Impedance matching circuit and impedance matching circuit control method

Abstract

The embodiment of the specification provides an impedance matching circuit and an impedance matching circuit control method. The impedance matching circuit comprises a main path matching unit and a branch switching unit, the main path matching unit and the branch switching unit are arranged between a radio frequency port and an antenna port; the branch switching unit comprises a bypass branch, at least one first matching branch and at least one second matching branch, and is used for adjusting an equivalent impedance between the radio frequency port and the antenna port; one end of the first matching branch is connected with the radio frequency port, the other end of the first matching branch is connected with the antenna port in conduction or disconnected through a first matching branch switch, or is connected with the ground through the first matching branch switch; one end of the bypass branch is connected with the radio frequency port, the other end of the bypass branch is connected with the antenna port in conduction or disconnected through a bypass branch switch; one end of the second matching branch is connected with the ground, and the other end of the second matching branch is connected with the antenna port in conduction or disconnected through a second matching branch switch, so that the flexibility of impedance adjustment is improved.

Description

Technical Field

[0001] The embodiments in this specification relate to the field of communication electronic integrated circuits, and particularly to impedance matching circuits and impedance matching circuit control methods. Background Technology

[0002] With the development of mobile communication technology, mobile terminals need to support an increasing number of communication frequency bands. Impedance matching circuits are usually set between the antenna and the radio frequency front-end to adjust the equivalent impedance between them. In related technologies, impedance matching circuits typically use matching components such as capacitors and inductors connected in series in the radio frequency signal transmission path, or matching components connected in parallel between the radio frequency signal transmission path and the ground terminal to achieve impedance adjustment.

[0003] However, factors such as the operating frequency band of the mobile terminal, the surrounding environment of the antenna, and the user's holding position can all cause changes in antenna impedance. The impedance matching circuit with a fixed connection method has a limited adjustable impedance range and matching topology, making it difficult to adapt to the impedance matching requirements under different operating conditions. Summary of the Invention

[0004] In view of this, embodiments of this specification provide an impedance matching circuit. One or more embodiments of this specification also relate to an impedance matching circuit control method, a radio frequency front-end circuit, a mobile terminal, and an impedance matching circuit control module, to address the technical deficiencies existing in the prior art.

[0005] According to a first aspect of the embodiments of this specification, an impedance matching circuit is provided, including a main matching unit and a branch switching unit, wherein the main matching unit and the branch switching unit are disposed between a radio frequency port and an antenna port; The branch switching unit includes a bypass branch, at least one first matching branch, and at least one second matching branch, used to adjust the equivalent impedance between the RF port and the antenna port; One end of the first matching branch is connected to the radio frequency port, and the other end of the first matching branch is connected to or disconnected from the antenna port through the first matching branch switch, or grounded through the first matching branch switch; One end of the bypass branch is connected to the radio frequency port, and the other end of the bypass branch is connected to or disconnected from the antenna port through the bypass branch switch; One end of the second matching branch is grounded, and the other end of the second matching branch is connected or disconnected from the antenna port through the second matching branch switch.

[0006] According to a second aspect of the embodiments of this specification, an impedance matching circuit control method is provided, applied to a controller in an impedance matching circuit control system, the impedance matching circuit control system further comprising the impedance matching circuit provided in the first aspect above; the impedance matching circuit control method includes: Obtain the target matching state of the impedance matching circuit, wherein the target matching state includes any one of the following: series matching state, parallel matching state, L-type matching state, π-type matching state, and bypass state. Based on the target matching state, determine the switch conduction state corresponding to the branch switching unit in the impedance matching circuit; Based on the switch conduction state, the control impedance matching circuit forms the target matching network corresponding to the target matching state.

[0007] According to a third aspect of the embodiments of this specification, a radio frequency front-end circuit is provided, including a radio frequency receiving path, a radio frequency transmitting path, and an impedance matching circuit as provided in the first aspect above.

[0008] According to a fourth aspect of the embodiments of this specification, a mobile terminal is provided, including a radio frequency receiving path, a radio frequency transmitting path, and a radio frequency front-end circuit as provided in the third aspect above.

[0009] According to a fifth aspect of the embodiments of this specification, an impedance matching circuit control module is provided, including a control program / instruction that, when executed by the impedance matching circuit control module, implements the steps of the impedance matching circuit control method provided in the second aspect above.

[0010] One embodiment of the impedance matching circuit provided in this specification changes the circuit topology and equivalent impedance between the RF port and the antenna port by controlling the connection states of the first matching branch, the bypass branch, and the second matching branch. This improves the adaptability of the impedance matching circuit to different antenna impedance states and enhances the flexibility of impedance adjustment. Attached Figure Description

[0011] Figure 1 a is a schematic diagram of a series matching circuit in a conventional scheme provided in this specification; Figure 1 b is a schematic diagram of a parallel matching circuit in a traditional scheme provided in this manual; Figure 1 c is a schematic diagram of an L-type matching circuit in a traditional scheme provided in this manual; Figure 2 This is a schematic diagram of an impedance matching circuit provided in one embodiment of this specification; Figure 3 This is a circuit diagram of a branch switching unit provided in one embodiment of this specification; Figure 4 a is a circuit diagram of an L-shaped matching network composed of a main path matching unit and a branch path switching unit, provided in one embodiment of this specification; Figure 4b is a circuit diagram of a parallel matching network consisting of a main path matching unit and a branch path switching unit, provided in one embodiment of this specification; Figure 4 c is a circuit diagram of a π-type matching network composed of a main path matching unit and a branch path switching unit, provided in one embodiment of this specification; Figure 5 This is a circuit diagram illustrating a different L-shaped matching network formed by a main path matching unit and a branch path switching unit, as provided in one embodiment of this specification. Figure 6a This is a circuit diagram illustrating a series matching network consisting of a main path matching unit and a branch path switching unit, as provided in one embodiment of this specification. Figure 6b This is a circuit diagram illustrating a different series matching network formed by a main path matching unit and a branch path switching unit, as provided in one embodiment of this specification. Figure 7 This is a schematic diagram of a bypass circuit consisting of a main path matching unit and a branch path switching unit, provided in one embodiment of this specification. Figure 8 This is a flowchart of an impedance matching circuit control method provided in one embodiment of this specification; Figure 9 This is a schematic diagram of another impedance matching circuit provided in one embodiment of this specification; Figure 10 This is a circuit diagram of another branch switching unit provided in one embodiment of this specification; Figure 11 This is a schematic diagram of a radio frequency front-end circuit structure provided in one embodiment of this specification; Figure 12 This is a schematic diagram of a mobile terminal structure provided in one embodiment of this specification; Figure 13 This is a schematic diagram of an impedance matching circuit control module structure provided in one embodiment of this specification. Detailed Implementation

[0012] Many specific details are set forth in the following description to provide a full understanding of this specification. However, this specification can be implemented in many other ways than those described herein, and those skilled in the art can make similar extensions without departing from the spirit of this specification. Therefore, this specification is not limited to the specific implementations disclosed below.

[0013] The terminology used in one or more embodiments of this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of one or more embodiments of this specification. The singular forms “a,” “described,” and “the” as used in one or more embodiments of this specification and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in one or more embodiments of this specification refers to and includes any or all possible combinations of one or more associated listed items. The term “at least one” as used in one or more embodiments of this specification means “one or more,” and “a plurality of” means “two or more.” The term “comprising” is an open-ended description and should be understood as “including but not limiting,” and may include other content in addition to what has been described.

[0014] It should be understood that although the terms first, second, etc., may be used to describe various information in one or more embodiments of this specification, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, first may also be referred to as second without departing from the scope of one or more embodiments of this specification, and similarly, second may also be referred to as first. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to a determination."

[0015] First, the terms and concepts used in one or more embodiments of this specification will be explained.

[0016] Impedance refers to the resistance of a circuit to alternating current (AC) signals, typically comprising resistive and reactive components. The reactive component can include capacitive and inductive reactance. In radio frequency (RF) circuits, impedance can vary with factors such as signal frequency, circuit structure, component parameters, and the antenna's environment.

[0017] Equivalent impedance: refers to the impedance presented by the relevant components and their connections when viewed from one port of a circuit to another.

[0018] Impedance matching refers to adjusting the circuit topology and / or component parameters in the radio frequency (RF) signal transmission path to ensure that the impedance relationship on both sides of the RF signal transmission path meets the corresponding RF signal transmission requirements. Impedance matching can reduce reflections of RF signals when they are transmitted between different circuits and improve the power transmission status of RF signals.

[0019] Matching network: A matching network is a circuit network formed by one or more matching elements and corresponding connecting lines, used to adjust the equivalent impedance. Matching networks can include at least one of series matching networks, parallel matching networks, L-type matching networks, and π-type matching networks. Different matching networks may have different series matching sections and parallel matching sections.

[0020] Bypass: refers to the formation of an optional signal transmission path outside the original radio frequency signal transmission path, enabling the radio frequency signal to bypass at least part of the circuit structure in the original radio frequency signal transmission path for transmission.

[0021] RF port: This refers to the port in an impedance matching circuit used to connect RF front-end circuits, RF transceiver circuits, or other RF signal processing circuits. RF signals can be input to the impedance matching circuit via the RF port, and can also be output from the impedance matching circuit via the RF port.

[0022] Antenna port: refers to the port in the impedance matching circuit used to connect the antenna or antenna feed point.

[0023] The MIPI (Mobile Industry Processor Interface) is a serial control interface used to transmit control information between RF front-end devices. The controller can use this interface to send control information such as device identifiers, register addresses, and register configuration values ​​to control the on / off state of corresponding switches in the branch switching unit.

[0024] Unique Slave Identifier (USID): This refers to the identification information assigned to slave devices on the communication bus, used to distinguish different slave devices connected to the same communication bus. The master device can carry the USID in the control information so that the corresponding slave device can identify and respond to the control information.

[0025] Input / Output Supply Voltage (VIO): This refers to the voltage used to power the input / output interface circuitry of a device. VIO can be used to determine the logic level range of interface signals to achieve level matching between different devices on the communication bus.

[0026] Serial Data (SDATA) signals are used in serial communication interfaces to transmit data such as device identifiers, register addresses, register configuration values, or status information. Controllers and controlled devices can transmit control or response information via the SDATA signal line.

[0027] Serial Clock (SCLK): This refers to the clock signal used in a serial communication interface to provide a timing reference for data transmission. Communication devices can transmit, sample, or parse the SDATA signal based on the clock edge of the SCLK signal.

[0028] Ground (GND): This refers to the reference potential terminal in a circuit, used to provide a common potential reference for power supply to devices and signal transmission. The GND terminals of different devices can be connected to each other to reduce communication anomalies caused by inconsistent reference potentials.

[0029] In the field of mobile terminal radio frequency (RF) front-end, the complexity of mobile phone RF systems has been continuously increasing over the past decade, showing a rapid growth trend. The application of 5G communication technology has further increased the complexity of mobile phone design. Given the limited internal space of a mobile phone, improving antenna performance has become one of the key issues in RF system design. To support the ever-increasing number of 3GPP frequency bands, mobile phone manufacturers typically incorporate more antennas into mobile terminals. With the increase in the number of antennas, antenna performance becomes more susceptible to external conditions, such as the phone's proximity to a person, metal, or other objects, and the different parts of the phone held by the user. Furthermore, the impedance of the antenna may change when communicating at different frequency bands. All of these factors can lead to impedance mismatch between the antenna and the RF front-end, increasing power transmission loss between them, thus affecting the overall RF performance of the mobile phone and potentially shortening battery life. To adapt to different external conditions and antenna impedance variations within different frequency ranges, related technologies typically incorporate impedance tuners between the RF front-end and the antenna. By matching the impedance of the antenna and the RF front-end, the transmission state of the RF signal is improved.

