CN108039869A - A kind of frequency mixer based on mutual conductance coefficient correcting principle - Google Patents

Abstract

The invention relates to a mixer based on a transconductance coefficient correction structure, comprising a transconductance stage circuit, a switch stage circuit and a load stage circuit electrically connected in sequence, and the transconductance stage circuit adopts a transconductance coefficient correction structure and a source degenerate inductance structure The transconductance level circuit is used to access the radio frequency voltage signal, and converts the radio frequency voltage signal into a radio frequency current signal; the switch level circuit is used to access the local oscillator signal and the radio frequency current signal, and controls the switch level circuit according to the local oscillator signal. A plurality of switch tubes are turned on in turn, and the radio frequency current signal is switched and modulated by using the plurality of switch tubes in turn to generate an intermediate frequency current signal; the load stage circuit is used to convert the intermediate frequency current signal into a voltage signal for output. In the present invention, the transconductance stage circuit adopts the transconductance coefficient correction structure, which improves the linearity of the mixer on the basis of low power consumption; meanwhile, adopts the source degenerate inductance structure, further improves the conversion gain and linearity of the circuit.

Description

A Mixer Based on Modified Structure of Transconductance Coefficient

technical field

The invention relates to a mixer, in particular to a mixer based on a transconductance coefficient correction structure.

Background technique

In recent years, in today's society with rapid development of information technology, wireless applications in mobile phones, personal computers, etc. Growth has led to the design of low power radio frequency integrated circuits. The radio frequency receiver is an important module of wireless communication, and its performance index affects the whole wireless communication system. Among them, the design of the mixer plays an important role in the RF transceiver system, and it is also the strongest part of the RF front-end signal, so the performance index of the mixer affects the performance index of the entire RF front-end, so the performance of the mixer is improved is of great significance. Weak signals present at the RF receiver are first amplified by the LNA and then passed to the mixer. Therefore, in the design of the mixer, it is necessary to comprehensively consider performance indicators such as conversion gain, noise, linearity, power consumption, and isolation, and to compromise the performance parameters of the mixer.

Contents of the invention

The technical problem to be solved by the present invention is to provide a mixer based on a transconductance coefficient correction structure, which improves the performance of the mixer on the basis of low power consumption.

The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a mixer based on a transconductance coefficient correction structure, including a transconductance stage circuit, a switch stage circuit and a load stage circuit electrically connected in sequence, wherein the transconductance stage circuit Adopt transconductance coefficient correction structure and source degenerate inductance structure;

The transconductance level circuit is used to access the radio frequency voltage signal, convert the radio frequency voltage signal into a radio frequency current signal, and repeatedly use the radio frequency current signal;

The switch level circuit is used to access the local oscillator signal and the radio frequency current signal, and according to the local oscillator signal, the multiple switch tubes set in the switch level circuit are controlled to be turned on in turn, and the multiple switch tubes are used to turn on the pair of switches in turn. The radio frequency current signal is switched and modulated to generate an intermediate frequency current signal and transmit it to the load stage circuit;

The load stage circuit is used to convert the intermediate frequency current signal into a voltage signal for output;

