Nuclear magnetic resonance pre-amplifier circuit

Abstract

The invention relates to the technical field of nuclear magnetic resonance, and discloses a nuclear magnetic resonance preamplifier circuit which comprises a gating module and a first-stage amplification submodule. The gating signal end of the gating module is connected to the control end of the third switching tube and the control end of the fourth switching tube through a first resistor; a second power supply end is connected to a second node through a sixth resistor and a second inductor; the second node is grounded through the first switching tube; a second power supply end is connected to a second node through a sixth resistor and a second inductor; and the second node is also grounded through a fifth capacitor. A gating control signal is added on the basis of the low-noise amplifier, and bias voltage of the first switching tube is closed or opened in a radio-frequency transmitting mode and a radio-frequency receiving mode respectively, so that closing and working conversion time, namely recovery time, is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear magnetic resonance, and in particular to a nuclear magnetic resonance preamplifier circuit. Background Art

[0002] Nuclear magnetic resonance technology is a non-destructive testing technology widely used in the field of analysis and imaging. When performing nuclear magnetic resonance analysis, the measurement and analysis of the shortest relaxation signal is an important factor in the evaluation of equipment performance indicators. Therefore, the preamplifier has two important indicators: one is low noise coefficient and high signal-to-noise ratio; the other is fast recovery time. Specifically, the preamplifier is a weak signal low-noise amplifier. When the radio frequency is transmitted, there is still a large signal entering the preamplifier after passing through the radio frequency coil and TR switch, which will cause the preamplifier to saturate. At this time, the relaxation signal will be filtered out by the saturated preamplifier and cannot be transmitted to the receiver for analysis after amplification; on the other hand, it takes about 50-100us for the commonly used preamplifier to enter the saturation state and then return to the normal linear region amplification state. This makes the short relaxation signal within 50us or even within 10us destined to be submerged in the saturated preamplifier and difficult to detect.

[0003] At present, the above problems are usually solved by the following two modes: one is to use a large signal preamplifier so that the large signal behind the TR switch still works in the linear region after entering the preamplifier. The disadvantage of this method is that the large signal preamplifier generally has a large noise coefficient and a low signal-to-noise ratio. The second method is to add a fast RF switch between the TR switch and the preamplifier to improve isolation, reduce the large signal entering the preamplifier to the weak signal range, and keep the preamplifier working in the linear region. Compared with the first mode, this method has greatly improved the overall noise coefficient and signal-to-noise ratio, but the disadvantage is that the newly added RF switch has insertion loss, which increases the noise coefficient and reduces the signal-to-noise ratio. Summary of the invention

[0004] In view of this, the present invention provides a nuclear magnetic resonance preamplifier circuit to solve the problems of long fast recovery time and low noise and high signal-to-noise ratio of the current preamplifier.

[0005] In a first aspect, the present invention provides a nuclear magnetic resonance preamplifier circuit, comprising: a gate control module and a first-stage amplification submodule;

[0006] The gate control module includes: a first resistor, a second resistor, a third switch tube and a fourth switch tube, the gate control signal end of the gate control module is connected to the control end of the third switch tube and the control end of the fourth switch tube through the first resistor; the gate control signal end of the gate control module is also grounded through the first resistor and the second resistor, the first power supply end is connected to the first node through the third switch tube; the first node is grounded through the fourth switch tube; the first node is connected to the control end of the first switch tube through the bias circuit;

[0007] In the first-stage amplifier circuit, the RF input terminal is connected to the first terminal of the first inductor; the first terminal of the first inductor is grounded through the first capacitor; the second terminal of the first inductor is grounded through the second capacitor; the second terminal of the first inductor is also connected to the control terminal of the first switch tube through the third capacitor; the control terminal of the first switch tube is also connected to the first node through the bias circuit;

[0008] The second power supply terminal is connected to the second node through the sixth resistor and the second inductor; the second node is grounded through the first switch tube; the second node is also grounded through the fifth capacitor; the second node is connected to the first end of the third inductor; the second end of the third inductor is grounded through the seventh capacitor; the second end of the third inductor is connected to the RF output terminal.