[0030] Currently, in the field of mobile terminal radio frequency front-end, the mainstream impedance matching technology solutions can be mainly divided into the following three categories.

[0031] The first type is the series matching scheme. See also Figure 1 a, Figure 1 Figure a shows a schematic diagram of a series matching circuit in a conventional scheme provided in this specification. Matching components such as capacitors and inductors can be connected in series in the feed path between the RF front-end and the antenna, allowing the RF signal to be transmitted to the antenna via these matching components. By setting the type and parameters of the matching components, the series reactance in the feed path can be changed, thereby adjusting the equivalent impedance between the RF front-end and the antenna.

[0032] The second type is the parallel matching scheme. See also Figure 1 b, Figure 1 Figure b shows a schematic diagram of a parallel matching circuit in a conventional scheme provided in this specification. A parallel matching branch connected to the ground terminal can be set on the feed path between the RF front-end and the antenna, and matching components such as capacitors and inductors can be installed in this parallel matching branch. By connecting the corresponding matching components in parallel to the feed path, the equivalent impedance to ground of the feed node can be changed to achieve impedance adjustment.

[0033] The third type is the L-shaped matching scheme. See also... Figure 1 c, Figure 1Figure c shows a schematic diagram of an L-type matching circuit in a conventional scheme provided in this specification. Series and parallel matching elements can be combined, with one matching element connected in series in the feed path and the other between the feed path and the ground terminal, thus forming an L-type matching network. Compared to using series or parallel matching alone, the L-type matching network can adjust the equivalent impedance between the RF front-end and the antenna from both series and parallel reactance perspectives. However, due to factors such as the parameter range, quality factor, parasitic parameters, and fixed circuit topology of the matching elements, the above impedance matching scheme can usually only be adjusted within a limited impedance range, making it difficult to simultaneously adapt to the matching requirements of different communication frequency bands, different antenna impedance states, and different external environments. Furthermore, in some operating states, the original matching elements may not need to participate in impedance adjustment, but they are still connected in the feed path, easily introducing additional insertion loss and affecting the transmission efficiency of the RF signal. Therefore, there is a need to provide an impedance matching circuit that can flexibly adjust the circuit topology according to actual matching requirements to adapt to different antenna impedance states and reduce its impact on RF signal transmission when the corresponding matching elements are not needed.

[0034] This specification provides an impedance matching circuit, and also relates to an impedance matching circuit control method, an RF front-end circuit, a mobile terminal, and an impedance matching circuit control module, which will be described in detail in the following embodiments.

[0035] It should be noted that the impedance matching circuit, impedance matching circuit control method, RF front-end circuit, and impedance matching circuit control module provided in the embodiments of this specification can be applied to RF signal transmission scenarios of wireless communication devices, and are particularly suitable for impedance matching and antenna impedance tuning between the RF front-end and the antenna. For example, the embodiments of this specification can be applied to mobile phones, tablets, wearable devices, vehicle communication devices, portable communication devices, and other mobile terminals with wireless communication functions, as well as base stations, wireless access devices, IoT terminals, and other electronic devices equipped with RF front-end circuits and antennas. In the corresponding application scenarios, the connection status of each matching branch and bypass branch can be adjusted according to factors such as the communication frequency band, the reception or transmission status of the RF signal, the antenna impedance status, and the surrounding environment of the antenna, so that the impedance matching circuit forms a corresponding matching network to adapt to the impedance matching requirements between the RF front-end and the antenna.

[0036] See Figure 2 , Figure 2 This specification shows a schematic diagram of an impedance matching circuit according to one embodiment. See also: Figure 3 , Figure 3This is a circuit diagram of a branch switching unit provided in one embodiment of this specification. The impedance matching circuit includes a main matching unit and a branch switching unit, which are disposed between the RF port and the antenna port. The branch switching unit includes a bypass branch, at least one first matching branch, and at least one second matching branch, used to adjust the equivalent impedance between the RF port and the antenna port; One end of the first matching branch is connected to the radio frequency port, and the other end of the first matching branch is connected to or disconnected from the antenna port through the first matching branch switch, or grounded through the first matching branch switch; One end of the bypass branch is connected to the radio frequency port, and the other end of the bypass branch is connected to or disconnected from the antenna port through the bypass branch switch; One end of the second matching branch is grounded, and the other end of the second matching branch is connected or disconnected from the antenna port through the second matching branch switch.

[0037] It should be noted that an RF port refers to a port in an impedance matching circuit used to connect to the RF front-end circuit. The RF front-end circuit may include at least one of an RF receiving path or an RF transmitting path.

[0038] An antenna port is a port in an impedance matching circuit used to connect an antenna or an antenna feed point. Radio frequency (RF) signals can be transmitted from the RF port to the antenna port via the impedance matching circuit, or vice versa.

[0039] The main matching unit is located between the RF port and the antenna port, forming the main RF transmission path between them. The branch switching unit can work with the main matching unit to change the circuit topology on the RF port side and / or the antenna port side by altering the connection status of different branches, thereby adjusting the equivalent impedance between the RF port and the antenna port.

[0040] Equivalent impedance refers to the impedance observed from the RF port towards the antenna port, or vice versa. The equivalent impedance can be determined by the main matching unit, the first matching branch, the bypass branch, the second matching branch, and their connection states. By adjusting the equivalent impedance, the impedance relationship between the RF port and the antenna port can be adapted to the corresponding RF signal transmission requirements.

[0041] Bypassing refers to setting up an optional signal transmission path outside the original radio frequency (RF) signal transmission path, allowing the RF signal to bypass some or all of the matching elements in the main matching unit when accessed through this path. In the embodiments of this specification, the bypass branch can be connected between the RF port and the antenna port. When the bypass branch is connected to the antenna port, it forms a low-impedance transmission path between the RF port and the antenna port, bypassing the main matching unit; when the bypass branch is disconnected from the antenna port, the RF signal can be transmitted through the main matching unit. The bypass branch can be used to reduce the impact of the corresponding matching element on the RF signal transmission when the matching element does not need to participate in impedance adjustment.

[0042] One end of the bypass branch is connected to the RF port, and the other end is connected to or disconnected from the antenna port via a bypass branch switch. When the bypass branch is connected to the antenna port, it forms a transmission path between the RF port and the antenna port. When the bypass branch is disconnected from the antenna port, it does not participate in the RF signal transmission between the RF port and the antenna port. Therefore, whether to connect the bypass branch can be selected based on the current impedance matching requirements.

[0043] One end of the first matching branch is connected to the RF port, and the other end of the first matching branch is connected to or disconnected from the antenna port through a first matching branch switch, or grounded through a first matching branch switch. This means that the first matching branch can have at least one of the following connection states: connected to the antenna port, disconnected from the antenna port, and grounded. Specifically, when the first matching branch is connected to the antenna port, it is connected between the RF port and the antenna port and can participate in adjusting the equivalent impedance between the RF port and the antenna port; when the first matching branch is grounded, it is connected between the RF port and the ground terminal and can adjust the equivalent impedance to ground on the RF port side; when the first matching branch is disconnected from the antenna port and not grounded, the first matching branch does not participate in the current impedance adjustment.

[0044] One end of the second matching branch is grounded, and the other end of the second matching branch is connected to or disconnected from the antenna port via a second matching branch switch. When the second matching branch is connected to the antenna port, it connects between the antenna port and the ground terminal, forming a ground-to-ground matching branch on the antenna port side, thereby adjusting the equivalent impedance to ground on the antenna port side. When the second matching branch is disconnected from the antenna port, it does not participate in the current impedance adjustment.

[0045] In practical applications, the first matching branch switch can take various forms, and the specific choice depends on the actual situation. This specification does not impose any limitations on this aspect. In one possible implementation, the first matching branch switch can be a multi-state switch capable of switching between the antenna port, the disconnected position, and the ground terminal. In another possible implementation, the first matching branch switch can also consist of multiple independent switches. For example, the first matching branch switch may include a path switch for controlling the connection or disconnection between the first matching branch and the antenna port, and a grounding switch for controlling whether the first matching branch is grounded or not. This specification does not limit the specific structure of the first matching branch switch, as long as it can achieve the corresponding connection state of the first matching branch.

[0046] Furthermore, the number of first matching branches and second matching branches can be one or more. When multiple first matching branches are provided, each first matching branch can be connected to, disconnected from, or grounded to the antenna port through a corresponding first matching branch switch. When multiple second matching branches are provided, each second matching branch can be connected to or disconnected from the antenna port through a corresponding second matching branch switch. Each matching branch can be controlled independently or collaboratively according to a preset switch combination; this specification does not limit this aspect in the embodiments.

[0047] The bypass branch switch and the second matching branch switch can be single-pole single-throw switches, radio frequency electronic switches, or switching circuits composed of multiple switching devices. The conduction state of the first matching branch switch, the bypass branch switch, and the second matching branch switch can be controlled by the control circuit or set according to a preset configuration. The specific device type, control method, and setting position of each switch can be selected according to the radio frequency band, power requirements, and circuit layout.

[0048] By applying the solutions described in this specification, the circuit topology and equivalent impedance between the RF port and the antenna port can be changed by controlling the connection states of the first matching branch, the bypass branch, and the second matching branch. This improves the adaptability of the impedance matching circuit to different antenna impedance states and enhances the flexibility of impedance adjustment.

[0049] In one optional embodiment of this specification, the other end of the second matching branch is connected to the antenna port through a second matching branch switch, and the main matching unit and the branch switching unit constitute any one of a parallel matching network, an L-type matching network, and a π-type matching network.

[0050] It should be noted that a parallel matching network refers to a circuit network that includes at least a matching branch connecting the RF signal transmission path and the ground terminal. In a parallel matching network, the second matching branch can serve as a matching branch connected in parallel to ground to adjust the equivalent impedance at the antenna port side.

[0051] An L-type matching network refers to a circuit network that includes a series matching section and a parallel matching section. The series matching section can be located between the RF port and the antenna port, while the parallel matching section can be located on either the RF port side or the antenna port side. When the second matching branch is connected to the antenna port, the second matching branch can form a parallel matching section on the antenna port side, which, together with the series matching section in the main matching unit, constitutes the L-type matching network.

[0052] A π-type matching network refers to a circuit network that includes parallel matching sections located on both sides of a series matching section. For example, the main matching unit can form a series matching section connected between the RF port and the antenna port, the first matching branch can form a parallel matching section on the RF port side, and the second matching branch can form a parallel matching section on the antenna port side, thereby constituting a π-type matching network.

[0053] There can be one second matching branch. In this case, the second matching branch can be selectively connected between the antenna port and the ground terminal by controlling the second matching branch switch corresponding to that second matching branch. There can also be multiple second matching branches, and each second matching branch can be equipped with a corresponding second matching branch switch, so that each second matching branch can be independently controlled to be connected or disconnected from the antenna port.

[0054] When multiple second matching branches are configured, one of the second matching branches can be connected to the antenna port, or multiple second matching branches can be connected to the antenna port simultaneously, depending on the target impedance matching requirements. Each second matching branch can provide the same or different impedance adjustment effects to form different equivalent impedances on the antenna port side. The number of second matching branches and their specific conduction combinations can be selected according to the operating frequency band, antenna impedance state, and required impedance adjustment range; this specification does not limit this.

