High-frequency high-gain low-noise amplifier with stepless matching function

Abstract

The invention belongs to the field of radio frequency integrated circuits, and particularly relates to a high-frequency high-gain two-stage low-noise amplifier without using inter-stage matching. The low-noise amplifier comprises a blocking capacitor, an input matching circuit, a first-stage amplifying circuit, a gain flatness adjusting inductor and a second-stage amplifying circuit. The blocking capacitor prevents direct current signals from interfering radio frequency input signals, the input matching circuit achieves simultaneous matching of power and noise, the first-stage amplifying circuit amplifies the radio frequency signals for the first time, the second-stage amplifying circuit amplifies the signals for the second time, the gain flatness adjusting inductor is connected between the first stage amplifying circuit and the second stage amplifying circuit, and the gain flatness is improved. The drain electrode (output) of the first-stage amplifier tube and the grid electrode of the second-stage amplifier tube share the same bias voltage instead of providing independent power supply voltage for the drain electrode of the first stage, so that the complex design process of inter-stage matching is avoided, meanwhile, the use of a transformer is avoided, and the area and the cost of a chip are reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of radio frequency integrated circuits, and in particular relates to a high-frequency, high-gain, low-noise amplifier without inter-stage matching. Background Art

[0002] The low noise amplifier (LNA) is a key component of the RF receiving front end. Its function is to amplify the RF signal sufficiently under the premise of generating the lowest possible noise to reduce the impact of the noise generated by the subsequent modules (such as mixers) on the RF signal. Therefore, low noise and high gain are the basic requirements of LNA.

[0003] In order to achieve higher gain, two-stage LNA is necessary, so conjugate matching is also required between the two stages to reduce reflection. However, at high frequencies (millimeter wave band), parasitic effects will become more prominent, and due to the limited gain of the first stage, the noise contribution of the second stage can no longer be ignored. Therefore, multi-stage noise matching technology can be used to further reduce the noise coefficient introduced by the second stage, thereby achieving a lower noise coefficient. That is, at high frequencies, noise matching is also required between the two stages.

[0004] In order to achieve conjugate matching and noise matching between the two poles at the same time, transformers are used in many technical solutions, such as placing one coil of the transformer between the two poles and the other pole coil at the input; or placing both coils between the two poles. However, the design of the transformer is relatively complicated. Under a given process, it is a very complicated and tedious process to design a transformer that meets the five parameters of the main coil inductance, the main coil quality factor, the coupling coefficient, the secondary coil inductance and the secondary coil quality factor. In addition, the manufacturing cost of the transformer is high, and it occupies a large area, which greatly increases the chip cost. Summary of the invention

[0005] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a high-frequency, high-gain, low-noise amplifier without inter-stage matching, which is a high-frequency, high-gain, two-stage LNA that does not require inter-stage matching. By sharing the same bias voltage for the first-stage output and the second-stage input instead of providing a separate power supply voltage for the first stage, the complex design process of inter-stage matching is avoided, the use of complex structure transformers is avoided, the design process is simplified, and the chip cost is reduced.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A high-frequency, high-gain, low-noise amplifier without inter-stage matching, comprising a series of cascaded DC-isolating capacitors C blockin , input matching circuit, first stage amplifier circuit, gain flatness adjustment inductor L gd and a second stage amplifier circuit;

[0008] The DC blocking capacitor C blockin One end is connected to the RF input signal of the low noise amplifier, and the other end is connected to the input matching circuit; the input matching circuit is connected to the DC blocking capacitor and the input end of the first stage amplifier circuit; the first stage amplifier circuit and the second stage amplifier circuit are connected by a gain flatness adjustment inductor L gd The output end of the second-stage amplifying circuit is used as the output end of the amplifier.

[0009] Since inter-stage matching is not required, the complex design process of inter-stage matching can be avoided, thereby reducing chip costs.

[0010] Furthermore, the first-stage amplifier circuit includes a first-stage amplifier tube M0, which is an NMOS transistor, a gate of which is an input terminal of the first-stage amplifier circuit, and a drain of which is an output terminal of the first-stage amplifier circuit.