[0009] The nuclear magnetic resonance preamplifier circuit provided by the embodiment of the present invention adds a GATE gate control signal on the basis of a low noise amplifier, and the gated GATE signal sends a high level in the transmission time period, and quickly turns off the bias voltage of the first switch tube after passing through the first resistor, the second resistor, the third switch tube and the fourth switch tube, so that its working mode is in a closed state, that is, the working current will not be in a saturated state, and there is no saturation recovery problem, thereby improving the fast recovery time in the transmission and receiving modes. In the receiving mode, the gated GATE signal sends a low level, and after passing through the first resistor, the second resistor, the third switch tube and the fourth switch tube, the bias voltage of the first switch tube is turned on after amplification and driving, so that the first switch tube is in a working amplification state, so as to improve the closing and working conversion time, that is, the recovery time. Preferably, after reasonable debugging of each circuit parameter, the recovery time can be controlled within 2uS.

[0010] In an optional implementation, the first switch tube and the fourth switch tube are NMOS tubes; and the third switch tube is a PMOS tube.

[0011] In the nuclear magnetic resonance preamplifier circuit provided by the embodiment of the present invention, when the GATE signal is at a high level, the third switch tube PMOS tube will be turned off, thereby blocking the path from the power supply to the first node; at the same time, the fourth switch tube NMOS tube will be turned on, pulling the first node to a low potential, which can effectively turn off the bias voltage of the first switch tube of the first-stage amplifier. On the contrary, when the GATE signal is at a low level, the third switch tube PMOS tube is turned on to provide a path from the power supply to the first node, and the NMOS tube is turned off, thereby turning on the bias voltage of the first switch tube.

[0012] In an optional implementation, the bias circuit includes a third resistor, a fourth resistor, and a fifth resistor;

[0013] The first node is grounded through the third resistor and the fifth resistor; the first node is connected to the control end of the first switch tube through the third resistor and the fourth resistor.

[0014] In the NMR preamplifier circuit provided by the embodiment of the present invention, the stability of the bias circuit can optimize the stability of the amplifier, reduce the performance changes caused by the bias voltage fluctuation, and provide a larger circuit parameter adjustment space. Designers can fine-tune the performance of the amplifier, such as gain, linearity, etc., by changing the resistance values ​​of these resistors to meet different application requirements.

[0015] In an optional implementation, the first node is further grounded via a third resistor and a fourth capacitor.

[0016] In the nuclear magnetic resonance preamplifier circuit provided by the embodiment of the present invention, the third resistor and the fourth capacitor form an RC network, which helps to stabilize the voltage of the first node and prevent voltage mutations caused by power supply voltage fluctuations or other external interference, thereby improving the stability of the entire circuit.

[0017] In an optional embodiment, the nuclear magnetic resonance preamplifier circuit also includes a first diode and a second diode; the RF input terminal is connected to the cathode of the first diode; the anode of the first diode is grounded; the RF input terminal is connected to the anode of the second diode; and the cathode of the second diode is grounded.

[0018] The nuclear magnetic resonance preamplifier circuit provided by the embodiment of the present invention forms a diode pair by means of a first diode, a first diode and a second diode, so as to effectively limit the amplitude of the input signal and prevent excessively high radio frequency signals from damaging a low noise amplifier or other sensitive components.

[0019] In an optional embodiment, the nuclear magnetic resonance preamplifier circuit also includes a third diode and a fourth diode; the second end of the first inductor is connected to the cathode of the third diode; the anode of the third diode is grounded; the second end of the first inductor is connected to the anode of the fourth diode; and the cathode of the fourth diode is grounded.

[0020] In the nuclear magnetic resonance preamplifier circuit provided by the embodiment of the present invention, the third diode and the fourth diode form a diode pair, which can be used as a limiter to limit the amplitude of the input signal to prevent excessive signals from damaging the amplifier. Therefore, it can not only protect the low-noise amplifier, but also improve the signal processing stability and reliability of the entire circuit.

[0021] In an optional implementation, the circuit further includes a second-stage amplifier circuit, and the second end of the third inductor is connected to the radio frequency output end through the second-stage amplifier circuit.

[0022] In an optional implementation, the second stage amplification circuit includes an eighth capacitor, an integrated amplifier; a seventh resistor, a fifth inductor and a ninth capacitor;

[0023] The second end of the third inductor is connected to the third node through the eighth capacitor and the integrated amplifier; the third node is connected to the RF output terminal through the ninth capacitor; and the second power supply terminal is connected to the third node through the seventh resistor and the fifth inductor.

