CMOS voltage-controlled oscillator applied to anti-interference unmanned aerial vehicle millimeter wave radar

Abstract

The invention relates to a CMOS voltage-controlled oscillator applied to an anti-interference unmanned aerial vehicle millimeter wave radar, which belongs to the field of millimeter wave radar design and comprises a resonance circuit, a negative resistance active circuit and two switching circuits with the same structure. The resonant circuit comprises a switched capacitor, a blocking capacitor, a resonant capacitor, a grounding resistor, a tuning resistor and a resonant inductor; the negative resistance active circuit comprises a cross coupling pair MOS tube and a current source. Each switch circuit comprises a switch MOS tube, a grounding resistor and a switch coupling inductor. The dual-phase transformer structure is used, the resonant inductor and the switch coupling inductor are mutually inducted, and therefore the inductance value of the resonant inductor is changed, and frequency band switching is achieved; vCO bandwidth tuning is realized through a combination mode of switch-on and switch-off of a switch capacitor and switch-on and switch-off of a switch coupling inductor; the CMOS technology is adopted for design, and miniaturization and integration of the VCO are achieved. While the performance and layout area of the voltage-controlled oscillator are ensured, the full-band broadband tuning range is realized, thereby improving the detectability and resolution of the millimeter wave radar, enabling the unmanned aerial vehicle to realize frequency hopping communication and spread spectrum communication, and effectively improving the anti-interference capability and safety of the unmanned aerial vehicle.

Description

Technical Field

[0001] The invention belongs to the field of millimeter wave radar design and relates to a CMOS voltage-controlled oscillator applied to an anti-interference unmanned aerial vehicle millimeter wave radar. Background Art

[0002] With the breakthrough of related technologies, drone technology has been rapidly developed and widely used. With the rapid development of science and technology, the application scenarios of drones are constantly expanding, from the initial photography and agricultural spraying to today's multi-functional services such as building cleaning and logistics transportation. With the increasing application of drones in various fields, drones are facing many challenges such as severe environmental interference and human interference, which puts higher requirements on their safety, reliability, adaptability and anti-interference in complex environments.

[0003] Millimeter-wave radar is a key sensor in the UAV flight control system. The reason why UAVs can complete various tasks in a refined manner is inseparable from it. At present, the limited perception ability of UAVs is still a major obstacle to the intelligent flight control system of UAVs, which may cause accidental collisions of UAVs, resulting in mission failure and property loss. The most common obstacle avoidance technologies for UAVs are millimeter-wave radars, infrared sensors, ultrasonic sensors, laser sensors, and visual sensors. Compared with other sensors, millimeter-wave radars have the characteristics of small size, light weight, low power consumption, strong stability, long detection distance, multiple tracking targets, high accuracy, high data refresh rate, wide spectrum range, high distance resolution, high speed measurement sensitivity, strong penetration ability, anti-interference, and strong anti-stealth ability. It fully meets the stringent requirements of UAVs for indicators such as size, weight, power consumption, detection distance, real-time and anti-detection. As an important part of the RF in millimeter-wave radars, broadband millimeter-wave voltage-controlled oscillators can further improve the detection capability and resolution of radars while reducing system costs.

[0004] UAV anti-interference technology refers to taking corresponding technical means and measures against various interference means to improve the anti-interference ability of the UAV system and ensure its stable operation in complex environments. Common UAV anti-interference technologies include frequency hopping communication, spread spectrum communication, anti-interference antenna, encrypted communication, intelligent identification and interference suppression, etc. Among them, frequency hopping communication is to continuously change the communication frequency so that the interference signal cannot accurately track and interfere with the communication link of the UAV, thereby effectively improving the anti-interference ability and security of the UAV communication system. Spread spectrum communication adopts broadband transmission to disperse the signal in a wider frequency band for transmission, thereby reducing the impact of interference signals on UAV communication, thereby improving the anti-multipath interference and anti-interference ability of the UAV communication system. As an important part of the radio frequency in the millimeter wave radar, the voltage-controlled oscillator that can work in three millimeter wave frequency bands can enable the UAV to perform frequency hopping communication and spread spectrum communication, thereby further improving the anti-interference ability of the UAV and ensuring the normal operation and performance of the UAV.