[0011] Furthermore, the input matching circuit includes a transformer Transformer and a capacitor C gs The transformer Transformer includes two coils: the main coil L pri and the secondary coil L sec The main coil L pri One end is connected to the DC blocking capacitor C blockin , the other end is connected to the input end of the first stage amplifier circuit; the secondary coil L sec One end is connected to the source of the first stage amplifier tube M0, and the other end is grounded. gs One end is connected to the gate of the first-stage amplifier tube M0, and the other end is connected to the source of the first-stage amplifier tube M0. pri and the secondary coil L sec It is an in-phase coupling method.

[0012] The beneficial effects of the above further solution are: the capacitor C gs The existence of reduces the size of the transformer's primary and secondary coils, reduces the area of ​​the transformer, and reduces the cost. The transformer achieves conjugate matching, noise matching, and broadband matching at the same time.

[0013] Furthermore, the second-stage amplifier circuit includes an amplifier tube M1 and an amplifier tube M2. The amplifier tube M1 and the amplifier tube M2 are both NMOS transistors, whose gates are the input terminals of the second-stage amplifier circuit, whose sources are grounded, and whose drains are connected to the source of the amplifier tube M2. The drain and gate of the amplifier tube M2 are connected to the power supply voltage AVDD, which is a diode connection mode, and no inductor or resistor is connected between the drain and the gate.

[0014] The beneficial effects of the above further solution are: the second stage amplifier circuit is actually a cascade structure, which has the following advantages: very high gain improvement, reduced influence of the amplifier tube Miller effect on the amplifier performance, improved reverse isolation performance, and independent design of input and output matching. No inductance is used at the drain to increase the gain, which reduces the area.

[0015] Furthermore, the drain of the first-stage amplifier tube M0 uses the bias voltage of the gate end of the amplifier tube M1 instead of the power supply voltage AVDD.

[0016] The beneficial effect of the above further scheme is that the first stage output does not directly use the power supply voltage AVDD, but is directly connected to the gate terminal of the second stage amplifier tube M1, sharing a voltage which is used as a bias voltage and is less than the power supply voltage AVDD, thereby reducing the power consumption of the first stage.

[0017] Furthermore, the gain flatness adjustment inductor L gd The drain of the first-stage amplifier tube M0 and the gate of the second-stage amplifier tube M1 are connected, and the gain flatness adjustment inductor Lgd serves as an inter-stage inductor and has the function of adjusting the gain flatness.

[0018] Furthermore, the high-frequency, high-gain, low-noise amplifier without inter-stage matching further comprises: an output matching circuit and a portion of choke inductors and resistors;

[0019] The output matching circuit is connected to the output end of the second-stage amplifier circuit to reduce the output return loss of the circuit; the partial choke inductor resistor is used to prevent the radio frequency signal from entering the power supply voltage.

[0020] Furthermore, the output matching circuit is composed of a capacitor C blockout 、Inductance L out and capacitor C out Composition; the capacitor C blockout One end is connected to the output end of the second stage amplifier circuit, and the other end is connected to the inductor L out The inductor L out One end is connected to C blockout , the other end is connected to capacitor C out , the capacitor C out One end is connected to the inductor L out , the other end is grounded, capacitor C out The non-grounded end of the amplifier is used as the output end of the amplifier;

[0021] The choke inductor resistor includes a resistor R chock 、Inductance L chock1 and inductor L chock2 The resistor R chockis a large resistance with a resistance of at least 10k ohms, one end of which is connected to the input end of the input matching circuit and the other end is connected to the bias voltage; the inductor L chock1 It is a high-value inductor with an inductance of at least 1nH, one end of which is connected to the gate of M1 and the other end is connected to the bias voltage; the inductor L chock2 It is a large inductor with an inductance of at least 1nH, one end of which is connected to the drain of M2 and the other end is connected to the power supply voltage AVDD.

