Radio frequency front-end module, impedance control method thereof and communication device

Abstract

The application discloses a radio frequency front-end module, an impedance control method thereof and a communication device. The radio frequency front-end module comprises a multiplexer and a switchable impedance network connected between an antenna end and a common end of the multiplexer. The switchable impedance network is configured to switch to a first impedance state to match the impedance of the common end with the impedance of the antenna end in response to a first working mode when the multiplexer works independently, and switch to a second impedance state to present high impedance on at least one target aggregated frequency band in response to a second working mode when the multiplexer performs carrier aggregation with the target aggregated frequency band. The radio frequency front-end module can dynamically adjust its impedance characteristics according to the working mode, thereby effectively reducing mutual interference between signals of different frequency bands in the carrier aggregation mode while ensuring the independent working performance of the multiplexer, and improving the overall performance of the system in a complex communication scenario.

Description

Technical Field

[0001] This application relates to the field of radio frequency communication technology, specifically to radio frequency front-end modules and their impedance control methods, and communication equipment. Background Technology

[0002] Radio frequency (RF) front-end modules are key components for signal transmission and reception in modern wireless communication equipment. With the evolution of mobile communication technology towards 5G and the exploration of future 6G, users' demands for data throughput and network connectivity reliability are constantly increasing. To overcome the limited bandwidth bottleneck provided by a single frequency band or carrier, carrier aggregation (CA) technology has become an essential component of communication standards. It allows terminals to simultaneously utilize multiple discrete or continuous frequency band resources for data transmission, thereby significantly improving overall transmission rate and spectrum utilization. Therefore, supporting flexible and efficient carrier aggregation operating modes has become an indispensable core capability and development trend for RF front-end modules.

[0003] To achieve multi-band support, RF front-end modules commonly employ an architecture that includes a multiplexer. Current RF front-end module designs primarily focus on optimizing the performance parameters of the multiplexer in its independent operating frequency band, such as insertion loss and out-of-band rejection. However, when the RF front-end module enables carrier aggregation, meaning the frequency band corresponding to the multiplexer operates simultaneously with the target aggregation frequency band, this RF front-end module, designed solely for optimizing the performance of the multiplexer itself, reveals its limitations. Leakage paths can occur between the multiplexer and other concurrent signal paths, leading to interference between signals from multiple different frequency bands. This degrades the overall performance of the RF front-end module in carrier aggregation scenarios, affecting aspects such as system linearity, noise figure, or transmit efficiency.

[0004] Therefore, for RF front-end modules, how to effectively overcome the performance degradation caused by mutual interference of signals in carrier aggregation scenarios without sacrificing the performance of the internal multiplexer when it works independently has become an urgent technical problem to be solved. Summary of the Invention

[0005] In view of this, embodiments of this application provide a radio frequency front-end module and its impedance control method, as well as a communication device.

[0006] In a first aspect, embodiments of this application provide a radio frequency front-end module, including a multiplexer and a switchable impedance network, wherein the switchable impedance network is connected between the antenna end and the common end of the multiplexer; The switchable impedance network is configured as follows: In response to the first operating mode when the multiplexer is operating independently, the system switches to a first impedance state to match the impedance of the common terminal with the impedance of the antenna terminal. In addition, in response to a second operating mode when the multiplexer performs carrier aggregation with at least one target aggregation band, it switches to a second impedance state to present high impedance on the target aggregation band.

[0007] In some embodiments, the switchable impedance network is configured to change the connection relationship of its internal components in response to the operating mode of the RF front-end module, so as to switch between a first impedance state and a second impedance state; wherein the operating mode of the RF front-end module includes the first operating mode and the second operating mode.

[0008] In some embodiments, in the first operating mode, the switchable impedance network switches to a first circuit structure, the first circuit structure including a first capacitive impedance unit connected between the antenna end and the common end; And / or, in the second operating mode, the switchable impedance network switches to a second circuit structure, the second circuit structure including a second capacitive impedance unit connected in series between the antenna end and the common end, and a first inductive impedance unit connected between the common end and the reference potential end.

[0009] In some embodiments, the capacitance value of the first capacitive impedance unit is greater than the capacitance value of the second capacitive impedance unit.

[0010] In some embodiments, the switchable impedance network includes a first capacitor, a second capacitor, a switch, and a first inductor. The first capacitor is connected in series between the common terminal and the antenna terminal. One end of the second capacitor is connected to the common terminal, and one end of the first inductor is connected to the reference potential terminal. The switch is configured as follows: In response to the first operating mode, the system switches to a first connection state to connect the other end of the second capacitor to the antenna end and disconnect the other end of the first inductor from the antenna end. The switchable impedance network switches to a first circuit structure that is disconnected from the first inductor. In response to the second operating mode, the system switches to a second connection state to disconnect the other end of the second capacitor from the antenna terminal and connect the other end of the first inductor to the antenna terminal, and the switchable impedance network switches to a second circuit structure connected to the first inductor.

[0011] In some embodiments, the capacitance value of the second capacitor is greater than the capacitance value of the first capacitor.

[0012] In some embodiments, the switchable impedance network includes: A second inductor connected between the common terminal and the reference potential terminal; And / or, at least one signal channel within the multiplexer is connected in parallel with a third inductor.

[0013] In some embodiments, the inductance of the first inductor is greater than that of the second inductor.

[0014] In some embodiments, the multiplexer is a quad-multiplexer that integrates transmit and receive paths for Band 1 and Band 3; and / or, the target aggregation band includes Band 40 and / or Band 41.

[0015] Secondly, embodiments of this application provide an impedance control method for a radio frequency front-end module as described in any one of the first aspects, comprising: The operating mode of the radio frequency front-end module is determined, including a first operating mode when the multiplexer in the radio frequency front-end module operates independently, and a second operating mode when the multiplexer performs carrier aggregation with at least one target aggregation frequency band. Based on the determined operating mode, a switching control signal is generated and output to the switchable impedance network in the RF front-end module to control the switchable impedance network to switch between the first impedance state and the second impedance state.

