of the second switch are turned on, the sum of the electrical length of the third branch transmission line, the electrical length of the fourth branch transmission line and the equivalent phase shift of the first switch differs from a third value less than or equal to a third preset error threshold, and the third value is a sum of an integer multiple of a second carrier wavelength corresponding to the fourth frequency band and one quarter of the second carrier wavelength; or, The difference between twice the electrical length of the third branch transmission line and the fourth value is less than or equal to a fourth preset error threshold, and the difference between twice the sum of the electrical length of the fourth branch transmission line and the equivalent phase shift of the first switch and the fourth value is less than or equal to the fourth preset error threshold, and the fourth value is an integer multiple of the second carrier wavelength.

11. The multi-port connection circuit according to claim 8, characterized in that: The first transmission path of the fifth frequency band includes: a first end of the first switch, a second end of the first switch, the first branch transmission line and the first common transmission line; The second transmission path of the fifth frequency band includes: a first end of the first switch, a third end of the first switch, the third branch transmission line, and the second common transmission line.

12. The multi-port connection circuit according to claim 8 or 11, characterized in that: The first receiving path of the fifth frequency band includes: the first common transmission line, the second branch transmission line, the second end of the second switch and the first end of the second switch; The second receiving path of the fifth frequency band includes: the second common transmission line, the fourth branch transmission line, the third end of the second switch and the fourth end of the second switch.

13. The multi-port connection circuit according to claim 11 or 12, characterized in that: The circuit further includes: a third switch, a fourth switch, a fifth branch transmission line, a sixth branch transmission line, a seventh branch transmission line, an eighth branch transmission line, a third common transmission line and a fourth common transmission line; The first end of the third switch and the second end of the third switch are two conductive ends, and the first end of the fourth switch and the second end of the fourth switch are two conductive ends; The second end of the third switch is connected to the first end of the fifth branch transmission line, and the second end of the fourth switch is connected to the first end of the sixth branch transmission line; The second end of the fifth branch transmission line and the second end of the sixth branch transmission line are both directly connected to the first end of the third common transmission line; The third end of the third switch and the fourth end of the third switch are two ends that can be conducted, and the third end of the fourth switch and the fourth end of the fourth switch are two ends that can be conducted; The third end of the third switch is connected to the first end of the seventh branch transmission line, and the third end of the fourth switch is connected to the first end of the eighth branch transmission line; The second end of the seventh branch transmission line and the second end of the eighth branch transmission line are both directly connected to the first end of the fourth common transmission line.

14. The multi-port connection circuit according to claim 13, characterized in that: The first end of the first switch and the fifth end of the first switch are two conductive ends, and the fifth end of the first switch is connected to the first end of the third switch; The third transmission path of the fifth frequency band includes: the first end of the first switch, the fifth end of the first switch, the first end of the third switch, the second end of the third switch, the fifth branch transmission line and the third common transmission line; The fourth transmission path of the fifth frequency band includes: the first end of the first switch, the fifth end of the first switch, the first end of the third switch, the third end of the third switch, the seventh branch transmission line and the fourth common transmission line.

15. The multi-port connection circuit according to claim 14, characterized in that: The third receiving path of the fifth frequency band includes: the third common transmission line, the sixth branch transmission line, the second end of the fourth switch and the first end of the fourth switch; The fourth receiving path of the fifth frequency band includes: the fourth common transmission line, the eighth branch transmission line, the third end of the fourth switch and the fourth end of the fourth switch.

16. The multi-port connection circuit according to claim 14, characterized in that: The third receiving path of the fifth frequency band includes: the third common transmission line, the fifth branch transmission line, the second end of the third switch and the fifth end of the third switch; The fourth receiving path of the fifth frequency band includes: the fourth common transmission line, the seventh branch transmission line, the third end of the third switch and the fourth end of the third switch.

17. A radio frequency front-end module, characterized in that: Comprising one or more multi-port connection circuits as claimed in claims 1 to 16.

18. An electronic device, characterized in that: It comprises one or more multi-port connection circuits as claimed in claims 1 to 16, or comprises the radio frequency front-end module as claimed in claim 17.

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