[0055] The specific matching network formed by the main matching unit and the branch switching unit can be determined based on the connection status of the first matching branch, the bypass branch, and the second matching branch. With the second matching branch connected to the antenna port, by changing the connection status of the first matching branch and the bypass branch, the main matching unit and the branch switching unit can form a parallel matching network, an L-shaped matching network, or a π-shaped matching network. The specific branch connection statuses corresponding to different matching networks will be described in subsequent embodiments.

[0056] For example, when the mobile terminal operates in different communication frequency bands or the antenna impedance changes due to the external environment, the second matching branch switch can be turned on to connect the second matching branch between the antenna port and the ground terminal; at the same time, the connection state of other branches can be adjusted according to the target equivalent impedance so that the impedance matching circuit forms one of a parallel matching network, an L-type matching network, or a π-type matching network.

[0057] See Figure 4 a, Figure 4 Figure a shows a circuit diagram illustrating an L-shaped matching network formed by a main path matching unit and a branch path switching unit according to an embodiment of this specification. Figure 4 In the embodiment shown in a, the second matching branch is connected to the antenna port through a second matching branch switch, the bypass branch is disconnected from the antenna port through a bypass branch switch, and the first matching branch is disconnected from the antenna port through a first matching branch switch and is not grounded. Therefore, the bypass branch and the first matching branch do not participate in the current impedance matching, and the main matching unit is located between the RF port and the antenna port.

[0058] The main matching unit forms a series matching section between the RF port and the antenna port, allowing RF signals to be transmitted from the RF port to the antenna port via the main matching unit. One end of the second matching branch is grounded, and the other end is connected to the antenna port via a second matching branch switch, thus connecting the antenna port and the ground terminal, forming a parallel matching section on the antenna port side. The series matching section formed by the main matching unit and the parallel matching section formed by the second matching branch together constitute an L-shaped matching network.

[0059] In this L-shaped matching network, the main matching unit adjusts the series equivalent impedance between the RF port and the antenna port, while the second matching branch adjusts the equivalent impedance to ground at the antenna port. Through the cooperation of the series and parallel matching sections, the equivalent impedance between the RF port and the antenna port can be adjusted. When the impedance matching circuit includes multiple second matching branches, one or more branches can be connected to the antenna port simultaneously to change the equivalent impedance of the parallel matching section, thus forming an L-shaped matching network with different impedance characteristics.

[0060] By applying the solutions described in this specification, different matching networks can be formed by connecting the second matching branch between the antenna port and the ground terminal, and cooperating with other branches in the main matching unit and the branch switching unit. This increases the selectable circuit topology of the impedance matching circuit and improves its adaptability to different antenna impedance states.

[0061] See Figure 4 b, Figure 4Figure b shows a circuit diagram of a main matching unit and a branch switching unit forming a parallel matching network according to an embodiment of this specification. The other end of the bypass branch is connected to the antenna port through a bypass branch switch, and the other end of the first matching branch is disconnected from the antenna port through a first matching branch switch. The main matching unit and the branch switching unit form a parallel matching network.

[0062] It should be noted that, in this embodiment, the bypass branch is connected between the RF port and the antenna port. When the bypass branch switch is turned on, the bypass branch can form a bypass transmission path between the RF port and the antenna port, enabling the RF signal to be transmitted between the RF port and the antenna port via the bypass branch, thereby bypassing at least part of the circuit structure in the main matching unit, or reducing the influence of the main matching unit on the equivalent impedance between the RF port and the antenna port.

[0063] The first matching branch is disconnected from the antenna port via a first matching branch switch, meaning the first matching branch is connected between the RF port and the antenna port without going through the first matching branch switch. In some embodiments, the first matching branch may also be in an ungrounded state, so that the first matching branch does not participate in the current impedance adjustment. Thus, the impedance matching circuit can mainly form a parallel matching network through the bypass branch and the second matching branch.

[0064] like Figure 4 As shown in Figure b, one end of the bypass branch is connected to the RF port, and the other end of the bypass branch is connected to the antenna port through a bypass branch switch, thereby forming a bypass transmission path between the RF port and the antenna port. The first matching branch is disconnected from the antenna port through a first matching branch switch, so the first matching branch is not connected between the RF port and the antenna port.

[0065] Simultaneously, one end of the second matching branch is grounded, and the other end of the second matching branch is connected to the antenna port through a second matching branch switch, thus connecting the second matching branch between the antenna port and the ground terminal. Since the RF port and the antenna port are connected through a bypass branch, the second matching branch is correspondingly connected in parallel between the RF signal transmission path and the ground terminal, thereby forming a parallel matching network.

[0066] In one possible implementation, the bypass branch can form a transmission path with a lower impedance relative to the main matching unit. When the bypass branch is switched on, the RF signal can be transmitted primarily through the bypass branch to reduce the impact of the matching elements in the main matching unit on the RF signal transmission. The second matching branch can adjust the equivalent impedance between the RF port and the antenna port by changing the equivalent impedance to ground on the antenna port side through its own impedance characteristics.

[0067] In another possible implementation, there can be multiple second matching branches, each connected to or disconnected from the antenna port via a corresponding second matching branch switch. When forming a parallel matching network, one or more second matching branches can be connected to the antenna port simultaneously to create different parallel equivalent impedances. The specific connected second matching branches can be determined based on the communication frequency band, antenna impedance status, or preset matching parameters.

[0068] For example, when the antenna impedance of the mobile terminal is suitable for adjustment using a parallel matching method, the bypass branch switch can be controlled to be turned on so that the bypass branch connects the RF port and the antenna port; the first matching branch switch can be controlled to be turned off so that the first matching branch is not connected between the RF port and the antenna port; and at least one second matching branch switch can be controlled to be turned on so that the corresponding second matching branch connects between the antenna port and the ground terminal. Thus, a system can be formed... Figure 4 The parallel matching network shown in b is an example of this.

[0069] The scheme implemented in this specification allows for the formation of a transmission path between the RF port and the antenna port via a bypass branch, and the equivalent impedance to ground on the antenna port side can be adjusted via a second matching branch. This creates a parallel matching network and reduces the impact of the first matching branch and the main matching unit, which do not require current impedance adjustment, on RF signal transmission.

[0070] See Figure 4 c, Figure 4 Figure c shows a circuit diagram of a π-type matching network formed by a main matching unit and a branch switching unit according to an embodiment of this specification. The other end of the first matching branch is grounded through a first matching branch switch, and the other end of the bypass branch is disconnected from the antenna port through a bypass branch switch. The main matching unit and the branch switching unit form a π-type matching network.

[0071] It should be noted that the other end of the first matching branch is grounded through the first matching branch switch. This means that the first matching branch is connected between the RF port and the ground terminal, thereby forming a parallel matching section on the RF port side of the main matching unit. The first matching branch switch may include a pass switch for controlling the first matching branch to be connected or disconnected from the antenna port, and a ground switch for controlling the first matching branch to be grounded or ungrounded. When forming a π-type matching network, the pass switch can be controlled to be disconnected, and the ground switch can be controlled to be connected, so that the first matching branch is grounded.

[0072] When the bypass branch is disconnected from the antenna port via the bypass branch switch, it means that the bypass branch does not form a bypass transmission path between the RF port and the antenna port. In this connection state, the main matching unit remains connected between the RF port and the antenna port, forming the series matching part in the π-type matching network.

[0073] exist Figure 4 In the embodiment shown in c, one end of the first matching branch is connected to the RF port, and the other end is grounded through the first matching branch switch. Therefore, the first matching branch is connected between the RF port and the ground terminal, forming a first parallel matching section on the RF port side. The main matching unit is connected between the RF port and the antenna port, forming a series matching section. One end of the second matching branch is grounded, and the other end is connected to the antenna port through the second matching branch switch, forming a second parallel matching section on the antenna port side.

[0074] Thus, the first parallel matching portion formed by the first matching branch, the series matching portion formed by the main matching unit, and the second parallel matching portion formed by the second matching branch are sequentially arranged to form a π-type matching network. The radio frequency signal can be transmitted from the radio frequency port to the antenna port via the main matching unit. The first matching branch and the second matching branch respectively adjust the equivalent impedance to ground on both sides of the main matching unit.

[0075] In this π-type matching network, the first matching branch can adjust the equivalent impedance to ground on the RF port side, the main matching unit can adjust the series equivalent impedance between the RF port and the antenna port, and the second matching branch can adjust the equivalent impedance to ground on the antenna port side. Through the cooperation of these three matching parts, the equivalent impedance between the RF port and the antenna port can be adjusted from both sides of the main matching unit.

[0076] In one possible implementation, there can be one second matching branch. By controlling the second matching branch switch corresponding to the second matching branch to be turned on, the second matching branch forms a second parallel matching part.

[0077] In another possible implementation, there can be multiple second matching branches. Each second matching branch can be connected to or disconnected from the antenna port through a corresponding second matching branch switch. When forming a π-type matching network, one second matching branch can be connected to the antenna port, or multiple second matching branches can be connected to the antenna port simultaneously to change the equivalent impedance to ground on the antenna port side.

[0078] Similarly, when there are multiple first matching branches, at least one first matching branch can be grounded to form a first parallel matching section on the RF port side. The number of grounded first matching branches and the number of conducted second matching branches can be determined based on the communication frequency band, antenna impedance state, and target equivalent impedance; this specification does not limit this in the embodiments.

[0079] For example, when the antenna impedance of the mobile terminal varies greatly, and a single series matching or single-sided parallel matching is insufficient to meet the current impedance adjustment requirements, the bypass branch switch can be controlled to open, keeping the main matching unit connected; at least one first matching branch can be grounded through the first matching branch switch; and at least one second matching branch can be connected to the antenna port through the second matching branch switch. Thus, a system can be formed... Figure 4 The π-type matching network shown in c is...

[0080] By applying the scheme of the embodiments in this specification, a first parallel matching section can be formed on the RF port side by grounding the first matching branch; by disconnecting the bypass branch from the antenna port, the main matching unit can remain connected and form a series matching section; and by connecting the second matching branch to the antenna port, a second parallel matching section can be formed on the antenna port side. Thus, a π-type matching network can be constructed, and the equivalent impedance to ground on the RF port side, the equivalent impedance of the series connection between the RF port and the antenna port, and the equivalent impedance to ground on the antenna port side can be adjusted respectively, improving the flexibility of impedance adjustment.

[0081] See Figure 5 , Figure 5 This specification illustrates a circuit diagram of a main matching unit and a branch switching unit forming another L-shaped matching network according to an embodiment of this specification. The other end of the first matching branch is grounded through a first matching branch switch, the other end of the second matching branch is disconnected from the antenna port through a second matching branch switch, and the other end of the bypass branch is disconnected from the antenna port through a bypass branch switch. The main matching unit and the branch switching unit form an L-shaped matching network.

[0082] It should be noted that in this embodiment, one end of the first matching branch is connected to the RF port, and the other end of the first matching branch is grounded through a first matching branch switch, thereby connecting the first matching branch between the RF port and the ground terminal, forming a parallel matching section located on the RF port side. Grounding the first matching branch means that the first matching branch is connected to the ground terminal, not that the antenna port is grounded.

[0083] The second matching branch being disconnected from the antenna port via the second matching branch switch means that the second matching branch is not connected between the antenna port and the ground terminal, and therefore the second matching branch does not participate in the current impedance adjustment. The bypass branch being disconnected from the antenna port via the bypass branch switch means that the bypass branch does not form a bypass transmission path between the RF port and the antenna port, and the main matching unit remains connected between the RF port and the antenna port.

