Stacked radio frequency switch and radio frequency module

Abstract

The application discloses a stacked radio frequency switch and a radio frequency module, and relates to the technical field of radio frequency integrated circuits.The voltage of the first radio frequency port of the stacked radio frequency switch is higher than that of the second radio frequency port in the off state; at least one switch tube closest to the first radio frequency port is a bulk contact type switch tube; the bulk terminal of the bulk contact type switch tube is led out and electrically connected to a bulk bias potential terminal to receive a bulk bias potential, thereby bearing high voltage stress by using the excellent harmonic suppression characteristics of the bulk contact type switch tube, and ensuring that the overall harmonic index of the switch meets the requirements; at the same time, at least one switch tube closest to the second radio frequency port is a bulk floating type switch tube; the bulk terminal of the bulk floating type switch tube is in an electrically floating state, thereby reducing the additional gate-bulk parasitic capacitance and signal leakage caused by the bulk terminal leading-out when the second radio frequency port also uses the bulk contact type switch tube, reducing the on-resistance and off-capacitance of the radio frequency switch, and improving the performance of the radio frequency switch as a whole.

Description

Technical Field

[0001] This application relates to the field of radio frequency integrated circuit technology, and in particular to a stacked radio frequency switch and radio frequency module. Background Technology

[0002] Radio frequency (RF) switches are core components in RF front-end systems that enable signal path switching. To improve voltage withstand capability and linearity, stacked RF switches use multiple switches connected in series to divide the voltage, distributing the voltage across each individual switch and improving the overall voltage withstand level and harmonic suppression capability of the RF switch. This has become the mainstream design solution for RF switches.

[0003] In traditional stacked RF switches, the series-connected switching transistors are typically body-contact (BC) metal-oxide-semiconductor field-effect transistors (MOSFETs). The body terminal of a body-contact MOSFET receives the body bias potential, effectively suppressing substrate bias effects and exhibiting good harmonic suppression characteristics, meeting the RF system's requirements for switching linearity. However, the body terminal of a body-contact MOSFET introduces additional gate-body parasitic capacitance, and the body connection path inevitably causes signal leakage. These additional parasitic effects and signal leakage paths result in a larger on-resistance (Ron) and a larger off-resistance (Coff) for body-contact MOSFETs, thus limiting the RF performance of stacked RF switches, such as insertion loss and isolation. Summary of the Invention

[0004] To address the aforementioned technical issues, this application provides a stacked RF switch and an RF front-end module, which reduces the on-resistance and off-resistance of the stacked RF switch while ensuring that the harmonic performance of the stacked RF switch meets the requirements, thereby improving the overall performance of the stacked RF switch.

[0005] To achieve the above objectives, this application provides the following technical solution:

[0006] In a first aspect, this application provides a stacked radio frequency switch, including N switching transistors connected in series between a first radio frequency port and a second radio frequency port, where N≥2 and N is an integer; when the stacked radio frequency switch is in the off state, the voltage across the first radio frequency port is higher than the voltage across the second radio frequency port.

[0007] Among the N switching transistors, at least one switching transistor closest to the first RF port is a body contact type switching transistor. The body terminal of the body contact type switching transistor is led out and electrically connected to the body bias potential terminal to receive the body bias potential.

[0008] Among the N switching transistors, at least one switching transistor closest to the second RF port is a body-floating switching transistor, and the body end of the body-floating switching transistor is in an electrically floating state.

[0009] Optionally, among the N switching transistors, the X consecutive switching transistors closest to the first RF port are the body contact type switching transistors, and the NX consecutive switching transistors closest to the second RF port are the body floating type switching transistors, where 1≤X≤N-1, and X is an integer.

[0010] Optionally, NX≤M, 1≤M≤N-1, and M is an integer; wherein, when NX=M, the third harmonic of the stacked RF switch is less than or equal to a preset threshold value.

[0011] Optionally, the body bias potential terminal is the first bias node; the body terminals of each of the body contact type switching transistors are respectively connected to the first intermediate node through a first resistor, and the first intermediate node is then connected to the first bias node through a second resistor.

[0012] Optionally, the body bias potential terminal is the first bias node; in the direction from the first RF port to the second RF port, the body terminal of the i-th body contact type switch is electrically connected to the body terminal of the (i+1)-th body contact type switch through a third resistor, and the body terminal of the last body contact type switch is then electrically connected to the first bias node through a fourth resistor, 1≤i, and i is an integer.

[0013] Optionally, the body bias potential terminal is the gate terminal of the body contact type switch; the body terminals of each body contact type switch are electrically connected to the gate terminal of the same body contact type switch through a diode, and the forward direction of the diode points from the body terminal of the body contact type switch to the gate terminal of the same body contact type switch.

[0014] Optionally, the source and drain terminals of each of the switching transistors are electrically connected through a fifth resistor, and the fifth resistors are connected in series in the direction from the first RF port to the second RF port.

[0015] Optionally, the gate terminal of each of the switching transistors is electrically connected to the second intermediate node through a sixth resistor, and the second intermediate node is then electrically connected to the second bias node through a seventh resistor.

[0016] Alternatively, in the direction from the first RF port to the second RF port, the gate terminal of the j-th switch is electrically connected to the gate terminal of the (j+1)-th switch through an eighth resistor, and the gate terminal of the last switch is then electrically connected to the second bias node through a ninth resistor, where 1≤j≤N-1 and j is an integer.

[0017] Optionally, the first RF port is a signal transceiver port, and the second RF port is a ground terminal;

[0018] Alternatively, the first RF port may be an antenna port, and the second RF port may be a signal transceiver port.

[0019] Secondly, this application provides a radio frequency front-end module, including an antenna port, a first signal transceiver port, and a second signal transceiver port; a first switch is provided between the antenna port and the first signal transceiver port, and a second switch is provided between the first signal transceiver port and a ground terminal; a third switch is provided between the antenna port and the second signal transceiver port, and a fourth switch is provided between the second signal transceiver port and the ground terminal;

[0020] Wherein, the second switch and / or the third switch are stacked radio frequency switches as described in any one of claims 1-9.