The transconductance stage circuit includes transistors M1-M7, inductor L1, capacitor C1, capacitor C2, resistor R1, resistor R2, resistor Rb1 and resistor Rb2; the gate of the transistor M1 is connected to the positive terminal RF+ of the radio frequency voltage signal, The drain of the transistor M1 is connected to one end of the inductor L1, the source of the transistor M1 is grounded, and the other end of the inductor L1 is connected to the drain of the transistor M2; the gate of the transistor M3 is connected to the The gate of the transistor M4 is connected, the drain of the transistor M3 is connected to the drain of the transistor M1, the drain of the transistor M3 is also connected to the switching circuit, and the source of the transistor M3 is grounded The gate of the transistor M2 is connected to the negative terminal RF- of the radio frequency voltage signal, and the source of the transistor M2 is grounded; the drain of the transistor M4 is connected to the drain of the transistor M2, and the drain of the transistor M4 is connected to the ground. The drain is also connected to the switching stage circuit, the source of the transistor M4 is grounded; one end of the resistor Rb2 is connected to the DC bias voltage v2, and the other end of the resistor Rb2 is connected to the gate of the transistor M3; The gate of the transistor M5 is connected to the positive terminal RF+ of the radio frequency voltage signal, the drain of the transistor M5 is connected to one end of the capacitor C1, the source of the transistor M5 is grounded, and the other end of the capacitor C1 is connected to The gate of the transistor M7 is connected; the gate of the transistor M6 is connected to the negative terminal RF- of the radio frequency voltage signal, the source of the transistor M6 is grounded, and the drain of the transistor M6 is connected to the drain of the transistor M5 One end of the resistor Rb1 is connected to the gate of the transistor M7, and the other end of the resistor Rb1 is connected to the DC bias voltage V1; the source of the transistor M7 is grounded, and the drain of the transistor M7 is connected to the gate of the transistor M7. One end of the resistor R2 is connected, and the other end of the R2 is connected to the voltage VDD; one end of the resistor R1 is connected to the drain of the transistor M5, and the other end of the resistor R1 is connected to the voltage VDD; the capacitor C2 One end is connected to the drain of the transistor M7, and the other end of the capacitor C2 is connected to the gate of the transistor M4.

The beneficial effects of the present invention are: in a mixer based on the transconductance coefficient correction structure of the present invention, the transconductance stage circuit adopts the transconductance coefficient correction structure, which improves the linearity of the mixer on the basis of low power consumption ; At the same time, the source degenerate inductance structure is adopted to further improve the conversion gain and linearity of the circuit.

On the basis of the above technical solutions, the present invention can also be improved as follows.

Further, the switching stage circuit includes transistors M8-M11, the gate of the transistor M8 is connected to the positive terminal LO+ of the local oscillator signal, the source of the transistor M8 is connected to the drain of the transistor M1, and the transistor M8 The drain of M8 is connected to the load stage circuit; the gate of the transistor M9 is connected to the negative terminal LO- of the local oscillator signal, and the source of the transistor M9 is connected to the source of the transistor M8. The drain of M9 is connected to the drain of the transistor M11; the gate of the transistor M10 is connected to the negative terminal LO- of the local oscillator signal, and the source of the transistor M10 is connected to the drain of the transistor M2, so The drain of the transistor M10 is connected to the drain of the transistor M8; the gate of the transistor M11 is connected to the negative terminal LO+ of the local oscillator signal, and the source of the transistor M11 is connected to the drain of the transistor M2, The drain of the transistor M11 is connected to the load stage circuit.

The beneficial effect of adopting the above further solution is: the local oscillator signal is connected, and the transistors are turned on in turn under the control of the local oscillator large signal, and the current is switched and modulated to realize frequency conversion.

Further, the load stage circuit includes a resistor R3, a resistor R4, a capacitor C3 and a capacitor C4; one end of the resistor R3 is connected to the drain of the transistor M8, and the other end of the resistor R3 is connected to the power supply voltage VDD; One end of the capacitor C3 is connected to the drain of the transistor M8, the other end of the capacitor C3 is connected to the power supply voltage VDD; one end of the resistor R4 is connected to the drain of the transistor M11, and the other end of the resistor R4 One end is connected to the power supply voltage VDD; one end of the capacitor C4 is connected to the drain of the transistor M11, and the other end of the capacitor C4 is connected to the power supply voltage VDD.

The beneficial effect of adopting the above further solution is that the load of the RC low-pass filter can provide a certain voltage gain, and can also filter out differential mode interference signals and signals leaked from the local oscillator to the intermediate frequency output terminal.

Further, it also includes a current injection circuit, the current injection circuit includes a transistor M12 and a transistor M13, the gate of the transistor M12 is connected to the DC bias voltage V0, and the source of the transistor M12 is connected to the power supply voltage VDD, so The drain of the transistor M12 is connected to the source of the transistor M9; the gate of the transistor M13 is connected to the gate of the transistor M12, and the drain of the transistor M13 is connected to the source of the transistor M10, The source of the transistor M13 is connected to the power supply voltage VDD.