[0084] exist Figure 5 In the illustrated embodiment, the main matching unit is connected between the RF port and the antenna port, forming the series matching portion of an L-shaped matching network. One end of the first matching branch is connected to the RF port, and the other end is grounded through a first matching branch switch, forming the parallel matching portion of the L-shaped matching network. The series matching portion and the parallel matching portion located on the RF port side together constitute the L-shaped matching network.

[0085] Radio frequency (RF) signals can be transmitted from the RF port to the antenna port via the main matching unit. The first matching branch connects the RF port to the ground terminal and can adjust the equivalent impedance to ground on the RF port side; the main matching unit can adjust the series equivalent impedance between the RF port and the antenna port. Through the cooperation of the first matching branch and the main matching unit, the equivalent impedance between the RF port and the antenna port can be adjusted.

[0086] Figure 5 The L-shaped matching network shown is Figure 4 The difference between the L-shaped matching networks shown in diagram a is: Figure 4 The parallel matching section in 'a' is formed by the second matching branch and is located on the antenna port side of the main matching unit; Figure 5 The parallel matching section is formed by the first matching branch and is located on the RF port side of the main matching unit. Therefore, the matching branch on the corresponding side can be selected to participate in impedance adjustment according to the impedance state of the RF port side and the antenna port side.

[0087] In one possible implementation, the impedance matching circuit includes a first matching branch, which can be grounded or disconnected by controlling the first matching branch switch corresponding to it. Figure 5 In the L-shaped matching network shown, the first matching branch switch grounds the first matching branch.

[0088] In another possible implementation, the impedance matching circuit may include multiple first matching branches, each with a corresponding first matching branch switch. When forming an L-shaped matching network, at least one of the first matching branches can be grounded, and the first matching branches not involved in the current impedance adjustment can be kept in an open state to obtain the corresponding RF port-side equivalent impedance to ground.

[0089] For example, when the current antenna impedance is suitable for setting up a parallel matching section on the RF port side of the main matching unit, the bypass branch switch can be controlled to open, keeping the main matching unit connected between the RF port and the antenna port; the second matching branch switch can be controlled to open, preventing the second matching branch from participating in the current impedance adjustment; and the first matching branch switch can be controlled to ground the first matching branch. Thus, a system can be formed... Figure 5 The L-shaped matching network shown.

[0090] By applying the scheme of the embodiments in this specification, a parallel matching section can be formed on the RF port side by grounding the first matching branch; by disconnecting the bypass branch and the second matching branch from the antenna port, the main matching unit can form a series matching section, and the influence of other branches on the current circuit topology can be reduced. Thus, an L-shaped matching network with the parallel matching section located on the RF port side can be constructed, and the equivalent impedance to ground on the RF port side and the series equivalent impedance between the RF port and the antenna port can be adjusted respectively.

[0091] See Figure 6a , Figure 6a This specification shows a circuit diagram illustrating a series matching network formed by a main path matching unit and a branch path switching unit, according to one embodiment of the present specification; see also Figure 6b , Figure 6b This specification illustrates a circuit diagram of a series matching network formed by a main matching unit and a branch switching unit, according to one embodiment of the present specification. The other end of the first matching branch is disconnected from the antenna port via a first matching branch switch, the other end of the bypass branch is disconnected via a bypass branch switch, and the other end of the second matching branch is disconnected via a second matching branch switch. The main matching unit and the branch switching unit form a series matching network; or... The other end of the first matching branch is connected to the antenna port through the first matching branch switch, the other end of the bypass branch is disconnected from the antenna port through the bypass branch switch, and the other end of the second matching branch is disconnected from the antenna port through the second matching branch switch. The main matching unit and the branch switching unit form a series matching network.

[0092] It should be noted that a series matching network refers to a circuit network that forms a series matching section between the RF port and the antenna port. The series matching section is set in the transmission path of the RF signal. When the RF signal is transmitted from the RF port to the antenna port, it passes through this series matching section, thereby adjusting the equivalent impedance between the RF port and the antenna port through the impedance characteristics of this series matching section.

[0093] Figure 6a Only the effective circuit path for forming a series matching network is shown; the first matching branch, bypass branch, and second matching branch are all in an open state, therefore... Figure 6a The text is omitted. Figure 6a In the illustrated embodiment, the first matching branch is disconnected from the antenna port via a first matching branch switch and is in a non-grounded state; the bypass branch is disconnected from the antenna port via a bypass branch switch; and the second matching branch is disconnected from the antenna port via a second matching branch switch. Therefore, the first matching branch, the bypass branch, and the second matching branch do not participate in the current impedance adjustment, and the main matching unit remains connected between the RF port and the antenna port.

[0094] In this connection state, the radio frequency signal between the RF port and the antenna port is transmitted through the main matching unit, which forms a series matching section, thus constituting... Figure 6a The series matching network is shown. The main matching unit can adjust the equivalent series impedance between the RF port and the antenna port through its own impedance characteristics.

[0095] For example, when the current impedance adjustment requirement can be met by the main matching unit alone, the first matching branch switch, the bypass branch switch and the second matching branch switch can be controlled to be disconnected, so that the first matching branch, the bypass branch and the second matching branch are not connected to the current circuit, thereby forming a series matching network by the main matching unit.

[0096] See Figure 6b , Figure 6b This specification shows a circuit diagram illustrating a main path matching unit and a branch path switching unit forming another series matching network according to an embodiment of this specification.

[0097] exist Figure 6b In the illustrated embodiment, one end of the first matching branch is connected to the RF port, and the other end of the first matching branch is connected to the antenna port via a first matching branch switch and is in a non-grounded state. The bypass branch is disconnected from the antenna port via a bypass branch switch, and the second matching branch is disconnected from the antenna port via a second matching branch switch. Therefore, the bypass branch and the second matching branch do not participate in the current impedance adjustment, and the first matching branch and the main matching unit are connected together between the RF port and the antenna port.

[0098] It should be noted that, in Figure 6b In the circuit shown, both the first matching branch and the main matching unit are connected between the RF port and the antenna port, forming two parallel transmission branches. The equivalent matching portion formed by the first matching branch and the main matching unit is located entirely between the RF port and the antenna port. Therefore, this equivalent matching portion still serves as the series matching portion in the RF signal transmission path, constituting a series matching network.

[0099] In other words, the first matching branch and the main matching unit can be connected in parallel, but the equivalent impedance formed by the two is connected in series between the RF port and the antenna port. Therefore, "the first matching branch and the main matching unit together form a series matching network" means that the equivalent matching part of the two is a series matching part in the entire RF transmission path, and does not mean that the first matching branch and the main matching unit must be connected in series with each other.

[0100] In this series matching network, the connection of the first matching branch can change the series equivalent impedance between the RF port and the antenna port. By controlling the first matching branch to be turned on or off with the antenna port, switching can be made between a series matching network formed solely by the main matching unit and a series matching network formed jointly by the first matching branch and the main matching unit.

[0101] When the impedance matching circuit includes multiple first matching branches, one of the first matching branches can be connected to the antenna port, or multiple first matching branches can be connected to the antenna port simultaneously to form different series equivalent impedances. The conduction state of each first matching branch can be determined based on the operating frequency band, the antenna impedance state, and the target equivalent impedance.

[0102] For example, when the series equivalent impedance formed by the main matching unit alone cannot meet the current impedance adjustment requirements, at least one first matching branch switch can be turned on, connecting the corresponding first matching branch between the RF port and the antenna port; simultaneously, the bypass branch switch and the second matching branch switch are turned off. Thus, the first matching branch and the main matching unit together form... Figure 6b Another type of cascaded matching network is shown.

[0103] By applying the scheme of the embodiments in this specification, disconnecting the first matching branch, the bypass branch, and the second matching branch from the antenna port, a series matching portion between the RF port and the antenna port can be formed by the main matching unit. Therefore, the series equivalent impedance between the RF port and the antenna port can be adjusted by the main matching unit. By connecting the first matching branch to the antenna port, the first matching branch and the main matching unit can jointly form a series equivalent matching portion between the RF port and the antenna port. Therefore, the series equivalent impedance can be further adjusted based on the series equivalent impedance provided by the main matching unit, increasing the selectable impedance parameters under series matching conditions.

[0104] See Figure 7 , Figure 7This specification illustrates a schematic diagram of a bypass circuit formed by a main path matching unit and a branch switching unit, according to an embodiment of this specification. The other end of the bypass branch is connected to the antenna port via a bypass branch switch, the other end of the first matching branch is disconnected from the antenna port via a first matching branch switch, and the other end of the second matching branch is disconnected from the antenna port via a second matching branch switch. The main path matching unit and the branch switching unit constitute the bypass circuit.

[0105] It should be noted that a bypass circuit refers to a bypass transmission path between the RF port and the antenna port, which is different from the transmission path of the main matching unit. This allows the RF signal to be transmitted between the RF port and the antenna port via the bypass transmission path. The bypass branch can be connected in parallel with the main matching unit and can be selectively connected between the RF port and the antenna port through a bypass branch switch.

[0106] exist Figure 7 In the illustrated embodiment, the main matching unit is connected between the RF port and the antenna port; one end of the bypass branch is connected to the RF port, and the other end is connected to the antenna port via a bypass branch switch that is in the ON state. Therefore, the bypass branch bridges the two ends of the main matching unit, forming a bypass transmission path between the RF port and the antenna port. When the bypass branch switch is ON, the bypass branch is connected in parallel with the main matching unit. The RF signal can be transmitted via the main matching unit or via the bypass branch. When the bypass branch has a relatively low impedance, the RF signal can be mainly transmitted between the RF port and the antenna port via the bypass branch, thereby reducing the impact of the main matching unit on the RF signal transmission and equivalent impedance.

[0107] In one possible implementation, a bypass element can be incorporated into the bypass branch, providing a low-impedance conduction path. When the bypass branch switch is turned on, the bypass element and the bypass branch switch together form a bypass transmission path between the RF port and the antenna port. In another possible implementation, the bypass branch can be constructed from conductive traces, switch conduction paths, or other circuit structures capable of forming a bypass connection between the RF port and the antenna port. The specific structure and impedance parameters of the bypass branch can be set according to the operating frequency band, RF power, and impedance characteristics of the main matching unit; this specification does not limit these aspects in the embodiments.

[0108] Figure 7 Only the effective circuit path for forming a bypass circuit is shown. In one specific embodiment, the first matching branch can be disconnected from the antenna port and be in a non-grounded state, and the second matching branch can be disconnected from the antenna port, so that the first and second matching branches do not participate in the current impedance adjustment. In other embodiments, the connection state of the first or second matching branch can be set according to the actual impedance adjustment requirements.

[0109] For example, when impedance compensation using the main matching unit is not required in the current communication frequency band, or when continued connection of the main matching unit would adversely affect RF signal transmission, the bypass branch switch can be turned on to connect the bypass branch to the RF port and the antenna port. The RF signal can then be primarily transmitted through the bypass branch, thereby forming... Figure 7 The bypass circuit shown.

[0110] By applying the solutions described in this specification and connecting the bypass branch to the antenna port, a bypass transmission path can be formed between the RF port and the antenna port. Therefore, when a bypass main matching unit is required, the impact of the main matching unit on the RF signal transmission between the RF port and the antenna port can be reduced.