[0021] Compared with existing technologies, the above technical solution has the following advantages:

[0022] The stacked RF switch provided in this application, in its off state, employs at least one bulk contact switch closest to the first RF port with higher voltage and stronger harmonic constraint. The bulk contact switch's body terminal is led out and electrically connected to the body bias potential terminal to receive the body bias potential. This allows the excellent harmonic suppression characteristics of the bulk contact switch to withstand high-voltage stress, ensuring that the overall harmonic performance of the RF switch meets system requirements. Simultaneously, at least one bulk floating switch is closest to the second RF port with lower voltage and sufficient harmonic margin. The body terminal of the bulk floating switch is electrically floating, which reduces the additional gate-body parasitic capacitance and signal leakage of the body terminal connection path caused by the use of a bulk contact switch in the second RF port. Thus, while ensuring that the first RF port is still dominated by the bulk contact switch for harmonic suppression and that the overall harmonic performance meets requirements, the overall on-resistance (Ron) and off-resistance (Coff) of the stacked RF switch are reduced, effectively improving the RF switch's conduction loss and off-resistance isolation performance, and enhancing the overall performance of the RF switch. Furthermore, this stacked RF switch can achieve performance improvement simply by differentiating the configuration of the selected components, without the need for additional control circuits or special process steps. It is fully compatible with existing standard semiconductor processes, resulting in low cost and easy mass production. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A schematic diagram of a stacked radio frequency switch provided in an embodiment of this application;

[0025] Figure 2 This is a simplified circuit diagram of a traditional stacked RF switch under ideal conditions.

[0026] Figure 3 for Figure 2 A schematic diagram showing the distribution of the voltage difference Vds between the source and drain terminals of each body-contact MOSFET.

[0027] Figure 4 A simplified circuit structure diagram of a traditional stacked RF switch in a practical situation;

[0028] Figure 5 for Figure 4 A schematic diagram showing the distribution of the voltage difference Vds between the source and drain terminals of each body-contact MOSFET.

[0029] Figure 6 The figure shows a comparison of the harmonic performance simulation results between a traditional stacked RF switch with all bulk contact MOSFETs and a stacked RF switch with a hybrid structure of bulk contact and bulk floating MOSFETs used in this application.

[0030] Figure 7 A comparison of the on-resistance simulation results of a traditional stacked RF switch with all bulk contact MOSFETs and a stacked RF switch with a hybrid structure of bulk contact and bulk floating MOSFETs used in this application.

[0031] Figure 8 The figure shows a comparison of the simulation results of the turn-off capacitance of a traditional stacked RF switch with all bulk contact MOSFETs and a stacked RF switch with a hybrid structure of bulk contact and bulk floating MOSFETs used in this application.

[0032] Figure 9 This is a schematic diagram showing the variation trend of the third harmonic of the stacked RF switch in this application with the number of the bulk floating switch transistors near the second RF port.

[0033] Figure 10 A schematic diagram of another stacked radio frequency switch provided in an embodiment of this application;

[0034] Figure 11 A schematic diagram of the circuit structure of another stacked radio frequency switch provided in an embodiment of this application;

[0035] Figure 12 This is a schematic diagram of the circuit structure of the radio frequency front-end module provided in an embodiment of this application. Detailed Implementation

[0036] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0037] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms are interchangeable where appropriate; this is merely a way of distinguishing objects with the same attributes in the embodiments of this application. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, so that a process, method, system, product, or apparatus that comprises a series of elements is not necessarily limited to those elements, but may include other elements not explicitly listed or inherent to those processes, methods, products, or apparatuses.

[0038] Figure 1 This application provides a schematic diagram of a stacked radio frequency switch circuit structure. Figure 1 As shown, the stacked RF switch includes N switching transistors connected in series between the first RF port D1 and the second RF port D2, where N ≥ 2 and N is an integer. Specifically, from the first RF port D1 to the second RF port D2, the stacked RF switch sequentially connects switching transistors M1, M2, ... up to switching transistor M... N When the stacked RF switches are in the off state, the RF signal is blocked. The voltage across the first RF port D1 is higher than that across the second RF port D2. That is, the first RF port D1 is the hot end that withstands the higher voltage, and the second RF port D2 is the cold end that withstands the lower voltage. The N switches are cascaded in sequence to divide the voltage and prevent a single switch from being damaged.

[0039] As discussed in the background section, the series-connected switching transistors in traditional stacked RF switches typically use a uniform type of body-contact MOSFET. This is because the body terminal of a body-contact MOSFET leads out and receives the body bias potential, effectively suppressing substrate bias effects and exhibiting good harmonic suppression characteristics, enabling the RF switch to possess excellent linearity. However, the body terminal of a body-contact MOSFET introduces additional gate-body parasitic capacitance, and the body terminal connection path inevitably causes signal leakage. These additional parasitic effects and signal leakage paths result in a larger on-resistance (Ron) and a larger off-resistance (Coff) for the body-contact MOSFET, thereby limiting the RF performance of the stacked RF switch, such as insertion loss and isolation.

[0040] Based on this, the inventors discovered that, as Figure 2 As shown, Figure 2 The diagram shows a simplified circuit structure of a conventional stacked RF switch (including N series-connected body contact MOSFETs) under ideal conditions. For a conventional ideal stacked RF switch, the signal current flowing through each body contact MOSFET is equal, i.e., I1 = I2 = ... = I... (N-1) =I N Therefore, the voltage division of each stage of the body contact MOSFET is uniform. Figure 3 It shows Figure 2 The schematic diagram shows the distribution of the voltage difference Vds between the source and drain terminals of each body-contact MOSFET. It can be seen that the voltage difference Vds between the source and drain terminals of each body-contact MOSFET is equal.

[0041] Figure 4 This diagram illustrates a simplified circuit structure of a traditional stacked RF switch (comprising N series-connected body-contact MOSFETs) in a practical scenario, as shown below. Figure 4 As shown, in traditional stacked RF switches, signal current leaks from the substrate of each body-contact MOSFET, such as... Figure 4 Leakage current Ileak1, Ileak2...Ileak (N-1) Ileak N This results in the signal current of each body-contact MOSFET (as shown in the figure, signal currents I1, I2...I...) (N-1) I N They are not the same; from the first RF port D1 to the second RF port D2, the signal current of each body contact MOSFET gradually decreases, so the voltage division of each body contact MOSFET gradually decreases from the first RF port D1 to the second RF port D2. Figure 5 It shows Figure 4 The schematic diagram shows the distribution of the voltage difference Vds between the source and drain terminals of each body-contact MOSFET. It can be seen that the voltage difference Vds between the source and drain terminals of each body-contact MOSFET gradually decreases from the first RF port D1 to the second RF port D2.