[0024] The nuclear magnetic resonance preamplifier circuit provided in the embodiment of the present invention can further improve the gain of the entire amplifier by adding a second-stage amplifier circuit. In addition, the signal is further optimized and shaped by the second-stage amplifier circuit.

[0025] In an optional implementation manner, the second end of the third inductor is further grounded through a seventh capacitor.

[0026] In the nuclear magnetic resonance preamplifier circuit provided by the embodiment of the present invention, the seventh capacitor, as a part of the output matching circuit, can help optimize the waveform and amplitude of the output signal, that is, by adjusting the capacitance of the capacitor, the distortion and reflection of the signal can be further reduced, and the purity and transmission efficiency of the signal can be improved.

[0027] In an optional implementation, the second power supply terminal is grounded through a tenth capacitor; the second power supply terminal is also grounded through an eleventh capacitor; the second power supply terminal is connected to the second node through a fourth inductor, a sixth resistor and a second inductor in sequence.

[0028] In the nuclear magnetic resonance preamplifier circuit provided by the embodiment of the present invention, the tenth capacitor and the eleventh capacitor serve as decoupling capacitors, which can further reduce noise and fluctuations on the power line and provide a more stable power supply voltage for the circuit. By adding the fourth inductor, transient changes at the power supply end can be isolated to a certain extent to smooth the power supply voltage and reduce circuit instability caused by power supply fluctuations. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 is a schematic diagram of a nuclear magnetic resonance preamplifier circuit according to an embodiment of the present invention;

[0031] Figure 2 is a circuit diagram of a nuclear magnetic resonance preamplifier circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0033] In the field of nuclear magnetic resonance analysis, the capture and measurement of the shortest relaxation signal is an important evaluation indicator of the equipment performance. This requires that the equipment must have a low noise coefficient and a high signal-to-noise ratio to prevent the relaxation signal from being filtered by a saturated preamplifier. On the other hand, it also requires a faster recovery time to prevent the short relaxation signal from being overwhelmed by the response time.

[0034] After patent retrieval and data search, the inventors found that there are currently two commonly used modes that have certain defects in optimizing the above problems. Specifically, using a large-signal preamplifier can be relatively simple and crude to make the large signal behind the TR switch still work in the linear region after entering the preamplifier. However, the large-signal preamplifier generally has a relatively large noise coefficient and it is difficult to meet the requirements of low signal-to-noise ratio; another method is to add a fast RF switch between the TR switch and the preamplifier to improve isolation, reduce the large signal entering the preamplifier to the weak signal range, and keep the preamplifier working in the linear region. This method has a significant improvement in overall noise coefficient and signal-to-noise ratio compared to the previous method. However, the newly added RF switch has insertion loss, which will increase the noise coefficient and reduce the signal-to-noise ratio.

[0035] According to an embodiment of the present invention, a nuclear magnetic resonance preamplifier circuit embodiment is provided, the nuclear magnetic resonance preamplifier circuit comprising: a gate control module and a first-stage amplification submodule;

[0036] The gate control module includes: a first resistor R1, a second resistor R2, a third switch tube Q3 and a fourth switch tube Q4, the gate control signal end of the gate control module is connected to the control end of the third switch tube Q3 and the control end of the fourth switch tube Q4 through the first resistor R1; the gate control signal end of the gate control module is also grounded through the first resistor R1 and the second resistor R2, the first power supply end is connected to the first node through the third switch tube Q3; the first node is grounded through the fourth switch tube Q4; the first node is connected to the control end of the first switch tube Q1 through the bias circuit;

[0037] In the first-stage amplifier circuit, the RF input terminal is connected to the first terminal of the first inductor L1; the first terminal of the first inductor L1 is grounded through the first capacitor C1; the second terminal of the first inductor L1 is grounded through the second capacitor C2; the second terminal of the first inductor L1 is also connected to the control terminal of the first switch tube Q1 through the third capacitor C3; the control terminal of the first switch tube Q1 is also connected to the first node through the bias circuit;

[0038] The second power supply terminal is connected to the second node through the sixth resistor R6 and the second inductor L2; the second node is grounded through the first switch tube Q1; the second node is also grounded through the fifth capacitor C5; the second node is connected to the first end of the third inductor L3; the second end of the third inductor L3 is grounded through the seventh capacitor C7; the second end of the third inductor L3 is connected to the RF output terminal.