[0016] Thirdly, embodiments of this application provide a communication device, including an antenna end and a radio frequency front-end module as described in any one of the first aspects, wherein the radio frequency front-end module is coupled to the antenna end.

[0017] The RF front-end module provided in this application addresses the challenge of effectively overcoming signal interference in carrier aggregation scenarios without sacrificing the performance of its internal multiplexer when operating independently. It addresses this issue by establishing a switchable impedance network between the antenna and the common terminal of the multiplexer. This network dynamically switches between a first impedance state and a second impedance state based on different operating modes of the RF front-end module. When the multiplexer operates independently, impedance matching between the common terminal and the antenna is achieved, optimizing signal transmission efficiency. Furthermore, when the multiplexer performs carrier aggregation with at least one target aggregation band, the network exhibits high impedance on that target aggregation band, significantly reducing loading and interference on the signal transmission path of that aggregation band. Therefore, the RF front-end module provided in this application overcomes the shortcomings of RF front-end modules in related technologies that cannot simultaneously handle both independent multiplexer operation and carrier aggregation operation. It achieves adaptive adjustment of impedance characteristics according to actual communication needs, effectively suppressing in-band interference during carrier aggregation without affecting the independent performance of the multiplexer, thus improving overall system performance and communication quality during multi-band collaborative operation. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the architecture of a radio frequency front-end module provided in an embodiment of this application.

[0020] Figure 2 This is a schematic diagram of the first circuit structure of a switchable impedance network in a first operating mode in a radio frequency front-end module provided according to some embodiments of this application.

[0021] Figure 3 This is a schematic diagram of the second circuit structure of a switchable impedance network in a radio frequency front-end module provided in the second operating mode according to some embodiments of this application.

[0022] Figure 4 This is a schematic diagram of the architecture of a radio frequency front-end module provided in another embodiment of this application.

[0023] Figure 5 This is a simulation diagram of the in-band insertion loss of the first transmit filter.

[0024] Figure 6 This is a simulation diagram of the in-band insertion loss of the first receiving filter.

[0025] Figure 7 This is a simulation diagram of the in-band insertion loss of the second transmit filter.

[0026] Figure 8 This is a simulation diagram of the in-band insertion loss of the second receiving filter.

[0027] Figure 9 This is a performance simulation diagram of the RF front-end module when the target carrier frequency band is Band40.

[0028] Figure 10 This is a performance simulation diagram of the RF front-end module when the target carrier frequency band is Band41.

[0029] Figure 11 This is a simulation diagram of the out-of-band performance of the four filters in the multiplexer during the switching of different operating modes.

[0030] Explanation of reference numerals in the attached figures: RF front-end module 100, antenna 200, multiplexer 110, switchable impedance network 120, common terminal 111, first circuit structure 121, second circuit structure 122, first transmit filter 112, first receive filter 113, second transmit filter 114, and second receive filter 115. Detailed Implementation

[0031] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0032] In the design of RF front-end modules, the multiplexer is a core component, responsible for filtering and separating transmit and receive signals in a specific frequency band. To ensure that the multiplexer has low insertion loss and good port matching within its operating frequency band, a common practice in related technologies is to set up an impedance matching network between the common terminal of the multiplexer and the antenna terminal. This transforms the impedance of the multiplexer's common terminal in this frequency band to match the impedance of the antenna terminal (e.g., 50 ohms), thereby effectively optimizing the signal transmission efficiency of the multiplexer in stand-alone operating mode.

[0033] An impedance matching network specifically set up between the antenna end and the common end for impedance matching may introduce unexpected reactive components on these aggregation bands when the multiplexer and at least one target aggregation band are working simultaneously for carrier aggregation. This may even form a low impedance path to the target aggregation band, resulting in poor coupling between the impedance of the multiplexer's band and the impedance of the target aggregation band. Consequently, signal energy crosstalks and loads between the two systems, thus deteriorating the system noise figure and power efficiency under carrier aggregation conditions.

[0034] To overcome the aforementioned problems, this invention proposes a novel technical approach. The core concept involves introducing a switchable impedance network between the common terminal and the antenna terminal of the multiplexer, replacing the original fixed impedance matching network. The switchable impedance network is dynamically controlled to switch to different impedance states depending on whether the RF front-end module is in a first operating mode where the multiplexer operates independently or in a second operating mode where it performs carrier aggregation with at least one target aggregation band. In the first operating mode, the switchable impedance network presents a first impedance state to optimize impedance matching in the multiplexer's operating frequency band, while in the second operating mode, it presents a second impedance state to provide high impedance in the target aggregation band. In other words, this application provides an impedance-reconfigurable RF front-end module to solve the problem that fixed impedance matching networks cannot dynamically adapt to dual operating mode requirements, achieving the technical effect of adaptively optimizing port impedance according to actual application scenarios, thereby improving the overall system performance.

[0035] To concretize the inventive concept, firstly, in conjunction with the appendix... Figure 1 Describe a typical implementation environment, in which, Figure 1 This is a schematic diagram of the architecture of a radio frequency front-end module 100 provided in one embodiment of this application. Figure 1 As shown, the RF front-end module 100 is connected to the antenna terminal 200 and includes a plurality of multiplexers 110 and a switchable impedance network 120. The switchable impedance network 120 is connected between the antenna terminal 200 and the common terminal 111 of the multiplexers 110. The switchable impedance network 120 is configured to: switch to a first impedance state in response to a first operating mode when the multiplexers 110 are operating independently, to match the impedance of the common terminal 111 with the impedance of the antenna terminal 200; and switch to a second impedance state in response to a second operating mode when the multiplexers 110 are performing carrier aggregation with at least one target aggregation band, to present a high impedance on the target aggregation band.