[0042] The deterioration of harmonics is closely related to the voltage division borne by each stage of the switching transistors in a stacked RF switch. The larger the voltage division of the switching transistors, the easier it is for the reverse bias diodes between the source and body terminals, and between the drain and source terminals and the body terminals of the switching transistors (such as body contact MOSFETs), to turn on, and the more likely soft breakdown will occur, leading to harmonic deterioration and abrupt changes. In other words, in the series link of a stacked RF switch, the closer the switching transistor is to the first RF port D1 (i.e., the hot end) with a higher voltage, the larger the voltage division it bears, the greater the risk of harmonic deterioration, and the higher the requirement for the harmonic suppression capability of the switching transistor itself. The closer the switching transistor is to the second RF port D2 (i.e., the cold end) with a lower voltage, the smaller the voltage division it bears, the smaller the risk of harmonic deterioration, and the more harmonic performance margin it has.

[0043] If all the switching transistors in a stacked RF switch are body-contact MOSFETs, although the overall harmonic performance can be guaranteed, the harmonic performance margin of the switching transistor at the second RF port D2 (i.e., the cold end) cannot be effectively utilized. Furthermore, the configuration of all body-contact MOSFETs will result in a larger overall on-resistance (Ron) and off-resistance (Coff) of the stacked RF switch due to the parasitic effect and signal leakage at the body end of the body-contact MOSFETs. This will limit the improvement of RF performance such as insertion loss and isolation of the stacked RF switch.

[0044] Therefore, the stacked RF switch provided in this application matches different types of switching transistors at different positions according to the voltage division distribution characteristics of the switching transistors in the series link, aiming to improve the on-resistance and off-capacitance performance of the RF switch while meeting the harmonic performance requirements.

[0045] like Figure 1 As shown, among the N switches in the stacked RF switch, at least one switch closest to the first RF port D1 (i.e., the hot end) is a body contact type switch 10. The body terminal B of the body contact type switch 10 is led out and electrically connected to the body bias potential terminal to receive the body bias potential; at least one switch closest to the second RF port D2 (i.e., the cold end) is a body floating type switch 20. The body terminal of the body floating type switch is in an electrically floating state.

[0046] In this design, the body terminal B of the body contact type switch 10 is led out and electrically connected to the body bias potential terminal. By receiving the body bias potential to stabilize its substrate potential, it can effectively suppress the nonlinear charge change caused by the weak conduction of the reverse bias diode between its drain and body terminals and between its source and body terminals under high voltage, and significantly attenuate distortion components such as the third harmonic. Therefore, it has excellent harmonic suppression characteristics. At least one of the switches closest to the first RF port D1 (i.e., the hot end) with the largest voltage division and the most stringent harmonic constraint is designated as the body contact type switch 10. The body contact type switch 10 closest to the first RF port D1 (i.e., the hot end) can dominate the harmonic suppression capability of the stacked RF switch, ensuring that the overall harmonic performance of the RF switch meets the system design requirements.

[0047] The body-floating switch 20 has no lead-out electrodes at its body end, and its substrate is electrically suspended. Compared with the body-contact switch, the body-floating switch eliminates the additional gate-body parasitic capacitance caused by the body-end lead-out structure. It also eliminates RF signal leakage caused by the body-end bias path. Therefore, the body-floating switch has lower on-resistance (Ron) and smaller turn-off capacitance (Coff). By designating at least one switch closest to the second RF port D2 (i.e., the cold end) with the smallest voltage division and sufficient harmonic margin as the body-floating switch 20, the low harmonic risk characteristics of the cold end can be fully utilized. At the cost of acceptable harmonic performance sacrifice, the overall on-resistance (Ron) and turn-off capacitance (Coff) of the stacked RF switch are effectively reduced, optimizing the insertion loss and turn-off isolation performance of the RF switch.

[0048] In this embodiment, the body contact type switch 10 can be a body contact type MOS transistor, and the body floating type switch 20 can be a body floating type MOS transistor.

[0049] It is understood that although the embodiments of this application specify that at least one of the N switches closest to the first RF port D1 (i.e., the hot end) in the stacked RF switch is a body contact switch 10, in practice, multiple consecutive switches close to the first RF port D1 (i.e., the hot end) can be configured as body contact switches 10 according to the overall harmonic margin of the RF switch, as long as the RF switch has sufficient harmonic suppression capability. Similarly, multiple consecutive switches close to the second RF port D2 (i.e., the cold end) can also be configured as body floating switches 20 to improve the on-resistance (Ron) and off-capacitance (Coff) performance of the RF switch.

[0050] When the stacked RF switch is in the off state, the gate terminal G of all switches is loaded with a turn-off control voltage, and the channel of each switch is turned off. The voltage between the first RF port D1 (i.e., the hot end) and the second RF port D2 (i.e., the cold end) is shared by N series-connected switches. The bulk contact switch 10, which is close to the first RF port D1 (i.e., the hot end), has a high voltage division capability due to its excellent harmonic suppression capability, which suppresses the harmonic degradation caused by substrate nonlinearity. The bulk floating switch 20, which is close to the second RF port D2 (i.e., the cold end), improves the isolation between the first RF port D1 (i.e., the hot end) and the second RF port D2 (i.e., the cold end) with its smaller turn-off capacitance. At the same time, the reduction of the turn-off capacitance further optimizes the RF performance of the RF switch in the off state.

[0051] When the stacked RF switch is in the ON state, the gate terminals G of all switches are loaded with a turn-on control voltage, and the channels of each switch are turned on. The RF signal can be transmitted between the first RF port D1 and the second RF port D2 with low loss. Since the on-resistance of the body-floating switch 20 near the second RF port D2 (i.e., the cold end) is lower than that of the body-contact switch of the same size, the total on-resistance of the stacked RF switch is less than that of the traditional stacked RF switch which is composed entirely of body-contact MOS transistors, which can effectively reduce the insertion loss of signal transmission.

[0052] Therefore, the stacked RF switch provided in this application embodiment, by setting at least one switch closest to the first RF port D1 (i.e., the hot end) as a body contact type switch 10 and at least one switch closest to the second RF port D2 (i.e., the cold end) as a body floating type switch 20, can reduce the overall on-resistance (Ron) and off-resistance (Coff) of the stacked RF switch while ensuring that the first RF port is still dominated by the body contact type switch for harmonic suppression and that the overall harmonic performance meets the requirements. This effectively improves the conduction loss and off-resistance isolation performance of the RF switch, thereby enhancing the overall performance of the RF switch. Furthermore, this stacked RF switch can achieve performance improvement simply through differentiated configuration of device selection, without the need for additional control circuits or special process steps. It is fully compatible with existing standard semiconductor processes, resulting in low cost and ease of mass production.

