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

Abstract

The invention relates to the technical field of radio frequency circuits, and provides a multi-port connecting circuit, a radio frequency front-end module and electronic equipment. The multi-port connection 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 breakable ends, and the first end of the second switch and the second end of the second switch are two breakable ends; the second end of the first switch is connected with the first end of the first branch transmission line. The second end of the second switch is connected with 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 with the first end of the first common transmission line. The circuit can reduce insertion loss on a signal path.

Description

Technical Field

[0001] 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

[0002] 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 getting higher and higher. For example, terminal devices need to support more frequency bands and have more antennas to adapt to more communication scenarios.

[0003] Usually, people will add more RF channels to the RF front-end module of the terminal device to expand the frequency band. However, due to the limited space of the terminal device, the number of antennas cannot be increased indefinitely to adapt to the expansion of the RF channel. Therefore, people often reduce the number of antennas by sharing the same antenna for multiple RF channels. Then, when the number of antennas is limited and the number of RF channels is large, the switching scenarios of each RF channel in the RF front-end module become complicated. In order to cope with complex RF channel switching scenarios, the traditional way is to increase the number of switches or replace switches with more ports to meet complex switching scenarios.

[0004] However, increasing the number of switches or replacing switches with ones with more ports will increase the insertion loss of a single RF channel, resulting in increased power consumption of the terminal equipment. Summary of the invention

[0005] 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.

[0006] 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 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; 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.

[0007] 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 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, thereby achieving the purpose of frequency gating. Figure 3 In the multi-port connection circuit shown, there is no need to add switches or combiners (duplexers) for frequency selection. Instead, different branch transmission lines and a common transmission line are directly connected to directly terminate the two switches, and the signal of the first frequency band is selected 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 costs; and avoids the increase in insertion loss caused by the introduction of too many components, reducing the loss on the signal path. When the multi-port connection circuit is used in the RF front-end module, since the introduction of switches can be reduced and the method of directly terminating the transmission line is adopted, the complexity of antenna switching is also simplified, thereby improving the specifications of TAS and CA services, and improving the transmission performance in the form of crossover of TAS and CA services.

[0008] 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.

[0009] 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 of the second frequency band can be transmitted with low loss. Without affecting the normal transmission of the signal of 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 of the second frequency band, so that the signal of the second frequency band cannot pass through, thereby achieving the purpose of frequency selection and reducing the loss in the signal path.

[0010] In a possible implementation, the impedance matching state is a state where the port is fifty ohm impedance matched; and / or the high impedance state is a state where the reflection coefficient of the port is greater than a preset threshold.

[0011] 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 ends that can be turned on; 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 ends that can be turned on.

[0012] The port forms of the first switch and the second switch can be flexibly selected as needed to meet the requirements in different scenarios.

[0013] In a possible implementation, the second frequency band is the frequency band of the 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 the 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 the 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 twice the electrical length of the first branch transmission line and 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.

[0014] Optionally, the first preset error threshold and the second preset error threshold may be the same or different.

[0015] 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. That is, when the signal of the second frequency band is high, RouteA, RouteB, and shifter off If the carrier wavelength λ satisfies any one of the following formulas (6) or (8), it can be ensured that during high-frequency signal transmission, the insertion loss of the signal path will not have additional insertion loss or only a small insertion loss will be introduced due to mismatch.

[0016] In a possible implementation, 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.

[0017] This implementation method can achieve channel selection of different frequencies without introducing switches, which simplifies the switch switching scenario, ensures low insertion loss of the signal path, and expands the usage scenarios, making the usage scenarios richer.

[0018] 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 ends that can be conducted, and the third end of the first switch and the fourth end of the first switch are two ends that can be conducted; 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 ends that can be conducted, and the third end of the second switch and the fourth end of the second switch are two ends that can be conducted.

[0019] 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.

[0020] In a possible implementation, the multi-port connection circuit also 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.

[0021] In a possible implementation, 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 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 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.

[0022] That is to say, the multi-port connection circuit can include two groups of terminated transmission lines, further simplifying the circuit, reducing the insertion loss of more signal paths, and further simplifying the complexity of signal path switching, and reducing costs. When the multi-port connection circuit is applied to the RF front-end module, 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 improving the transmission performance in the form of TAS and CA services crossing.

[0023] 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 the 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 fourth value and the equivalent phase shift of the first switch is less than or equal to the fourth preset error threshold, and the fourth value is an integer multiple of the second carrier wavelength.

[0024] 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 in the foregoing text.

[0025] 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.

[0026] In a 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.

[0027] 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.

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

[0029] 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.

[0030] In a 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 two ends that can be conducted, and the first end of the fourth switch and the second end of the fourth switch are two ends that can be conducted; 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.

[0031] In this implementation, the multi-port connection circuit can also include four groups of terminated transmission lines, which further simplifies the circuit, reduces the insertion loss of more signal paths, further simplifies the complexity of signal path switching, and reduces costs. When the multi-port connection circuit is used in the RF front-end module, 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 improving the transmission performance in the form of TAS and CA services crossing.

[0032] In a possible implementation, 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. 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.

[0033] In this implementation, the multi-port connection circuit can meet the scenario of switching four antennas in the transmitting state, expand the usage scenarios, and improve product specifications.

[0034] 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.

[0035] In this implementation, the multi-port connection circuit can meet the scenario of switching four antennas in the receiving 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 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.

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

[0038] In a second aspect, a radio frequency front-end module is provided, comprising one or more multi-port connection circuits as in any one of the technical solutions of the first aspect.

[0039] In a third aspect, an electronic device is provided, comprising one or more multi-port connection circuits as in any one of the technical solutions of the first aspect.

[0040] 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.