[0111] In one optional embodiment of this specification, the main matching unit is provided with a main matching element, which includes at least one of a capacitor and an inductor; The first matching branch is provided with a first matching element, which includes at least one of a capacitor and an inductor. Bypass components are provided in the bypass branch circuit; The second matching branch is provided with a second matching element, which includes at least one of a capacitor and an inductor.

[0112] It should be noted that including at least one of capacitors and inductors can mean including only capacitors, only inductors, or both capacitors and inductors. When the corresponding matching element includes both capacitors and inductors, the capacitors and inductors can together form the corresponding matching structure. The number, connection method, and parameters of capacitors and inductors can be set according to the operating frequency band, antenna impedance state, and target equivalent impedance; the embodiments in this specification do not limit this.

[0113] The main matching element, the first matching element, and the second matching element are matching elements respectively disposed in the main matching unit, the first matching branch, and the second matching branch, and are independent of each other. The capacitors and / or inductors included in each of the above matching elements are used to indicate the component types that can be used for the corresponding matching element, and do not indicate that the main matching element, the first matching element, and the second matching element share the same capacitor or the same inductor. The main matching element, the first matching element, and the second matching element can each be selected from at least one of capacitors and inductors, and the component types and component parameters of each matching element can be the same or different, which can be set according to the impedance adjustment requirements of the corresponding matching branch.

[0114] A main path matching element is a component placed in the main radio frequency (RF) transmission path between the RF port and the antenna port to adjust the equivalent series impedance between them. The main path matching element can be connected between the RF port and the antenna port, allowing the RF signal to be transmitted between them via the main path matching element. In series matching networks, L-type matching networks, or π-type matching networks, the main path matching element can form the series matching portion of the corresponding matching network.

[0115] In one possible implementation, the main matching element may consist only of a capacitor, and the capacitive impedance provided by the capacitor adjusts the series equivalent impedance between the RF port and the antenna port. In another possible implementation, the main matching element may consist only of an inductor, and the inductive impedance provided by the inductor adjusts the series equivalent impedance between the RF port and the antenna port. In yet another possible implementation, the main matching element may include both a capacitor and an inductor, which together form the main matching structure to adjust the series equivalent impedance between the RF port and the antenna port.

[0116] The first matching element is disposed in the first matching branch. The first matching element can form different matching sections depending on the connection state of the first matching branch. When the first matching branch is connected to the antenna port through the first matching branch switch, the first matching element is connected between the RF port and the antenna port, and together with the main matching element, forms an equivalent matching section located between the RF port and the antenna port. When the first matching branch is grounded through the first matching branch switch, the first matching element is connected between the RF port and the ground terminal, forming a parallel matching section located on the RF port side. When the first matching branch is disconnected from the antenna port and is in a non-grounded state, the first matching element may not participate in the current impedance adjustment.

[0117] In one possible implementation, the first matching element may consist only of a capacitor. When the first matching branch is connected to the antenna port, the capacitor, together with the main matching element, can adjust the equivalent impedance between the RF port and the antenna port; when the first matching branch is grounded, the capacitor can form a capacitor-to-ground matching portion on the RF port side. In another possible implementation, the first matching element may consist only of an inductor. When the first matching branch is connected to the antenna port, the inductor, together with the main matching element, can adjust the equivalent impedance between the RF port and the antenna port; when the first matching branch is grounded, the inductor can form an inductor-to-ground matching portion on the RF port side. In yet another possible implementation, the first matching element may include both a capacitor and an inductor, which together form the matching structure in the first matching branch and participate in forming the equivalent matching portion between the RF port and the antenna port, or form a parallel matching portion on the RF port side, depending on the connection state of the first matching branch.

[0118] A bypass element is disposed in the bypass branch. When the bypass branch is connected to the antenna port through the bypass branch switch, the bypass element can form a bypass transmission path between the RF port and the antenna port to bypass the main matching element or reduce the impact of the main matching element on the RF signal transmission. In one possible implementation, the bypass element may include a 0Ω resistor. In another possible implementation, the bypass element may include a low-resistance conductive trace, a low-resistance connection device, or a low-resistance circuit structure formed by the switch conduction path. The specific impedance of the bypass element can be set according to the operating frequency band, RF power, insertion loss requirements, and circuit layout; this specification does not limit this.

[0119] The second matching element is disposed in the second matching branch. Since one end of the second matching branch is grounded, when the other end of the second matching branch is connected to the antenna port through the second matching branch switch, the second matching element is connected between the antenna port and the ground terminal to form a parallel matching section on the antenna port side. The second matching element can adjust the equivalent impedance to ground on the antenna port side through its impedance characteristics. When the second matching branch is disconnected from the antenna port, the second matching element does not participate in the current impedance adjustment.

[0120] In one possible implementation, the second matching element may consist only of a capacitor, forming a capacitor-to-ground matching portion on the antenna port side when the second matching branch is connected to the antenna port. In another possible implementation, the second matching element may consist only of an inductor, forming an inductor-to-ground matching portion on the antenna port side when the second matching branch is connected to the antenna port. In yet another possible implementation, the second matching element may include both a capacitor and an inductor, which together form the matching structure in the second matching branch, forming a parallel matching portion on the antenna port side when the second matching branch is connected to the antenna port.

[0121] In an impedance matching circuit comprising multiple first matching branches, the first matching elements in different first matching branches may have the same or different component compositions. For example, the first matching element in one first matching branch may consist only of a capacitor, the first matching element in another first matching branch may consist only of an inductor, and the first matching element in yet another first matching branch may consist of both a capacitor and an inductor. Each first matching branch can be independently controlled by a corresponding first matching branch switch.

[0122] Similarly, when the impedance matching circuit includes multiple second matching branches, the second matching elements in different second matching branches can have the same or different component compositions. When multiple second matching branches are simultaneously connected to the antenna port, each second matching element can be connected in parallel between the antenna port and the ground terminal, and together form the parallel equivalent impedance on the antenna port side.

[0123] It should be noted that, Figure 4 a to Figure 7 The circuit structure of each matching network is illustrated using specific components such as capacitors and 0Ω resistors. However, the specific component types shown in the figures are only used to illustrate one possible implementation and do not constitute a limitation on the main matching component, the first matching component, the bypass component, and the second matching component.

[0124] For example, the main matching element can be a capacitor, the first matching element can be a capacitor, the bypass element can be a 0Ω resistor, and the second matching element can be a capacitor or an inductor. When both the first and second matching branches are disconnected, the main matching element can form... Figure 6a The illustrated series matching network; when the first matching branch is connected to the antenna port, the first matching element can form a series matching network with the main matching element. Figure 6b Another series matching network is shown; when the first matching branch is grounded, the first matching element can form a parallel matching portion on the RF port side; when the second matching branch is connected to the antenna port, the second matching element can form a parallel matching portion on the antenna port side; when the bypass branch is connected to the antenna port, the bypass element can form a parallel matching portion on the antenna port side. Figure 7 The bypass transmission path is shown.

[0125] By applying the scheme of the embodiments in this specification, matching elements including at least one of capacitors and inductors are respectively provided in the main matching unit, the first matching branch, and the second matching branch, and a bypass element is provided in the bypass branch. Appropriate matching elements or bypass elements can be selected to participate in the current circuit according to impedance adjustment requirements. Therefore, different capacitive impedances, inductive impedances, or impedances formed by both capacitors and inductors can be provided, increasing the range of selectable impedance parameters.

[0126] See Figure 8 , Figure 8 A flowchart illustrating an impedance matching circuit control method according to an embodiment of this specification is shown. The impedance matching circuit control method is applied to a controller in an impedance matching circuit control system, which further includes the aforementioned impedance matching circuit. Specifically, the method includes the following steps: Step 802: Obtain the target matching state of the impedance matching circuit, wherein the target matching state includes any one of the following: series matching state, parallel matching state, L-type matching state, π-type matching state, and bypass state.

[0127] It should be noted that the controller in the impedance matching circuit control system refers to a control device that can acquire the target matching state, determine the switch conduction state, and control the impedance matching circuit to switch the circuit topology.

[0128] The target matching state refers to the impedance matching state that the impedance matching circuit intends to achieve under current operating conditions. Different target matching states can correspond to different circuit topologies and can be formed through different connection states of the first matching branch, bypass branch, and second matching branch. The target matching state can be used to characterize whether the current configuration requires series matching, parallel matching, L-type matching, π-type matching, or bypass mode to be used for the RF transmission path between the RF port and the antenna port.

[0129] In practical applications, there are various ways to obtain the target matching state of an impedance matching circuit, and the specific method chosen depends on the actual situation. This specification does not limit the specific methods used in this embodiment. In one possible implementation, the controller can obtain the target matching state based on pre-configured matching state information. The pre-configured matching state information may include the correspondence between communication frequency bands and matching states, the correspondence between operating modes and matching states, or the correspondence between different radio frequency paths and matching states. The controller can query the target matching state from the pre-configured matching state information based on the communication frequency band, radio frequency path, or operating mode currently corresponding to the impedance matching circuit. For example, the controller can pre-store the correspondence between different communication frequency bands and series matching states, parallel matching states, L-type matching states, π-type matching states, or bypass states. When the mobile terminal switches from the first communication frequency band to the second communication frequency band, the controller can determine the preset matching state corresponding to the second communication frequency band as the target matching state.

[0130] In another possible implementation of this specification, the controller can determine the target matching state based on the current operating parameters of the impedance matching circuit or the antenna. The current operating parameters may include at least one of the following: antenna impedance parameters, RF signal reflection parameters, standing wave ratio (SWR) parameters, RF output parameters, and received signal parameters. The controller can compare the current operating parameters with preset conditions, or select the target matching state from multiple candidate matching states based on the current operating parameters. For example, the controller can obtain the current impedance state of the antenna and determine the matching results when using series matching, parallel matching, L-type matching, π-type matching, and bypass matching states, respectively, and select the matching state that matches the current impedance state as the target matching state. As another example, when the antenna and the RF front end are already within a preset impedance range, the controller can determine the bypass state as the target matching state.

[0131] In another possible implementation of this specification, the target matching state can be determined by other processing modules, RF transceiver circuits, or baseband processing circuits in the impedance matching circuit control system and sent to the controller. After receiving the control information indicating the corresponding matching state, the controller can obtain the target matching state based on the control information.

[0132] For example, when the mobile terminal is operating in the target communication frequency band and the antenna impedance changes due to the user's holding state, the controller can determine to use the π-type matching method for impedance adjustment based on the target communication frequency band and the current antenna impedance state, and use the π-type matching state as the target matching state of the impedance matching circuit.

[0133] Step 804: Determine the switch conduction state corresponding to the branch switching unit in the impedance matching circuit based on the target matching state.

[0134] It should be noted that the switch conduction state refers to the operating state of each branch switch in the branch switching unit when forming the target matching state. The switch conduction state can include at least one of the following: conduction state, disconnection state, and grounding state. For the first matching branch, the switch conduction state corresponding to the first matching branch can be used to indicate whether the first matching branch is connected to the antenna port, disconnected from the antenna port, or grounded. For the bypass branch, the switch conduction state corresponding to the bypass branch can be used to indicate whether the bypass branch is connected to or disconnected from the antenna port. For the second matching branch, the switch conduction state corresponding to the second matching branch can be used to indicate whether the second matching branch is connected to or disconnected from the antenna port. When the first matching branch switch includes a first access switch and a first grounding switch, the first matching branch being connected to the antenna port can correspond to the first access switch being connected and the first grounding switch being disconnected; the first matching branch being disconnected can correspond to both the first access switch and the first grounding switch being disconnected; the first matching branch being grounded can correspond to the first access switch being disconnected and the first grounding switch being connected.