[0053] Optionally, in some embodiments of this application, such as Figure 1 As shown, in the stacked RF switch, X consecutive switches near the first RF port D1 (hot end) can be designated as body contact switches 10, and N consecutive switches near the second RF port D2 (cold end) can be designated as body floating switches 20; where 1 ≤ X ≤ N-1, and X is an integer. That is, in the direction from the first RF port D1 (hot end) to the second RF port D2 (cold end), switches M1 to M2... XAll X-stage switching transistors are body contact type 10, starting from switching transistor M. (X+1) To the switching transistor M N All NX-level switches are bulk-floating switches 20, and the two types of switches are arranged in a continuous partitioned configuration in the series link. The value of X can be flexibly set according to the harmonic performance requirements of the stacked RF switches, as well as the performance optimization goals of the on-resistance and turn-off capacitor.

[0054] For example, when N=2 and X=1, the stacked RF switch includes two switches connected in series. The switch closer to the first RF port D1 (i.e., the hot end) is a body contact switch 10, and the switch closer to the second RF port D2 (i.e., the cold end) is a body-floating switch 20. When N=4, X can be 2, and the stacked RF switch includes four switches connected in series. The two consecutive switches closer to the first RF port D1 (i.e., the hot end) are body contact switches 10, and the two consecutive switches closer to the second RF port D2 (i.e., the cold end) are body-floating switches 20.

[0055] It is understandable that the continuous partitioned arrangement of the stacked RF switches is highly compatible with the actual voltage distribution characteristics of its series links. As analyzed above, when the stacked RF switches are turned off, the voltage of each stage of the switches decreases progressively from the first RF port D1 to the second RF port D2. The switches in the hot end region experience high voltage, resulting in a high risk of harmonic degradation and requiring high harmonic suppression capabilities. The switches in the cold end region experience low voltage, resulting in a low risk of harmonic degradation and sufficient harmonic performance margin. In this embodiment, the bulk contact switches 10 are continuously arranged in the hot end region with higher voltage, which can completely cover the high voltage stress range and ensure that all switches subjected to high voltage have excellent harmonic suppression capabilities, preventing the bulk floating switches 20 from mixing into the high voltage region and causing local harmonic degradation and out of control. At the same time, the bulk floating switches 20 are continuously arranged in the cold end region with lower voltage, which can utilize the harmonic performance margin of each stage of the cold end switches in batches to replace devices with better conduction and turn-off performance, achieving a step-by-step optimization of conduction resistance and turn-off capacitance. Furthermore, this continuous partitioned arrangement simplifies circuit and layout design. Since all body-contact switching transistors 10 are continuously distributed in the hot-end region, their body-end bias circuits can be centrally planned and designed, resulting in shorter body-end wiring paths and less introduced parasitic effects. This not only improves the stability of the bias potential but also helps to reduce the chip layout area and lower implementation costs.

[0056] Therefore, when the stacked RF switch is in the off state, the X individual contact type switches 10 arranged consecutively share the voltage division in the high-voltage region. Each stage of the contact type switches 10 suppresses substrate nonlinearity through body bias, thus cooperating to ensure the overall linearity of the RF switch. The remaining NX individual floating type switches 20 share the voltage division in the low-voltage region, improving port isolation with a smaller turn-off capacitance. When the stacked RF switch is in the on state, the NX individual floating type switches 20 participate in signal transmission with lower on-resistance, effectively reducing the total on-resistance of the entire series link and reducing signal insertion loss.

[0057] Figure 6 The diagram shows a comparison of harmonic performance simulation results between a conventional stacked RF switch consisting entirely of body-contact MOSFETs and a stacked RF switch employing a hybrid structure of body-contact and body-floating MOSFETs as described in this application. Both the conventional and the stacked RF switches in this application include four MOSFETs. In the stacked RF switch of this application, the two MOSFETs closest to the hot end are body-contact MOSFETs (10), and the two MOSFETs closest to the cold end are body-floating MOSFETs (20). Figure 6 In the diagram, H1_BC, H2_BC, and H3_BC correspond to the fundamental frequency signal, second harmonic, and third harmonic of a traditional stacked RF switch consisting entirely of bulk contact MOSFETs, respectively. H1_BC+BF, H2_BC+BF, and H3_BC+BF correspond to the fundamental frequency signal, second harmonic, and third harmonic of the stacked RF switch employing a hybrid structure of bulk contact and floating-type MOSFETs, respectively. Simulation results show that at a fundamental frequency of 20.0 GHz, the fundamental frequency signal H1_BC of the traditional stacked RF switch consisting entirely of bulk contact MOSFETs is 20.0 dBm, the second harmonic H2_BC is -101.0 dBm, and the third harmonic H3_BC is -85.35 dBm. The fundamental frequency signal H1_BC+BF of the stacked RF switch employing a hybrid structure of bulk contact and floating-type MOSFETs, as described in this application, is 20.0 dBm, and the second harmonic H2_BC+BF is -101.3 dBm. The third harmonic H3_BC+BF is -73.27dBm; the fundamental frequency signal power of the two structures is exactly the same, indicating that there is basically no difference in signal conduction and transmission capabilities; the second harmonic levels are very close, both at extremely low levels, and the performance difference is negligible; the third harmonic shows a significant difference. Compared with the traditional stacked RF switch with all body contact type MOSFETs, the third harmonic H3_BC+BF of the stacked RF switch with a hybrid structure of body contact type and body floating type MOSFETs in this application increases by about 12dB, and the third harmonic is somewhat deteriorated.