[0036] The radio frequency (RF) front-end module 100 is a key component in wireless communication devices (such as mobile phones, base stations, and IoT modules) responsible for processing RF signals. Its core function is to filter, select, and synthesize transmit and receive signals of different frequencies between the antenna terminal 200 and the baseband circuitry of the communication device. The multiplexer 110 has a common terminal 111 and at least two signal ports, each corresponding to a different communication frequency band. For example, one signal port of the multiplexer 110 can be connected to a transmit filter in the Band 1 (B1) band, and another signal port can be connected to a receive filter in the Band 3 (B3) band. The switchable impedance network 120 can be directly or indirectly connected to the signal transmission path between the antenna terminal 200 and the common terminal 111 of the multiplexer 110 via other passive components. The antenna terminal 200 is used to connect to or couple to an external antenna.

[0037] In the RF front-end module 100 provided in this application embodiment, its switchable impedance network 120 is configured as a dynamically reconfigurable impedance transformation circuit, and can automatically or controllably switch between at least two different impedance states in response to the operating mode of the RF front-end module 100, so as to adapt to the operating conditions of the multiplexer 110 in different scenarios. The operating modes of the RF front-end module 100 provided in this application embodiment include a first operating mode and a second operating mode. Specifically, when the RF front-end module 100 is in the first operating mode, that is, when the multiplexer 110 is in an independent operating state where it does not simultaneously transmit and receive signals with signal links of other frequency bands, the switchable impedance network 120 is controlled to switch to the first impedance state. In this first impedance state, the main function of the switchable impedance network 120 is to properly match the impedance of the multiplexer 110 seen from the common terminal 111 in its operating frequency band with the system characteristic impedance (typically 50 ohms) at the antenna terminal 200. The impedance matching between the common terminal 111 and the antenna terminal 200 is designed to minimize signal reflection loss when passing through the common terminal 111 of the multiplexer 110, thereby optimizing the performance of the multiplexer 110 when operating independently, such as reducing the noise figure of the receiving channel or improving the power-added efficiency and linearity of the transmitting channel. When the RF front-end module 100 is in a second operating mode, i.e., when the multiplexer 110 needs to perform carrier aggregation simultaneously with signal transmission links of at least one other operating frequency band (e.g., Band 40 and / or Band 41), the switchable impedance network 120 is controlled to switch to the second impedance state. In this second impedance state, the switchable impedance network 120 is specifically configured to present high impedance (e.g., much greater than 50 ohms, ideally close to an open circuit) on the "other operating frequency bands". The introduction of this high impedance characteristic results in a significant impedance mismatch when viewed from the common terminal 111 of the multiplexer 110 towards the antenna terminal 200 in a carrier aggregation scenario, for the signal in the target aggregation frequency band that is carrier aggregated with the signal frequency band of the multiplexer 110. This effectively cuts off the energy coupling path between the common terminal 111 of the multiplexer 110 and the signal transmission link of the target aggregation frequency band, thereby effectively suppressing mutual interference between signals of different frequency bands during carrier aggregation and optimizing the overall system performance of the RF front-end module 100 during carrier aggregation, such as reducing intermodulation distortion and improving channel isolation.

[0038] As can be seen from the above, the RF front-end module 100 provided in this application addresses the problem of signal interference in carrier aggregation scenarios, which is difficult to effectively overcome without sacrificing the performance of its internal multiplexer when it operates independently. This is achieved by setting a switchable impedance network between the antenna end 200 and the common end 111 of the multiplexer 110. Based on the network's response to different operating modes of the RF front-end module 100, it dynamically switches between a first impedance state and a second impedance state. When the multiplexer 110 operates independently, impedance matching between the common end 111 and the antenna end 200 is achieved, optimizing signal transmission efficiency. Furthermore, when the multiplexer 110 performs carrier aggregation with at least one target aggregation frequency band, the network exhibits high impedance on that target aggregation frequency band, thereby significantly reducing loading and interference on the signal transmission path of that aggregation frequency band. Therefore, the RF front-end module 100 provided in this application overcomes the shortcomings of the RF front-end modules provided in the related technology, which cannot take into account the performance of both independent multiplexer operation and carrier aggregation operation. It realizes adaptive adjustment of impedance characteristics according to actual communication needs, and can effectively suppress in-band interference during carrier aggregation without affecting the independent operation performance of the multiplexer, thereby improving the overall system performance and communication quality when multiple frequency bands work together.

[0039] To respond to the different operating modes of the RF front-end module 100 and to achieve the switching between the two impedance states, the switchable impedance network 120 is specifically configured to contain a reconfigurable circuit structure. The reconfigurable circuit structure means that when the operating mode changes, the circuit structure of the switchable impedance network 120 can be reconfigured (switched) from the current structure to another structure. Different circuit structures of the switchable impedance network 120 have different impedance states, thereby achieving the switching between the first impedance state and the second impedance state. The switchable impedance network 120 can respond to changes in the operating mode of the RF front-end module 100 by changing the connection relationships between its internal components, so that it has different circuit structures in different operating modes, thereby achieving the switching between the first impedance state and the second impedance state. Changing the connection relationships between the internal components of the switchable impedance network 120 can be accomplished based on the switching action of switching elements.

[0040] This method, which changes the connection relationship of internal components in response to the switching of operating modes, thereby altering the circuit structure (network topology) of the switchable impedance network 120 and achieving impedance state switching in different operating modes, allows the RF front-end module 100 to switch to two impedance states with distinct circuit structures and deeply independently optimized in two preset, discrete operating modes (independent operation and carrier aggregation). One of these circuit structures is tuned to achieve near-ideal low-loss matching in the multiplexer operating frequency band, while the other constructs a sharp high-impedance resonant point in a specific aggregation interference frequency band. This hardware-level "hard switching" ensures the maximization and determinism of performance in each state, while also offering fast switching speed, simple control, and strong anti-interference capability.

[0041] Of course, in other embodiments, the switching between the first impedance state and the second impedance state is not limited to reconstructing the circuit structure of the switchable impedance network 120. It can also be achieved by adjusting the impedance parameters of the internal components in the switchable impedance network 120. That is, in other embodiments, the circuit structure of the switchable impedance network 120 is the same in different operating modes of the RF front-end module 100, only the impedance parameters of its internal components are different.