[0041] 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

[0042] Figure 1 is a schematic diagram of the structure of a terminal device 100 provided in an embodiment of the present application;

[0043] Figure 2 It is a common circuit structure diagram including multiple signal channels;

[0044] Figure 3 is a schematic diagram of a structure of a multi-port connection circuit provided in an embodiment of the present application;

[0045] Figure 4 is a structural diagram of another example of a multi-port connection circuit provided in an embodiment of the present application;

[0046] Figure 5 is a simplified model schematic diagram of a multi-port connection circuit provided in an embodiment of the present application;

[0047] Figure 6 It is a simplified model schematic diagram of a circuit under an ideal state provided by an embodiment of the present application;

[0048] Figure 7is an equivalent circuit diagram of a multi-port connection circuit provided in an embodiment of the present application;

[0049] Figure 8 is an equivalent circuit diagram of a multi-port connection circuit provided in an embodiment of the present application;

[0050] Fig. 9 is a structural diagram of another example of a multi-port connection circuit provided in an embodiment of the present application;

[0051] Fig.10 is a structural diagram of another example of a multi-port connection circuit provided in an embodiment of the present application;

[0052] Fig.11 is a structural diagram of another example of a multi-port connection circuit provided in an embodiment of the present application;

[0053] Fig.12 is a structural diagram of another example of a multi-port connection circuit provided in an embodiment of the present application;

[0054] Fig.13 is a structural diagram of another example of a multi-port connection circuit provided in an embodiment of the present application;

[0055] Fig.14 is a structural diagram of another example of a multi-port connection circuit provided in an embodiment of the present application;

[0056] Fig.15 yes Fig.14 A simplified circuit structure diagram of a multi-port connection circuit is shown;

[0057] Fig.16 yes Fig.15 A signal flow diagram in the circuit structure shown;

[0058] Fig.17 yes Fig.15 Another signal flow diagram in the circuit structure shown;

[0059] Fig.18 yes Fig.15 Another signal flow diagram in the circuit structure shown;

[0060] Fig.19 yes Fig.15 Another signal flow diagram in the circuit structure shown;

[0061] Fig. 20 yes Fig.15 Another signal flow diagram in the circuit structure shown;

[0062] Fig.21 yes Fig.15 Another signal flow diagram in the circuit structure shown;

[0063] Fig. 22 yes Fig.15 Another signal flow diagram in the circuit structure shown;

[0064] Fig.23 yes Fig.15 Another signal flow diagram in the circuit structure shown;

[0065] Fig.24 yes Fig.15 Another signal flow diagram in the circuit structure shown;

[0066] Fig.25 yes Fig.15 Another signal flow diagram in the circuit structure shown;

[0067] Fig.26 is a structural diagram of another example of a multi-port connection circuit provided in an embodiment of the present application;

[0068] Fig. 27 An equivalent circuit diagram of a multi-port connection circuit provided in an embodiment of the present application;

[0069] Fig.28 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

[0070] The technical solutions in the embodiments of the present application will be described below in conjunction with the 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 only a description of the association relationship of associated objects, indicating that there can be three relationships, 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.

[0071] In the following, the terms "first", "second", and "third" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", and "third" may explicitly or implicitly include one or more of the features.

[0072] The multi-port connection circuit and radio frequency 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 (UMPC), netbooks, personal digital assistants (PDA), etc. The embodiments of the present application do not impose any restrictions on the specific types of terminal devices.

[0073] 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 getting higher and higher. Terminal devices need to support more frequency bands and have more antennas to adapt to more communication scenarios.

[0074] Usually, people will add more RF channels to the RF front-end module of the terminal device to expand the frequency band. For example, for terminal devices of global specifications, the frequency bands and frequency band combinations to be supported in different regions are different, so more frequency bands need to be supported to cover a wider area, which will lead to an increase in the number of RF channels in the terminal device, so more switch ports are required. For example, in the scenario of non-standalone (NSA) networking (5th Generation Mobile Communication Technology, 5G), or in the scenario of carrier aggregation (CA), multiple RF channels need to be transmitted simultaneously. Such requirements increase the complexity of 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 adapt to the expansion of RF channels. People often reduce the number of antennas by sharing the same antenna for multiple RF channels. 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. In order to cope with complex RF channel switching scenarios, the number of switches can be increased or replaced with switches with more ports to meet complex switching scenarios. 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 terminal devices.

[0075] The embodiment of the present application provides a multi-port connection circuit that can be applied to a radio frequency front-end module or a terminal device. By designing the port impedance of each radio frequency channel of the multi-port connection circuit, each radio frequency channel presents an impedance matching state for the frequency of the signal that needs to be passed directly, and can transmit the signal with low loss; for the signal that does not need to pass through, it presents a high impedance state, forming an open circuit characteristic to prevent the signal from passing through. In this way, different radio frequency channels can select signals of different frequencies without introducing switches, simplifying the circuit, avoiding the increase in insertion loss caused by introducing switches or combiners, reducing the loss of the path, and reducing costs at the same time.

[0076] For example, Figure 1 1 is a schematic diagram of the structure of an example 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 screen 194, and a subscriber identification module (SIM) card interface 195, etc. The sensor module 180 may include a pressure sensor 180A, a gyroscope sensor 180B, 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.

[0077] It is understood that the structure illustrated in the embodiment of the present application does 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 in the figure, or combine some components, or split some components, or arrange the components differently. The components shown in the figure may be implemented in hardware, software, or a combination of software and hardware.

[0078] 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 processor (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), etc. Different processing units may be independent devices or integrated into one or more processors.

[0079] 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.

[0080] 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.

[0081] Antenna 1 and antenna 2 are used to transmit and receive electromagnetic wave signals. Figure 1 The structures of antenna 1 and antenna 2 in the figure are only an example. Each antenna in the terminal device 100 can be used to cover a single or multiple communication frequency bands. Different antennas can also be reused to improve the utilization of the antennas. For example, antenna 1 can be reused as a diversity antenna for a wireless local area network. In some other embodiments, the antenna can be used in combination with a tuning switch.

[0082] 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.

[0083] The modem processor may include a modulator and a demodulator. Among them, the modulator is used to modulate the low-frequency baseband signal to be sent 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 the low-frequency baseband signal is processed by the baseband processor, it is passed to the application processor. The application processor outputs a sound signal through an audio device (not limited to a speaker 170A, a receiver 170B, etc.), or displays an image or video through a 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 arranged in the same device as the mobile communication module 150 or other functional modules.

[0084] 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., which are 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, modulates the frequency of the electromagnetic wave signal and performs filtering, and sends the processed signal to the processor 110. The wireless communication module 160 can also receive the signal to be sent from the processor 110, modulate the frequency of it, amplify it, and convert it into electromagnetic waves for radiation through the antenna 2.

[0085] 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).

[0086] In the above Figure 1 In the terminal device shown, the mobile communication module 150 and / or the wireless communication module 160 may be shown in the form of a radio frequency front-end module. Figure 1 Taking the terminal device of the structure shown as an example, the multi-port connection circuit provided in the embodiment of the present application is specifically described in combination with the accompanying drawings and application scenarios. It should be noted that in the RF front-end module, the multi-port connection circuit shown in the embodiment of the present application can be used to simplify the circuit structure by switching the RF channel (signal path) through a switch. Of course, the multi-port connection circuit provided in the embodiment of the present application is not limited to use in the RF front-end module, but can also be used in other scenarios of selection signals, which is not limited by the embodiment of the present application. Next, an exemplary description is given for the scenario in which the multi-port connection circuit is used in the RF front-end module.