The beneficial effect of adopting the above further solution is: by adding the current injection circuit, the current of the transconductance stage can be increased, and the current flowing through the switch stage can be reduced, so that the DC voltage drop of the load resistance is reduced, thereby increasing the output swing Amplitude to improve the linearity of the mixer, further, can also reduce the flicker noise and thermal noise caused by the direct mechanism of the switching stage.

Further, the transistors M1 to M11 are all NMOS transistors, and the transistor M12 and the transistor M13 are both PMOS transistors.

Description of drawings

Fig. 1 is a kind of circuit schematic diagram of the mixer based on the transconductance correction structure of the present invention;

Fig. 2 is the emulation diagram of conversion gain changing with local oscillator power in a kind of mixer based on transconductance coefficient correction structure of the present invention;

Fig. 3 is the emulation diagram of conversion gain changing with output frequency in a kind of mixer based on transconductance coefficient correction structure of the present invention;

Fig. 4 is the noise figure simulation result figure of a kind of mixer based on the transconductance coefficient correction structure of the present invention;

Fig. 5 is a linearity simulation result diagram of a mixer based on a transconductance correction structure of the present invention;

FIG. 6 is a screenshot of power consumption of a mixer based on a transconductance correction structure according to the present invention.

Detailed ways

The principles and features of the present invention are described below in conjunction with the accompanying drawings, and the examples given are only used to explain the present invention, and are not intended to limit the scope of the present invention.

As shown in Figure 1, a mixer based on a transconductance coefficient correction structure includes a transconductance stage circuit, a switch stage circuit and a load stage circuit electrically connected in sequence, wherein the transconductance stage circuit uses a transconductance coefficient correction Structure and source degenerate inductance structure;

The transconductance level circuit is used to access the radio frequency voltage signal, convert the radio frequency voltage signal into a radio frequency current signal, and repeatedly use the radio frequency current signal;

The switch level circuit is used to access the local oscillator signal and the radio frequency current signal, and according to the local oscillator signal, the multiple switch tubes set in the switch level circuit are controlled to be turned on in turn, and the multiple switch tubes are used to turn on the pair of switches in turn. The radio frequency current signal is switched and modulated to generate an intermediate frequency current signal and transmit it to the load stage circuit;

The load stage circuit is used to convert the intermediate frequency current signal into a voltage signal for output.

Specifically: the transconductance stage circuit includes a transistor M1, a transistor M2, a transistor M3, a transistor M4, a transistor M5, a transistor M6, a transistor M7, an inductor L1, a capacitor C1, a capacitor C2, a resistor R1, a resistor R2, a resistor Rb1 and a resistor Rb2; the gate of the transistor M1 is connected to the positive terminal RF+ of the radio frequency voltage signal, the drain of the transistor M1 is connected to one end of the inductance L1, the source of the transistor M1 is grounded, and the other end of the inductance L1 One end is connected to the drain of the transistor M2; the gate of the transistor M3 is connected to the gate of the transistor M4, the drain of the transistor M3 is connected to the drain of the transistor M1, and the drain of the transistor M3 is connected to the drain of the transistor M3. The drain is also connected to the switching stage circuit, the source of the transistor M3 is grounded; the gate of the transistor M2 is connected to the negative terminal RF- of the radio frequency voltage signal, and the source of the transistor M2 is grounded; the transistor M2 The drain of M4 is connected to the drain of the transistor M2, the drain of the transistor M4 is also connected to the switching stage circuit, the source of the transistor M4 is grounded; one end of the resistor Rb2 is connected to a DC bias voltage v2, the other end of the resistor Rb2 is connected to the gate of the transistor M3; the gate of the transistor M5 is connected to the positive terminal RF+ of the radio frequency voltage signal, and the drain of the transistor M5 is connected to one end of the capacitor C1 connected, the source of the transistor M5 is grounded, the other end of the capacitor C1 is connected to the gate of the transistor M7; the gate of the transistor M6 is connected to the negative terminal RF- of the radio frequency voltage signal, and the transistor M6 The source level of the transistor M6 is connected to the drain of the transistor M5; one end of the resistor Rb1 is connected to the gate of the transistor M7, and the other end of the resistor Rb1 is connected to a DC bias voltage V1; the source of the transistor M7 is grounded, the drain of the transistor M7 is connected to one end of the resistor R2, and the other end of the R2 is connected to the voltage VDD; one end of the resistor R1 is connected to the drain of the transistor M5 The other end of the resistor R1 is connected to the voltage VDD; one end of the capacitor C2 is connected to the drain of the transistor M7, and the other end of the capacitor C2 is connected to the gate of the transistor M4.