[0042] Please see Figure 2 The diagram shown is a schematic diagram of the first circuit structure of the switchable impedance network 120 in a first operating mode of a radio frequency front-end module 100 provided according to some embodiments of this application. In the first operating mode, the switchable impedance network 120 switches to the first circuit structure 121. The first circuit structure 121 includes a first capacitive impedance unit connected between the antenna terminal 200 and the common terminal 111. Of course, the first circuit structure 121 may further include a second inductive impedance unit connected between the common terminal 111 and the reference potential terminal.

[0043] The first capacitive impedance unit can be connected in parallel with an inductor on the signal path of the multiplexer 110's operating frequency band, or it can work together with the second inductive impedance unit to form a simple L-shaped matching network. Its parameters are optimized to achieve good conjugate matching from the common terminal 111 to the antenna terminal 200 within the operating frequency band of the multiplexer 110 (e.g., Band 1 / Band 3 bands). The first capacitive impedance unit refers to a capacitive element or combination of capacitive elements that performs the main impedance transformation function in the first operating mode. The second inductive impedance unit refers to a unit that provides a fixed inductive load to broaden the impedance matching bandwidth of the switchable impedance network 120 in the first operating mode and assist in adjusting the overall resonant frequency of the first circuit structure 121. It may include a single inductor or a combination of multiple inductors.

[0044] By reasonably setting the capacitance value of the first capacitive impedance unit, or by reasonably setting the capacitance value of the first capacitive impedance unit and the inductance value of the second inductive impedance unit, the first circuit structure 121 can match the impedance of the common terminal 111 with the impedance of the antenna terminal 200, so as to reduce the insertion loss of the multiplexer 110 and improve the high signal transmission efficiency of the multiplexer 110 in the first working mode.

[0045] Please see Figure 3 The diagram illustrates a second circuit structure of a switchable impedance network 120 in a radio frequency front-end module 100 according to some embodiments of this application, operating in a second mode. In this second operating mode, the switchable impedance network 120 switches to the second circuit structure 122. The second circuit structure 122 includes a second capacitive impedance unit connected in series between the antenna terminal 200 and the common terminal 111, and a first inductive impedance unit connected between the common terminal 111 and the reference potential terminal. Alternatively, the second circuit structure 122 may further include the aforementioned second inductive impedance unit.

[0046] The second capacitive impedance unit refers to a capacitive element connected in series between the antenna end 200 and the common end 111 when the switchable impedance network 120 is switched to the second circuit structure 122 (corresponding to the second operating mode, i.e., carrier aggregation mode). It works together with the first inductive impedance unit connected in parallel on the operating frequency band signal path of the multiplexer 110, or with the first and second inductive impedance units, to accurately generate parallel resonance in the target aggregation frequency band (e.g., Band 40 and / or Band 41 frequency bands) that needs to be suppressed. This results in a high impedance in the target aggregation frequency band, thereby suppressing signal leakage from the target aggregation frequency band to the operating frequency band signal path of the multiplexer 110, thus effectively suppressing interference between signals of different frequency bands during carrier aggregation.

[0047] The second circuit structure 122 is a topology of series capacitor and parallel inductor. Its core function is to form a parallel resonant circuit. By precisely designing the values ​​of the second capacitive impedance unit and the first inductive impedance unit, the circuit can resonate in the "other operating frequency bands" that need to be isolated. As a result, the impedance seen from the common terminal in this frequency band reaches a maximum value, that is, it presents a high impedance state for the target aggregation frequency band. Thus, the second circuit structure 122 is like setting up a "barrier" for the interference frequency band on the signal path of the multiplexer 110's operating frequency band, which greatly reduces the mutual loading effect between the common terminal 111 and the signal transmission link of the target aggregation frequency band. This effectively suppresses the interference between signals of different frequency bands during carrier aggregation and significantly improves the coexistence performance and overall linearity of the system.

[0048] In some embodiments, the inductance value of the aforementioned second inductive impedance unit is greater than that of the first inductive impedance unit. In the second operating mode, when the first inductive impedance unit with the larger inductance value is connected to the circuit via a switch and connected in parallel with the smaller fixed second inductive impedance unit, the total equivalent inductance value after parallel connection will be slightly smaller than that of the individual second inductive impedance unit. This configuration allows the resonant frequency of the parallel resonant network composed of the equivalent inductance and the second capacitive impedance unit to be precisely set in a higher target convergence frequency band (such as Band 40 and / or Band 41). At the same time, since the parallel connection reduces the total inductance of the second circuit structure 122 and increases the Q value of the second circuit structure 122, it helps to form a sharper resonant point with a higher impedance peak in the target convergence frequency band, thereby achieving deep isolation of interference signals. In the first operating mode, the first inductive impedance unit is disconnected, leaving only the second inductive impedance unit with a smaller inductance value fixedly connected to the reference potential terminal. This second inductive impedance unit with a smaller inductance value provides a milder inductive load for the operating frequency band of the multiplexer 110 (such as Band 1 and / or Band 3 bands), which is beneficial for working with the first capacitive impedance unit to achieve wider bandwidth and lower loss impedance matching in this frequency band.

[0049] Based on the RF front-end module 100 provided in this application embodiment, its switchable impedance network 120 has a first circuit structure 121 and a second circuit structure 122 respectively in response to different operating modes. The specific implementation of the first circuit structure 121 and the second circuit structure 122 has design flexibility; they can be designed as two independent circuit modules with completely non-shared components, with one of them connected to the signal path between the antenna end and the common end via a switching element (such as a multi-throw switch); or they can be designed as a unified network sharing some core components, such as... Figure 1 As shown, a first capacitor C1 (as the first capacitive impedance unit connected in series in the main path) and a first inductor L1 (as the fixed second inductive impedance unit) are used together, and then a switch (such as...) is used. Figure 1 The switch S in the circuit switches different branches to change the overall topology of the switchable impedance network 120, thereby realizing the electrical functions of the first circuit structure 121 and the second circuit structure 122 respectively.