[0022] The beneficial effects of the above further solution are: using the output matching circuit can reduce the output return loss of the circuit. Using part of the choke inductor resistor can prevent the radio frequency signal from entering the power supply voltage.

[0023] Furthermore, the high-frequency, high-gain, low-noise amplifier without inter-stage matching further includes: an input pad capacitor C padin and input inductance L in ;

[0024] The input pad capacitance C padin Considering the capacitance of the input pad to ground, the RF input signal passes through the input inductor L in Connect the DC blocking capacitor C blockin , and through the input pad capacitor C padin Ground.

[0025] The beneficial effect of the above further solution is that the influence of the pad area on the input matching is taken into account, and the structural inductance is used to offset the influence of the input pad capacitance on the matching network, thereby improving the accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a circuit schematic diagram of the present invention.

[0027] Figure 2 It is a circuit schematic diagram provided in Example 1 of the present invention.

[0028] Figure 3 This is a circuit schematic diagram provided by Example 2 of the present invention.

[0029] Figure 4 It is a simulation result diagram of the gain and maximum gain of Example 2 of the present invention.

[0030] Figure 5 It is a simulation result diagram of the noise coefficient and the minimum noise coefficient coefficient of Example 2 of the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose and technical solution of the present invention more clear, the present invention is further described in detail in conjunction with the following examples. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0032] refer to Figure 1 As shown, the present invention is a high-frequency high-gain two-stage low-noise amplifier without using inter-stage matching. The low-noise amplifier is cascaded with a DC-isolating capacitor C blockin , input matching circuit, first stage amplifier circuit, gain flatness adjustment inductor L gd And the second stage amplifier circuit. DC blocking capacitor C blockin The interference of DC signal on RF input signal is avoided. The input matching circuit realizes the simultaneous matching of power and noise. The first stage amplification circuit amplifies the RF signal for the first time, and the second stage amplification circuit amplifies the signal for the second time. The gain flatness adjustment inductor L gd Connect between two stages to improve gain flatness.

[0033] The first stage amplifier circuit mainly includes a first stage amplifier tube M0, or may be only one first stage amplifier tube M0. The first stage amplifier tube M0 is an NMOS transistor, whose gate is the input end of the first stage amplifier circuit and whose drain is the output end of the first stage amplifier circuit.

[0034] Among them, the second-stage amplifier circuit mainly includes an amplifier tube M1 and an amplifier tube M2, and can also be composed of only the amplifier tube M1 and the amplifier tube M2. The amplifier tube M1 and the amplifier tube M2 are both NMOS transistors, whose gates are the input ends of the second-stage amplifier circuit, the sources are grounded, and the drains are connected to the source of the amplifier tube M2. The drain and gate of the amplifier tube M2 are connected to the power supply voltage AVDD, and no inductor or resistor is connected between the drain and the gate.

[0035] The present invention avoids the complicated design process of inter-stage matching by making the drain (output) of the first-stage amplifier tube and the gate of the second-stage amplifier tube share the same bias voltage instead of providing a separate power supply voltage to the drain of the first stage, while avoiding the use of a transformer and reducing the area and cost of the chip.

[0036] The specific application form and corresponding principle of the present invention can be further explained through the following two specific embodiments.

[0037] Example 1

[0038] The present invention provides a high-frequency, high-gain, low-noise amplifier without inter-stage matching, which mainly includes: a DC isolation capacitor C blockin , input matching circuit, first stage amplifier circuit, gain flatness adjustment inductor L gd , the second stage amplifying circuit, the output matching circuit and some choke inductors and resistors. Obviously, the low noise amplifier can also be composed of the above parts only.

[0039] Among them, the DC blocking capacitor C blockinOne end is connected to the RF input signal of the low noise amplifier, and the other end is connected to the input matching circuit. blockin Its function is to prevent the DC bias voltage from affecting the RF signal.

