Bias circuit for low noise amplifier and radio frequency low noise amplifier

Abstract

Disclosed in the present invention are a bias circuit for a low noise amplifier and a radio frequency low noise amplifier. The bias circuit comprises a bias circuit control module and a bias current providing module; the bias circuit control module is connected to a common gate circuit of the low noise amplifier, and the bias circuit control module is used for controlling the bias circuit to be switched on or off and suppressing, when the bias circuit is switched off, voltage leakage and current leakage of the common gate circuit; and the bias current providing module is connected to a common source circuit of the low noise amplifier, and the bias current providing module is used for providing a current bias in response to a current offset of the low noise amplifier to stabilize the current of the low noise amplifier. According to the bias circuit of the present invention, when a current offset occurs in the common source circuit in high-low temperature environments, a current bias is provided, and when the bias circuit is switched off, voltage leakage and / or current leakage of the common gate circuit is suppressed, such that the target of stabilizing an LNA current in high-low temperature environments is achieved.

Description

Bias circuit for low noise amplifier and RF low noise amplifier Technical Field

[0001] The present invention relates to the technical field of low noise amplifiers, and in particular to a bias circuit for a low noise amplifier and a radio frequency low noise amplifier. Background Art

[0002] The primary function of a radio frequency low-noise amplifier (LNA) is to amplify weak signals received by an antenna from the air. This amplified signal is then output to subsequent stages or the system's transceiver chip with minimal interference, where it can demodulate the data required by the system. Therefore, its noise figure and RF scattering parameters are two key determinants of the LNA's performance in a system. Physical factors can cause the current in an LNA chip's circuit to deviate from its normal temperature value in high and low temperature environments, affecting the LNA's noise figure and RF scattering parameters. This can even lead to overcurrent, overvoltage breakdown, and complete product damage. Therefore, ensuring current stability in these environments is crucial for RF LNAs.

[0003] As the communications industry continues to demand higher levels of integration for RF LNAs, the requirements for their operating frequency, range, coverage, and radiated power are also increasing. The components and processes used in RF LNA integrated circuits, at high integration and high frequencies, place increasing demands on the product's noise figure and scattering parameter characteristics, not only at room temperature but also in high and low-temperature environments. This has resulted in traditional LNA designs being unable to meet these stringent requirements. To address this issue, it is necessary to provide RF LNAs with improved performance and reliability in these environments, ensuring the system's RF reception performance and quality in both high and low-temperature environments.

[0004] Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defect in the prior art that the current in the circuit of a low-noise amplifier chip in high and low temperature environments will be affected by physical factors of the device and will deviate from the normal temperature value, thereby affecting the noise coefficient and RF scattering parameters of the low-noise amplifier. A bias circuit for a low-noise amplifier and a RF low-noise amplifier are provided.

[0006] The present invention solves the above technical problems through the following technical solutions:

[0007] The present invention provides a bias circuit for a low-noise amplifier, the bias circuit comprising a bias circuit control module and a bias current providing module; the bias current providing module is connected to a power supply through the bias circuit control module;

[0008] The bias circuit control module is connected to the common-gate circuit of the low-noise amplifier, and the bias circuit control module is used to control the opening or closing of the bias circuit, and suppress the voltage leakage and / or current leakage of the common-gate circuit when the bias circuit is closed;

[0009] The bias current providing module is connected to the common source circuit of the low noise amplifier. The bias current providing module is used to provide a current bias in response to a current offset of the low noise amplifier to stabilize the current of the low noise amplifier.

[0010] Preferably, the bias current providing module forms a current mirror to provide a current bias to the common source circuit according to a reference current and the current offset.

[0011] Preferably, the bias current providing module includes a first field effect transistor; the first field effect transistor is connected to a power supply through the bias circuit control module;

[0012] The first field effect transistor is connected in parallel to the gate of the common source circuit.

[0013] Preferably, the bias circuit control module includes a switch unit and a leakage suppression unit; one end of the switch unit is connected to a power supply, and the other end of the switch unit is connected to one end of the leakage suppression unit and the bias current providing module; the other end of the leakage suppression unit is connected to the control end of the common-gate circuit;

[0014] The switch unit is used to control the opening or closing of the bias circuit;

[0015] The leakage suppression unit is configured to suppress voltage leakage and / or current leakage of the common-gate circuit by pulling down the voltage of the control terminal of the common-gate circuit when the bias circuit is turned off.