Transconductance stages can be implemented using pseudo-differential, fully differential, and source-degenerated schemes. Pseudo-differential is ideal for implementing the transduction stage, which improves the third-order input intercept point (IIP3), but degrades the second-order input intercept point (IIP2) because it creates common-mode second-order distortion. Additionally, the tail current sources at the source terminals of the fully differential input transistors create high impedance, which suppresses second-order nonlinear currents, and there is a mismatch in the load and switching transistors, causing even-order intermodulation in the signal path, increasing The third-order intermodulation current IM3 is obtained. In order to improve the third-order input intercept point (IIP3) and eliminate the third-order distortion, the elimination mechanism is set in the transconductance stage of the mixer, and the transconductance coefficient correction technology structure is used. By adding extra circuitry to the transconductance stage, a non-linear term is created, which improves the linearity of the mixer by changing its magnitude and phase. As shown in Fig. 1, the transistor M5 and the transistor M6 are nonlinear transistors, which convert the input voltage signal into a nonlinear current. Since the drains of the transistors M5 and M6 are connected, the differential term of the current is removed, the current is output through the resistors R1 and R2, and the output current is amplified by the transistor M3. The small-signal model of transistor M1 expresses the drain current in Taylor series expansion as:

i _d1 ＝g _m1 v _gs +g' _m1 v ² _gs +g” _m1 v ³ _gs +... (1)

Among them, Vgs=Vg–VS, Vg is the gate voltage, VS is the source voltage, g _m1 , g' _m1 ,

g" _m1 respectively represent the first-order, second-order and third-order transconductance coefficients of transistor M1.

It can be found from the above formula that changing the drain current of the MOS transistor can change the transconductance coefficient.

The gate voltage _VG of transistor M3 can be expressed as:

where _D2 is the second-order transconductance coefficient of _VG .

By writing KCL at the drains of M5 and M6, using the transistor relation and the frequency domain representation of the loop equation, the second-order transconductance of VG is expressed as:

Among them, by changing the values of C ₁ , R ₁ and R ₂ , the phase and amplitude of D ₂ can be changed.

The drain current (I1+) of transistor M1 can be defined as:

I ₁ +＝H ₁ (w)V _RF+ +H ₂ (w1,w2)V ² _RF+ +H ₃ (w1,w2,w3)V ³ _RF+ +... (7)

where H1, H2, and H3 are the first-order, second-order, and third-order transconductance coefficients of I ₁ +, respectively, and are also named the first-order, second-order, and third-order transconductance cores.

In the above formula, H1, H2 and H3 can be expressed as:

H ₁ (w)=g _m1 (8)

The above formula shows that the first-order transconductance of the transconductance stage H ₁ (w) is equal to the main transconductance of the transistor characteristic g _m1 , and the linearity can be improved when H ₃ (w1,w2,w3) is eliminated.