[0005] At the 2019 World Radiocommunication Conference, the unified millimeter wave frequency bands are 24.25GHz~27.5GHz, 37GHz~43.5GHz, and 66GHz~71GHz. These frequency bands have wide bandwidths and high frequencies, and it is very challenging to design and implement a voltage-controlled oscillator with low phase noise, low power consumption, and a wide tuning range. At present, most voltage-controlled oscillators are designed to work at 24.25GHz~27.5GHz, and a few voltage-controlled oscillators can work at 24.25GHz~27.5GHz and 37GHz~43.5GHz. No voltage-controlled oscillator has been found to be able to work in three frequency bands. In addition, compared with other processes, the voltage-controlled oscillator of the CMOS process has the advantages of high integration, miniaturization, low cost, low power consumption, system simplification, strong robustness, wide voltage adjustment range, and strong anti-interference ability.

[0006] Therefore, in order to meet the stringent requirements of UAVs on volume, weight, power consumption, detection distance, real-time and anti-detection indicators, it is of great significance to study how to achieve a full-band wide-band tuning range while ensuring the performance and layout area of ​​the voltage-controlled oscillator, thereby improving the detection capability and resolution of the millimeter-wave radar, enabling UAVs to realize frequency-hopping communication and spread spectrum communication, and effectively improving the anti-interference ability and safety of UAVs. Summary of the invention

[0007] In order to solve the above problems existing in the prior art, the present invention provides a CMOS voltage-controlled oscillator applied to anti-interference UAV millimeter-wave radar. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0008] The present invention provides a CMOS voltage-controlled oscillator applied to an anti-interference UAV millimeter-wave radar, comprising:

[0009] A resonant circuit, a negative resistance active circuit, and a switch circuit 1 and a switch circuit 2 with the same structure.

[0010] The resonant circuit includes: a switching capacitor, a DC blocking capacitor, a resonant capacitor, a grounding resistor, a tuning resistor and a resonant inductor. In the resonant circuit, the DC blocking capacitor C1, the grounding resistor R1, the switching capacitor Var1, the tuning resistor R3, the switching capacitor Var2, the grounding resistor R2 and the DC blocking capacitor C2 are connected in series in sequence, the other ends of the DC blocking capacitors C1 and C2 are respectively connected to the two ends of the resonant inductor L1, the other ends of the grounding resistors R1 and R2 are both grounded, the other end of the tuning resistor R3 is connected to the input control voltage Vctrl1, the resonant capacitors C3 and C4 are connected in series, and the other ends of the resonant capacitors C3 and C4 are respectively connected to the two ends of the resonant inductor L1.

[0011] The negative resistance active circuit includes: a cross-coupled MOS transistor and a current source. In the negative resistance active circuit, the drain of the cross-coupled MOS transistor M1 and the drain of the cross-coupled MOS transistor M2 are respectively connected to the two ends of the resonant inductor L1, the gate of the cross-coupled MOS transistor M1 is connected to the drain of the cross-coupled MOS transistor M2, the drain of the cross-coupled MOS transistor M1 is connected to the gate of the cross-coupled MOS transistor M2, the source of the cross-coupled MOS transistor M1 is connected to the source of the cross-coupled MOS transistor M2, and is connected in series with the input end of the current source I1, and the output end of the current source I1 is grounded;

[0012] The switch circuits all include a switch coupling inductor and a switch MOS tube. In switch circuit 1, the two ends of the switch coupling inductor L2 are respectively connected to the drain and source of the switch MOS tube M3, the base of the switch MOS tube M3 is connected to the control voltage Vctrl2, the drain and source are both connected to the grounding resistors R4 and R5, and the other ends of the grounding resistors R4 and R5 are both grounded. In switch circuit 2, the two ends of the switch coupling inductor L3 are connected to the drain and source of the switch MOS tube M4, the base of the switch MOS tube M4 is connected to the control voltage Vctrl3, the drain and source are both connected to the grounding resistors R6 and R7, and the other ends of the grounding resistors R6 and R7 are both grounded.