[0039] The schematic diagram of the NMR preamplifier circuit is as follows: Figure 1 As shown, it consists of a gate signal and a low-noise preamplifier.

[0040] NMR preamplifier circuit Figure 2 As shown, specifically, the circuit is composed of a gating module and a first-stage amplifier module, wherein the gating module uses a first resistor R1, a second resistor R2, a third switch tube Q3 and a fourth switch tube Q4 to control the gating signal, and the signal is connected to the control ends of Q3 and Q4 respectively through R1, and is grounded through R1 and R2 at the same time to adjust the bias voltage of the first switch tube Q1; the first-stage amplifier module includes a radio frequency input end, a first inductor L1, a first capacitor C1, a second capacitor C2 and a third capacitor C3, a first switch tube Q1 and a second inductor L2, a sixth resistor R 6 and other components, the RF signal is input through the first inductor L1, and is grounded through C1 and C2 to form an input matching, the third capacitor C3 is connected to the Q1 control terminal for signal amplification, and the bias voltage of Q1 is controlled by the gating module to achieve fast opening or closing; in addition, the second power supply terminal is powered to the second node through R6 and L2, the node is grounded through Q1, and is connected to the RF output terminal through L3 and C7 to form an output matching circuit, thereby ensuring a fast recovery time in the transmitting and receiving modes. Preferably, after reasonable debugging of each circuit parameter, the recovery time can be controlled within 2uS.

[0041] In some optional implementations, the first switch tube and the fourth switch tube are NMOS tubes; and the third switch tube is a PMOS tube.

[0042] The nuclear magnetic resonance preamplifier circuit can optionally use an NMOS tube as the fourth switch tube Q4, and the third switch tube Q3 uses a PMOS tube. In this configuration, when the gated GATE signal is at a high level, the PMOS tube Q3 is turned on, so that the current at the first power supply end can flow to the first node through Q3, and then provide a bias voltage for the first switch tube Q1 through the bias circuit, but because the GATE signal acts on the control ends of Q3 and Q4 at the same time, the NMOS tube Q4 is also in a conducting state to pull the first node to the ground potential, which actually turns off the bias of the first switch tube Q1, so that Q1 stops amplifying the radio frequency signal. On the contrary, in the receiving mode, the GATE signal is at a low level, the PMOS tube Q3 is turned off, and the NMOS tube Q4 is also turned off due to the low-level signal. At this time, the first node obtains an appropriate bias voltage through other bias resistors, so that Q1 is in an amplifying state. The combined use of this NMOS and PMOS tubes realizes the fast and reliable switching of the working state of the low-noise amplifier in the transmitting and receiving modes.

[0043] In some optional embodiments, the bias circuit includes a third resistor, a fourth resistor, and a fifth resistor;

[0044] The first node is grounded through the third resistor and the fifth resistor; the first node is connected to the control end of the first switch tube through the third resistor and the fourth resistor.

[0045] The bias circuit is composed of a third resistor R3, a fourth resistor R4 and a fifth resistor R5, wherein the first node is not only grounded through the series path of the third resistor R3 and the fifth resistor R5 to form a bias voltage divider, but also connected to the control end of the first switch tube Q1 through the series path of the third resistor R3 and the fourth resistor R4, so as to accurately control the operating point voltage of Q1, ensuring that Q1 can stably and efficiently amplify the RF signal in the receiving mode, and at the same time quickly cut off its bias voltage through the gating signal in the transmitting mode to achieve rapid recovery.

[0046] In some optional implementations, the first node is also grounded via a third resistor R3 and a fourth capacitor C4.

[0047] An RC network consisting of a third resistor R3 and a fourth capacitor C4 is added between the first node and the ground, which provides an additional grounding path for the first node, helps to stabilize the potential of the first node, and can also effectively bypass the high-frequency noise in the circuit through the fourth capacitor C4, further improving the anti-interference ability and stability of the circuit.