The formula for the third-order intersection point is:

According to the above derivation, it can be found that by adjusting C1, R1 and R2 to change the phase and amplitude of D2, the gate voltage of transistor M3 will change, and the drain current will change accordingly, and the transconductance coefficient can be corrected. According to formula (11), when the transconductance coefficient changes, it can be used to improve the input third-order intermodulation point IIP3, that is, by introducing an interaction term that is the same as the third-order intermodulation current of the transconductance stage but has an opposite phase to improve The IIP3 value of a CMOS active mixer changes its magnitude and phase value depending on the tuning of the added resistors in the circuit. Due to the increased number of transistors at the RF port of the proposed mixer, the noise of the mixer is slightly increased. In a radio frequency receiver, the higher the conversion gain of the previous stage mixer, the lower the noise performance requirement of the latter stage circuit. The gain expression for the mixer is:

The transconductance stage also adopts a source degenerate inductance structure, outputs radio frequency current, has better input matching characteristics, and improves the conversion gain and linearity of the circuit. The drain connection inductance of transistor M1 and transistor M2 can reduce the flicker noise of the indirect mechanism caused by the parasitic capacitance of the source stage of the switching circuit, and also suppress the coupling of the radio frequency signal to the ground path through the parasitic capacitance, and improve the conversion gain of the mixer. Capacitor C2 provides better input matching characteristics and also improves the linearity of the circuit.

Specifically: the switching stage circuit includes a transistor M8, a transistor M9, a transistor M10 and a transistor M11, the gate of the transistor M8 is connected to the positive terminal LO+ of the local oscillator signal, and the source of the transistor M8 is connected to the transistor M1 The drain of the transistor M8 is connected to the load stage circuit; the gate of the transistor M9 is connected to the negative terminal LO- of the local oscillator signal, and the source of the transistor M9 is connected to the transistor M8 The source of the transistor M9 is connected to the drain of the transistor M11; the gate of the transistor M10 is connected to the negative terminal LO- of the local oscillator signal, and the source of the transistor M10 is connected to the The drain of the transistor M2 is connected, the drain of the transistor M10 is connected to the drain of the transistor M8; the gate of the transistor M11 is connected to the negative terminal LO+ of the local oscillator signal, and the source of the transistor M11 is connected to the The drain of the transistor M2 is connected, and the drain of the transistor M11 is connected to the load stage circuit.

The switch stage is connected to the local oscillator signal, and the transistors are turned on in turn under the control of the large local oscillator signal. When LO+ is turned on, the transistor M8 and the transistor M11 are turned on, and the transistor M9 and the transistor M11 are turned off; when the LO- is turned on At this time, the transistor M9 and the transistor M10 are turned on, and the transistor M8 and the transistor M11 are turned off, so as to switch and modulate the current to realize frequency conversion.

Specifically: the load stage circuit includes a resistor R3, a resistor R4, a capacitor C3, and a capacitor C4; one end of the resistor R3 is connected to the drain of the transistor M8, and the other end of the resistor R3 is connected to the power supply voltage VDD; One end of the capacitor C3 is connected to the drain of the transistor M8, and the other end of the capacitor C3 is connected to the power supply voltage VDD; one end of the resistor R4 is connected to the drain of the transistor M11, and the other end of the resistor R4 is connected to the drain of the transistor M11. The other end is connected to the power supply voltage VDD; one end of the capacitor C4 is connected to the drain of the transistor M11, and the other end of the capacitor C4 is connected to the power supply voltage VDD.

When the differential mode signal is input, capacitors are set on both sides of the load branch to provide the load required for the conversion gain, and the RC low-pass filter load can provide a certain voltage gain and also play a role in filtering.

Specifically: the present invention also includes a current injection circuit, the current injection circuit includes a transistor M12 and a transistor M13, the gate of the transistor M12 is connected to the DC bias voltage V0, the source of the transistor M12 is connected to the power supply voltage VDD connected, the drain of the transistor M12 is connected to the source of the transistor M9; the gate of the transistor M13 is connected to the gate of the transistor M12, and the drain of the transistor M13 is connected to the source of the transistor M10 The source of the transistor M13 is connected to the power supply voltage VDD.