[0013] Furthermore, the first voltage-controlled oscillation unit includes a resonant circuit and a negative resistance active circuit, the second voltage-controlled oscillation unit includes a resonant circuit, a switch circuit 1 and a negative resistance active circuit, and the third voltage-controlled oscillation unit includes a resonant circuit, a switch circuit 2 and a negative resistance active circuit.

[0014] Furthermore, the capacitance value is changed by changing the voltage difference across the varactor, thereby changing the resonant frequency, thereby achieving continuous adjustable output frequency.

[0015] Furthermore, by adjusting the size of the control voltage Vctrl2 / Vctrl3, the on and off of the switch MOS tube M3 / M4 is controlled, thereby controlling whether the switch coupling inductor L2 / L3 is connected to the transformer, and by changing the coupling coefficient of the transformer, the resonant inductance value of the LC loop in the resonant circuit is changed, thereby changing the frequency of the oscillation signal, thereby achieving the purpose of expanding the bandwidth.

[0016] Furthermore, the resonant inductor L1, the switch coupling inductor L2, and the switch coupling inductor L3 are arranged in sequence from inside to outside.

[0017] Furthermore, the resonant inductors L1, L2, L3 and the switch coupled inductor L4 in the resonant circuit form a single-phase multi-winding transformer structure, wherein the switch coupled inductor L4 is the input winding, and the resonant inductors L1, L2, L3 are the output windings.

[0018] Furthermore, when the voltage-controlled oscillator is working, only one voltage-controlled oscillator unit works normally at a time. When the first voltage-controlled oscillator unit is working, the voltage-controlled oscillator outputs a high-frequency signal, and the frequency range of the output signal is 67.5 GHz to 72.5 GHz. When the second voltage-controlled oscillator unit is working, the voltage-controlled oscillator outputs a mid-frequency signal, and the frequency range of the output signal is 38.5 GHz to 45 GHz. When the third voltage-controlled oscillator unit is working, the voltage-controlled oscillator outputs a low-frequency signal, and the frequency range of the output signal is 26.75 GHz to 29 GHz.

[0019] Furthermore, taking various influencing factors into comprehensive consideration, after the voltage-controlled oscillator is finally processed into a physical object, the output frequency range will be reduced by 1.5 GHz as a whole. The output frequency range of the voltage-controlled oscillator after the reduction can completely and accurately cover all frequency bands currently allocated to millimeter waves.

[0020] The beneficial effects of the present invention are:

[0021] The schematic diagram of a CMOS voltage-controlled oscillator for anti-interference UAV millimeter-wave radar according to the present invention is as follows: Figure 1 As shown. The present invention uses a dual-phase transformer structure to make the resonant inductor and the switch coupling inductor mutually inductive, thereby changing the inductance value of the resonant inductor and realizing frequency band switching; the VCO bandwidth is tuned by combining the switch capacitor on and off and the switch coupling inductor on and off; the CMOS process is used for design to realize the miniaturization and integration of the VCO. While ensuring the performance and layout area of ​​the voltage-controlled oscillator, a full-band wideband tuning range is achieved, thereby improving the detection capability and resolution of the millimeter-wave radar, enabling the drone to realize frequency hopping communication and spread spectrum communication, and improving the anti-interference ability and safety of the drone. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of a CMOS voltage-controlled oscillator used in an anti-interference UAV millimeter-wave radar according to the present invention;

[0023] Figure 2 It is a schematic diagram of the structure of the transformer of the present invention. DETAILED DESCRIPTION

[0024] In order to further understand the present invention, the technical solutions in the present invention will be described below in conjunction with the accompanying drawings and specific embodiments. These descriptions are only to further explain the features and advantages of the present invention, but the protection scope of the present invention is not limited thereto.