[0050] If the first circuit structure 121 and the second circuit structure 122 adopt independent structures, then these two circuit structures can be independently and without compromise optimized to their respective performance limits (such as the lowest insertion loss under independent operation and the highest isolation under carrier aggregation), and the crosstalk between states is extremely low. If the first circuit structure 121 and the second circuit structure 122 adopt a shared component structure, then the total number of components and the physical size of the circuit can be reduced, the manufacturing cost can be reduced, and the consistency and predictability of performance in the two states can be improved due to the stability of some key component parameters, which is more conducive to the realization of highly integrated modules.

[0051] In some embodiments, the capacitance value of the first capacitive impedance unit in the first circuit structure 121 is greater than the capacitance value of the second capacitive impedance unit in the second circuit structure 122. The larger capacitance value of the first capacitive impedance unit can provide more adequate capacitive compensation in the operating frequency band of the multiplexer 110 (such as Band 1 / Band 3), enabling it to work in conjunction with the inductive part of the circuit to achieve wider bandwidth and lower loss impedance matching, thereby maximizing signal transmission efficiency. When the smaller second capacitive impedance unit (used in carrier aggregation mode) is used in conjunction with the first inductive impedance unit, the resonant frequency of the parallel resonant circuit can be accurately placed in the target aggregation frequency band (such as Band 40 / Band 41) requiring high impedance isolation, forming a sharper and deeper impedance peak, thereby achieving better inter-band isolation.

[0052] The following will combine Figure 1 The switchable impedance network 120, which shares components with the first circuit structure 121 and the second circuit structure 122, will be described in further detail. For example... Figure 1 As shown, in some embodiments, the switchable impedance network 120 includes a first capacitor C1, a second capacitor C2, a switch S, and a first inductor L1. The first capacitor C1 is connected in series between the common terminal 111 and the antenna terminal 200, one end of the second capacitor C2 is connected to the common terminal 111, and one end of the first inductor L1 is connected to the reference potential terminal. The reference potential terminal refers to the electrical node or conductive plane within the RF front-end module 100 that provides a unified and stable zero-potential reference for all related circuit units; in this embodiment, it is the ground terminal. However, in other embodiments, the reference potential terminal does not necessarily refer to earth or the device casing, but rather to a common low-impedance grounding network or grounding plane on the integrated circuit, packaging substrate, or printed circuit board. Furthermore, in this embodiment, the switchable impedance network 120 further includes a second inductor L2, which is connected between the common terminal 111 and the reference potential terminal, i.e., connected in parallel on the operating frequency band signal path of the multiplexer 110.

[0053] In this embodiment, switch S is configured to: switch to a first connection state in response to a first operating mode, connecting the other end of the second capacitor C2 to the antenna terminal 200 and disconnecting the other end of the first inductor L1 from the antenna terminal 200, thereby switching the switchable impedance network 120 to a first circuit structure 121 disconnected from the first inductor L1; and switch to a second connection state in response to a second operating mode, disconnecting the other end of the second capacitor C2 from the antenna terminal 200 and connecting the other end of the first inductor L1 to the antenna terminal 111, thereby switching the switchable impedance network 120 to a second circuit structure 122 connected to the first inductor L1. That is, in this embodiment, the first circuit structure 121 and the second circuit structure 122 share the first capacitor C1 and the second inductor L2, and the first capacitor C1 constitutes the aforementioned first capacitive impedance unit, the first capacitor C1 and the second capacitor C2 are connected in parallel to constitute the aforementioned second capacitive impedance unit, the first inductor L1 constitutes the aforementioned first inductive impedance unit, and the second inductor L2 constitutes the aforementioned second inductive impedance unit.

[0054] In this embodiment, switch S can be, but is not limited to, a single-pole double-throw switch. Its moving end 1 is connected to one end of the first capacitor C1 and is connected to the antenna end 200. Its first stationary end 2 is connected to the other end of the second capacitor C2 (the end not connected to the common end 111), and its second stationary end 3 is connected to the other end of the first inductor L1 (the end not connected to the reference potential end). Of course, in other embodiments, switch S can also be other types of path selection switches, and its positional relationship in the switchable impedance network 120 is not limited to... Figure 1 As shown. When the RF front-end module 100 is in the first operating mode, the moving end 1 of switch S is connected to the first stationary end 2, and the first inductor L1 is disconnected from the switchable impedance network 120. Then the switchable impedance network 120 switches to the first circuit structure 121 (excluding the first inductor L1) composed of the first capacitor C1, the second capacitor C2, and the second inductor L2. When the RF front-end module 100 is in the second operating mode, the moving end 1 of switch S is connected to the second stationary end 3, the first inductor L1 is connected to the switchable impedance network 120, and the second capacitor C2 is in an open circuit state. Then the switchable impedance network 120 switches to the second circuit structure 122 (excluding the second capacitor C2) composed of the first capacitor C1, the first inductor L1, and the second inductor L2.

[0055] The switchable impedance network 120 provided in this embodiment can be constructed using only a few passive components (first capacitor C1, second capacitor C2, first inductor L1, and second inductor L2) and a switch S. By using switch S to physically select between the second capacitor C2 and the first inductor L1, the circuit structure with different impedance states corresponding to different operating modes is directly reconstructed. In the first operating mode, switch S switches to a first switching state where the first inductor L1 is disconnected from the switchable impedance network 120, and the second capacitor C2 is connected in parallel. This allows the second capacitor C2 and the series-connected first capacitor C1 to form a capacitively dominant impedance transformation network, whose parameters can be independently optimized to achieve near-ideal low insertion loss matching within the operating frequency band of the multiplexer 110. In the second operating mode, switch S switches to a second connection state where the first inductor L1 is connected and the second capacitor C2 is disconnected. This forms a circuit structure with sharp parallel resonance characteristics in the target convergence frequency band, thereby generating a deterministic high impedance isolation state in that frequency band. The switchable impedance network 120 provided in this application embodiment is easy to control and has a simple circuit structure, which helps to reduce the production cost of the RF front-end module 100 and the requirements for integration process.