[0016] Preferably, the leakage suppression unit includes a second field effect transistor, and the switch unit includes a third field effect transistor;

[0017] The drain of the third field effect transistor is connected to a power supply, the gate is connected to a control voltage required by the bias circuit, and the source is connected to the gate of the common source circuit and the drain of the second field effect transistor respectively;

[0018] The gate of the second field effect transistor is grounded through a first resistor and connected to the control voltage through a second resistor. The source of the second field effect transistor is grounded. The drain of the second field effect transistor is also connected to the gate of the common-gate circuit.

[0019] Preferably, the bias circuit further comprises a first voltage stabilizing module, and the first voltage stabilizing module is connected in parallel to the common source circuit;

[0020] The first voltage stabilization module is used to provide a stable voltage reference to stabilize the voltage of the common source circuit; and / or,

[0021] The bias circuit further includes a second voltage stabilizing module, which is connected in parallel to the common-gate circuit;

[0022] The second voltage stabilization module is used to provide a stable voltage reference to stabilize the voltage of the common-gate circuit.

[0023] Preferably, the first voltage stabilizing module includes a first voltage stabilizing device group; the first voltage stabilizing devices are connected in series and then in parallel to the gate of the common source circuit; and / or,

[0024] The second voltage stabilizing module includes a second voltage stabilizing device group; the second voltage stabilizing devices are connected in series with each other and then in parallel to the gate of the common-gate circuit.

[0025] Preferably, the bias circuit further comprises a first decoupling module, and the first decoupling module is connected in parallel to the common source circuit;

[0026] The first decoupling module is used to perform radio frequency decoupling on the bias circuit and the common source circuit to improve the stability of the common source circuit; and / or,

[0027] The bias circuit further includes a second decoupling module, wherein the second decoupling module is connected in parallel to the common-gate circuit;

[0028] The second decoupling module is used to perform radio frequency decoupling on the bias circuit and the common-gate circuit to improve the stability of the common-gate circuit.

[0029] Preferably, the first decoupling module includes at least one first capacitor, one end of the first capacitor is connected to the gate of the common source circuit, and the other end is grounded; and / or,

[0030] The second decoupling module includes at least one second capacitor, one end of the second capacitor is connected to the gate of the common-gate circuit, and the other end is grounded.

[0031] The present invention also provides a radio frequency low noise amplifier, which includes the bias circuit for the low noise amplifier as described above.

[0032] The positive progress effect of the present invention is:

[0033] The bias circuit for a low-noise amplifier provided by the present invention provides a current bias to stabilize the current of the low-noise amplifier when a current offset occurs in the common-source circuit of the LNA in high and low-temperature environments through a bias current providing module. Furthermore, the bias circuit control module suppresses voltage leakage and / or current leakage in the common-gate circuit when the bias circuit is turned off, thereby achieving the goal of stabilizing the LNA operating current in high and low-temperature environments and ensuring the performance and quality of the LNA product in both high and low-temperature environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] To more clearly illustrate the technical solutions of the embodiments of this specification, the following briefly describes the drawings required for describing the embodiments. Obviously, the drawings described below are merely examples or embodiments of this specification. Those skilled in the art can apply this specification to other similar scenarios based on these drawings without inventive effort. Unless otherwise apparent from the context or otherwise noted, the same reference numerals in the figures represent the same structure or operation.

[0035] FIG1 is a first structural diagram of a bias circuit for a low-noise amplifier in Embodiment 1 of the present invention.

[0036] FIG2 is a second structural diagram of the bias circuit for the low noise amplifier in Embodiment 1 of the present invention.

[0037] FIG3 is a third structural diagram of the bias circuit for the low noise amplifier in Embodiment 1 of the present invention.

[0038] FIG4 is a fourth structural diagram of the bias circuit for the low noise amplifier in Embodiment 1 of the present invention.

[0039] FIG5 is a fifth structural diagram of the bias circuit for the low noise amplifier in Embodiment 1 of the present invention.

[0040] FIG6 is a sixth structural diagram of the bias circuit for the low noise amplifier in Embodiment 1 of the present invention.