[0135] In practical applications, there are multiple ways to determine the switch conduction state corresponding to the branch switching unit in the impedance matching circuit based on the target matching state. The specific method chosen depends on the actual situation, and this specification does not impose any limitations on this approach. In one possible implementation, the controller can query the switch conduction state corresponding to the target matching state based on a preset mapping relationship between matching states and switch conduction states. This mapping relationship can be stored in the form of a switch state table, a register configuration table, or a state coding table. For example, when the target matching state is a parallel matching state, the controller can determine that the bypass branch switch and at least one second matching branch switch are conducting based on the switch state table, and determine that the first matching branch switch disconnects the first matching branch from the antenna port and does not ground. When the target matching state is a π-type matching state, the controller can determine that the first matching branch is grounded, the bypass branch is disconnected from the antenna port, and determine that at least one second matching branch is conducting with the antenna port. When the target matching state is a bypass state, the controller can determine that the bypass branch switch is conducting. The controller can also determine whether the first and second matching branches are in an open state based on the specific configuration of the bypass state.

[0136] In another possible implementation of this specification, the controller can determine the branches that need to be connected or disconnected based on the target circuit topology corresponding to the target matching state, and further determine the on / off state of the corresponding branch switches. For example, when the target matching state is an L-type matching state, the controller can first determine whether the parallel matching part is located on the RF port side or the antenna port side of the main matching unit. When the parallel matching part is located on the RF port side, the controller can determine that the first matching branch is grounded, the bypass branch is disconnected, and the second matching branch is disconnected; when the parallel matching part is located on the antenna port side, the controller can determine that the first matching branch is disconnected, the bypass branch is disconnected, and the second matching branch is on.

[0137] In another possible implementation of this specification, when the impedance matching circuit includes multiple first matching branches or multiple second matching branches, the controller can further determine the target matching branch to be turned on based on the target equivalent impedance, and determine the switch on state corresponding to each target matching branch. For example, the impedance matching circuit includes two second matching branches, one of which has a capacitor and the other has an inductor. The controller can determine whether to turn on only the second matching branch with the capacitor, only the second matching branch with the inductor, or both second matching branches simultaneously, based on the target matching state and the required equivalent impedance at the antenna port side.

[0138] For example, when the target matching state obtained in step 802 is a π-type matching state, the controller can determine that the target state of the first matching branch switch is to ground the first matching branch, the target state of the bypass branch switch is to open, and the target state of at least one second matching branch switch is to be on. Thus, the switch on-states used to form the π-type matching network can be obtained.

[0139] Step 806: Based on the switch conduction state, control the impedance matching circuit to form the target matching network corresponding to the target matching state.

[0140] It should be noted that the target matching network refers to the circuit network formed after the impedance matching circuit is configured according to the switch conduction state determined in step 804. The target matching network can be any of the following: series matching network, parallel matching network, L-type matching network, π-type matching network, or bypass circuit.

[0141] The control impedance matching circuit constitutes the target matching network. It can control the corresponding switch in the branch switching unit to turn on, turn off, or ground the corresponding branch, so as to change the connection relationship between the first matching branch, the bypass branch, the second matching branch and the radio frequency port, the antenna port and the ground terminal, so that the impedance matching circuit forms a circuit topology corresponding to the target matching state.

[0142] In practical applications, there are various ways to control the impedance matching circuit to form the target matching network corresponding to the target matching state based on the switch conduction state. The specific method is selected according to the actual situation, and this specification does not limit this approach. In one possible implementation, the controller can generate corresponding switch control signals based on the switch conduction state and send these signals to the first matching branch switch, the bypass branch switch, and the second matching branch switch, respectively. Each branch switch can respond to the corresponding switch control signal and switch to an on, off, or grounded state. For example, when the target matching state is a parallel matching state, the controller can send an on control signal to the bypass branch switch to connect the bypass branch to the antenna port; send an off control signal to the first matching branch switch to prevent the first matching branch from participating in the current impedance adjustment; and send an on control signal to at least one second matching branch switch to connect the corresponding second matching branch between the antenna port and the ground terminal. Thus, the impedance matching circuit can form a parallel matching network.

[0143] In another possible implementation of this specification, the controller can convert the switch on state into register configuration data and write the register configuration data into the branch switching unit through the control interface. The branch switching unit can decode the register configuration data and control the switching of each branch switch according to the decoding result. The control interface may include a mobile industry processor interface, a serial control interface, or other interfaces capable of transmitting control information. When the control interface is a mobile industry processor interface, the controller can write the configuration data corresponding to the switch on state into the corresponding register, and the decoding circuit in the branch switching unit generates the switch control signal corresponding to each branch switch. For example, when the target matching state is a π-type matching state, the controller can generate register configuration data to indicate that the first matching branch is grounded, the bypass branch is disconnected, and the second matching branch is on. After receiving the register configuration data, the branch switching unit can control the first matching branch to connect between the RF port and the ground terminal, control the bypass branch to disconnect from the antenna port, and control the second matching branch to connect between the antenna port and the ground terminal, thereby forming a π-type matching network.

[0144] In another possible implementation of this specification, the controller can acquire the operating parameters corresponding to the impedance matching circuit after controlling the switching of each branch switch, and determine whether to maintain the current target matching network based on the operating parameters. If the operating parameters do not meet the corresponding conditions, the controller can reacquire the target matching state or redetermine the switch conduction state to switch to another matching network. It should be noted that the above-mentioned redetermination or switching process is an optional control method and is not a necessary condition for implementing the impedance matching circuit control method of claim 9.

[0145] For example, when the target matching state is in the bypass state, the controller can control the bypass branch switch to turn on according to the corresponding switch on state, so that the bypass branch is connected between the RF port and the antenna port. When the bypass branch has a relatively low impedance, the RF signal can be mainly transmitted through the bypass branch, thereby making the impedance matching circuit constitute the bypass circuit corresponding to the target matching state.

[0146] For example, when the target matching state is a series matching state, the controller can control the first matching branch, the bypass branch and the second matching branch to be disconnected from the antenna port, so that the main matching unit forms a series matching network; or, control at least one first matching branch to be connected to the antenna port, while controlling the bypass branch and the second matching branch to be disconnected from the antenna port, so that the first matching branch and the main matching unit together form another series matching network.

[0147] By applying the scheme of the embodiments in this specification, the target matching state of the impedance matching circuit can be obtained first, and then the switching state of the branch switching unit corresponding to the target matching state can be determined. The impedance matching circuit can then be controlled to form the corresponding target matching network according to the switching state. Therefore, the impedance matching circuit can be configured among series matching networks, parallel matching networks, L-type matching networks, π-type matching networks, and bypass circuits according to the target matching state, improving the correspondence between the impedance matching circuit control process and the target matching requirements, and increasing the flexibility of impedance matching circuit control.

[0148] See Figure 9 , Figure 9 A schematic diagram of another impedance matching circuit provided in one embodiment of this specification is shown. See also Figure 10 , Figure 10 A circuit diagram of another branch switching unit provided in one embodiment of this specification is shown. Figure 9 It can be used to illustrate the connection relationship between the main path matching unit, the first matching branch, the bypass branch, and the second matching branch. Figure 10 It can be used to further explain the internal switching structure and control interface of the branch switching unit.

[0149] exist Figure 9 In the illustrated embodiment, an impedance matching circuit can be positioned between the RF front-end and the antenna. One end of the impedance matching circuit forms an RF port for connecting the RF front-end; the other end forms an antenna port for connecting the antenna. RF signals can be transmitted from the RF port to the antenna port via the impedance matching circuit, or vice versa. A main path matching unit is positioned between the RF port and the antenna port. Figure 9Taking the inclusion of a capacitor in the main matching unit as an example, the capacitor in the main matching unit is connected in series between the RF port and the antenna port, forming a series matching section in the RF signal transmission path. The capacitive impedance provided by this capacitor can adjust the equivalent series impedance between the RF port and the antenna port. In other embodiments, the main matching unit can also include an inductor, or both a capacitor and an inductor.

[0150] The tributary switching unit may include a first matching tributary, a bypass tributary, and two second matching tributaries. The first matching tributary, the bypass tributary, and the two second matching tributaries are respectively connected to four RF ports of the tributary switching unit. The four RF ports are... Figure 9 and Figure 10 These are denoted as RF1, RF2, RF3, and RF4, respectively. RF1 corresponds to the first matching branch, RF2 corresponds to the bypass branch, and RF3 and RF4 each correspond to two second matching branches. The branch switching unit may further include a first matching branch switch, a bypass branch switch, and a second matching branch switch. Each matching branch can be selectively connected to the antenna port or the ground terminal via the corresponding matching branch switch.

[0151] One end of the first matching branch is connected to the RF port side of the main matching unit, and the other end is connected to RF1. Figure 9 Taking the example of setting a capacitor in the first matching branch, this capacitor can serve as a first matching element. The first matching branch switch may include a first pass switch and a first ground switch, wherein the first pass switch is in Figure 10 The first ground switch is SW1. Figure 10 This is represented as SWH1. RF1 can be selectively connected to the antenna common port ANT via SWH1, and can also be selectively connected to the ground terminal GND via SWH1. The antenna common port ANT and... Figure 9 The antenna ports in the diagram are connected accordingly.

[0152] When SW1 is on and SWH1 is off, RF1 and ANT are on, and the first matching branch is connected between the RF port and the antenna port. At this time, the capacitor in the first matching branch and the capacitor in the main matching unit are connected between the same two nodes, and the equivalent matching part formed by the two is located between the RF port and the antenna port, which can be used to adjust the equivalent impedance in the series matching state.

[0153] When SW1 is open and SWH1 is on, RF1 is connected to GND, and the first matching branch is connected between the RF port and the ground terminal, forming a parallel matching section on the RF port side of the main matching unit. When all other switches are open, the first matching branch and the main matching unit cooperate to form an L-shaped matching network; when at least one of SW3 and SW4 is on, the first matching branch, the main matching unit, and the corresponding second matching branch can cooperate to form a π-shaped matching network.

[0154] When both SW1 and SWH1 are disconnected, the first matching branch is neither connected to the antenna port nor grounded. The first matching branch can be excluded from the current impedance adjustment, and all other switches are disconnected.

[0155] One end of the bypass branch is connected to the RF port side of the main matching unit, and the other end is connected to RF2. Bypass components can be included in the bypass branch; these components can be 0Ω resistors, low-impedance conducting components, or other components capable of forming a low-impedance transmission path. The bypass branch switch can include a bypass access switch and a bypass-to-ground switch, wherein the bypass access switch is... Figure 10 The circuit breaker is designated as SW2, and the bypass to ground switch is located in... Figure 10 This is represented as SWH2. RF2 can be selectively connected to ANT via SW2, and can be selectively connected to GND via SWH2.

[0156] When SW2 is turned on, RF2 and ANT are also turned on. The bypass branch is connected across the two ends of the main matching unit, forming a bypass transmission path between the RF port and the antenna port. When the impedance of the bypass branch is relatively low, the RF signal can be mainly transmitted through the bypass branch, thereby reducing the impact of the main matching unit on the RF signal transmission and equivalent impedance.

[0157] When SW2 is disconnected, the bypass branch is not connected to the antenna port, and the RF signal can be transmitted through the main matching unit. SWH2 is used to selectively connect RF2 to GND. In the series matching, parallel matching, L-type matching, π-type matching, and bypass states described in this embodiment, SWH2 can remain disconnected.