[0056] In some embodiments, the capacitance of the first capacitor C1 is greater than the capacitance of the second capacitor C2. In the first operating mode, the second capacitor C2 and the first capacitor C1 work together to form an impedance matching network. By forming a specific capacitive reactance ratio between the larger first capacitor and the smaller second capacitor, the complex impedance of the common terminal 111 in its operating frequency band can be transformed and pulled to the system impedance (e.g., 50 ohms) of the antenna terminal 200 more effectively. This achieves a near-ideal matching state with a wider bandwidth and lower insertion loss, maximizing signal transmission efficiency.

[0057] In some embodiments, the inductance value of the first inductor L1 is greater than that of the second inductor L2. In the second operating mode requiring carrier aggregation, when the first inductor L1 with a larger inductance value is connected to the switchable impedance network 120 via switch S to be connected in parallel with the second inductor L2 with a smaller inductance value, the equivalent inductance after parallel connection is mainly dominated by the second inductor L2 with a smaller inductance value. However, the connection of the first inductor L1 significantly changes the Q value and frequency characteristics of the second circuit structure 122, which serves as a resonant circuit. This allows the entire second circuit structure 122 to form a resonant point with extremely high impedance peak and very sharp frequency selectivity in the higher target aggregation frequency bands (such as Band 40 and / or Band 41), thereby achieving deep isolation from interference frequency bands. In the first operating mode, only the second inductor L2 with a smaller inductance value plays a role, providing a milder and more bandwidth-friendly inductive load for the multiplexer 110 operating frequency bands (such as B1 and / or B3). By combining and switching between large and small inductors, the switchable impedance network 120 can achieve drastic changes and separate optimizations in impedance characteristics in two modes, ensuring that both the high-impedance isolation state and the well-matched state can achieve their respective best performance.

[0058] In some embodiments, the constituent elements of the switchable impedance network 120 can be arranged separately or at least partially integrated. For example, the switch S, the first capacitor C1, and the second capacitor C2 can be arranged separately or integrated. Similarly, the first inductor L1 and the second inductor L2 can also be arranged separately or integrated, and there is no limitation on this.

[0059] In some embodiments, the multiplexer 110 is a quadplexer integrating transmit and receive paths of Band 1 (first operating band) and Band 3 (second operating band). The target aggregation band for carrier aggregation with the multiplexer 110 can be at least one of Band 40 (approximately 2300MHz) and Band 41 (approximately 2600MHz). In this embodiment, the multiplexer 110 is capable of simultaneously processing received and transmitted signals of Band 1 and Band 3. The multiplexer 110 includes a first transmit filter 112 for processing transmitted signals of Band 3, a first receive filter 113 for processing received signals of Band 3, a second transmit filter 114 for processing transmitted signals of Band 1, and a second receive filter 115 for processing received signals of Band 1. In this embodiment, the common terminal 111 is the common terminal of the signal channels of Band 1 and Band 3. It should be noted that, in other embodiments, the multiplexer 110 can also be a binary multiplexer, a triple multiplexer, or other types of multiplexers, and the frequency bands supported by each type of multiplexer are not limited to Band 1 and Band 2. Furthermore, in other embodiments, the target aggregation frequency band is not limited to Band 40 and Band 41.

[0060] In this embodiment, the radio frequency front-end module 100 also includes a power amplifier (PA) connected to each of the transmit filters in the multiplexer 110. The power amplifier up-converts and amplifies the radio frequency transmit signal from the baseband or intermediate frequency signal of the transceiver, and increases its power so that it has enough energy to be radiated through the multiplexer 110 and the antenna terminal 200.

[0061] In addition, the RF front-end module 100 also includes a low-noise amplifier (LNA) connected to each of the receive filters in the multiplexer 110. The LNA initially amplifies the weak RF signal received downlink from the antenna 200 and filtered by the multiplexer 110, while introducing as little additional noise as possible for subsequent downconversion and processing.

[0062] In some embodiments, the "target aggregation band" for carrier aggregation may include the Band40 (approximately 2300MHz) band and / or the Band41 (approximately 2600MHz) band. The RF front-end module 100 provided in this embodiment, through its switchable impedance network 120, effectively solves the problem of mutual interference between the Band1+Band3 quadplexers and the Band40 and / or Band41 bands during carrier aggregation.

[0063] Please see Figure 4 As shown, in some embodiments, a third inductor is connected in parallel on at least one signal channel (operating frequency band path) within the multiplexer 110; that is, in some embodiments, the RF front-end module 100 also includes at least one third inductor. In this embodiment, the multiplexer 110 is still taken as a Band1+Band3 quad-multiplexer integrating the transmit and receive paths of Band1 and Band3 frequency bands. The target aggregation frequency band for carrier aggregation with the multiplexer 110 can still be at least one of the Band40 and Band41 frequency bands.

[0064] The third inductor connected in parallel on the signal channel of its Band 1 frequency band is inductor L3, and the third inductor connected in parallel on the signal channel of its Band 3 frequency band is inductor L4. One end of the third inductor connected in parallel on each signal channel is connected to the channel signal port of that signal channel, and the other end is connected to the reference potential terminal. In the RF front-end module 100 provided in this application embodiment, each signal channel in the multiplexer 110 can independently adjust its zero and pole positions, improve in-band insertion loss or out-of-band rejection by using the third inductor connected in parallel on its channel. This can effectively reduce the mutual coupling between different channels inside the multiplexer 110, especially in the high-frequency band, thereby further improving the overall performance and design freedom of the multiplexer 110. In this embodiment, the switchable impedance network 120 does not include the second inductor L2. It should be noted that in other embodiments, when the third inductor is present, the second inductor L2 can still be added to the switchable impedance network 120 based on requirements.