[0041] FIG7 is a seventh structural diagram of the bias circuit for the low-noise amplifier in Embodiment 1 of the present invention.

[0042] FIG8 is an eighth structural diagram of the bias circuit for the low noise amplifier in Embodiment 1 of the present invention.

[0043] FIG9 is a ninth structural diagram of the bias circuit for the low noise amplifier in Embodiment 1 of the present invention. DETAILED DESCRIPTION

[0044] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples.

[0045] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various places herein does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0046] As used herein, unless the context clearly indicates otherwise, the terms "a," "an," "an," and / or "the" are not intended to refer to the singular but may include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list. A method or apparatus may also include additional steps or elements.

[0047] The definitions of "first" and "second" herein, and the descriptions "first," "second," etc., are provided for illustrative purposes only and are not intended to be sequential or to limit the number of devices herein. They should not be construed as limiting this disclosure. For example, a first element could be referred to as a second element without departing from the scope of this disclosure. Similarly, a second element could be referred to as a first element.

[0048] Example 1

[0049] Please refer to Figure 1, which is a first structural diagram of a bias circuit for a low-noise amplifier in this embodiment. Specifically, as shown in Figure 1, the bias circuit includes a bias circuit control module 1 and a bias current providing module 2; the bias current providing module 2 is connected to a power supply through the bias circuit control module 1;

[0050] The bias circuit control module 1 is connected to the common-gate circuit 3 of the low-noise amplifier. The bias circuit control module 1 is used to control the opening or closing of the bias circuit and suppress voltage leakage and / or current leakage of the common-gate circuit 3 when the bias circuit is closed.

[0051] The bias current providing module 2 is connected to the common source circuit 4 of the low noise amplifier. The bias current providing module 2 is used to provide a current bias in response to a current offset of the low noise amplifier to stabilize the current of the low noise amplifier.

[0052] Specifically, the low-noise amplifier of this embodiment uses the classic cascode LNA (common-source, common-gate low-noise amplifier) ​​structure as an example. After the input signal is processed by input matching circuit 5, it is amplified by common-source circuit 4 and common-gate circuit 3, and then converted into an output signal by output matching circuit 6. Under high and low temperature environments, the currents in the common-source and common-gate circuits of the LNA may deviate from their normal temperature values ​​due to physical factors of the devices, thereby affecting the LNA's noise figure and radio frequency scattering parameters. The bias circuit for the low-noise amplifier provided in this embodiment uses a bias current supply module to provide a current bias to stabilize the low-noise amplifier current when the common-source circuit experiences a current offset in the LNA under high and low temperature environments. Furthermore, the bias circuit control module suppresses voltage and / or current leakage in the common-gate circuit when the bias circuit is turned off. This achieves the goal of stabilizing the LNA operating current in high and low temperature environments (e.g., -40°C to +85°C), ensuring the performance and quality of the LNA product under these conditions.

[0053] Please refer to Figure 2, which is a second schematic diagram of the bias circuit for a low-noise amplifier in this embodiment. Specifically, as shown in Figure 2, in an optional embodiment, the bias current providing module 2 forms a current mirror to provide a current bias to the common source circuit based on the reference current and the current offset.

[0054] In this embodiment, the bias current providing module 2 includes a first field effect transistor M3 ; the first field effect transistor M3 is connected to the power supply through the bias circuit control module 1 ; the first field effect transistor M3 is connected in parallel to the gate of the common source circuit.

[0055] In another optional embodiment, the bias circuit control module 1 includes a switching unit 11 and a leakage suppression unit 12; one end of the switching unit 11 is connected to the power supply, and the other end of the switching unit 11 is connected to one end of the leakage suppression unit 12 and the bias current providing module 2; the other end of the leakage suppression unit 12 is connected to the control end of the common-gate circuit 3; the switching unit 11 is used to control the opening or closing of the bias circuit; the leakage suppression unit 12 is used to suppress the voltage leakage and / or current leakage of the common-gate circuit by lowering the voltage of the control end of the common-gate circuit 3 when the bias circuit is turned off.