[0087] Figure 2 Figure a in FIG. 1 is a schematic diagram of a part of the RF channel of a common RF front-end module with multiple switches cascaded. Figure 2 As shown in Figure a, for a single-channel high-frequency signal and a single-channel intermediate-frequency signal, they need to pass through two-stage switches to reach antenna 1 (ANT1) or antenna 2 (ANT2) from a double-pole double-throw switch or a double-pole four-throw switch; if the high-frequency signal or the intermediate-frequency signal reaches antenna 1 (ANT1) or antenna 2 (ANT2) in a carrier aggregation state (CA) or a dual-link state (DC), it needs to pass through two-stage switches and a combiner (or duplexer). Figure 2 Figure b in FIG. 1 is another common schematic diagram of a portion of RF channels in which multiple switches are cascaded in an RF front-end module. Figure 2 As shown in Figure b, the signals of B34, B39, B40 and the GMS high frequency transmission signal (GSM_HB_TX) also need to pass through a two-stage switch to reach antenna 1 (ANT1) or antenna 2 (ANT2).

[0088] Regarding the above Figure 2 In the scenario where the RF channel needs to be switched, the present application embodiment provides a multi-port connection circuit, which can be specifically referred to in Figure 4 As shown, it includes: a first switch, a second switch, a first branch transmission line, a second branch transmission line and a first common transmission line. Among them, 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.

[0089] Optionally, the first switch may be a single-pole double-throw switch, the second end of the first switch may be a common end of the switch, and the first end of the first switch may be any one of the two discrete ends. Optionally, the first 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 first switch may be a common end of the first switch, and the first end of the first switch may be any one of the multiple discrete ends. Figure 3 In the example, the first switch is a single-pole four-throw switch, and the first end of the first switch is a discrete end 1. Optionally, the first 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.

[0090] Optionally, the second switch may be a single-pole double-throw switch, the second end of the second switch may be a 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 a common end of the second switch, and the first end of the second switch may be any one of the multiple discrete ends. Figure 3 In the example, the second switch is a single-pole four-throw switch, and the first end of the second switch is a 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.

[0091] 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.

[0092] 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. Figure 3 The first end is marked with a number "1", and the second end is marked with a number "2".

[0093] for Figure 3 For the entire multi-port connection circuit shown, 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.

[0094] It should be noted that the off state of a certain end of a certain switch in the embodiment of the present application 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 suspended state. Specifically, the off state of a certain end of a certain switch may be a situation where the port and other ports of the switch are not conductive, but other ports may be conductive; or it may be a situation where none of the ports of the switch are conductive, that is, the entire switch is in the off state (also referred to as the off state). In addition, we expect the impedance of the port in the off state to be close to an infinite high impedance state.

[0095] That is to say, when the signal of the first frequency band flows into the multi-port connection circuit from port 1, since 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, the signal of the first frequency band can be transmitted to port 2 with a small insertion loss. In other words, the transmission coefficient (S12) between port 1 and port 2 is large, showing a low-loss direct transmission characteristic. Furthermore, for the first frequency band, since the first end of the second switch is in a high-impedance state in the first frequency band, which is equivalent to an open circuit state, the signal of the first frequency band flowing in from port 1 cannot pass through the second switch to reach port 3.

[0096] When the signal of the first frequency band flows into the multi-port connection circuit from port 2, since 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, the signal of the first frequency band can be transmitted to port 1 with a small insertion loss. In other words, the transmission coefficient (S21) between port 2 and port 1 is large, showing a low-loss direct transmission characteristic. Furthermore, for the first frequency band, since the first end of the second switch is in a high-impedance state in the first frequency band, which is equivalent to an open circuit state, the signal of the first frequency band flowing in from port 2 cannot reach port 3 through the second switch.

[0097] 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 with 0 ohms is relatively small, such as 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.

[0098] Optionally, the impedance matching state can be achieved by adjusting the line width and 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.

[0099] Optionally, the high impedance state can also be achieved by adjusting the line width and material of the first common transmission line and / or the second branch transmission line to adjust the impedance, or 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 to adjust the impedance. For the implementation of the matching network, please refer to the relevant description in the impedance matching state.

[0100] Optionally, the high impedance state may be a state where the port impedance is a larger value, for example, the port impedance is 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 impedance. Generally, in the high impedance state, the reflection state of the port is expected to be total reflection. Taking port 3 as an example, the reflection coefficient S33 is targeted to be close to 0, the larger the better, for example, greater than -0.5 dB.

[0101] From this we can see that both the impedance matching state and the high impedance state can be achieved by debugging the matching network on the signal path. Figure 4 An example of a matching network in the form of a T-type network composed of lumped parameter elements is shown. Figure 4 In the matching network, each matching position can be a capacitor or an inductor, and the specific capacitance value and inductance value are based on achieving the required impedance matching state.

[0102] In order to clearly illustrate the port impedance 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 turned off, Figure 3 or Figure 4 The circuit shown simplifies to Figure 5 Model shown. Figure 5 The port impedances of port 1 and port 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.

[0103] Above Figure 3 In the multi-port connection circuit shown, the second end of the first transmission line and the second end of the second branch transmission line are 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, thereby achieving the purpose of frequency gating. Figure 3In the multi-port connection circuit shown, there is no need to add switches or combiners (duplexers) for frequency selection. Instead, different branch transmission lines and a common transmission line are directly connected to directly terminate the two switches, and the signal of the first frequency band is selected 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 costs; and avoids the increase in insertion loss caused by the introduction of too many components, reducing the loss on the signal path. When the multi-port connection circuit is used in the RF front-end module, since the introduction of switches can be reduced and the method of directly terminating the transmission line is adopted, the complexity of antenna switching is also simplified, thereby improving the specifications of TAS and CA services, and improving the transmission performance in the form of crossover of TAS and CA services.

[0104] Optionally, in the above Figure 3 In the multi-port circuit shown, the channels of port 1 and port 3 can also be used to select the signal of the second frequency band. 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 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 of the second frequency band can be transmitted with low loss. Without affecting the normal transmission of the signal of 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 of the second frequency band, so that the signal of the second frequency band cannot pass through, thereby achieving the purpose of frequency selection and reducing the loss on the signal path.