[0025] The present invention provides a CMOS voltage-controlled oscillator for use in anti-interference UAV millimeter-wave radar, such as Figure 1 As shown, it may include:

[0026] It includes a resonant circuit, a negative resistance active circuit, and a switch circuit 1 and a switch circuit 2 with the same structure.

[0027] The resonant circuit includes: a switching capacitor, a DC blocking capacitor, a resonant capacitor, a grounding resistor, a tuning resistor and a resonant inductor. In the resonant circuit, the DC blocking capacitor C1, the grounding resistor R1, the switching capacitor Var1, the tuning resistor R3, the switching capacitor Var2, the grounding resistor R2 and the DC blocking capacitor C2 are connected in series in sequence, the other ends of the DC blocking capacitors C1 and C2 are respectively connected to the two ends of the resonant inductor L1, the other ends of the grounding resistors R1 and R2 are both grounded, the other end of the tuning resistor R3 is connected to the input control voltage Vctrl1, the resonant capacitors C3 and C4 are connected in series, and the other ends of the resonant capacitors C3 and C4 are respectively connected to the two ends of the resonant inductor L1.

[0028] The negative resistance active circuit includes: a cross-coupled MOS transistor and a current source. In the negative resistance active circuit, the drain of the cross-coupled MOS transistor M1 and the drain of the cross-coupled MOS transistor M2 are respectively connected to the two ends of the resonant inductor L1, the gate of the cross-coupled MOS transistor M1 is connected to the drain of the cross-coupled MOS transistor M2, the drain of the cross-coupled MOS transistor M1 is connected to the gate of the cross-coupled MOS transistor M2, the source of the cross-coupled MOS transistor M1 is connected to the source of the cross-coupled MOS transistor M2, and is connected in series with the input end of the current source I1, and the output end of the current source I1 is grounded;

[0029] The switch circuits all include a switch coupling inductor and a switch MOS tube. In switch circuit 1, the two ends of the switch coupling inductor L2 are respectively connected to the drain and source of the switch MOS tube M3, the base of the switch MOS tube M3 is connected to the control voltage Vctrl2, the drain and source are both connected to the grounding resistors R4 and R5, and the other ends of the grounding resistors R4 and R5 are both grounded. In switch circuit 2, the two ends of the switch coupling inductor L3 are connected to the drain and source of the switch MOS tube M4, the base of the switch MOS tube M4 is connected to the control voltage Vctrl3, the drain and source are both connected to the grounding resistors R6 and R7, and the other ends of the grounding resistors R6 and R7 are both grounded.

[0030] In the embodiment of the present invention, three inductors are designed as a transformer, and the chip area occupied by the inductors is reduced by overlapping large areas with small areas. Figure 2 As shown, the resonant inductor L1 and the switch coupling inductors L2 and L3 in the resonant circuit form a dual-phase transformer structure, wherein the resonant inductor L1, the switch coupling inductor L2, and the switch coupling inductor L3 are arranged in sequence from the inside to the outside, the switch coupling inductors L2 and L3 are input windings, and the resonant inductor L1 is an output winding.

[0031] In the embodiment of the present invention, Figure 2 As shown, the switch coupling inductors L2 and L3 are octagonal inductors, and the resonant inductor L1 is an octagonal inductor with a center tap, thereby improving the inductor symmetry and reducing the layout area.

[0032] In the embodiment of the present invention, the coupling between the resonant inductor L1 and the switch coupling inductors L2 and L3 is relatively strong, and the coupling between the switch coupling inductors L2 and L3 is relatively weak.