[0056] Specifically, the leakage suppression unit 12 includes a second field effect transistor M4, and the switch unit 11 includes a third field effect transistor M5;

[0057] The drain of the third field effect transistor M5 is connected to the power supply, the gate is connected to the control voltage required by the bias circuit, and the source is connected to the gate of the common source circuit 4 and the drain of the second field effect transistor M4 respectively;

[0058] The gate of the second field effect transistor M4 is grounded through the first resistor R5 and connected to the control voltage through the second resistor R6 . The source of the second field effect transistor M4 is grounded. The drain of the second field effect transistor M4 is also connected to the gate of the common-gate circuit 3 .

[0059] In addition, the bias circuit may further include a first voltage stabilizing module 7, which is connected in parallel to the common source circuit 4; the first voltage stabilizing module 7 is used to provide a stable voltage reference to stabilize the voltage of the common source circuit 4;

[0060] The bias circuit may further include a second voltage stabilizing module 8 , which is connected in parallel to the common-gate circuit 3 ; the second voltage stabilizing module 8 is configured to provide a stable voltage reference to stabilize the voltage of the common-gate circuit 3 .

[0061] Specifically, the first voltage stabilizing module 7 includes a first voltage stabilizing device group; the first voltage stabilizing devices are connected in series and then connected in parallel to the gate of the common source circuit 4; the second voltage stabilizing module 8 includes a second voltage stabilizing device group; the second voltage stabilizing devices are connected in series and then connected in parallel to the gate of the common gate circuit 3.

[0062] In an optional embodiment, the bias circuit may further include a first decoupling module 9, which is connected in parallel to the common source circuit 4; the first decoupling module 9 is used to perform radio frequency decoupling on the bias circuit and the common source circuit 4 to improve the stability of the common source circuit;

[0063] The bias circuit further includes a second decoupling module 10 , which is connected in parallel to the common-gate circuit 3 ; the second decoupling module is used to perform radio frequency decoupling between the bias circuit and the common-gate circuit 3 to improve the stability of the common-gate circuit.

[0064] In this embodiment, the first decoupling module 9 includes at least one first capacitor C1, one end of the first capacitor C1 is connected to the gate of the common-source circuit 4, and the other end is grounded; the second decoupling module 10 includes at least one second capacitor C2, one end of the second capacitor C2 is connected to the gate of the common-gate circuit, and the other end is grounded.

[0065] The bias circuit is further described below with reference to Figure 2. A high-frequency RF signal enters the matching circuit 5 and then enters the G electrode (gate) of the field-effect transistor M1 in the common-source circuit 4. The S electrode (source) of the field-effect transistor M1 is connected to the inductor L2 and then to ground. The D electrode (drain) of the field-effect transistor M1 is connected to the S electrode of the field-effect transistor M2 in the common-gate circuit 3. One side of the D electrode of the field-effect transistor M2 is connected to the inductor L1 and then to the power supply voltage VCC, and the other side is connected to the output matching circuit 6 for signal output. The gates of the field-effect transistors M1 and M2 are connected to the bias circuit. After passing through the bias resistor R1, the gate of the field effect transistor M1 is first connected in parallel to the first capacitor C1 of the first decoupling module 9 and connected to the ground. Then, a first field effect transistor M3 of the bias current providing module 2 connected in series with a resistor R2 is connected in parallel. After passing through a series resistor R3, a group of series-connected diodes D1 to D1n (n≥1) of the first voltage stabilizing module 7 are connected in parallel and then connected to the ground. Then, the signal is connected to the S electrode of the third field effect transistor M5 of the switch unit 11 through the resistor R4. The D electrode of the third field effect transistor M5 is connected to the power supply voltage VCC, and the G electrode of the third field effect transistor M5 is connected to the control voltage required by the circuit. The signal on one side of the S-pole of the third field-effect transistor M5 is connected to the G-pole of the field-effect transistor M1, and on the other side, the signal is connected in parallel to the second field-effect transistor M4 of the leakage suppression unit 12. The G-pole of the second field-effect transistor M4 is connected to the resistor R5. The S-pole of the second field-effect transistor M4 and the other end of the resistor R5 are connected to the ground. The G-pole of the second field-effect transistor M4 is also connected in series with the resistor R6 to the control voltage. The signal passes through the series resistor R7 and then in parallel with a series resistor R8 and diodes D2 to D2n (n≥1) of the second voltage stabilization module 8, and then connected to the ground. It is then connected to the G-pole of the field-effect transistor M2 through the series resistor R9, and the second capacitor C2 of the second decoupling module 10 is connected in parallel at the G-pole of the field-effect transistor M2 to connect to the ground.