[0105] 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, without the need to introduce components such as switches and combiners, and can achieve frequency selection and ensure low insertion loss characteristics of the signal path.

[0106] In order to clearly Figure 3 The implementation principle of the embodiment shown in the figure is described, and the factors affecting the insertion loss on the signal path are described here. Figure 3 Taking the multi-port connection circuit shown in the figure as an example, the insertion loss composition from port 2 to port 1 in the first frequency band may include the following:

[0107] 1. Insertion loss of the first common transmission line, denoted as IL common ;

[0108] 2. Insertion loss of the first branch transmission line, denoted as IL A ;

[0109] 3. The device insertion loss of the first switch when it is in the on state, denoted as IL1;

[0110] 4. The return loss introduced by the second branch transmission line and the insertion loss introduced by the impedance mismatch state are recorded as IL B ;

[0111] 5. The return loss introduced by the port of the second switch in the off state due to the inability of the impedance to reach the infinite high impedance state and the insertion loss introduced by the impedance mismatch state are recorded as IL off .

[0112] Therefore, when the signal of the first frequency band flows from port 2 to port 1, the insertion loss IL of the entire signal path is totle for:

[0113] IL totle =IL common +IL A +IL1+IL B +IL off Formula (1)

[0114] When the first common transmission line and the components in the multi-port connection circuit are fixed, the ideal insertion loss IL from port 2 to port 1 is ideal for:

[0115] IL ideal =IL common +IL1 formula (2)

[0116] The equivalent circuit diagram of the multi-port connection circuit under ideal insertion loss can be found in Figure 6 As shown, the insertion loss of the signal path from port 2 to port 1 in the first frequency band is IL common +IL1,IL common and IL1 are fixed insertion losses and cannot be avoided.

[0117] Then subtract the above formula (1) from formula (2) to get the additional insertion loss IL totle -IL ideal , which can be expressed as the following relationship:

[0118] IL totle -IL ideal =IL A +IL B +IL off Formula (3)

[0119] The three terms on the right side of formula (3): IL A IL B IL off It is an adjustable indicator that affects insertion loss.

[0120] It can be understood that the carrier wavelength is the ratio of the speed of light to the frequency, that is, it satisfies the relationship v = λ × f. Among them, the speed of light in air v can be approximated to the value of the speed of light in vacuum 3×10 8 m / s. For the communication frequency f used in mobile communication in the range of 450MHz to 7200MHz, the corresponding carrier wavelength λ is in the range of: 0.04 meters (m) (corresponding to 7200MHz) ≤ λ ≤ 0.67m (corresponding to 450MHz).

[0121] For common lower communication frequencies, the carrier wavelength is relatively long. For example, the carrier wavelength corresponding to a frequency of 2000MHz is 0.15m, which is 15 centimeters (cm). The length of the transmission line on the signal path is usually as short as possible, for example, it can be 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. Then, 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 paid attention to to meet the signal transmission requirements. In other words, for relatively low communication frequencies, only factors that affect impedance matching, such as materials, line width, and matching networks, need to be considered.

[0122] However, for higher communication frequencies, the carrier wavelength is relatively short. For example, the carrier wavelength corresponding to 7200MHz is 0.04m, or 4cm. When the transmission line length on the signal path is about 5mm, it is a comparable length compared to the 4cm carrier wavelength. In other words, when the transmission line length is close to the carrier wavelength, it is necessary to pay attention to the phase change during signal transmission.

[0123] 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 any one of the following formulas (4) or (5) to ensure low insertion loss:

[0124] RouteA+RouteB=αλ+kλ / 4, formula (4)

[0125] 2×RouteA=2×RouteB=αλ+kλ Formula (5)

[0126] Wherein, α is an integer, and the values ​​of α in formula (4) and formula (5) may be the same or different. Optionally, the ideal value of k is 1. However, in actual circuits, k may 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) may be different. When k takes a value close to 1, the above formula (4) and formula (5) are approximately true, that is, when k takes a value of 1, the equal sign in formula (4) and formula (5) may be an approximately equal sign (≈). 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).

[0127] by Figure 3 Taking the circuit structure shown as an example, if RouteA, RouteB and carrier wavelength λ satisfy formula (4), then for port 2 and port 3, the phase difference between the transmitted signal (also called 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. Port 3 is in an open circuit state when viewed from port 2, and port 2 is also in an open circuit state when viewed from port 3. In other words, for a port, another 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 carrier wavelength λ satisfy formula (4), the additional insertion loss IL in the signal path between port 1 and port 2 caused by the existence of the second branch transmission line and the second switch can be avoided or reduced. B and IL off , thus ensuring lower insertion loss in the signal path.

[0128] 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, which is 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 carrier phase), so there is no loss to the signal. Taking the signal path from port 1 to port 2 as an example, it is equivalent to not introducing or reducing the additional insertion loss IL B and IL off , thus ensuring lower insertion loss in the signal path.

[0129] That is to say, if RouteA, RouteB and carrier wavelength λ satisfy any one of formula (4) or formula (5), it can be ensured that during high-frequency signal transmission, the insertion loss of the signal path will not have additional insertion loss due to mismatch or only a small insertion loss will be introduced. Of course, if RouteA, RouteB and carrier wavelength λ do not satisfy any one of formula (4) and formula (5), it means that during high-frequency signal transmission, the insertion loss of the signal path will have a large additional insertion loss due to mismatch, resulting in a larger insertion loss of the signal path and affecting the transmission performance.

[0130] However, when the switch is in the off state, it is not physically disconnected in the strict sense, that is, it cannot reach an infinite high impedance state. Therefore, the switch or the port of the switch in the off state will still produce return loss for the transmitted signal, affecting the insertion loss in the signal path, that is, IL off But IL off The size of IL 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 IL even in the off state. off At this time, the phase of the signal can be changed by adding a phase shift network in the path to offset the phase change caused by the return loss. At this time, the phase change caused by the return loss can be regarded as the equivalent phase shift of the switch, recorded as shifter off Then RouteA, RouteB, shifter off and the carrier wavelength λ need to satisfy either the following formula (6) or formula (7) to ensure low insertion loss:

[0131] RouteA+RouteB+shifter off =αλ+kλ / 4, formula (6)

[0132] 2×RouteA=2×(RouteB+shifter off )=αλ+kλ Formula (7)

[0133] Wherein, α is an integer, and the values ​​of α in formula (6) and formula (7) may be the same or different. Optionally, the ideal value of k is 1. However, in actual circuits, k may 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) may be different. When k takes a value close to 1, the above formulas (4) and (5) are approximately valid, that is, when k takes a value of 1, the equal sign in formula (6) and formula (7) may be an approximate equal sign (≈). Whether k takes a value close to 1, or k takes a value equal to 1 and the equal sign is changed to an approximate equal sign, they can all be called RouteA, RouteB, shifter off and the carrier wavelength satisfy formula (6) or formula (7).