[0033] In the embodiment of the present invention, the transformer is composed of multiple groups of inductors, so different metal layers are used to prevent metal overlap. The resonant inductor L1 uses the thickest layer of metal in this design process, and its parasitic resistance and other related parameters are relatively small, the loss is small, and the Q value is high. The switch coupling inductors L2 and L3 use the metal layer adjacent to the resonant inductor L1.

[0034] In the embodiment of the present invention, the resonant inductor L1, the resonant capacitor C3, the resonant capacitor C4, the blocking capacitor C1, the blocking capacitor C2, the grounding resistor R1, the grounding resistor R2, the tuning resistor R3, the switch capacitor Var1 and the switch capacitor Var2 constitute the resonant cavity of the first voltage-controlled oscillator unit. The resonant inductor L1, the switch coupling inductor L2, the resonant capacitor C3, the resonant capacitor C4, the blocking capacitor C1, the blocking capacitor C2, the grounding resistor R1, the grounding resistor R2, the tuning resistor R3, the switch capacitor Var1 and the switch capacitor Var2 constitute the resonant cavity of the second voltage-controlled oscillator unit. The resonant inductor L1, the switch coupling inductor L2, the switch coupling inductor L3, the resonant capacitor C3, the resonant capacitor C4, the blocking capacitor C1, the blocking capacitor C2, the grounding resistor R1, the grounding resistor R2, the tuning resistor R3, the switch capacitor Var1 and the switch capacitor Var2 constitute the resonant cavity of the third voltage-controlled oscillator unit.

[0035] In an embodiment of the present invention, the negative resistance active circuit adopts an NMOS row cross-coupling structure and uses an NMOS transistor as a negative resistance unit of a voltage-controlled oscillator. Compared with other structures, while achieving the same transconductance, the layout is smaller, the parasitic capacitance is smaller, and it is more conducive to achieving a wide bandwidth.

[0036] In the embodiment of the present invention, the cross coupling in the negative resistance active circuit provides negative resistance to the MOS transistor to compensate for the loss of the resonant cavity, so that the circuit generates an oscillation signal.

[0037] In the embodiment of the present invention, the resistors R1, R2, and R3 all have the function of preventing signal and current leakage. The resistors R4, R5, R6, and R7 prevent the RF signal from leaking to the ground on the one hand, and provide a 0V potential for the drain and source of the switch MOS tubes M2 and M3 on the other hand.

[0038] In the embodiment of the present invention, the bandwidth of the voltage-controlled oscillator is roughly adjusted by controlling the on and off of the switch coupling inductor. By adjusting the size of the control voltage Vctrl2 / Vctrl3, the on and off of the switch MOS tube M3 / M4 is controlled, thereby controlling whether the switch coupling inductor L2 / L3 is connected to the transformer. When the switch MOS tubes M3 and M4 are both turned off, no switch coupling inductor is connected to the transformer, and the inductance value of the resonant inductor L1 remains unchanged. At this time, the circuit outputs a high-frequency signal. When the switch MOS tube M3 is turned on and M4 is turned off, only the switch coupling inductor L2 is connected to the transformer, the resonant inductor L1 and the switch coupling inductor L2 are mutually inductive, and the inductance value of the resonant inductor L1 increases. At this time, the circuit outputs a mid-frequency signal. When the switch MOS tubes M3 and M4 are both turned on, the switch coupling inductors L2 and L3 are both connected to the transformer. The resonant inductor L1 is mutually inductive with the switch coupling inductor L3 again on the basis of the mutual inductance with the switch coupling inductor L2. The inductance value of the resonant inductor L1 is the largest, and the circuit outputs a low-frequency signal. In this way, the coupling coefficient of the transformer is changed, and then the resonant inductance value of the LC loop in the resonant circuit is changed, thereby changing the frequency of the oscillation signal, so as to achieve the purpose of expanding the bandwidth.