[0048] In some optional embodiments, the nuclear magnetic resonance preamplifier circuit also includes a first diode and a second diode; the RF input terminal is connected to the cathode of the first diode; the anode of the first diode D1 is grounded; the RF input terminal is connected to the anode of the second diode; and the cathode of the second diode D2 is grounded.

[0049] A bidirectional limiting protection circuit consisting of a first diode D1 and a second diode D2 is added to the RF input end. The cathode of the first diode D1 is connected to the RF input end, and the anode is grounded, which is used to limit the forward overvoltage of the RF input signal; the anode of the second diode D2 is connected to the RF input end, and the cathode is grounded, which is used to limit the negative overvoltage of the RF input signal. Such a design can effectively protect the low-noise amplifier from possible damage caused by excessive RF input signals, thereby improving the reliability and stability of the entire circuit.

[0050] In some optional embodiments, the nuclear magnetic resonance preamplifier circuit also includes a third diode D3 and a fourth diode D4; the second end of the first inductor L1 is connected to the cathode of the third diode D3; the anode of the third diode D3 is grounded; the second end of the first inductor L1 is connected to the anode of the fourth diode D4; and the cathode of the fourth diode D4 is grounded.

[0051] A bidirectional protection circuit consisting of a third diode D3 and a fourth diode D4 is added to the second end of the first inductor L1. The cathode of the third diode D3 is connected to the second end of the first inductor L1, and the anode is grounded, which is used to provide protection at the positive peak of the RF signal; the anode of the fourth diode D4 is connected to the second end of the first inductor L1, and the cathode is grounded, which is used to provide protection at the negative peak of the RF signal. Such a design can effectively prevent the RF signal from being too large and damaging the subsequent amplification circuit, thereby improving the reliability and stability of the entire nuclear magnetic resonance preamplifier circuit.

[0052] In some optional implementations, the circuit further includes a second-stage amplifier circuit, and the second end of the third inductor is connected to the radio frequency output end through the second-stage amplifier circuit.

[0053] The nuclear magnetic resonance preamplifier circuit of the present invention further comprises a second-stage amplifier circuit, which is connected to the output end of the first-stage amplifier circuit, namely, the second end of the third inductor L3, and transmits the amplified radio frequency signal to the radio frequency output end.

[0054] In some optional implementations, the second stage amplification circuit includes an eighth capacitor, an integrated amplifier; a seventh resistor, a fifth inductor and a ninth capacitor;

[0055] The second end of the third inductor is connected to the third node through the eighth capacitor and the integrated amplifier; the third node is connected to the RF output terminal through the ninth capacitor; and the second power supply terminal is connected to the third node through the seventh resistor and the fifth inductor.

[0056] The second-stage amplifier circuit is specifically composed of the eighth capacitor C8, the integrated amplifier Q2, the seventh resistor R7, the fifth inductor L5 and the ninth capacitor C9. Among them, the second end of the third inductor L3 is first connected to the input end of the integrated amplifier Q2 through the eighth capacitor C8 to form the input of the signal; the output end of the integrated amplifier Q2 is connected to the third node, and the node is connected to the RF output end through the ninth capacitor C9 to achieve the output of the signal. At the same time, in order to provide the bias voltage for the normal operation of the integrated amplifier Q2, the second power supply end is connected to the third node through the seventh resistor and the fifth inductor to ensure that the integrated amplifier Q2 can stably amplify the RF signal at a suitable voltage. Such a design not only enhances the amplification effect of the signal, but also optimizes the matching performance of the circuit, so that the entire preamplifier circuit has higher sensitivity and stability in nuclear magnetic resonance applications. Specifically, the integrated amplifier Q2 can use an integrated internal matching amplifier with a frequency range of DC-4GHz, an internal matching impedance of 50 ohms, a gain of 20dB, and a P1dB output of 15dBm.

[0057] In some optional implementations, the second end of the third inductor L3 is also grounded through a seventh capacitor C7.

[0058] The second end of the third inductor L3 is connected to the RF output terminal and grounded through the seventh capacitor C7. This design helps to improve the impedance matching of the circuit and improve the signal transmission efficiency. At the same time, the second stage amplifier circuit is connected to the second end of the third inductor L3 to ensure further amplification of the signal.