[0134] by Figure 3 As an example of the circuit structure shown in the figure, if RouteA, RouteB, shifter off and the carrier wavelength λ satisfy formula (6), then for port 2 and port 3, the phase difference between the transmitted signal (also called 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. Then, port 2 is in an open circuit state when looking at port 3, and port 3 is also in an open circuit state when looking at port 2. In other words, for a port, another 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 IL 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. B and IL off , thus ensuring lower insertion loss in the signal path.

[0135] 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 returns 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, which is 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, shifter off and the carrier wavelength λ satisfy formula (6), which is equivalent to not introducing or reducing the additional insertion loss IL B and IL off , thus ensuring lower insertion loss in the signal path.

[0136] That is to say, if RouteA, RouteB and carrier wavelength λ satisfy any one of formula (6) or formula (7), it can be ensured that during high-frequency signal transmission, the insertion loss of the signal path will not be introduced due to mismatch or only a small insertion loss will be introduced. off If the carrier wavelength λ does not satisfy any of the equations (6) and (7), it means that during high-frequency signal transmission, the insertion loss of the signal path will have a large additional insertion loss due to mismatch, such as IL B and IL off It is relatively large, which causes the insertion loss of the signal path to increase and affects the transmission performance.

[0137] Based on the above description of the characteristics of high-frequency signal transmission, the present application embodiment also provides a multi-port connection circuit, the specific structure of which can be seen in Figure 3 or Figure 4 As shown, 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.

[0138] 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, when the signal of 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 in the first frequency band, and the first end of the second switch is in a high impedance state in the first frequency band. At this time, the signal of the first frequency band can pass through the signal path from port 1 to port 2 with low loss.

[0139] 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 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 can be less than or equal to the first preset error threshold value with a first value, and the first value is the sum of an integer multiple of the first carrier wavelength corresponding to one-quarter of the second frequency band (αλ) 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, then the shifter in formula (6) off Then it represents the equivalent phase shift corresponding to the second end of the first switch when it is turned off. Then for the signal path between port 1 and port 3, the additional insertion loss IL caused by the introduction of the first branch transmission line and the first switch can be avoided or reduced. A and IL off, which can ensure low insertion loss of the signal path between port 1 and port 3.

[0140] 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 turned on, 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 electrical length of the second branch transmission line and the sum of the equivalent phase shift corresponding to the first switch in 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 may be the same or different. Both may 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 port off state is the first switch, and the signal path is from port 1 to port 3, then the shifter in formula (7) off Then it represents the equivalent phase shift corresponding to the second end of the first switch when it is turned off, and the adaptive evolution of formula (7) is formula (8):

[0141] 2×RouteB=2×(RouteA+shifter off )=αλ+kλ Formula (8)

[0142] Where 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 approximate equal sign (≈). Whether k takes a value close to 1, or k takes a value equal to 1 and the equal sign is changed to an approximate equal sign, they can all be called RouteA, RouteB, shifter off and the carrier wavelength satisfy formula (8).

[0143] 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.

[0144] Based on the same principle as the above formula (7), for the signal path between port 1 and port 3, the additional insertion loss IL caused by the introduction of the first branch transmission line and the first switch can be avoided or reduced. A and IL off , ensuring that the signal path between port 1 and port 3 has the characteristic of low insertion loss.

[0145] 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 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.

[0146] It should be noted that the carrier wavelength corresponding to the frequency band described above may 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 is a fixed frequency, the carrier wavelength is the wavelength corresponding to the fixed frequency; if the input signal is a signal with a frequency point that changes within a frequency band, the carrier wavelength may be the wavelength corresponding to the center frequency of the frequency band, so as to be compatible with the characteristics of the entire frequency band as much as possible.

[0147] 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 a lower insertion loss, then Figure 3 The structural diagram of the multi-port connection circuit shown can be equivalent to Figure 7 The equivalent circuit diagram is shown. Figure 7 The path corresponding to the second switch in (including the second switch and the second branch transmission line) is equivalent to not existing.

[0148] 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 can be transmitted on the signal path between port 1 and port 3 with lower insertion loss, then Figure 3 The structural diagram of the multi-port connection circuit shown in FIG. Figure 8 . Figure 8 The path corresponding to the first switch in (including the first switch and the first branch transmission line) is equivalent to not existing.

[0149] In the above Figure 3 On the basis of the shown embodiment, a first phase shift network can be added at the first port of the first switch, and the first phase shift network can be a filter or a trap. It should be noted that the filter and the trap can be realized by series and / or parallel capacitors and inductors, and 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 required signal of the first frequency band and suppress the unnecessary signal of the second frequency band, and realize the required impedance matching state while the frequency is selected. Optionally, a second phase shift network can be added at the first port of the second switch, and 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 each component in the second phase shift network are not exactly the same as those of the first phase shift network. The second phase shift network can select the required signal of the second frequency band and suppress the unnecessary signal of the first frequency band, and realize the required impedance matching state while the frequency is selected. For details, please refer to Fig. 9 As shown, Fig. 9 The first phase shift network and the second phase shift network in the embodiment are both shown in the form of a Π-type network. Optionally, the first phase shift network and the second phase shift network can be as follows: Fig. 9 The lumped parameter components shown may also be modular components, such as a surface acoustic wave filter (SAW) and a modular notch filter (Notch). The specific form of the phase shift network is not limited in the embodiment of the present application. Optionally, the first phase shift network and the second phase shift network may exist at the same time or not, as long as they can meet the impedance state of each port when the frequency needs to be selected.