[0158] Figure 9 The two second matching branches shown are connected to RF3 and RF4 respectively. One end of the second matching branch connected to RF3 is grounded, and the other end is connected to RF3. Figure 9 Taking the example of setting a capacitor in the second matching branch. One end of the second matching branch connected to RF4 is grounded, and the other end is connected to RF4. Figure 9 Taking the setting of an inductor in the second matching branch as an example.

[0159] The second matching branch switch corresponding to RF3 may include a second path switch and a second ground switch, wherein the corresponding second path switch is in Figure 10 The symbol SW3 corresponds to the second ground switch in Figure 10 This is represented as SWH3. RF3 can be selectively connected to ANT via SW3, and can also be selectively connected to GND via SWH3. When SW3 is on, RF3 is connected to ANT, and the second matching branch corresponding to RF3 is connected between the antenna port and the ground terminal, forming the capacitance-to-ground matching part on the antenna port side. When SW3 is off, the second matching branch corresponding to RF3 is not connected to the antenna port.

[0160] The second matching branch switch corresponding to RF4 may also include a second path switch and a second ground switch, wherein the corresponding second path switch is in Figure 10 The symbol SW4 corresponds to the second ground switch in Figure 10 This is represented as SWH4. RF4 can be selectively connected to ANT via SW4, and can also be selectively connected to GND via SWH4. When SW4 is on, RF4 is connected to ANT, and the second matching branch corresponding to RF4 is connected between the antenna port and the ground terminal, forming the inductance-to-ground matching part on the antenna port side. When SW4 is off, the second matching branch corresponding to RF4 is not connected to the antenna port.

[0161] In some embodiments, only SW3 can be controlled to conduct, allowing the capacitive second matching branch to participate in impedance adjustment; only SW4 can be controlled to conduct, allowing the inductive second matching branch to participate in impedance adjustment; or both SW3 and SW4 can be controlled to conduct simultaneously, connecting the two second matching branches in parallel between the antenna port and the ground terminal. Thus, the equivalent impedance at the antenna port side, whether capacitive, inductive, or a combination of capacitance and inductance, can be selected based on the target impedance.

[0162] Figure 10 In this context, ANT stands for Antenna Common Port. ANT can be connected to... Figure 9 The antenna ports are connected to RF1, RF2, RF3, and RF4 via SW1, SW2, SW3, and SW4 respectively. RF1 to RF4 represent the four radio frequency ports of the tributary switching unit, and are respectively connected to... Figure 9 The first matching branch, the bypass branch, and the two second matching branches are connected accordingly.

[0163] SW1 to SW4 are the path switches in the branch switching unit. SW1 is the first path switch in the first matching branch switch, connected between RF1 and ANT; SW2 is the bypass path switch in the bypass branch switch, connected between RF2 and ANT; SW3 and SW4 are the second path switches in the two second matching branch switches, connected between RF3 and ANT, and RF4 and ANT respectively. By controlling the corresponding path switches to be on or off, the connection of the corresponding RF port to ANT can be controlled.

[0164] SWH1 to SWH4 are ground switches in the branch switching unit. SWH1 is the first ground switch in the first matching branch switch, connected between RF1 and GND; SWH2 is the bypass ground switch in the bypass branch switch, connected between RF2 and GND; SWH3 and SWH4 are the second ground switches in the two second matching branch switches, connected between RF3 and GND and RF4 and GND respectively. By controlling the corresponding ground switches to be on or off, the connection of the corresponding RF port to GND can be controlled.

[0165] It should be noted that SW1 to SW4 and SWH1 to SWH4 can be controlled independently, or multiple switches can be controlled to conduct simultaneously according to a preset switch combination. Therefore, the branch switching unit can connect multiple matching branches at the same time according to different impedance matching requirements, instead of being limited to selecting a single RF port from RF1 to RF4.

[0166] The decoder represents the decoding circuit. The decoding circuit can receive control information from the controller, decode the control information, and generate switching control signals for controlling SW1 to SW4 and SWH1 to SWH4 respectively based on the decoding result. Figure 10 To simplify the accompanying drawings, not all control lines between the Decoder and each switch are shown in detail.

[0167] USID represents a unique slave device identifier, which can be used to identify or address tributary switching units. When multiple RF front-end devices are connected to the same control bus, the controller can determine the target device corresponding to the control information based on the USID.

[0168] VIO stands for Interface Power Supply, which provides operating voltage to the Decoder and related digital circuits for the control interface. The voltage corresponding to VIO can be set according to the interface voltage requirements of the branch switching unit.

[0169] SDATA stands for Serial Data Terminal, which can be used to receive control data sent by the controller. Control data may include at least one of the following: device address, register address, register configuration value, and information indicating the on / off state of each switch.

[0170] SCLK represents the serial clock input, which can be used to receive clock signals sent by the controller. The decoder can sample or parse the control data transmitted by SDATA based on the clock provided by SCLK.

[0171] GND represents the ground terminal and can be used as the reference potential terminal for the branch switching unit. When SWH1 to SWH4 are turned on, the corresponding RF ports can be connected to GND. Figure 9 One end of each of the two second matching branches can also be connected to GND.

[0172] In one possible implementation, the controller can send control information to the tributary switching unit via the MIPI RF front-end control interface. The controller can generate corresponding register configuration values ​​based on the target matching status and send these values ​​to the tributary switching unit identified by the USID via SDATA and SCLK. Upon receiving the register configuration values, the decoder can control the corresponding SW and SWH switches to turn on or off to form a target matching network.

[0173] exist Figure 9 and Figure 10 In the specific embodiment shown, different impedance matching states can be formed by different combinations of switches.

[0174] When SW1 to SW4 and SWH1 to SWH4 are all disconnected, the first matching branch, the bypass branch and the two second matching branches do not participate in the current impedance adjustment. The radio frequency signal is transmitted through the capacitor in the main matching unit. The impedance matching circuit can form a series matching network composed of the main matching unit.

[0175] When SW1 is on, SWH1 is off, and SW2 to SW4 are off, the first matching branch is connected between the RF port and the antenna port, and together with the main matching unit, forms an equivalent matching section located between the RF port and the antenna port. This equivalent matching section can participate in impedance adjustment as a series matching section, thereby forming another series matching network.

[0176] When SW2 is turned on, and at least one of SW3 and SW4 is turned on, the bypass branch forms a low-impedance transmission path between the RF port and the antenna port, reducing the influence of the main matching unit; simultaneously, the corresponding second matching branch is connected between the antenna port and the ground terminal. Thus, a parallel matching network can be formed.

[0177] When SW2 is disconnected, SWH1 is disconnected, and at least one of SW3 and SW4 is turned on, the main matching unit forms a series matching part, and the corresponding second matching branch forms a parallel matching part on the antenna port side. Together, they constitute an L-shaped matching network.

[0178] When SW2 to SW4 are all disconnected, SW1 is disconnected and SWH1 is turned on, the main matching unit forms a series matching part, and the first matching branch forms a parallel matching part on the RF port side. Together, they form another L-shaped matching network.

[0179] When SW2 is off, SW1 is off, SWH1 is on, and at least one of SW3 and SW4 is on, the first matching branch forms the first parallel matching portion on the RF port side, the main matching unit forms the series matching portion, and the corresponding second matching branch forms the second parallel matching portion on the antenna port side. These three matching portions cooperate sequentially to form a π-type matching network. In one specific implementation, SWH1 and SW3 can be controlled to be on simultaneously, or SWH1 and SW4 can be controlled to be on simultaneously; in some embodiments, SW3 and SW4 can also be controlled to be on simultaneously to form a second parallel matching portion composed of multiple second matching branches.

[0180] When SW2 is turned on and SW1, SW3, SW4 and all ground switches are turned off, the bypass branch can form a low-impedance bypass transmission path between the RF port and the antenna port, and the impedance matching circuit is in bypass mode. This bypass mode can be used to reduce the RF transmission loss introduced by the main matching components when the main matching unit does not need to participate in the current impedance adjustment.

[0181] Through the above methods, impedance matching circuits can selectively form series matching networks, parallel matching networks, L-type matching networks, π-type matching networks, or bypass circuits based on the same branch switching unit and its switch combinations. The controller can also select corresponding switch combinations according to the communication frequency band, antenna impedance state, or preset tuning configuration, and configure and control the state of each switch through the MIPI register to adapt to different impedance matching requirements. In other embodiments, the controller can also configure through the MIPI register to control the corresponding matching elements to be connected in series or in parallel to the feed circuit, and control the bypass branch to form a bypass transmission path when impedance matching is not required.

[0182] See Figure 11 , Figure 11 A schematic diagram of a radio frequency front-end circuit structure according to one embodiment of this specification is shown. Figure 11 As shown, this specification also provides an RF front-end circuit 1100, including an RF receiving path 1102, an RF transmitting path 1104, and the impedance matching circuit 1106 described in the above embodiments.

[0183] It should be noted that the RF front-end circuit 1100 refers to a circuit disposed between the antenna and the RF transceiver circuit, used for receiving and / or transmitting RF signals. The RF front-end circuit 1100 can be applied to mobile phones, tablets, wearable devices, and other electronic devices with wireless communication functions, but this specification does not limit its application to these applications.

[0184] The radio frequency (RF) receiving path 1102 refers to a circuit path used for transmitting and processing RF signals in the receiving direction. The RF receiving path 1102 can receive RF signals input from the antenna side and transmit these signals to subsequent RF transceiver circuits. The RF receiving path 1102 may include one or more RF circuits for implementing RF signal reception; however, the specific circuit structure of the RF receiving path 1102 is not limited in the embodiments described in this specification.

[0185] The radio frequency (RF) transmission path 1104 refers to a circuit path used for transmitting and processing RF signals in the transmission direction. The RF transmission path 1104 can receive the RF signal to be transmitted from the RF transceiver circuit and transmit the RF signal to the antenna side. The RF transmission path 1104 may include one or more RF circuits for transmitting RF signals; the specific circuit structure of the RF transmission path 1104 is not limited in the embodiments described in this specification.

[0186] Impedance matching circuit 1106 can be any of the impedance matching circuits described in the foregoing embodiments. Impedance matching circuit 1106 includes a main matching unit and a branch switching unit, and can adjust the equivalent impedance between the RF port and the antenna port by changing the connection state of the first matching branch, the bypass branch and the second matching branch.

[0187] exist Figure 11 In the illustrated embodiment, the impedance matching circuit 1106 is connected to both the RF receiving path 1102 and the RF transmitting path 1104 to perform impedance matching in conjunction with them. It should be noted that... Figure 11 The vertical arrangement of the modules in the diagram is only for illustrating the functional modules included in the RF front-end circuit 1100 and their connection relationships. It does not limit the RF receiving path 1102, impedance matching circuit 1106 and RF transmitting path 1104 to be connected in series in the order shown in the diagram, nor does it limit the specific transmission direction of the RF signal.

[0188] In one possible operating state, the RF receiving path 1102 is used to transmit RF signals in the receiving direction, and the impedance matching circuit 1106 can form a matching network corresponding to the current receiving operating state to participate in adjusting the equivalent impedance during the RF receiving process. In another possible operating state, the RF transmitting path 1104 is used to transmit RF signals in the transmitting direction, and the impedance matching circuit 1106 can form a matching network corresponding to the current transmitting operating state to participate in adjusting the equivalent impedance during the RF transmitting process.