[0058] Figure 7The diagram shows a comparison of the on-resistance Ron simulation results between a conventional stacked RF switch consisting entirely of body-contact MOSFETs and a stacked RF switch employing a hybrid structure of body-contact and body-floating MOSFETs as described in this application. Both the conventional and the stacked RF switches in this application include four MOSFETs. In the stacked RF switch of this application, the two MOSFETs closest to the hot end are body-contact MOSFETs (10), and the two MOSFETs closest to the cold end are body-floating MOSFETs (20). Figure 7 In this paper, Ron_BC corresponds to a traditional stacked RF switch consisting entirely of body-contact MOSFETs, while Ron_BC+BF corresponds to the stacked RF switch in this application, which employs a hybrid structure of body-contact and body-floating MOSFETs. Simulation results show that the on-resistance Ron_BC+BF of the stacked RF switch in this application, with its hybrid structure, is 5.493Ω, while the on-resistance Ron_BC of the traditional stacked RF switch, consisting entirely of body-contact MOSFETs, is 5.5Ω. This indicates that the stacked RF switch in this application, with its hybrid structure, has lower conduction losses and superior signal transmission performance.

[0059] Figure 8 The diagram shows a comparison of simulation results for the turn-off capacitor Coff of a traditional stacked RF switch consisting entirely of body-contact MOSFETs and a stacked RF switch employing a hybrid structure of body-contact and body-floating MOSFETs as described in this application. Both the traditional and the stacked RF switches in this application include four MOSFETs. In the stacked RF switch of this application, the two MOSFETs closest to the hot end are body-contact MOSFETs (10), and the two MOSFETs closest to the cold end are body-floating MOSFETs (20). Figure 8 In the diagram, Coff_BC corresponds to a traditional stacked RF switch consisting entirely of body-contact MOSFETs, while Coff_BC+BF corresponds to the stacked RF switch in this application, which employs a hybrid structure of body-contact and body-floating MOSFETs. Simulation results show that the turn-off capacitance Coff_BC+BF of the stacked RF switch with this hybrid structure is 118.4 fF, while the turn-off capacitance Coff_BC of the traditional stacked RF switch consisting entirely of body-contact MOSFETs is 119.0 fF. This indicates that the stacked RF switch with this hybrid structure has a smaller port parasitic capacitance and better turn-off isolation performance in the off state.

[0060] Based on the above three sets of simulation results, it can be seen that after replacing the part of the switching transistors near the cold end in the stacked RF switch with the body-floating switching transistors, the on-resistance and turn-off capacitance are effectively improved. At the same time, the harmonic performance will deteriorate as expected. Overall, it is in line with the design idea of ​​"sacrificing controllable harmonics for improved on- and off-resistance performance", and the deterioration of harmonic performance is mainly due to the third harmonic.

[0061] Based on this, the inventors further studied the influence of the number of bulk-floating switching transistors placed near the cold end in a stacked RF switch on the overall harmonic performance. Figure 9 The diagram illustrates the trend of the third harmonic distortion (THD) of the stacked RF switch of this application as a function of the number of bulk-floating transistors near the second RF port D2 (i.e., the cold end). The trend shows that as the number of bulk-floating transistors near the cold end gradually increases, the overall THD of the RF switch continuously deteriorates. In other words, when the number N of transistors connected in series in the stacked RF switch is fixed, the more bulk-floating transistors near the cold end and the fewer bulk-contact transistors near the hot end, the worse the overall harmonic performance of the RF switch.

[0062] Based on this variation pattern, in practical design, given a fixed number N of switching transistors connected in series in a stacked RF switch, the number of bulk-floating switching transistors near the cold end can be gradually increased until the third harmonic of the stacked RF switch deteriorates to a preset critical value (e.g., -50dBm). At this point, the number M of bulk-floating switching transistors near the cold end is the maximum number that can be set. As long as the number of bulk-floating switching transistors near the cold end does not exceed M, the third harmonic of the stacked RF switch can meet the performance requirements.

[0063] Therefore, optionally, in some embodiments of this application, among the N switching transistors of the stacked RF switch, the number of consecutive volume-floating switching transistors 20 closest to the second RF port D2 (i.e., the cold end) is NX≤M, 1≤M≤N-1, and M is an integer; wherein, when NX=M, the third harmonic of the stacked RF switch is less than or equal to a preset threshold value (e.g., -50dBm). The preset threshold value (e.g., -50dBm) is the upper limit of the harmonic performance index of the RF system for the RF switch, that is, the harmonic design qualification threshold.

[0064] In actual circuit design, the preset threshold value of the third harmonic of the RF switch can be determined first according to the system design specifications. Then, starting from the structure of all body contact type switches, the body contact type switches at the cold end are gradually replaced with body floating type switches. The overall third harmonic level is simulated and tested after each replacement. When the third harmonic amplitude rises to the preset threshold value, the number of body floating type switches near the cold end is M.

[0065] Understandably, by limiting the design rule to NX≤M, the number of bulk floating switches near the cold end can be maximized while ensuring that the harmonic performance of the stacked RF switches always meets the performance requirements. This achieves optimal improvement in on-resistance and turn-off capacitance performance, resulting in the best balance between harmonic performance and on / off performance. This design method can quantitatively guide the selection and quantity ratio of components in stacked RF switches, adapting to application scenarios with different harmonic performance requirements.

[0066] It should be noted that this application is not limited to the arrangement of the continuous partitions described above, where "X consecutive switching transistors near the first RF port D1 (i.e., the hot end) are body contact type switching transistors 10, and NX consecutive switching transistors near the second RF port D2 (i.e., the cold end) are body floating type switching transistors 20". Based on the premise that at least one switching transistor closest to the first RF port D1 (i.e., the hot end) is a body contact type switching transistor 10, and at least one switching transistor closest to the second RF port D2 (i.e., the cold end) is a body floating type switching transistor 20, the intermediate stage switching transistors located at the first RF port D1 (i.e., the hot end) and the second RF port D2 (i.e., the cold end) can be flexibly selected according to actual performance requirements. Especially in the low-voltage region near the second RF port D2 (i.e., the cold end), a mixed arrangement of body contact type switching transistors and body floating type switching transistors is supported.

[0067] Specifically, the switching transistors in the low-voltage region near the second RF port D2 (i.e., the cold end) experience lower voltage division. When it is necessary to retain some harmonic margin, and some body-floating switching transistors already provide sufficient improvement in on-resistance and turn-off capacitance, body-contact switching transistors can be interspersed among the body-floating switching transistors near the second RF port D2 (i.e., the cold end). By adjusting the mixing ratio, fine-tuning of harmonic performance and on / off performance can be achieved. However, in the high-voltage region near the first RF port D1 (i.e., the hot end), due to the high voltage division of the switching transistors, the risk of harmonic degradation is high. Therefore, body-contact switching transistors should be used as much as possible to avoid significant degradation of overall harmonic performance.