[0150] Fig. 9The multi-port connection circuit shown 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 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 (that is, port 2) and the second end of the first common transmission line (that is, port 1) are in an impedance matching state in the first frequency band. Among them, 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 will be suppressed and cannot pass. The second end of the second phase shift network (port 3) and the second end of the first common transmission line (that is, port 1) are in an impedance matching state in the second frequency band. Among them, 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 will be suppressed and cannot pass. Fig. 9 In the embodiment shown, by adding phase shift networks of corresponding frequencies to the two paths respectively, the frequency gating is realized when the two switches are turned on, which can be applied to the scenario where two signals are concurrent, such as the non-independent networking scenario (NSA) and the carrier aggregation (CA) scenario. This implementation method can also realize the gating of channels of different frequencies without introducing switches, which simplifies the switch switching scenario, ensures the low insertion loss of the signal path, and expands the use scenarios, making the use scenarios richer.

[0151] In the above embodiments, the first switch and the second switch are described as single-pole multi-throw switches as an example. 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, which 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.

[0152] In some scenarios, the first switch and / or the second switch may also be a multi-pole multi-throw switch, such as a double-pole double-throw, double-pole triple-throw, double-pole four-throw, triple-channel three-throw, three-to-four-throw, etc., which have more terminals and more channels. The first switch and the second switch may be the same or different. Fig.10In the example, the first switch is a three-pole three-throw switch and the second switch is a double-pole four-throw switch. Fig.10 As shown, the third end of the first switch (the end marked with "3") and the first end of the first switch are two ends that can be conducted, and the third end of the first switch and the fourth end of the first switch (the end marked with "4") are two ends that can be conducted. Optionally, the third end of the second switch (the end marked with "3") and the first end of the second switch are two ends that can be conducted, and the third end of the second switch and the fourth end of the second switch (the end marked with "4") are two ends that can be conducted. Optionally, the unconnected ends of the first switch and the second switch can be connected to other signal paths to achieve multi-channel switching.

[0153] When the first switch and / or the second switch is a multi-pole multi-throw switch, the multi-port connection circuit can also be as follows: Fig.11 As shown, it includes: a third branch transmission line, a fourth branch transmission line and a second common transmission line. Fig.11 For Fig.10 Based on the example, Fig.11 A group of terminated transmission lines including a third branch transmission line, a fourth branch transmission line and a second common transmission line is 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 above embodiments, which will not be repeated here. Fig.11 The signal path where the third branch transmission line is located corresponds to the fourth port of the first switch, that is, Fig.11 Port 5 in , and the signal path where the fourth branch transmission line is located corresponds to the fourth port of the second switch, that is, Fig.11 Port 6 in the figure, and the second end of the second branch transmission line corresponds to Fig.11 In fact, since the third end of the first switch can also be connected to the first end, the third end of the second switch can also be connected to the first end, as long as the corresponding port impedance state meets the requirements of the gating frequency and low insertion loss.

[0154] exist Fig.11In the multi-port connection circuit shown, 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 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 turned on, if the fourth frequency band is a frequency band where the carrier wavelength and the transmission line size are incomparable, 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, then the selection and transmission of the fourth frequency band signal with low insertion loss characteristics can be guaranteed. The specific implementation principles and beneficial effects can be found in the above text as Figures 3 to 9 Optionally, the third frequency band may be the same as or different from the first frequency band, and the fourth frequency band may be the same as or different from the second frequency band. No further details will be given here.

[0155] exist Fig.11 In the illustrated embodiment, 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, if the fourth frequency band is a frequency band in which the carrier wavelength and the transmission line size are comparable, 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 the third value is less than or equal to the third preset error threshold, and 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 twice the electrical length of the fourth 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 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 set of relationships in the above formula (6) and formula (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 formula (6) and formula (8) in the previous text, which will not be repeated here.

[0156] The third preset error threshold and the fourth preset error threshold may be the same or different. Both may 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 third preset error threshold and the fourth preset error threshold. Moreover, 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 in the foregoing text, and the embodiment of the present application does not limit them.

[0157] In some embodiments, the above Fig.11 The structure shown 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 to say, 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 to say, 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.

[0158] If the fifth frequency band is in the MIMO receiving state, it can also include two receiving paths. Among them, the first receiving path includes: a first common transmission line, a second branch transmission line, a second end of the second switch, and a first end of the second switch. That is to say, the receiving signal of the fifth frequency band can be received by one antenna, and 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 in sequence. In addition, the second receiving path includes: a second common transmission line, a fourth branch transmission line, a third end of the second switch, and a fourth end of the second switch. That is to say, the receiving signal of the fifth frequency band can also be received by another antenna, and 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 in sequence.

[0159] Optionally, the fifth frequency band may be the same frequency band as any one of the first frequency band, the second frequency band, the third frequency band or the fourth frequency band, or may be a different frequency band, which is not limited in the embodiment of the present application. The first end and the fourth end of the first switch in the two transmission paths of the fifth frequency band are not limited to the first end and the fourth end, but may also be ports in the first switch that can be connected to the second end and the third end respectively, which may be adjusted according to the design of the overall circuit, which is not limited in the embodiment of the present application.

[0160] Next, the application of the multi-port connection circuit provided in the embodiment of the present application in an actual circuit is described. Figure 2 Take the circuit shown in Figure a in the figure as an example. After the multi-port connection circuit is introduced, the structure of the original circuit has changed. Fig.12 As shown in Figure a. Figure 2 In Figure a, the combiner is reduced. That is to say, if the high-frequency signal or the carrier aggregation state (CA) or dual link state (DC) of the intermediate frequency signal reaches antenna 1 (ANT1) or antenna 2 (ANT2), it needs to pass through two-stage switches instead of a combiner. When the port impedance state meets the requirements, different signal paths can realize the selection of high-frequency signals and intermediate frequency signals, and at the same time, low insertion loss can be achieved, and the circuit is simplified, reducing costs. For another example, Figure 2 Take the circuit shown in Figure b in the figure as an example. After the multi-port connection circuit is introduced, the structure of the original circuit has changed. For details, please refer to Fig.12 As shown in Figure b. Fig.12 In Figure b, for the GSM high frequency transmission signal (GSM_HB_TX), B34, B39 and B40 band signals, only one switch is needed to connect to the antenna. Figure 2 As shown in Figure b, a switch is reduced in the path of GSM high-frequency transmission signals, B34, B39 and B40 frequency band signals. 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.

[0161] In the above Fig.12 Based on the embodiment shown in FIG. a, the signal path of the single-channel high-frequency signal and the single-channel intermediate-frequency signal can also adopt a set of terminated transmission lines. For details, see Fig.13 shown. Fig.13 In the figure, port 2 and port 5 correspond to the terminals of the same switch, and port 3 and port 6 correspond to the terminals of the same switch. Fig.13 As shown in the figure, since a set of terminated transmission lines is introduced, 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 switch itself are the same, in general, the more switch ports there are, the greater the insertion loss, and the fewer switch ports there are, the smaller the insertion loss. Fig.13 In the circuit shown, due to the introduction of an additional set of terminated transmission lines, the number of switch ports is reduced, which can reduce the insertion loss of the entire signal path.