[0040] The input matching circuit mainly includes a transformer and a capacitor C gs , or it can be composed of only two. The transformer Transformer includes the main coil L pri and the secondary coil L sec Two coils, or just these two coils. Main coil L pri One end is connected to the DC blocking capacitor C blockin , the other end is connected to the gate of the first-stage amplifier tube M0; the auxiliary coil L sec One end is connected to the source of the first-stage amplifier tube M0, and the other end is grounded. pri and L sec It is a common coupling mode. Capacitor C gs One end is connected to the gate of the first stage amplifier tube M0, and the other end is connected to the source of the first stage amplifier tube M0. The function of the input matching circuit is to achieve simultaneous matching of power and noise.

[0041] The first stage amplifier circuit is composed of the first stage amplifier tube M0. M0 is an NMOS transistor, the gate is the input end, the drain is the output end, and the interstage inductor L gd Connect the gate terminal of the second-stage amplifier tube M1 and use the gate bias voltage of M2 instead of the power supply voltage AVDD. gd The function of is to adjust the gain flatness, and the function of the first-stage amplifier circuit is to achieve the first amplification of the RF signal.

[0042] The second stage amplifier circuit is composed of transistors M1 and M2. M1 is an NMOS transistor, with the gate as the input terminal, the source grounded, the drain connected to the source of another NMOS tube M2, the gate and drain of M2 connected to the power supply voltage AVDD, and M2 is a diode connection. The drain of M2 is not connected to an inductor or resistor. The function of the second stage amplifier circuit is to achieve the second amplification of the RF signal.

[0043] The output matching circuit consists of capacitor C blockout 、Inductance L out and capacitor C out Composition. Capacitor C blockout One end is connected to the drain of M2, and the other end is connected to the inductor L out ; Inductance L out One end is connected to C blockout , the other end is connected to capacitor C out ; Capacitor C out One end is connected to the inductor L out , the other end is grounded, and the signal is from capacitor Cout The non-ground terminal output. blockout In addition to matching, it also has a DC isolation function. The function of the output matching circuit is to reduce the output return loss of the circuit.

[0044] The choke inductor resistor includes the resistor R chock 、Inductance L chock1 and inductor L chock2 ; Resistance R chock is a large resistance resistor, and in this embodiment, the resistance is at least 10k ohms, one end of which is connected to the input end of the input matching circuit, and the other end is connected to the bias voltage V bias0 , its function is to prevent the RF signal from entering the bias voltage source; the inductor L chock1 It is a high-value inductor. According to the designed frequency, its inductance in this embodiment is at least 1nH. One end is connected to the gate of M1, and the other end is connected to the bias voltage V bias1 , its function is to prevent the RF signal from entering the bias voltage source; the inductor L chock2 It is a large inductor. According to the designed frequency, its inductance in this embodiment is at least 1nH. One end is connected to the drain of M2, and the other end is connected to the voltage source AVDD. Its function is to prevent the RF signal from entering the power supply voltage. bias0 and V bias1 Set according to gain requirements.

[0045] Combine the following Figure 2 The principle of the circuit is explained:

[0046] Resistor R chock 、Inductance L chock1 、Inductance L chock2 , DC blocking capacitor C blockin and the DC blocking capacitor C blockout This ensures the reliability of the circuit's DC path and reduces interference to RF signals. The capacitor C in the matching circuit gs The required transformer inductance is reduced. Since the transformer is in-phase coupled, the inductance of the primary and secondary coils is further reduced, and the area is reduced. After the RF signal passes through the matching network, the return loss is small and it enters the first stage amplifier circuit for the first amplification. The first stage LNA uses a common source amplifier circuit of transistor M0, which has a large amplification factor. gd The gate-drain capacitance, gate-source capacitance of M0 and gate-source capacitance of M1 form a resonant network, which has the function of adjusting the zero poles and further adjusting the gain flatness. The RF signal after the first stage amplification flows through the inductor L gdAfter that, it flows into the second stage amplifier circuit, that is, the gate of M1, for the second amplification. The cascade structure amplifier circuit of the second stage amplifier circuit has a higher amplification factor than the common source, and also has the advantages of low Miller effect and high reverse isolation. The drain of M2 does not need to increase the gain by adding inductance or resistance. After the second amplification, the RF signal flows to the load through the output matching network.