[0068] The specific electrical connections of each terminal of the body contact type switch 10 and the body floating type switch 20 in the stacked RF switch are explained below.

[0069] For the electrical connection method of the body terminal B of the body contact type switch 10 in the stacked RF switch, the options are as follows: Figure 1 As shown, the body bias potential terminal electrically connected to the body terminal B of the body contact type switch 10 can be set as the first bias node J1. The first bias node J1 is used to provide a uniform body bias potential Vb to all body contact type switch 10s. For example, the first bias node J1 can be a power supply terminal. Specifically, as shown... Figure 1As shown, the body terminal B of each body contact type switch 10 is electrically connected to the same first intermediate node Z1 through a first resistor R1, and the first intermediate node Z1 is then electrically connected to the first bias node J1 through a second resistor R2.

[0070] Each first resistor R1 serves as an interstage isolation and current limiting resistor, which can prevent radio frequency signal crosstalk between the body terminals B of different body contact type switches 10, and at the same time limit the leakage of radio frequency signals from the body terminals B of the body contact type switches 10 to the common bias path. The second resistor R2 serves as the total isolation resistor, which can further attenuate the radio frequency signal leaking to the first intermediate node Z1, block the radio frequency energy from interfering with the first bias node J1, and ensure the stability of the body bias potential Vb.

[0071] By adopting this centralized biasing method for the body terminal B of each body contact type switch 10, all body contact type switch 10 share the same main bias path, which makes the body bias potential of each body contact type switch 10 consistent, the circuit topology clear, and facilitates centralized layout.

[0072] Another option for the electrical connection method of the body terminal of the body contact type switch 10 in the stacked RF switch is, as follows: Figure 10 As shown, Figure 10 A schematic diagram of another stacked RF switch provided in this application embodiment is shown. It can be seen that the body bias potential terminal electrically connected to the body terminal B of the body contact type switch 10 is also set as the first bias node J1. For example, the first bias node J1 can be a power supply terminal, but the body terminal biases of each body contact type switch 10 are connected in a cascaded chain manner. Specifically, in the direction from the first RF port D1 (i.e., the hot end) to the second RF port D2 (i.e., the cold end), the body terminal B of the i-th body contact type switch 10 is electrically connected to the body terminal B of the (i+1)-th body contact type switch 10 through the third resistor R3. After all the body terminals B of the body contact type switch 10 are connected in series, the body terminal B of the last body contact type switch 10 closest to the second RF port D2 (i.e., the cold end) is then electrically connected to the first bias node J1 through the fourth resistor R4.

[0073] By employing this cascaded chain connection method for the body terminals B of each body-contact type switch 10, the third resistors R3 at each stage sequentially form the series attenuation nodes of the bias link. During the transmission of the RF signal from the body terminal B of the body-contact type switch 10 closest to the first RF port D1 (i.e., the hot end) to the first bias node J1, it will gradually attenuate through multiple stages of third resistors R3, effectively reducing the RF signal leakage at the body terminals B of each body-contact type switch 10. Simultaneously, this chain-connection wiring configuration closely matches the series arrangement of the switches, allowing the layout wiring to extend smoothly along the series link, resulting in short wiring paths and a compact layout.

[0074] Another option for the electrical connection method of the body terminal of the body contact type switch 10 in the stacked RF switch is, for example... Figure 11 As shown, Figure 11 A schematic diagram of another stacked RF switch provided in this application embodiment is shown. It can be seen that the body bias potential terminal electrically connected to the body terminal B of the body contact type switch 10 is the gate terminal G of the body contact type switch 10 itself, eliminating the need for an additional independent global body bias node. Specifically, the body terminals B of each body contact type switch 10 are electrically connected to the gate terminal of the same body contact type switch 10 through a diode Q1, and the forward conduction direction of the diode Q1 points from the body terminal B of the body contact type switch 10 to the gate terminal of the same body contact type switch 10.

[0075] Thus, when the stacked RF switch is in the off state, a turn-off control voltage (usually a negative potential) is applied to the gate terminal G of all the switching transistors. At this time, the potential of the body terminal B of the body contact type switch 10 is higher than the potential of its gate terminal G. The diode Q1 is forward-biased, clamping the potential of the body terminal B of the body contact type switch 10 to a level close to the potential of its gate terminal G. This ensures that a sufficient reverse bias voltage is maintained between the source terminal S, drain terminal D and body terminal B of the body contact type switch 10, suppressing the weak conduction of the substrate parasitic diode and ensuring the harmonic suppression performance of the RF switch. When the stacked RF switch is in the on state, a turn-on control voltage (usually a positive potential) is applied to the gate terminal G of all the switching transistors. At this time, the potential of the gate terminal G of the body contact type switch 10 is higher than the potential of its body terminal B. The diode Q1 is reverse-biased and the body terminal B is approximately in a floating state, without introducing additional parasitic effects and signal loss in the conduction path.

[0076] By adopting this self-biased connection method for the body terminal B of each body contact type switch 10, there is no need to configure an additional global body bias power supply and long-distance bias wiring, which greatly simplifies the bias circuit design and reduces the chip layout area. At the same time, it eliminates the RF signal leakage path caused by the global body bias path, which can further optimize the on-resistance and off-capacitance performance of the switch and improve the overall RF performance of the RF switch.

[0077] For the electrical connection method of the source terminal S and drain terminal D of each switch in a stacked RF switch, options include, for example... Figure 1 , Figure 10 and Figure 11As shown, in a stacked RF switch, a fifth resistor R5 is electrically connected between the source terminal S and the drain terminal D of each switch transistor. From the first RF port D1 to the second RF port D2, since N switches are connected in series along the signal path, with the source terminals S and drain terminals D of adjacent switches connected end-to-end, each fifth resistor R5 is connected in series along with the series arrangement of the switches, forming a voltage divider chain in parallel with the series link of the switches. Specifically, a fifth resistor R5 is connected in parallel between the source terminal S and the drain terminal D of switch transistor M1, and a fifth resistor R5 is also connected in parallel between the source terminal S and the drain terminal D of switch transistor M2. Since the drain terminal D of switch transistor M1 is directly connected to the source terminal S of switch transistor M2, the corresponding two fifth resistors R5 are also connected end-to-end. This process continues, with N fifth resistors R5 cascaded along the series link to form a complete voltage divider resistor branch.