[0162] When the above multi-port connection circuit is applied to the RF front-end module, the circuit diagram of the relevant part can be found in Fig.14First, Fig.14 The functions and marked symbols of each component in the figure are explained. Usually, the filter that appears 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 necessary frequency; the notch filter can suppress the signal that needs to be suppressed and pass other signals of necessary frequency; 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. Usually, couplers on multiple different signal paths can also be connected to each other and share a power detection port. Fig.14 In, 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 discrete ends of the duplexer can select two signals of different frequencies, and the common end can pass signals of different frequencies; the four discrete ends of the quadplexer can select four signals of different frequencies respectively, 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 Fig.14 In the figure shown, the transmission line shown by the black thick line is the terminated transmission line in the multi-port connection circuit described in this application. Fig.14 Four groups of terminated transmission lines are shown in FIG. Originally, each group of terminated transmission lines uses a single-pole double-throw switch to achieve frequency gating or path gating, or multiple groups of terminated transmission lines can use multi-pole multi-throw switches to achieve frequency gating or path gating. After adopting the technical solution of the present application, there is no need to use multiple single-pole double-throw switches or multi-pole multi-throw switches, which reduces the introduction of switch elements. Next, Fig.14 The circuit shown in the figure describes the signal flow in different working states to illustrate Fig.14 While reducing the insertion loss of the path, the specifications of the original circuit will not be reduced.

[0163] In order to clearly describe the signal flow under the TAS service, Fig.14 The irrelevant components and connecting lines in the circuit are simplified. The simplified circuit structure diagram can be seen in Fig.15 shown. Fig.15 can be considered to include two groups such as Fig.11 The multi-port connection circuit shown can be used, for example, Fig.11 Based on the multi-port connection circuit shown in FIG. 1 , a second group of multi-port connection circuits is added.

[0164] The second group of multi-port connection circuits includes: a third switch ( Fig.15 The first switch -2), the fourth switch ( Fig.15 The second switch-2 in the embodiment of the present invention is connected to the fifth branch transmission line, the sixth branch transmission line, the seventh branch transmission line, the eighth branch transmission line, the third common transmission line and the fourth common transmission line. Among them, the first end of the third switch and the second end of the third switch are two ends that can be turned on, and the first end of the fourth switch and the second end of the fourth switch are two ends that can be turned on. 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 turned on, and the third end of the fourth switch and the fourth end of the fourth switch are two ends that can be turned on. 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.

[0165] Above Fig.15 In the example, two groups of multi-port connection circuits can respectively realize dual antenna switching. For details, please refer to Fig.11 The description of operation in the fifth frequency band will not be repeated here. Fig.15 The two groups of multi-port connection circuits in the embodiment can also be combined into an integral 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.

[0166] exist Fig.15 For the first transmission path (n41_TX_TAS2) and the second transmission path (n41_TX_TAS1) of the fifth frequency band, see Fig.17 and Fig.16As shown. For the fifth frequency band, a third transmission path (n41_TX_TAS4) can be added, including: 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. At the same time, a fourth transmission path (n41_TX_TAS4) can be added for the fifth frequency band, including: 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. For details, please refer to Fig.19 and Fig.18 shown.

[0167] exist Fig.15 For the first receiving channel (n41_RX1) and the second receiving channel (n41_RX2) of the fifth frequency band, see Fig. 20 As shown. A third receiving path may be added for the fifth frequency band, including: a third common transmission line, a sixth branch transmission line, a second end of a fourth switch, and a first end of a fourth switch. In addition, the fourth receiving path of the fifth frequency band includes: a fourth common transmission line, an eighth branch transmission line, a third end of a fourth switch, and a fourth end of a fourth switch. It should be noted that the first end of the fourth switch and the fourth end of the fourth switch may also be other ports of the fourth switch, as long as they can be respectively connected to the second end and the third end of the fourth switch.

[0168] Optionally, the third receiving path of the fifth frequency band may further include: a third common transmission line, a fifth branch transmission line, a second end of a third switch, and a 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, a third end of a third switch, and a fourth end of the third switch. It should be noted that the fourth end of the third switch and the fifth end of the third switch here may also be other ports of the third switch, as long as they can be respectively connected to the second end and the third end of the third switch.

[0169] In the above Fig.15 In the multi-port connection circuit shown, taking the fifth frequency band as n41 as an example, it can also be compatible with the four-antenna TAS service and the four-antenna MIMO scenario of the sixth frequency band. Fig.15 The circuit schematic diagram shown describes the signal trend of the multi-antenna switching scenario of n41 and B1 / B3 by taking the sixth frequency band as B1 or B3 (expressed as B1 / B3) as an example.

[0170] exist Fig.15 In the n41 frequency band, the four-antenna TAS service can be realized. The four transmission paths can be respectively shown as follows: Fig.16 , Fig.17 , Fig.18 and Fig.19The arrows shown indicate the pathway. Fig.16 As shown, in the first n41 signal path indicated by n41_TX_TAS1, the transmission signal of the n41 frequency band reaches antenna 4 (ANT4) after passing through the multi-port connection circuit, and the signal of the n41 frequency band is transmitted through ANT4. Fig.17 As shown, in the second n41 signal path indicated by n41_TX_TAS2, the transmission signal of the n41 frequency band reaches antenna 3 (ANT3) after passing through the multi-port connection circuit, and the signal of the n41 frequency band is transmitted through ANT3. Fig.18 As shown, in the third n41 signal path indicated by n41_TX_TAS3, the transmission signal of the n41 frequency band reaches antenna 2 (ANT2) after passing through the multi-port connection circuit, and the signal of the n41 frequency band is transmitted through ANT2. Fig.19 As shown, 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.

[0171] Fig. 20 The following is a schematic diagram of the four receiving paths of n41 in the MIMO scenario. The four receiving paths are represented by n41_RX1, n41_RX2, n41_RX3 and n41_RX4 respectively.

[0172] Above Figures 16 to 20 It shows that when the multi-port connection circuit is introduced into the RF front-end module, the path switching function of the TAS service and MIMO service of n41 will not be affected. Since the introduction of switches is reduced, the complexity of antenna switching can be simplified, the transmission performance of TAS service and MIMO service can be improved, and the loss of signal path can be reduced.