[0047] The beneficial effects of this embodiment are: the inter-stage matching circuit is omitted, reducing the chip area and cost; the gain flatness can be adjusted by one inductor, reducing the chip area and cost; the advantages of the cascade amplifier circuit are retained; the input matching and output matching have little mutual influence.

[0048] Example 2

[0049] The present invention provides a high-frequency, high-gain, low-noise amplifier without inter-stage matching, comprising: an input pad capacitor C padin , input inductance L in , DC blocking capacitor, input matching circuit, first stage amplifier circuit, gain flatness adjustment inductor L gd , the second stage amplifier circuit, the output matching circuit and some choke inductors and resistors.

[0050] Among them, the input pad capacitance C padin The capacitance of the input pad to the ground is considered. When the pad area is large, this capacitance will seriously affect the input matching, so it should be considered during design. padin One end is connected to the RF signal and the input inductor L in , the other end is grounded, the input inductor L in The function of the input inductor L is to offset the effect of the input pad capacitance on the matching network. in The other end is connected to the DC blocking capacitor C blockin , DC blocking capacitor C blockin One end is connected to the input inductor L in , and the other end is connected to the input matching circuit. C blockin Its function is to prevent the DC bias voltage from affecting the RF signal.

[0051] The input matching circuit mainly includes a transformer and a capacitor C gs , or it can be composed of only two. The transformer Transformer includes the main coil L pri and the secondary coil L sec Two coils, or only these two coils. One end of the main coil Lpri is connected to a DC blocking capacitor C blockin , the other end is connected to the gate of the first-stage amplifier tube M0; the auxiliary coil L sec One end is connected to the source of the first-stage amplifier tube M0, and the other end is grounded. pri and Lsec It is a common coupling mode. Capacitor C gs One end is connected to the gate of the first stage amplifier tube M0, and the other end is connected to the source of the first stage amplifier tube M0. The function of the input matching circuit is to achieve simultaneous matching of power and noise.

[0052] The first stage amplifier circuit is composed of transistor M0. M0 is an NMOS transistor with the gate as the input terminal and the drain as the output terminal. The inductor L is adjusted by the inter-stage gain flatness. gd Connect the gate terminal of the second-stage amplifier tube M1 and use the gate bias voltage of M2 instead of the power supply voltage AVDD. gd The function of is to adjust the gain flatness, and the function of the first-stage LNA circuit is to achieve the first amplification of the RF signal.

[0053] The second stage amplifier circuit is composed of transistors M1 and M2. M1 is an NMOS transistor, with the gate as the input terminal, the source grounded, the drain connected to the source of another NMOS tube M2, the gate and drain of M2 connected to the power supply voltage AVDD, and M2 is a diode connection. The drain of M2 is not connected to an inductor or resistor. The function of the second stage amplifier circuit is to achieve the second amplification of the RF signal.

[0054] The output matching circuit consists of capacitor C blockout 、Inductance L out and capacitor C out Composition. Capacitor C blockout One end is connected to the drain of M2, and the other end is connected to the inductor L out ; Inductance L out One end connected to C blockout , the other end is connected to capacitor C out ; Capacitor C out One end is connected to the inductor L out , the other end is grounded, and the signal is from capacitor C out The non-ground terminal output. blockout In addition to matching, it also has a DC isolation function. out It also has the function of simulating the capacitance of the output pad to ground. The function of the output matching circuit is to reduce the output return loss of the circuit.