[0066] It is worth noting that in this embodiment, field-effect transistors M1, M2, M3, and M4 can be E-mode (enhancement-mode) devices, and field-effect transistor M5 can be a D-mode (depletion-mode) device. Field-effect transistors M3 and M4 only require minimal footprint to achieve their functions. This embodiment does not limit the type of transistors used in the bias circuit. The bias circuit can also use CMOS (Complementary Metal Oxide Semiconductor) transistors or other low-noise devices, or a mixture of different transistor types. Please refer to FIG3 , which is a third schematic diagram of the bias circuit for a low-noise amplifier in this embodiment. The resistor used in the bias circuit of this embodiment can be replaced with other devices having the same function. Please refer to Figure 4, which is a fourth structural schematic diagram of the bias circuit for the low-noise amplifier in this embodiment. The diode used in the bias circuit of this embodiment can be replaced with other devices having the same voltage-stabilizing characteristics, such as a PHEMT E-mode (pseudo-high electron mobility enhanced) device G connected in parallel with DS to form a voltage-stabilizing device. Please refer to Figure 5, which is a fifth structural schematic diagram of the bias circuit for the low-noise amplifier in this embodiment, or a transistor connected in parallel with the emitter to form a voltage-stabilizing device. Please refer to Figure 6, which is a sixth structural schematic diagram of the bias circuit for the low-noise amplifier in this embodiment. The circuits other than the bias circuit (in the dotted box) in this embodiment are for reference only, but this embodiment does not limit them.

[0067] In addition, please refer to Figure 7, which is a seventh schematic diagram of the bias circuit for a low-noise amplifier in this embodiment. The second capacitor C2 of the second decoupling module can also be connected in series with a resistor R10 and then to ground, and the first capacitor C1 of the first decoupling module can also be connected in series with a resistor R11 and then to ground, further adjusting the RF stability of the LNA. Please refer to Figure 8, which is an eighth schematic diagram of the bias circuit for a low-noise amplifier in this embodiment. The series resistor 9 can also be replaced with a series inductor L4, and the series resistor 1 can also be replaced with a series inductor L3. Please refer to Figure 9, which is a ninth structural diagram of the bias circuit for a low-noise amplifier in this embodiment. In the first voltage stabilization module, resistor R4 cooperates with diodes D1 to D1n connected in series to achieve gate voltage stabilization of field-effect transistor M1. In the second voltage stabilization module, resistor R8 cooperates with diodes D2 to D2n connected in series to achieve gate voltage stabilization of field-effect transistor M2. If the control circuit voltage is relatively stable, the bias circuit may not be configured with the first voltage stabilization module and / or the second voltage stabilization module. Resistor R8 may be added to the second decoupling module, and resistor R8 is connected in parallel to ground to adjust the required voltage for the gate of field-effect transistor M2.

[0068] The bias circuit for a low-noise amplifier provided in this embodiment uses a bias current providing module to provide a current bias to stabilize the low-noise amplifier's current when a current offset occurs in the common-source circuit under high and low-temperature conditions. Furthermore, the bias circuit control module suppresses voltage and / or current leakage in the common-gate circuit when the bias circuit is turned off, thereby achieving the goal of stabilizing the LNA's operating current under high and low-temperature conditions. Furthermore, by configuring a voltage stabilizing module and a decoupling module for the common-source circuit and the common-gate circuit, respectively, a stable voltage reference is provided for the LNA under high and low-temperature conditions, enhancing the LNA's radio frequency stability without negatively impacting the LNA's radio frequency scattering parameters or noise figure, thereby ensuring the performance and quality of the LNA product under high and low-temperature conditions.

[0069] Example 2

[0070] This embodiment provides a radio frequency low noise amplifier, which includes the bias circuit for the low noise amplifier in Embodiment 1.

[0071] The bias circuit of the radio frequency low noise amplifier provided in the embodiment achieves the goal of stabilizing the LNA operating current in high and low temperature environments by utilizing the bias circuit for the low noise amplifier described above, thereby ensuring the performance and quality of the LNA product in high and low temperature environments.