[0078] When the stacked RF switches are in the off state, the channels of each switch are turned off. Due to the influence of substrate leakage current and the dispersion of device parasitic parameters, the actual voltage division between the first RF port D1 (i.e., the hot end) and the second RF port D2 (i.e., the cold end) exhibits a non-uniform distribution, with the first RF port D1 (i.e., the hot end) being higher and the second RF port D2 (i.e., the cold end) being lower. Switches closer to the first RF port D1 (i.e., the hot end) are prone to voltage stress exceeding design values, exacerbating substrate nonlinearity and causing harmonic degradation. However, by introducing a series resistor chain consisting of the fifth resistor R5, the source-drain DC potentials of each stage of the switches in the off state can be more evenly distributed through the resistor chain, smoothing out the voltage difference between each stage, reducing the overvoltage risk of switches closer to the first RF port D1 (i.e., the hot end), and making the voltage stress borne by each stage of the switches more balanced. This structure can improve the overall withstand voltage reliability of the switches and suppress nonlinear distortion caused by local overvoltage, maintaining the stability of harmonic performance.

[0079] When the stacked RF switch is in the ON state, the switch channel is fully open. The channel on-resistance is much smaller than the value of the fifth resistor R5. The RF signal is mainly transmitted through the low-resistance channel. The fifth resistor R5 has a very weak signal shunting effect on the conduction path and will not significantly increase the insertion loss. Its impact on the switch conduction performance is negligible.

[0080] It is understandable that this source-drain parallel resistor chain structure is applicable to both body contact type and body floating type switching transistors, without distinguishing between device types. It is compatible with the aforementioned various body bias schemes and device layout schemes, further optimizing the voltage division uniformity of the stacked link and improving the operational robustness and performance consistency of the RF switch.

[0081] For the electrical connection method of the gate terminals G of each switch in a stacked RF switch, options include, for example... Figure 1 and Figure 11As shown, the gate terminal G of each switch is electrically connected to the second intermediate node Z2 through the sixth resistor R6. The second intermediate node Z2 is then electrically connected to the second bias node J2 through the seventh resistor R7. Specifically, for each switch in the series link, the gate terminal G is connected in series with a sixth resistor R6. The other ends of all the sixth resistors R6 are connected to the same second intermediate node Z2. The second intermediate node Z2 is then connected to the second bias node J2 through the seventh resistor R7. The second bias node J2 is used to provide a unified gate terminal control voltage Vg for all switches in the entire link, including the positive potential in the on state and the negative potential in the off state. The control voltage is synchronously applied to the gate terminal G of all switches through a centralized bias path, realizing unified control of the on and off states of the stacked RF switches. For example, the second bias node J2 can be a power supply terminal.

[0082] This centralized gate bias structure ensures good consistency of the gate control potential of each stage of the switching transistors, guaranteeing synchronous turn-on and turn-off of all switches in the series link. This avoids voltage imbalance and performance degradation caused by delays in the turn-on or turn-off of some devices. Simultaneously, each sixth resistor R6 provides inter-stage RF isolation, preventing RF signals at the gate G of the switching transistors from interfering with the common bias node and avoiding crosstalk and leakage of RF energy through the gate bias path. The seventh resistor R7, as the overall isolation resistor, further attenuates the RF components leaking to the second intermediate node Z2, suppressing the parasitic effects introduced by the second bias node J2 on the performance of the main RF path. This topology is clear, has good control potential uniformity, and facilitates centralized layout.

[0083] Another option, such as Figure 10 As shown, the gate terminals G of each switch transistor adopt a cascaded chain bias connection structure. Specifically, in the direction from the first RF port D1 (i.e., the hot end) to the second RF port D2 (i.e., the cold end), the gate terminal G of the j-th switch transistor is electrically connected to the gate terminal G of the (j+1)-th switch transistor through the eighth resistor R8. The gate terminals G of all switches are connected in series to form a chain gate bias path. The gate terminal G of the last switch transistor closest to the second RF port is then electrically connected to the second bias node J2 through the ninth resistor R9, where 1≤j≤N-1, and j is an integer. The second bias node J2 is used to output the gate terminal control voltage Vg of the switch transistors, including a positive potential turn-on control voltage and a negative potential turn-off control voltage. The gate terminal control voltage is synchronously applied to the gate terminals G of all switches through the chain gate path to achieve unified control of the on / off state of the stacked RF switches.

[0084] In this cascaded gate bias structure, the eighth resistors R8 at each stage are connected in series to form a multi-stage attenuation node in the gate bias link. When the stacked RF switch is in the off state, the RF signal attenuates step by step from the first RF port D1 (i.e., the hot end) to the second RF port D2 (i.e., the cold end). The RF signal induced at the gate terminal G of the switch near the first RF port D1 (i.e., the hot end) will be gradually attenuated by the multiple stages of the eighth resistors R8 during its transmission to the second bias node J2. This effectively reduces the RF signal leakage in the gate bias path, reduces the impact of the control port on the performance of the main RF path, and avoids RF signal intrusion into the back-end control circuit, thus preventing operational stability issues. Furthermore, the eighth resistors R8 at each stage naturally have a current-limiting function for gate electrostatic discharge, which can improve the ESD protection capability of the switch gate oxide layer.

[0085] It should be noted that the bias connection structure of the body terminal of the body contact type switch 10 in the stacked RF switch can use the same topology as the bias connection structure of the gate terminals of each switch, or they can use different topologies. In actual circuit design, to ensure the consistency of the layout, improve the convenience of routing and parameter matching, the bias connection method of the body terminal of the body contact type switch 10 and the gate terminals of each switch is usually designed to be the same, for example, using a centralized bias structure or a cascaded chain bias structure simultaneously, such as... Figure 1 and Figure 10 As shown, this facilitates unified planning of bias paths along the series link of the switching transistors, reduces wiring crossovers and parasitic parameter differences, and further improves the consistency of circuit performance and the compactness of the layout.

[0086] Accordingly, embodiments of this application also provide a radio frequency front-end module. Figure 12 A schematic diagram of the circuit structure of the radio frequency front-end module provided in an embodiment of this application is shown, as follows: Figure 12 As shown, the RF front-end module adopts a single-pole double-throw switch architecture, including an antenna port ANT, a first signal transceiver port S1, and a second signal transceiver port S2; a first switch K1 is provided between the antenna port ANT and the first signal transceiver port S1, and a second switch K2 is provided between the first signal transceiver port S1 and the ground terminal; a third switch K3 is provided between the antenna port ANT and the second signal transceiver port S2, and a fourth switch K4 is provided between the second signal transceiver port S2 and the ground terminal; wherein, the second switch K2 and / or the third switch K3 adopts a stacked RF switch provided in any of the aforementioned embodiments.