[0065] In some embodiments, the radio frequency front-end module 100 is Figure 1 Taking the example shown, the parameter settings of each component in its circuit can be as follows: the inductance value of the first inductor L1 is about 2nH, the inductance value of the second inductor L2 is about 5nH, the capacitance value of the first capacitor C1 is about 2pF, the capacitance value of the second capacitor C2 is about 6pF, and its multiplexer 110 is a Band1+Band3 quad-multiplexer. The target aggregation frequency band for carrier aggregation with the multiplexer 110 can still be at least one of the Band40 and Band41 frequency bands. (This is followed by a continuation of the previous sentence.) Figures 5 to 11 The performance of the radio frequency front-end module 100 provided in the embodiments of this application will be further described in detail.

[0066] Please refer to the following documents separately. Figures 5 to 8 As shown, where, Figure 5 This is a simulation diagram of the in-band insertion loss of the first transmit filter 112. Figure 6 This is a simulation diagram of the in-band insertion loss of the first receiving filter 113. Figure 7 This is a simulation diagram of the in-band insertion loss of the second transmit filter 114. Figure 8The simulation diagrams for the in-band insertion loss of the second receiving filter 115 show the comparison of simulation results for the signal insertion loss as a function of frequency in the Band3 / Band1 transmit / receive channels of the multiplexer 110 under two different operating modes. The dashed lines represent the insertion loss curves when the switchable impedance network 120 is in the first impedance state, while the solid lines represent the insertion loss curves when the switchable impedance network 120 is in the second impedance state.

[0067] from Figures 5 to 8 It can be seen that the transmit / receive channels in the Band3 / Band1 bands exhibit significantly lower and flatter insertion loss within their core operating frequency bands. This means that the signal transmission efficiency between the multiplexer 110 and the antenna 200 is higher, with less power loss, thus significantly optimizing the noise figure and power-added efficiency of the Band3 / Band1 band communication path. Meanwhile, from... Figures 5 to 8 It can also be seen that although the in-band insertion loss of this Band3 / Band! band channel increases slightly in carrier aggregation mode (solid line), this is a necessary and acceptable trade-off for constructing a high-impedance isolation state in aggregated bands (such as Band40 / Band41). Therefore, through Figures 5 to 8 This demonstrates that the RF front-end module 100 can switch impedance states to ensure that the multiplexer 110 prioritizes its key transmission performance when working independently, thereby achieving dynamic and scenario-based performance optimization and enabling effective signal isolation in carrier aggregation mode.

[0068] Please see Figure 9 and Figure 10 As shown, where, Figure 9 This is a performance simulation diagram of the RF front-end module 100 when the target carrier frequency band is Band 40. Figure 10 The first image shows a performance simulation diagram of the RF front-end module 100 in the target carrier frequency band Band 41. The second image illustrates a simulation comparison of the input impedance (or related isolation and return loss parameters) in different operating modes, viewed from antenna end 200 towards common end 111 in the corresponding target aggregation frequency band. Figure 9 and Figure 10 The dashed line represents the impedance characteristics of the switchable impedance network 120 in the Band 40 / Band 41 frequency band when it is in the first impedance state. At this time, the impedance value is low, which means that the path will put a significant load on the signals in these frequency bands. Figure 9 and Figure 10 The solid line represents the characteristics of the switchable impedance network 120 when it switches to the second impedance state. It exhibits sharp impedance peaks or return loss troughs near the center frequencies of Band 40 and Band 41, clearly indicating the "high impedance" state. Figure 9 and Figure 10 This demonstrates that the switchable impedance network 120, in its second operating mode, can precisely generate parallel resonances in specific, discrete target aggregation frequency bands (Band40 and Band41), thereby achieving extremely high input impedance in these bands. This high impedance state makes the common terminal 111 almost "invisible" to Band40 / Band41 signals, greatly reducing the mutual loading effect between signal transmission paths. This minimizes mutual interference between frequency bands during carrier aggregation, directly improving the system's linearity, isolation, and overall throughput performance in concurrent operating scenarios.

[0069] Please see Figure 11 As shown, this is a simulation diagram of the out-of-band performance of the four filters in the multiplexer 110 during the switching of different operating modes. It shows the changes in the suppression characteristics (i.e., out-of-band suppression or isolation) of each filter in the multiplexer 110 outside its respective operating passband when the switchable impedance network 120 switches between the first impedance state and the second impedance state. Figure 11 The simulation results show that the mode switching of the switchable impedance network 120 can precisely change the matching characteristics of the common terminal 111, while having a negligible impact on the inherent frequency-selective filtering performance of each filter within it. Regardless of whether the switchable impedance network 120 is in optimized independent operation or optimized carrier aggregation mode, the out-of-band rejection curves of the corresponding channels of the filters within the multiplexer 110 maintain a high degree of consistency and excellent attenuation levels.

[0070] In some embodiments, this application also provides an impedance control method for an RF front-end module 100 as provided in any embodiment of this application. The impedance control method includes: determining an operating mode of the RF front-end module; generating a switching control signal based on the determined operating mode; and outputting the switching control signal to a switchable impedance network in the RF front-end module to control the switchable impedance network to switch between a first impedance state and a second impedance state. Determining the operating mode includes determining whether the current operating mode is a first operating mode where the multiplexer 110 in the RF front-end module 100 operates independently, or a second operating mode where the multiplexer 110 performs carrier aggregation with at least one target aggregation frequency band.

[0071] In some embodiments, the current operating mode (first operating mode or second operating mode) can be determined based on scheduling information from the upper-layer communication protocol. Specifically, it is necessary to determine whether the communication task at the current and next moment involves only the frequency band served by the multiplexer 110 (triggering the first operating mode), or whether the frequency band served by the multiplexer 110 needs to be used simultaneously with at least one target aggregation frequency band (such as Band 40 / Band 41) for carrier aggregation (triggering the second operating mode). If it is determined to be the first operating mode, control logic (e.g., a low-level voltage) corresponding to controlling the switchable impedance network 120 to switch to the first impedance state is generated; if it is determined to be the second operating mode, control logic (e.g., a high-level voltage) corresponding to controlling the switch to the second impedance state is generated.