[0072] Although specific embodiments of the present invention have been described above, those skilled in the art will appreciate that these are merely illustrative and that the scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, and such changes and modifications are intended to fall within the scope of the present invention.

Claims

1. A bias circuit for a low-noise amplifier, characterized in that, the bias circuit includes a bias circuit control module and a bias current providing module; the bias current providing module is connected to a power supply through the bias circuit control module; the bias circuit control module is connected to the common-gate circuit of the low-noise amplifier, and the bias circuit control module is used to control the opening or closing of the bias circuit and suppress voltage leakage and / or current leakage of the common-gate circuit when the bias circuit is closed; the bias current providing module is connected to the common-source circuit of the low-noise amplifier, and the bias current providing module is used to provide a current bias in response to a current offset of the low-noise amplifier to stabilize the current of the low-noise amplifier.

2. The bias circuit according to claim 1, characterized in that, the bias current providing module forms a current mirror to provide a current bias to the common-source circuit according to a reference current and the current offset.

3. The bias circuit according to claim 1, characterized in that, the bias current providing module includes a first field-effect transistor; the first field-effect transistor is connected to a power supply through the bias circuit control module; the first field-effect transistor is connected in parallel to the gate of the common-source circuit.

4. The bias circuit according to claim 1, characterized in that, the bias circuit control module includes a switch unit and a leakage suppression unit; one end of the switch unit is connected to a power supply, and the other end of the switch unit is connected to one end of the leakage suppression unit and the bias current providing module; the other end of the leakage suppression unit is connected to the control end of the common-gate circuit; the switch unit is used to control the opening or closing of the bias circuit; the leakage suppression unit is used to suppress voltage leakage and / or current leakage of the common-gate circuit by pulling down the voltage of the control end of the common-gate circuit when the bias circuit is closed.

5. The bias circuit according to claim 4, characterized in that, the leakage suppression unit includes a second field-effect transistor, and the switch unit includes a third field-effect transistor; the drain of the third field-effect transistor is connected to a power supply, the gate is connected to the control voltage required by the bias circuit, and the source is connected to the gate of the common-source circuit and the drain of the second field-effect transistor respectively; the gate of the second field-effect transistor is grounded through a first resistor and connected to the control voltage through a second resistor, the source of the second field-effect transistor is grounded, and the drain of the second field-effect transistor is also connected to the gate of the common-gate circuit.

6. The bias circuit according to claim 1, characterized in that, the bias circuit further includes a first voltage stabilizing module, and the first voltage stabilizing module is connected in parallel to the common-source circuit; the first voltage stabilizing module is used to provide a stable voltage reference to stabilize the voltage of the common-source circuit; and / or, the bias circuit further includes a second voltage stabilizing module, and the second voltage stabilizing module is connected in parallel to the common-gate circuit; the second voltage stabilizing module is used to provide a stable voltage reference to stabilize the voltage of the common-gate circuit.

7. The bias circuit according to claim 6, characterized in that, The first voltage regulation module includes a first voltage regulator component group; the first voltage regulator components are connected in series with each other and then connected in parallel to the gate of the common-source circuit; and / or, The second voltage regulation module includes a second voltage regulator component group; the second voltage regulator components are connected in series with each other and then connected in parallel to the gate of the common-gate circuit.

8. The bias circuit according to claim 1, characterized in that, the bias circuit further includes a first decoupling module, and the first decoupling module is connected in parallel to the common-source circuit; the first decoupling module is used for performing radio frequency decoupling on the bias circuit and the common-source circuit to improve the stability of the common-source circuit; and / or, the bias circuit further includes a second decoupling module, and the second decoupling module is connected in parallel to the common-gate circuit; the second decoupling module is used for performing radio frequency decoupling on the bias circuit and the common-gate circuit to improve the stability of the common-gate circuit.

9. The bias circuit according to claim 8, characterized in that, the first decoupling module includes at least one first capacitor, one end of the first capacitor is connected to the gate of the common-source circuit, and the other end is grounded; and / or, the second decoupling module includes at least one second capacitor, one end of the second capacitor is connected to the gate of the common-gate circuit, and the other end is grounded.

10. A radio frequency low noise amplifier, characterized in that, the radio frequency low noise amplifier includes the bias circuit for a low noise amplifier according to any one of claims 1-9.

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