[0059] In some optional embodiments, the second power supply terminal is grounded through the tenth capacitor C10; the second power supply terminal is also grounded through the eleventh capacitor C11; the second power supply terminal is connected to the second node through the fourth inductor L4, the sixth resistor R6 and the second inductor L2 in sequence.

[0060] The second power supply terminal is not only grounded through the tenth capacitor C10 and the eleventh capacitor C11 to provide additional filtering and stabilization, but is also connected to the second node through the fourth inductor L4, the sixth resistor R6 and the second inductor L2 in sequence. Such a design helps to improve the power supply quality of the power supply and reduce the impact of power supply noise on circuit performance, thereby further improving the stability and gain performance of the low noise amplifier.

[0061] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A nuclear magnetic resonance preamplifier circuit, characterized in that: The nuclear magnetic resonance preamplifier circuit comprises: a gate control module and a first-stage amplification submodule; The gate control module comprises: a first resistor, a second resistor, a third switch tube and a fourth switch tube, the gate control signal end of the gate control module is connected to the control end of the third switch tube and the control end of the fourth switch tube through the first resistor; the gate control signal end of the gate control module is also grounded through the first resistor and the second resistor, the first power supply end is connected to the first node through the third switch tube; the first node is grounded through the fourth switch tube; the first node is connected to the control end of the first switch tube through the bias circuit; In the first-stage amplifier circuit, the RF input terminal is connected to the first terminal of the first inductor; the first terminal of the first inductor is grounded through the first capacitor; the second terminal of the first inductor is grounded through the second capacitor; the second terminal of the first inductor is also connected to the control terminal of the first switch tube through the third capacitor; the control terminal of the first switch tube is also connected to the first node through the bias circuit; The second power supply terminal is connected to the second node through the sixth resistor and the second inductor; the second node is grounded through the first switch tube; the second node is also grounded through the fifth capacitor; the second node is connected to the first end of the third inductor; the second end of the third inductor is grounded through the seventh capacitor; the second end of the third inductor is connected to the RF output terminal.

2. The circuit according to claim 1, characterized in that The first switch tube and the fourth switch tube are NMOS tubes; the third switch tube is a PMOS tube.

3. The circuit according to claim 2, characterized in that The bias circuit includes a third resistor, a fourth resistor and a fifth resistor; The first node is grounded through the third resistor and the fifth resistor; the first node is connected to the control end of the first switch tube through the third resistor and the fourth resistor.

4. The circuit according to claim 3, characterized in that The first node is also grounded through the third resistor and the fourth capacitor.

5. The circuit according to claim 2, characterized in that The nuclear magnetic resonance preamplifier circuit also includes a first diode and a second diode; the radio frequency input end is connected to the cathode of the first diode; the anode of the first diode is grounded; the radio frequency input end is connected to the anode of the second diode; and the cathode of the second diode is grounded.

6. The circuit according to claim 2, characterized in that The nuclear magnetic resonance preamplifier circuit also includes a third diode and a fourth diode; the second end of the first inductor is connected to the cathode of the third diode; the anode of the third diode is grounded; the second end of the first inductor is connected to the anode of the fourth diode; the cathode of the fourth diode is grounded.

7. The circuit according to any one of claims 1 to 6, characterized in that: The circuit also includes a second-stage amplifier circuit, and the second end of the third inductor is connected to the radio frequency output end through the second-stage amplifier circuit.

8. The circuit according to claim 7, characterized in that The second-stage amplifier circuit includes an eighth capacitor, an integrated amplifier, a seventh resistor, a fifth inductor and a ninth capacitor; The second end of the third inductor is connected to the third node through the eighth capacitor and the integrated amplifier; the third node is connected to the RF output end through the ninth capacitor; The second power supply terminal is connected to the third node through the seventh resistor and the fifth inductor.

9. The circuit according to claim 7, characterized in that The second end of the third inductor is also grounded through a seventh capacitor.

10. The circuit according to claim 7, characterized in that The second power supply terminal is grounded through a tenth capacitor; the second power supply terminal is also grounded through an eleventh capacitor; the second power supply terminal is connected to the second node through a fourth inductor, a sixth resistor and a second inductor in sequence.

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