[0087] This RF front-end module enables time-division multiplexing of two transceiver paths. Specifically, when the path corresponding to the first signal transceiver port S1 is operational, the first switch K1 is turned on, the second switch K2 is turned off, the third switch K3 is turned off, and the fourth switch K4 is turned on. The RF signal is transmitted between the antenna port ANT and the first signal transceiver port S1 via the first switch K1. At this time, for the second switch K2 connected to ground in parallel, the side closer to the first signal transceiver port S1 in the off state experiences a higher RF voltage, which is the hot end; the side closer to the ground has an extremely low voltage swing, which is the cold end. Therefore, the second switch K2 can adopt the stacked RF switch provided in any of the aforementioned embodiments, with the first RF port D1 (i.e., the hot end) serving as the signal transceiver port (i.e., the first signal transceiver port S1), and the second RF port D2 (i.e., the cold end) serving as the ground. By adopting the stacked RF switch of this application, the off-state capacitance of the switch can be reduced under the premise of controllable harmonic performance, improving the isolation to ground in the off state, while reducing the branch loss in the on state.

[0088] When the corresponding path of the second signal transceiver port S2 is working, the third switch K3 is turned on and the fourth switch K4 is turned off. At the same time, the first switch K1 is turned off and the second switch K2 is turned on. The radio frequency signal is transmitted between the antenna port ANT and the second signal transceiver port S2 via the third switch K3. At this time, for the third switch K3 connected in series in the main signal path, the side closer to the antenna port ANT in the off state experiences a higher voltage swing, which is the hot end; the side closer to the second signal transceiver port S2 has a relatively lower voltage swing, which is the cold end. Therefore, the third switch K3 can adopt the stacked radio frequency switch provided in any of the aforementioned embodiments, with the first radio frequency port D1 (i.e., the hot end) being the antenna port and the second radio frequency port D2 (i.e., the cold end) being the signal transceiver port (i.e., the second signal transceiver port S2). After the third switch K3 adopts the stacked radio frequency switch of this application, the overall harmonic suppression capability can be guaranteed by the bulk contact type switch on the antenna side, and the on-resistance and off-capacitance can be optimized by the bulk floating type switch on the transceiver port side. While meeting the system linearity requirements, the signal insertion loss is reduced and the off-isolation performance is improved.

[0089] The various parts of this manual are described in a combination of parallel and progressive methods. Each part focuses on the differences between the other parts, and the same or similar parts can be referred to each other.

[0090] The features described above regarding the disclosed embodiments can be substituted or combined with each other to enable those skilled in the art to implement or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A stacked radio frequency switch, characterized in that, It includes N switching transistors connected in series between the first RF port and the second RF port, where N≥2 and N is an integer; when the stacked RF switch is in the off state, the voltage across the first RF port is higher than the voltage across the second RF port. Among the N switching transistors, at least one switching transistor closest to the first RF port is a body contact type switching transistor. The body terminal of the body contact type switching transistor is led out and electrically connected to the body bias potential terminal to receive the body bias potential. Among the N switching transistors, at least one switching transistor closest to the second RF port is a body-floating switching transistor, and the body end of the body-floating switching transistor is in an electrically floating state.

2. The stacked radio frequency switch according to claim 1, characterized in that, Of the N switching transistors, the X consecutive switching transistors closest to the first RF port are the body contact type switching transistors, and the NX consecutive switching transistors closest to the second RF port are the body floating type switching transistors, where 1≤X≤N-1 and X is an integer.

3. The stacked radio frequency switch according to claim 2, characterized in that, NX≤M, 1≤M≤N-1, and M is an integer; wherein, when NX=M, the third harmonic of the stacked RF switch is less than or equal to a preset threshold value.

4. The stacked radio frequency switch according to claim 1, characterized in that, The body bias potential terminal is the first bias node; the body terminals of each of the body contact type switching transistors are respectively connected to the first intermediate node through a first resistor, and the first intermediate node is then connected to the first bias node through a second resistor.

5. The stacked radio frequency switch according to claim 1, characterized in that, The body bias potential terminal is the first bias node; in the direction from the first RF port to the second RF port, the body terminal of the i-th body contact type switch is electrically connected to the body terminal of the (i+1)-th body contact type switch through a third resistor, and the body terminal of the last body contact type switch is then electrically connected to the first bias node through a fourth resistor, 1≤i, and i is an integer.

6. The stacked radio frequency switch according to claim 1, characterized in that, The body bias potential terminal is the gate terminal of the body contact type switch; the body terminals of each body contact type switch are electrically connected to the gate terminal of the same body contact type switch through a diode, and the forward direction of the diode points from the body terminal of the body contact type switch to the gate terminal of the same body contact type switch.

7. The stacked radio frequency switch according to claim 1, characterized in that, The source and drain terminals of each of the switching transistors are electrically connected through a fifth resistor, and the fifth resistors are connected in series in the direction from the first RF port to the second RF port.

8. The stacked radio frequency switch according to claim 1, characterized in that, The gate terminals of each of the aforementioned switching transistors are electrically connected to the second intermediate node via a sixth resistor, and the second intermediate node is then electrically connected to the second bias node via a seventh resistor. Alternatively, in the direction from the first RF port to the second RF port, the gate terminal of the j-th switch is electrically connected to the gate terminal of the (j+1)-th switch through an eighth resistor, and the gate terminal of the last switch is then electrically connected to the second bias node through a ninth resistor, where 1≤j≤N-1 and j is an integer.

9. The stacked radio frequency switch according to any one of claims 1-8, characterized in that, The first RF port is a signal transceiver port, and the second RF port is a ground terminal; Alternatively, the first RF port may be an antenna port, and the second RF port may be a signal transceiver port.

10. A radio frequency front-end module, characterized in that, It includes an antenna port, a first signal transceiver port, and a second signal transceiver port; a first switch is provided between the antenna port and the first signal transceiver port, and a second switch is provided between the first signal transceiver port and a ground terminal; a third switch is provided between the antenna port and the second signal transceiver port, and a fourth switch is provided between the second signal transceiver port and the ground terminal; Wherein, the second switch and / or the third switch are stacked radio frequency switches as described in any one of claims 1-9.

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