[0173] In the above Fig.14 and Fig.15 In the circuit shown, the B1 and B3 frequency bands can also realize the four-antenna TAS service, and the four transmission paths can be respectively shown as follows: Fig.21 , Fig. 22 , Fig.23 and Fig.24 The arrows shown indicate the pathway. Fig.21 As shown, in the first B1 / B3 (indicating B1 or B3) signal path indicated by B1 / B3_TX_TAS1, the transmission signal of the B1 / B3 frequency band reaches ANT1 after passing through the multi-port connection circuit, and the signal of the B1 / B3 frequency band is transmitted through ANT1. Fig. 22As shown, in the second B1 / B3 signal path indicated by B1 / B3_TX_TAS2, the transmission signal of the B1 / B3 frequency band reaches ANT2 after passing through the multi-port connection circuit, and the signal of the B1 / B3 frequency band is transmitted through ANT2. Fig.23 As shown, in the third B1 / B3 signal path indicated by B1 / B3_TX_TAS3, the transmission signal of the B1 / B3 frequency band reaches ANT3 after passing through the multi-port connection circuit, and the signal of the B1 / B3 frequency band is transmitted through ANT3. Fig.24 As shown, in the fourth B1 / B3 signal path indicated by B1 / B3_TX_TAS4, the transmission signal of the B1 / B3 frequency band reaches ANT4 after passing through the multi-port connection circuit, and the signal of the B1 / B3 frequency band is transmitted through ANT4.

[0174] Fig.25 Figure 1 is a schematic diagram of the four receiving paths of B1 / B3 in the MIMO scenario. The four receiving paths are represented by B1 / B3_RX1, B1 / B3_RX2, B1 / B3_RX3 and B1 / B3_RX4. The received signal of B1 / B3 can be entered as follows: Fig.14 The quadplexer shown performs selection of different signal paths, which will not be described in detail here.

[0175] Above Figure 21 to Figure 25 It shows that when the multi-port connection circuit is introduced into the RF front-end module, the path switching function of the TAS service and MIMO service of B1 / B3 will not be affected. Since the introduction of switches is reduced, the complexity of antenna switching can also be simplified, the transmission performance of TAS and MIMO services can be improved, and the loss of signal paths can be reduced.

[0176] Fig.26 This 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: Fig.26 The meaning of the icons and labels of each component in Fig.14 The description is not repeated here. Fig.26 Among them, ANT3 can be used as the antenna for MIMO scenarios of intermediate frequency signals (B1\B3 and other frequency bands); ANT4 can be used as the 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 the antenna for the n78 frequency band; ANT2 can be used as the diversity antenna for intermediate frequency signals (B1\B3 and other frequency bands) and high frequency signals (B7 and other frequency bands).

[0177] Fig.26In some circuits of the RF front-end module shown, the introduction of a multi-port connection circuit will not affect the path switching function in various scenarios, but can also simplify the circuit and reduce path loss.

[0178] Fig. 27 An equivalent circuit diagram of a multi-port connection circuit provided in an embodiment of the present application.

[0179] The foregoing 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.

[0180] For details, please refer to Fig. 27 The equivalent circuit diagram of the multi-port connection circuit shown. Fig. 27 Figure a is a schematic diagram of the actual multi-port connection circuit. When port 1 to port 2 transmits the signal of the first frequency band, the ideal state can be Fig. 27 The a graph in is equivalent to Fig. 27 The circuit diagram is shown in Figure b. In order to make a clear comparison of 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 can be obtained, which can be seen in Fig.28 As shown. Fig.28 It can be seen that Fig. 27 The actual circuit shown in FIG. 1 has a smaller insertion loss increase than the ideal circuit. The specific value can be explained by the reading of the marked point. The specific values ​​of the marked points at each frequency point of the S parameter can be sorted into the parameters in Table 1.

[0181] Table 1

[0182] Frequency (MHz) S21(dB) S54(dB) Insertion loss gain (dB) 1710 1.5 1.3 -0.2 1810 1.6 1.4 -0.2 2170 1.8 1.6 -0.2 2500 2.3 1.8 -0.5 2690 2.5 1.9 -0.6 Frequency (MHz) S31(dB) S54(dB) Insertion loss gain (dB) 1710 1.5 1.3 -0.2 1810 1.6 1.4 -0.2 2170 1.8 1.6 -0.2 2500 2.0 1.8 -0.2 2690 2.1 1.9 -0.2

[0183] Combination Fig.28From Table 1, S21 is the insertion loss of the signal path from port 1 to port 2 at different frequency points when transmitting signals, which are 1.5dB, 1.6dB, 1.8dB, 2.3dB and 2.5dB at 1710MHz, 1810MHz, 2170MHz, 2500MHz and 2690MHz respectively; S54 is the insertion loss of the signal path from port 5 to port 4 at different frequency points when transmitting signals, which are 1.3dB, 1.4dB, 1.6dB, 1.8dB and 1.9dB at 1710MHz, 1810MHz, 2170MHz, 2500MHz and 2690MHz respectively. The insertion loss of common switches is greater than 0.3dB in the frequency band below 2170MHz, and the insertion loss is often close to 1dB in the frequency band above 2500MHz. 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 large insertion loss of more than 0.3 dB caused by the introduction of switches. 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 large insertion loss of nearly 1 dB caused by the introduction of switches. The technical solution of the embodiment of the present application has obvious benefits.

[0184] Similarly, if the signal is transmitted through the signal path of port 1 and port 3, the data of S31 can be referred to. It can be seen that increasing the insertion loss on the common transmission line by 0.2dB can avoid the large insertion loss caused by the introduction of the switch, which has obvious benefits and can reduce the insertion loss while selecting different frequency signals.

[0185] 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.

[0186] 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.

[0187] An embodiment of the present application also provides an electronic device, comprising the RF front-end module described in any of the above embodiments.

[0188] 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.

[0189] In several embodiments provided in the present 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 only 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 may be selected according to actual needs to achieve the purpose of the scheme of this embodiment.

[0190] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0191] 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, including several instructions to enable a device (which can be a single-chip microcomputer, chip, etc.) or a processor (processor) to perform all or part of the steps of the various embodiments of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read only memory (ROM), random access memory (RAM), disk or optical disk and other media that can store program code.

[0192] The above contents are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A 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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