The current injection circuit adopts the current injection technology, using the transistor M12 and the transistor M13 as the shunt source, and its gate bias voltage is controlled by the v0 voltage, which can adjust the ratio of the injection current to the transconductance stage current to achieve a better performance parameter. The current injection reduces the current flowing through the switching tube, thereby reducing the noise caused by the direct mechanism of the switching stage, and improving the noise performance. We set a reasonable value of inductance L1 to make it resonate with the parasitic capacitance; when the resonant frequency resonates at ω _RF , the conversion gain of the mixer is improved; when the resonant frequency point is selected at 2ω _RF , the impedance of the parasitic capacitance decreases As small as 1/3 of the original, the second harmonic nonlinearity caused by parasitic capacitance is minimized; from the above analysis, it can be seen that when the resonance point is at different frequencies, the linearity or gain performance is at a specific frequency A good optimization can be achieved; in this example, by selecting the appropriate inductance L1, the resonant frequency of the total parasitic capacitance at the common source node is between the RF fundamental wave and the RF second harmonic, and the conversion gain and noise of this scheme , linearity performance parameters can be improved.

FIG. 2 is a simulation diagram of the conversion gain of the mixer according to the present invention varying with the local oscillator power. It can be seen from FIG. 2 that the conversion gain of the mixer can reach more than 28.4 dB.

As shown in FIG. 3 , the simulation diagram of the conversion gain of the mixer according to the present invention varies with the output frequency. It can be seen from FIG. 3 that the conversion gain of the mixer is 28.4 dB.

FIG. 4 is a simulation diagram of the noise figure of the mixer of the present invention. It can be seen from FIG. 4 that the noise figure of the mixer is 8dB.

FIG. 5 is a simulation diagram of the linearity of the mixer of the present invention. It can be seen from FIG. 5 that the linearity of the mixer is 10.34dBm.

FIG. 6 is a power consumption diagram of the mixer of the present invention. It can be seen from FIG. 6 that the power consumption of the mixer is 6.86mW.

In summary, the transconductance stage circuit of the mixer based on transconductance correction in the present invention adopts a transconductance correction structure, by adding an additional circuit to the transconductance stage, a nonlinear term is generated, and by changing its amplitude and phase , to improve the linearity of the mixer. The transconductance stage circuit also adopts a source degenerate inductance structure, so that the conversion gain of the mixer is improved.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within range.

Claims (5)