[0039] In the embodiment of the present invention, the bandwidth of the voltage-controlled oscillator is finely adjusted by controlling the switching capacitor to be turned on and off. Since one end of the varactor is at a potential of 0V, the potential of the other end is determined by the tuning voltage Vctrl1. Therefore, by changing the voltage difference across the varactor in the resonant circuit, that is, changing the voltage value of Vctrl1, the capacitance value is changed, and then the resonant frequency is changed, so that the output frequency can be continuously adjusted.

[0040] In the embodiment of the present invention, the center frequency, total resonant inductance, and total resonant capacitance C of the voltage-controlled oscillator in different operating frequency bands will change. By reasonably selecting the above parameters, the voltage-controlled oscillator can be made to oscillate in different frequency bands. When the first voltage-controlled oscillator is working, the resonant inductance L1 is 68.96pH, the total resonant capacitance is 4.819fF, and the value range of the switch capacitors Var1 and Var2 is 0 to 0.37fF. When the second voltage-controlled oscillator unit is working, the resonant inductance L1 is 11.11pH, the total resonant capacitance is 12.5fF, and the value range of the switch capacitors Var1 and Var2 is 0 to 2.29fF. When the third voltage-controlled oscillator unit is working, the resonant inductance L1 is 172.4pH, the total resonant capacitance is 174.705fF, and the value range of the switch capacitors Var1 and Var2 is 0 to 15.3fF.

[0041] In the embodiment of the present invention, when the voltage-controlled oscillator is working, only one voltage-controlled oscillator unit works normally at a time. When the first voltage-controlled oscillator unit is working, the voltage-controlled oscillator outputs a high-frequency signal, and the frequency range of the output signal is 67.5 GHz to 72.5 GHz. When the second voltage-controlled oscillator unit is working, the voltage-controlled oscillator outputs a mid-frequency signal, and the frequency range of the output signal is 38.5 GHz to 45 GHz. When the third voltage-controlled oscillator unit is working, the voltage-controlled oscillator outputs a low-frequency signal, and the frequency range of the output signal is 26.75 GHz to 29 GHz.

[0042] It should be noted that in the description of the present invention, it should be understood that the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second", and "third" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A CMOS voltage-controlled oscillator used in anti-interference UAV millimeter-wave radar, characterized in that: It includes a resonant circuit, a negative resistance active circuit, and a switch circuit 1 and a switch circuit 2 with the same structure. The resonant circuit includes: a switching capacitor, a DC blocking capacitor, a resonant capacitor, a grounding resistor, a tuning resistor and a resonant inductor. In the resonant circuit, the DC blocking capacitor C1, the grounding resistor R1, the switching capacitor Var1, the tuning resistor R3, the switching capacitor Var2, the grounding resistor R2 and the DC blocking capacitor C2 are connected in series in sequence, the other ends of the DC blocking capacitors C1 and C2 are respectively connected to the two ends of the resonant inductor L1, the other ends of the grounding resistors R1 and R2 are both grounded, the other end of the tuning resistor R3 is connected to the input control voltage Vctrl1, the resonant capacitors C3 and C4 are connected in series, and the other ends of the resonant capacitors C3 and C4 are respectively connected to the two ends of the resonant inductor L1. The negative resistance active circuit includes: a cross-coupled MOS transistor and a current source. In the negative resistance active circuit, the drain of the cross-coupled MOS transistor M1 and the drain of the cross-coupled MOS transistor M2 are respectively connected to the two ends of the resonant inductor L1, the gate of the cross-coupled MOS transistor M1 is connected to the drain of the cross-coupled MOS transistor M2, the drain of the cross-coupled MOS transistor M1 is connected to the gate of the cross-coupled MOS transistor M2, the source of the cross-coupled MOS transistor M1 is connected to the source of the cross-coupled MOS transistor M2, and is connected in series with the input end of the current source I1, and the output end of the current source I1 is grounded. The switch circuits all include a switch coupling inductor and a switch MOS tube. In switch circuit 1, the two ends of the switch coupling inductor L2 are respectively connected to the drain and source of the switch MOS tube M3, the base of the switch MOS tube M3 is connected to the control voltage Vctrl2, the drain and source are both connected to the grounding resistors R4 and R5, and the other ends of the grounding resistors R4 and R5 are both grounded. In switch circuit 2, the two ends of the switch coupling inductor L3 are respectively connected to the drain and source of the switch MOS tube M4, the base of the switch MOS tube M4 is connected to the control voltage Vctrl3, the drain and source are both connected to the grounding resistors R6 and R7, and the other ends of the grounding resistors R6 and R7 are both grounded.