[0072] In some embodiments, the generated switching control signal is output to the switchable impedance network 120 in the RF front-end module 100, specifically applied to the control terminal of the switch S within it. In response to this electrical signal, the switch S changes the connection relationship of its internal metal contacts, thereby switching the topology of the entire switchable impedance network 120 between the first circuit structure 121 and the second circuit structure 122, as described in the previous embodiments, ultimately achieving a change in impedance state from the first impedance state to the second impedance state, or vice versa. Through this dynamic control, the impedance characteristics of the RF front-end module 100 are always matched to the current communication scenario, achieving optimal performance.

[0073] Some embodiments of this application also provide a communication device, which includes an antenna end and a radio frequency (RF) front-end module according to any embodiment of this application. The common terminal of the RF front-end module is coupled to the antenna end and is used to receive RF signals from the antenna end or transmit RF signals to the antenna end. The communication device provided in the embodiments of this application also includes an RF transceiver circuit connected to its RF front-end module, and each frequency band port of the RF front-end module is connected to the RF transceiver circuit. The RF transceiver circuit may include, but is not limited to, a low-noise amplifier, a power amplifier, a mixer, etc.

[0074] In addition, the communication device provided in this application embodiment also includes a baseband processor connected to its radio frequency front-end module and radio frequency transceiver circuit respectively. The baseband processor is used to execute the impedance control method provided in this application embodiment to generate a switching control signal and output the switching control signal to the radio frequency front-end module to control the working state of the switchable impedance network in the radio frequency front-end module.

[0075] The communication device provided in this application embodiment is based on a radio frequency front-end module with a switchable impedance network, which can achieve adaptive performance optimization in different communication modes.

[0076] It should be noted that the elements described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0077] It should be understood that multiple components and / or parts can be provided by a single integrated component or part. Alternatively, a single integrated component or part can be divided into multiple separate components and / or parts. The use of the public designation "a" or "an" to describe a component or part does not imply the exclusion of other components or parts.

[0078] It should be understood that although terms such as “first” or “second” may be used in this disclosure to describe various elements (such as a first end and a second end), these elements are not defined by these terms, which are only used to distinguish one element from another.

[0079] The basic principles of this disclosure have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this disclosure are merely examples and not limitations, and should not be considered as essential features of each embodiment of this disclosure. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the scope of this disclosure to the necessity of employing the aforementioned specific details for implementation.

[0080] The above are merely specific embodiments of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A radio frequency front-end module, characterized in that, It includes a multiplexer and a switchable impedance network, wherein the switchable impedance network is connected between the antenna end and the common end of the multiplexer; The switchable impedance network is configured as follows: In response to the first operating mode when the multiplexer is operating independently, the system switches to a first impedance state to match the impedance of the common terminal with the impedance of the antenna terminal. In addition, in response to a second operating mode when the multiplexer performs carrier aggregation with at least one target aggregation band, it switches to a second impedance state to present high impedance on the target aggregation band.

2. The radio frequency front-end module according to claim 1, characterized in that, The switchable impedance network is configured to change the connection relationship of its internal components in response to the operating mode of the RF front-end module, so as to switch between the first impedance state and the second impedance state; wherein the operating mode of the RF front-end module includes the first operating mode and the second operating mode.

3. The radio frequency front-end module according to claim 2, characterized in that, In the first operating mode, the switchable impedance network switches to a first circuit structure, the first circuit structure including a first capacitive impedance unit connected between the antenna end and the common end; And / or, in the second operating mode, the switchable impedance network switches to a second circuit structure, the second circuit structure including a second capacitive impedance unit connected in series between the antenna end and the common end, and a first inductive impedance unit connected between the common end and the reference potential end.

4. The radio frequency front-end module according to claim 3, characterized in that, The capacitance value of the first capacitive impedance unit is greater than the capacitance value of the second capacitive impedance unit.

5. The radio frequency front-end module according to claim 3, characterized in that, The switchable impedance network includes a first capacitor, a second capacitor, a switch, and a first inductor. The first capacitor is connected in series between the common terminal and the antenna terminal. One end of the second capacitor is connected to the common terminal, and one end of the first inductor is connected to the reference potential terminal. The switch is configured as follows: In response to the first operating mode, the system switches to a first connection state to connect the other end of the second capacitor to the antenna terminal and disconnect the other end of the first inductor from the antenna terminal. The switchable impedance network switches to a first circuit structure that is disconnected from the first inductor. In response to the second operating mode, the system switches to a second connection state to disconnect the other end of the second capacitor from the antenna end and connect the other end of the first inductor to the antenna end, and the switchable impedance network switches to a second circuit structure connected to the first inductor.

6. The radio frequency front-end module according to claim 5, characterized in that, The capacitance value of the second capacitor is greater than the capacitance value of the first capacitor.

7. The radio frequency front-end module according to claim 5, characterized in that, The switchable impedance network includes: A second inductor connected between the common terminal and the reference potential terminal; And / or, at least one signal channel within the multiplexer is connected in parallel with a third inductor.

8. The radio frequency front-end module according to claim 7, characterized in that, The inductance of the first inductor is greater than that of the second inductor.

9. The radio frequency front-end module according to any one of claims 1 to 8, characterized in that, The multiplexer is a quad-multiplexer that integrates transmit and receive paths for both Band 1 and Band 3 frequency bands. And / or, the target aggregation frequency band includes the Band40 band and / or the Band41 band.

10. An impedance control method for a radio frequency front-end module as described in any one of claims 1 to 9, characterized in that, include: The operating mode of the radio frequency front-end module is determined, including a first operating mode when the multiplexer in the radio frequency front-end module operates independently, and a second operating mode when the multiplexer performs carrier aggregation with at least one target aggregation frequency band. Based on the determined operating mode, a switching control signal is generated and output to the switchable impedance network in the RF front-end module to control the switchable impedance network to switch between the first impedance state and the second impedance state.

11. A communication device, characterized in that, It includes an antenna end and a radio frequency front-end module as described in any one of claims 1 to 9, wherein the radio frequency front-end module is coupled to the antenna end.

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