[0055] The choke inductor resistor includes the resistor R chock 、Inductance L chock1 and inductor L chock2 ; Resistance R chock is a large resistance resistor, and in this embodiment, the resistance is at least 10k ohms, one end of which is connected to the input end of the input matching circuit, and the other end is connected to the bias voltage V bias0 , its function is to prevent the RF signal from entering the bias voltage source; the inductor L chock1It is a high-value inductor. According to the designed frequency, its inductance in this embodiment is at least 1nH. One end is connected to the gate of M1, and the other end is connected to the bias voltage V bias1 , its function is to prevent the RF signal from entering the bias voltage source; the inductor L chock2 It is a large inductor. According to the designed frequency, its inductance in this embodiment is at least 1nH. One end is connected to the drain of M2, and the other end is connected to the voltage source AVDD. Its function is to prevent the RF signal from entering the power supply voltage. bias0 and V bias1 Set according to gain requirements.

[0056] Combine the following Figure 3 The principle of the circuit is explained:

[0057] Resistor R chock 、Inductance L chock1 、Inductance L chock2 , DC blocking capacitor C blockin and the DC blocking capacitor C blockout This ensures the reliability of the circuit DC path and reduces interference to the RF signal. Input inductance L in and input pad capacitance C padin It is a parallel relationship. From its transfer function, we can know that by changing the values ​​of the two, the input RF signal can be reduced as little as possible. The capacitor C in the matching circuit gs The required transformer inductance is reduced. Since the transformer is in-phase coupled, the inductance of the primary and secondary coils is further reduced, and the area is reduced. After the RF signal passes through the matching network, the return loss is small and it enters the first-stage low-noise amplifier circuit for the first amplification. The first-stage amplifier circuit uses a common source amplifier circuit with a large amplification factor. gd The gate-drain capacitance, gate-source capacitance of M0 and gate-source capacitance of M1 form a resonant network, which has the function of adjusting the zero poles and further adjusting the gain flatness. The RF signal after the first stage amplification flows through the inductor L gd After that, it flows into the second stage amplifier circuit, which is the gate of M1, for the second amplification. The second stage amplifier circuit is an amplifier circuit of cascode structure, which has a higher amplification factor than the common source, and also has the advantages of low Miller effect and high reverse isolation. The drain of M2 does not need to increase the gain by adding inductance. After the second amplification, the RF signal flows to the load through the output matching network.

[0058] The beneficial effects of this embodiment are: the capacitance of the input and output pads to ground is taken into account; the inter-stage matching circuit is omitted, reducing the area and cost of the chip; the gain flatness can be adjusted by an inductor, reducing the area and cost of the chip; the advantages of the cascode stage amplifier circuit are retained; the input matching and the output matching have little mutual influence.

[0059] The detailed effects of this embodiment are as follows Figure 4 and Figure 5 exhibit, Figure 4 In the figure, the horizontal axis is frequency in GHz. The solid line represents the gain that can be achieved when both output and input matching are the best, in dB. The dotted line is the gain under actual matching. The two are very close in the range of 20 GHz to 28 GHz, indicating that the input and output have achieved good matching without using inter-stage matching. Figure 5 In the figure, the horizontal axis is frequency in GHz. The solid line represents the noise figure when the noise matching is the best, that is, the minimum noise figure in dB. The dotted line is the noise under actual noise matching. The two are very close in the range of 21GHz to 29GHz, indicating that the noise matching is completed only at the input end without using inter-stage matching.

Claims

1. A high-frequency, high-gain, low-noise amplifier without inter-stage matching, characterized in that: Including the DC blocking capacitors C connected in series blockin , input matching circuit, first stage amplifier circuit, gain flatness adjustment inductor L gd and a second stage amplifier circuit; The DC blocking capacitor C blockin One end is connected to the RF input signal of the low noise amplifier, and the other end is connected to the input matching circuit; the input matching circuit is connected to the DC blocking capacitor and the input end of the first stage amplifier circuit; the first stage amplifier circuit and the second stage amplifier circuit are connected by a gain flatness adjustment inductor L gd The output end of the second-stage amplifying circuit is used as the output end of the amplifier.

2. The high-frequency, high-gain, low-noise amplifier without inter-stage matching according to claim 1, characterized in that: The first-stage amplifier circuit includes a first-stage amplifier tube M0 , which is an NMOS transistor, a gate of which is an input terminal of the first-stage amplifier circuit, and a drain of which is an output terminal of the first-stage amplifier circuit.