2. The CMOS voltage-controlled oscillator used for anti-interference UAV millimeter-wave radar according to claim 1 is characterized in that: The first voltage-controlled oscillation unit includes a resonant circuit and a negative resistance active circuit, the second voltage-controlled oscillation unit includes a resonant circuit, a switch circuit 1 and a negative resistance active circuit, and the third voltage-controlled oscillation unit includes a resonant circuit, a switch circuit 1, a switch circuit 2 and a negative resistance active circuit.

3. The CMOS voltage-controlled oscillator used for anti-interference UAV millimeter-wave radar according to claim 1 is characterized in that: By changing the voltage difference across the varactor to change the capacitance value, and then changing the resonant frequency, the output frequency can be continuously adjusted.

4. The CMOS voltage-controlled oscillator for anti-interference UAV millimeter-wave radar according to claim 1 is characterized in that: By adjusting the control voltage Vctrl2 / Vctrl3, the on / off of the switch MOS tube M3 / M4 is controlled, thereby controlling whether the switch coupling inductor L2 / L3 is connected to the transformer. By changing the coupling coefficient of the transformer, the resonant inductance value of the LC loop in the resonant circuit is changed, thereby changing the frequency of the oscillation signal, thereby achieving the purpose of expanding the bandwidth.

5. The CMOS voltage-controlled oscillator used for anti-interference UAV millimeter-wave radar according to claim 1 is characterized in that: The resonant inductor L1, the switch coupling inductor L2, and the switch coupling inductor L3 are placed in sequence from the inside to the outside.

6. The CMOS voltage-controlled oscillator used for anti-interference UAV millimeter-wave radar according to claim 5, characterized in that: The resonant inductors L1, L2, L3 and the switch coupling inductor L4 in the resonant circuit form a dual-phase transformer structure, wherein the switch coupling inductors L2 and L3 are input windings, and the resonant inductor L1 is an output winding.

7. The CMOS voltage-controlled oscillator used for anti-interference UAV millimeter-wave radar according to claim 2 is characterized in that: When the voltage-controlled oscillator is working, only one voltage-controlled oscillator unit works normally at a time. When the first voltage-controlled oscillator unit is working, the voltage-controlled oscillator outputs a high-frequency signal, and the frequency range of the output signal is 67.5GHz to 72.5GHz. When the second voltage-controlled oscillator unit is working, the voltage-controlled oscillator outputs a mid-frequency signal, and the frequency range of the output signal is 38.5GHz to 45GHz. When the third voltage-controlled oscillator unit is working, the voltage-controlled oscillator outputs a low-frequency signal, and the frequency range of the output signal is 26.75GHz to 29GHz.

8. The CMOS voltage-controlled oscillator used for anti-interference UAV millimeter-wave radar according to claim 7, characterized in that: Taking various influencing factors into consideration, after the voltage-controlled oscillator is finally processed into a physical object, the output frequency range will be reduced by 1.5 GHz as a whole. The output frequency range of the voltage-controlled oscillator after the reduction can completely and accurately cover all currently allocated millimeter-wave frequency bands.

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