1. A mixer based on a transconductance correction structure, characterized in that: comprising a transconductance stage circuit, a switch stage circuit and a load stage circuit electrically connected in sequence, wherein the transconductance stage circuit adopts a transconductance correction Structure and source degenerate inductance structure; The transconductance level circuit is used to access the radio frequency voltage signal, convert the radio frequency voltage signal into a radio frequency current signal, and repeatedly use the radio frequency current signal; The switch level circuit is used to access the local oscillator signal and the radio frequency current signal, and according to the local oscillator signal, the multiple switch tubes set in the switch level circuit are controlled to be turned on in turn, and the multiple switch tubes are used to turn on the pair of switches in turn. The radio frequency current signal is switched and modulated to generate an intermediate frequency current signal and transmit it to the load stage circuit; The load stage circuit is used to convert the intermediate frequency current signal into a voltage signal for output; The transconductance stage circuit includes transistors M1-M7, inductor L1, capacitor C1, capacitor C2, resistor R1, resistor R2, resistor Rb1 and resistor Rb2; the gate of the transistor M1 is connected to the positive terminal RF+ of the radio frequency voltage signal, The drain of the transistor M1 is connected to one end of the inductor L1, the source of the transistor M1 is grounded, and the other end of the inductor L1 is connected to the drain of the transistor M2; the gate of the transistor M3 is connected to the The gate of the transistor M4 is connected, the drain of the transistor M3 is connected to the drain of the transistor M1, the drain of the transistor M3 is also connected to the switching circuit, and the source of the transistor M3 is grounded The gate of the transistor M2 is connected to the negative terminal RF- of the radio frequency voltage signal, and the source of the transistor M2 is grounded; the drain of the transistor M4 is connected to the drain of the transistor M2, and the drain of the transistor M4 is connected to the ground. The drain is also connected to the switching stage circuit, the source of the transistor M4 is grounded; one end of the resistor Rb2 is connected to the DC bias voltage v2, and the other end of the resistor Rb2 is connected to the gate of the transistor M3; The gate of the transistor M5 is connected to the positive terminal RF+ of the radio frequency voltage signal, the drain of the transistor M5 is connected to one end of the capacitor C1, the source of the transistor M5 is grounded, and the other end of the capacitor C1 is connected to The gate of the transistor M7 is connected; the gate of the transistor M6 is connected to the negative terminal RF- of the radio frequency voltage signal, the source of the transistor M6 is grounded, and the drain of the transistor M6 is connected to the drain of the transistor M5 One end of the resistor Rb1 is connected to the gate of the transistor M7, and the other end of the resistor Rb1 is connected to the DC bias voltage V1; the source of the transistor M7 is grounded, and the drain of the transistor M7 is connected to the gate of the transistor M7. One end of the resistor R2 is connected, and the other end of the R2 is connected to the voltage VDD; one end of the resistor R1 is connected to the drain of the transistor M5, and the other end of the resistor R1 is connected to the voltage VDD; the capacitor C2 One end is connected to the drain of the transistor M7, and the other end of the capacitor C2 is connected to the gate of the transistor M4. 2. A mixer based on a transconductance correction structure according to claim 1, characterized in that: the switch stage circuit includes transistors M8-M11, the gate of the transistor M8 is connected to the positive signal of the local oscillator signal The terminal LO+ is connected, the source of the transistor M8 is connected to the drain of the transistor M1, and the drain of the transistor M8 is connected to the load stage circuit; the gate of the transistor M9 is connected to the negative terminal of the local oscillator signal LO-connection, the source of the transistor M9 is connected to the source of the transistor M8, the drain of the transistor M9 is connected to the drain of the transistor M11; the gate of the transistor M10 is connected to the local oscillator signal The negative terminal LO- is connected, the source of the transistor M10 is connected to the drain of the transistor M2, the drain of the transistor M10 is connected to the drain of the transistor M8; the gate of the transistor M11 is connected to the local oscillator The negative terminal of the signal is connected to LO+, the source of the transistor M11 is connected to the drain of the transistor M2, and the drain of the transistor M11 is connected to the load stage circuit. 3. A mixer based on a transconductance correction structure according to claim 2, characterized in that: the load stage circuit includes a resistor R3, a resistor R4, a capacitor C3 and a capacitor C4; one end of the resistor R3 Connected to the drain of the transistor M8, the other end of the resistor R3 is connected to the power supply voltage VDD; one end of the capacitor C3 is connected to the drain of the transistor M8, and the other end of the capacitor C3 is connected to the power supply voltage VDD connected; one end of the resistor R4 is connected to the drain of the transistor M11, and the other end of the resistor R4 is connected to the power supply voltage VDD; one end of the capacitor C4 is connected to the drain of the transistor M11, and the capacitor The other end of C4 is connected to the power supply voltage VDD. 4. A mixer based on a transconductance correction structure according to claim 3, characterized in that: it also includes a current injection circuit, the current injection circuit includes a transistor M12 and a transistor M13, the gate of the transistor M12 The pole of the transistor M12 is connected to the DC bias voltage V0, the source of the transistor M12 is connected to the power supply voltage VDD, the drain of the transistor M12 is connected to the source of the transistor M9; the gate of the transistor M13 is connected to the source of the transistor M13 The gate of the transistor M12 is connected, the drain of the transistor M13 is connected to the source of the transistor M10 , and the source of the transistor M13 is connected to the power supply voltage VDD. 5. The mixer based on a transconductance correction structure according to claim 4, wherein the transistors M1-M11 are all NMOS transistors, and the transistors M12-M13 are all PMOS transistors.