3. The high-frequency, high-gain, low-noise amplifier without inter-stage matching according to claim 2, characterized in that: The input matching circuit includes a transformer Transformer and a capacitor C gs The transformer Transformer includes two coils: the main coil L pri and the secondary coil L sec The main coil L pri One end is connected to the DC blocking capacitor C blockin , the other end is connected to the input end of the first stage amplifier circuit; the secondary coil L sec One end is connected to the source of the first stage amplifier tube M0, and the other end is grounded. gs One end is connected to the gate of the first-stage amplifier tube M0, and the other end is connected to the source of the first-stage amplifier tube M0.

4. The high-frequency, high-gain, low-noise amplifier without inter-stage matching according to claim 3, characterized in that: The main coil L pri and the secondary coil L sec It is an in-phase coupling method.

5. The high-frequency, high-gain, low-noise amplifier without inter-stage matching according to any one of claims 2 to 4, characterized in that: The second-stage amplifier circuit includes an amplifier tube M1 and an amplifier tube M2. The amplifier tube M1 and the amplifier tube M2 are both NMOS transistors, whose gates are the input terminals of the second-stage amplifier circuit, whose sources are grounded, and whose drains are connected to the source of the amplifier tube M2. The amplifier tube M2 is connected in a diode manner, whose drains and gates are connected to the power supply voltage AVDD, and no inductor or resistor is connected between the drains and the gates.

6. The high-frequency, high-gain, low-noise amplifier without inter-stage matching according to claim 5, characterized in that: The drain of the first-stage amplifier tube M0 uses the bias voltage of the gate end of the amplifier tube M1.

7. The high-frequency, high-gain, low-noise amplifier without inter-stage matching according to claim 5, characterized in that: The gain flatness adjustment inductor L gd Connect the drain of the first-stage amplifier tube M0 and the gate of the second-stage amplifier tube M1 to adjust the gain flatness.

8. The high-frequency, high-gain, low-noise amplifier without inter-stage matching according to claim 5, characterized in that: The high-frequency, high-gain, low-noise amplifier without inter-stage matching further includes: an output matching circuit and a portion of choke inductors and resistors; The output matching circuit is connected to the output end of the second-stage amplifier circuit to reduce the output return loss of the circuit; the partial choke inductor resistor is used to prevent the radio frequency signal from entering the power supply voltage.

9. The high-frequency, high-gain, low-noise amplifier without inter-stage matching according to claim 8, characterized in that: The output matching circuit consists of capacitor C blockout 、Inductance L out and capacitor C out Composition; the capacitor C blockout One end is connected to the output end of the second stage amplifier circuit, and the other end is connected to the inductor L out The inductor L out One end is connected to C blockout , the other end is connected to capacitor C out , the capacitor C out One end is connected to the inductor L out , the other end is grounded, capacitor C out The non-grounded end of the amplifier is used as the output end of the amplifier; The choke inductor resistor includes a resistor R chock 、Inductance L chock1 and inductor L chock2 The resistor R chock is a large resistance with a resistance of at least 10k ohms, one end of which is connected to the input end of the input matching circuit and the other end is connected to the bias voltage; the inductor L chock1 It is a high-value inductor with an inductance of at least 1nH, one end of which is connected to the gate of M1 and the other end is connected to the bias voltage; the inductor L chock2 It is a large inductor with an inductance of at least 1nH, one end of which is connected to the drain of M2 and the other end is connected to the power supply voltage AVDD.

10. The high-frequency, high-gain, low-noise amplifier without inter-stage matching according to claim 8, characterized in that: The high-frequency, high-gain, low-noise amplifier without inter-stage matching also includes: an input pad capacitor C padin and input inductance L in ; The input pad capacitance C padin Considering the capacitance of the input pad to ground, the RF input signal passes through the input inductor L in Connect the DC blocking capacitor C blockin , and through the input pad capacitor C padin Ground.

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