[0189] The matching network formed by the impedance matching circuit 1106 can include any one of the following: series matching network, parallel matching network, L-type matching network, π-type matching network, or bypass circuit. The impedance matching circuit 1106 can control the corresponding branch switch in the branch switching unit to be turned on, turned off, or grounded according to the current communication frequency band, target matching status, or preset control information of the RF receiving path 1102 or RF transmitting path 1104.

[0190] For example, when the RF receiving path 1102 is in operation, the impedance matching circuit 1106 can form a corresponding target matching network according to the target matching state corresponding to the receiving frequency band; when the RF transmitting path 1104 is in operation, the impedance matching circuit 1106 can form a corresponding target matching network according to the target matching state corresponding to the transmitting frequency band. The specific structure, switching control method, and methods for forming different matching networks of the impedance matching circuit 1106 can be found in the embodiments of the impedance matching circuit and impedance matching circuit control method described above, and will not be repeated here.

[0191] By applying the scheme of the embodiments of this specification, by setting an impedance matching circuit 1106 in the RF front-end circuit 1100 including the RF receiving path 1102 and the RF transmitting path 1104, the impedance matching circuit 1106 can participate in the impedance adjustment during the RF receiving process and the RF transmitting process, thereby enabling the RF front-end circuit 1100 to adapt to the corresponding RF receiving state and RF transmitting state.

[0192] See Figure 12 , Figure 12 A schematic diagram of a mobile terminal structure provided in one embodiment of this specification is shown. Figure 12 As shown, this specification also provides a mobile terminal 1200, which includes an antenna 1202, a baseband circuit 1204, and the radio frequency front-end circuit 1100 described in the above embodiments.

[0193] It should be noted that mobile terminal 1200 refers to an electronic device with wireless communication capabilities. Mobile terminal 1200 may include mobile phones, tablets, wearable devices, vehicle communication devices, or other electronic devices capable of transmitting and receiving wireless signals via an antenna; however, this specification does not limit this type of device.

[0194] Antenna 1202 is used to receive and / or transmit radio frequency signals. Antenna 1202 can be a single-frequency antenna, a multi-frequency antenna, a broadband antenna, or an antenna capable of covering multiple communication frequency bands. In some embodiments, mobile terminal 1200 may include one antenna 1202; in other embodiments, mobile terminal 1200 may also include multiple antennas 1202, and different antennas 1202 may correspond to the same or different communication frequency bands.

[0195] The baseband circuit 1204 is used to perform baseband processing on the communication data in the mobile terminal 1200. Baseband processing may include at least one of encoding, decoding, modulation, demodulation, data processing, and communication control. The baseband circuit 1204 can interact with the radio frequency front-end circuit 1100 to cooperate in receiving and transmitting radio frequency signals.

[0196] The radio frequency (RF) front-end circuit 1100 is disposed in the communication link between the antenna 1202 and the baseband circuit 1204. The RF front-end circuit 1100 may include an RF receiving path 1102, an RF transmitting path 1104, and an impedance matching circuit 1106. The RF receiving path 1102 is used to transmit and / or process the RF signals received by the antenna 1202; the RF transmitting path 1104 is used to transmit and / or process the RF signals to be transmitted through the antenna 1202; and the impedance matching circuit 1106 is used to adjust the equivalent impedance between the RF front-end circuit 1100 and the antenna 1202.

[0197] It should be noted that, Figure 12 The connecting lines in the diagram indicate signal connections or functional cooperation between the antenna 1202, the RF front-end circuit 1100, and the baseband circuit 1204. They do not limit the direct connection between modules, nor do they restrict the specific physical location or arrangement of the modules within the mobile terminal 1200. Modules can also be connected via other RF devices, connecting lines, or interface circuits (not shown).

[0198] During the radio frequency (RF) signal reception process, antenna 1202 can receive external RF signals. The RF signals are transmitted and processed through impedance matching circuit 1106 and RF receiving path 1102, and the corresponding signals are provided to baseband circuit 1204. Impedance matching circuit 1106 can form a corresponding matching network according to the current receiving frequency band or the impedance state of antenna 1202 to adjust the equivalent impedance between antenna 1202 and RF front-end circuit 1100.

[0199] During the radio frequency (RF) signal transmission process, the data to be transmitted obtained by the baseband circuit 1204 can be further processed by the RF front-end circuit 1100. The RF transmission path 1104 transmits the RF signal to be transmitted to the impedance matching circuit 1106, and then transmits it outward by the antenna 1202. The impedance matching circuit 1106 can form a corresponding matching network according to the current transmission frequency band or the impedance state of the antenna 1202.

[0200] In one possible implementation, the RF receiving path 1102 and the RF transmitting path 1104 can share the impedance matching circuit 1106. The impedance matching circuit 1106 can form a corresponding series matching network, parallel matching network, L-type matching network, π-type matching network, or bypass circuit depending on whether the mobile terminal 1200 is currently in a receiving or transmitting state. In another possible implementation, the mobile terminal 1200 can support multiple communication frequency bands. When the mobile terminal 1200 switches communication frequency bands, the connection state of each matching branch in the impedance matching circuit 1106 can be adjusted accordingly, so that the impedance matching circuit 1106 forms a matching network corresponding to the current communication frequency band.

[0201] For example, when the impedance of the antenna 1202 changes due to the change in the user's holding position, the impedance matching circuit 1106 can be controlled to adjust the connection state of the first matching branch, the bypass branch and the second matching branch, thereby changing the equivalent impedance between the antenna 1202 and the radio frequency front-end circuit 1100.

[0202] By applying the scheme of the embodiments of this specification, by setting a radio frequency front-end circuit 1100 in a mobile terminal 1200 including an antenna 1202 and a baseband circuit 1204, the equivalent impedance on the antenna 1202 side can be adjusted by the impedance matching circuit 1106 in the radio frequency front-end circuit 1100, so that the mobile terminal 1200 can adapt to the corresponding radio frequency signal receiving state and radio frequency signal transmitting state.

[0203] See Figure 13 , Figure 13 A schematic diagram of an impedance matching circuit control module structure according to one embodiment of this specification is shown. Figure 13 As shown, this specification also provides an impedance matching circuit control module 1300, including a control program / instruction, which, when executed by the impedance matching circuit control module 1300, implements the steps of the above-described impedance matching circuit control method.

[0204] It should be noted that control programs / instructions include computer program code, which can be in the form of source code, object code, executable files, or some intermediate form.

[0205] The above is a schematic scheme of an impedance matching circuit control module according to this embodiment. It should be noted that the technical solution of this impedance matching circuit control module and the technical solution of the impedance matching circuit control method described above belong to the same concept. For details not described in detail in the technical solution of the impedance matching circuit control module, please refer to the description of the technical solution of the impedance matching circuit control method described above.

[0206] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that the embodiments in this specification are not limited to the described order of actions, because according to the embodiments in this specification, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in this specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the embodiments in this specification.

[0207] By applying the solutions described in the embodiments of this specification and executing control programs or control commands, the impedance matching circuit control module 1300 can determine the corresponding switch conduction state according to the target matching state, and control the impedance matching circuit to form the corresponding target matching network. Thus, control over different matching states of the impedance matching circuit can be achieved.

[0208] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0209] The preferred embodiments disclosed above are merely illustrative of this specification. The optional embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the embodiments described herein. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the embodiments, thereby enabling those skilled in the art to better understand and utilize this specification. This specification is limited only by the claims and their full scope and equivalents.

Claims

1. An impedance matching circuit, characterized in that, It includes a main path matching unit and a branch path switching unit, which are disposed between the radio frequency port and the antenna port; The branch switching unit includes a bypass branch, at least one first matching branch, and at least one second matching branch, used to adjust the equivalent impedance between the radio frequency port and the antenna port; One end of the first matching branch is connected to the radio frequency port, and the other end of the first matching branch is connected or disconnected from the antenna port through the first matching branch switch, or grounded through the first matching branch switch; One end of the bypass branch is connected to the radio frequency port, and the other end of the bypass branch is connected to or disconnected from the antenna port through a bypass branch switch; One end of the second matching branch is grounded, and the other end of the second matching branch is connected or disconnected from the antenna port through the second matching branch switch.

2. The circuit according to claim 1, characterized in that, The other end of the second matching branch is connected to the antenna port through the second matching branch switch. The main matching unit and the branch switching unit constitute any one of the following: a parallel matching network, an L-type matching network, and a π-type matching network.

3. The circuit according to claim 2, characterized in that, The other end of the bypass branch is connected to the antenna port through the bypass branch switch, and the other end of the first matching branch is disconnected from the antenna port through the first matching branch switch. The main matching unit and the branch switching unit constitute the parallel matching network.

4. The circuit according to claim 2, characterized in that, The other end of the first matching branch is grounded through the first matching branch switch, and the other end of the bypass branch is disconnected from the antenna port through the bypass branch switch. The main matching unit and the branch switching unit constitute the π-type matching network.

5. The circuit according to claim 1, characterized in that, The other end of the first matching branch is grounded through the first matching branch switch, the other end of the second matching branch is disconnected from the antenna port through the second matching branch switch, and the other end of the bypass branch is disconnected from the antenna port through the bypass branch switch. The main matching unit and the branch switching unit form an L-shaped matching network.

6. The circuit according to claim 1, characterized in that, The other end of the first matching branch is disconnected from the antenna port through the first matching branch switch, the other end of the bypass branch is disconnected through the bypass branch switch, and the other end of the second matching branch is disconnected through the second matching branch switch. The main matching unit and the branch switching unit form a series matching network. or, The other end of the first matching branch is connected to the antenna port through the first matching branch switch, the other end of the bypass branch is disconnected from the antenna port through the bypass branch switch, and the other end of the second matching branch is disconnected from the antenna port through the second matching branch switch. The main matching unit and the branch switching unit constitute the series matching network.

7. The circuit according to claim 1, characterized in that, The other end of the bypass branch is connected to the antenna port through the bypass branch switch, the other end of the first matching branch is disconnected from the antenna port through the first matching branch switch and the other end of the second matching branch is disconnected from the antenna port through the second matching branch switch, and the main matching unit and the branch switching unit constitute a bypass circuit.

8. The circuit according to any one of claims 1 to 7, characterized in that, The main circuit matching unit is provided with a main circuit matching element, which includes at least one of a capacitor and an inductor; The first matching branch is provided with a first matching element, which includes at least one of a capacitor and an inductor; The bypass branch is equipped with a bypass element; The second matching branch is provided with a second matching element, which includes at least one of a capacitor and an inductor.

9. A method for controlling an impedance matching circuit, characterized in that, A controller applied in an impedance matching circuit control system, the impedance matching circuit control system further comprising the impedance matching circuit as described in any one of claims 1 to 8; the method comprising: Obtain the target matching state of the impedance matching circuit, wherein the target matching state includes any one of series matching state, parallel matching state, L-type matching state, π-type matching state, and bypass state; Based on the target matching state, determine the switch conduction state corresponding to the branch switching unit in the impedance matching circuit; Based on the switch conduction state, the impedance matching circuit is controlled to form the target matching network corresponding to the target matching state.

10. A radio frequency front-end circuit, characterized in that, It includes a radio frequency receiving path, a radio frequency transmitting path, and an impedance matching circuit as described in any one of claims 1 to 8.

11. A mobile terminal, characterized in that, It includes an antenna, a baseband circuit, and the radio frequency front-end circuit as described in claim 10.

12. An impedance matching circuit control module, characterized in that, It includes a control program / instruction that, when executed by the impedance matching circuit control module, implements the steps of the method of claim 9.

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