Anti-radiation low-phase noise voltage-controlled oscillator based on SOI process

Abstract

The invention discloses an anti-radiation low-phase noise voltage-controlled oscillator based on an SOI (Silicon On Insulator) process, relates to the technical field of oscillators, and is used for solving the technical problem that the existing voltage-controlled oscillator based on the SOI process cannot realize low phase noise and high anti-radiation capability at the same time. The anti-radiation low-phase noise voltage-controlled oscillator based on the SOI technology comprises an energy storage unit and a negative transconductance unit. The energy storage unit forms a resonant cavity through an inductor and a capacitor; the negative transconductance unit is connected with the energy storage unit; the negative transconductance unit at least comprises a first cross-coupled pair and a second cross-coupled pair which are formed by a plurality of transistors; the first cross coupling pair is used for generating negative resistance to compensate the loss of the energy storage unit, and the second cross coupling pair serves as a current switching network; the first cross coupling pair and the second cross coupling pair form a negative resistance characteristic, direct-current energy is converted into alternating-current oscillation energy, loss of the resonant cavity is compensated, and a generated oscillation signal is output from the output node.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oscillator technology, and more particularly, to an anti-radiation low phase noise voltage controlled oscillator based on SOI process. BACKGROUND

[0002] The voltage controlled oscillator is a core module in modern radio frequency and analog hybrid signal circuit system, and is widely used in high-performance communication systems, high-speed data converters and precision measuring instruments. The core phase noise and frequency tuning range of the voltage controlled oscillator directly determine the signal-to-noise ratio, communication quality, positioning accuracy and anti-interference ability of the whole system. Space radiation can cause single event effects of the oscillator, resulting in frequency jump or instantaneous phase mutation. At the same time, the long-term cumulative total dose effect can change the parameters of the transistor and LC element, causing the oscillator frequency to drift or stop. Therefore, in a harsh radiation environment, it is a rigid requirement to ensure that the voltage controlled oscillator remains stable in key indicators and is not significantly degraded by high-energy particles, in order to ensure the reliable operation of the system.

[0003] The voltage controlled oscillator of the prior art is usually a standard bulk silicon CMOS (complementary metal oxide semiconductor) or bipolar process. However, the parasitic PN junction inherent in the bulk silicon process will produce significant leakage and charge accumulation under high dose radiation, resulting in frequency drift, tuning range compression, and even functional failure of the voltage controlled oscillator. Although reinforcement measures such as deep well isolation can alleviate the problem to some extent, these methods usually introduce additional parasitic capacitance, which reduces the Q value of the resonant cavity and degrades the phase noise. At the same time, the substrate coupling effect in the traditional process is serious, and it is extremely sensitive to noise and radiation disturbance. The conventional circuit structure is still prone to significant deterioration in oscillation amplitude, frequency and phase noise characteristics when facing the effects of radiation-induced MOS transistor threshold voltage drift and increased leakage current. Therefore, the existing voltage controlled oscillator based on SOI process often cannot balance the low phase noise and anti-radiation ability optimally. SUMMARY

[0004] The present application aims to provide an anti-radiation low phase noise voltage controlled oscillator based on SOI process, which solves the technical problem that the existing voltage controlled oscillator based on SOI process cannot simultaneously achieve low phase noise and high anti-radiation ability. In view of this, the present application is implemented by the following scheme.

[0005] The present application provides an anti-radiation low phase noise voltage controlled oscillator based on SOI process, comprising: An energy storage unit, which constitutes a resonant cavity through an inductor and a capacitor; A negative transconductance unit connected to the energy storage unit; The negative transconductance unit is arranged to at least include a first cross-coupled pair and a second cross-coupled pair composed of multiple transistors; the first cross-coupled pair is used to generate negative resistance to compensate for the loss of the energy storage unit, and the second cross-coupled pair acts as a current switch network. The first cross-coupled pair and the second cross-coupled pair form a negative resistance characteristic, convert direct current energy into alternating oscillation energy, compensate for the loss of the resonant cavity, and output the generated oscillation signal from the output node.

[0006] Compared with the prior art, in the SOI process-based anti-radiation low-phase-noise voltage-controlled oscillator of the present application, the energy storage unit forms a resonant cavity through an inductor and a capacitor, the varactor reverse bias technology can be used to eliminate the parasitic diode between the n-well and the substrate, the n-well of the varactor is grounded, the radiation hardening in the varactor is realized, and thus the anti-radiation capability of the voltage-controlled oscillator is improved; the negative transconductance unit can use stacked transistors, when a single particle of radiation is incident on one of the transistors, the other transistor is hardly affected, and thus only a small amount of single-particle current pulse flows to the ground terminal or the power terminal, thereby effectively reducing the single-particle effect of the circuit and further improving the anti-radiation capability of the voltage-controlled oscillator and reducing the phase noise; further, in the above technical solution, the negative transconductance unit is arranged to at least include a first cross-coupled pair and a second cross-coupled pair composed of multiple transistors; the first cross-coupled pair is used to generate negative resistance to compensate for the loss of the energy storage unit, and the second cross-coupled pair acts as a current switch network; the first cross-coupled pair and the second cross-coupled pair form a negative resistance characteristic, convert direct current energy into alternating oscillation energy, compensate for the loss of the resonant cavity, and output the generated oscillation signal from the output node; specifically, at the moment of initial power-up, the thermal noise of the transistors or the power supply disturbance generates a weak voltage difference at the output node, the inductor and the capacitor of the energy storage unit form a resonant cavity, oscillation is formed through alternating conversion of electromagnetic energy, the first cross-coupled pair and the second cross-coupled pair (cross-coupled transistors) form a negative resistance characteristic, continuously convert direct current energy into alternating oscillation energy, and compensate for the loss of the resonant cavity; the generated oscillation signal is directly output from the output node of the voltage-controlled oscillator as a sine wave; further, the SOI process-based anti-radiation low-phase-noise voltage-controlled oscillator of the present application can use adaptive body bias technology, so that the threshold voltage is reduced, a larger negative transconductance is further generated, and the phase noise of the voltage-controlled oscillator is improved. Through the above technical solution of the present application, the technical problem that the existing SOI process-based voltage-controlled oscillator cannot simultaneously realize low phase noise and high anti-radiation capability is solved.

[0007] Further, the SOI process-based anti-radiation low-phase-noise voltage-controlled oscillator of the present application further includes a transconductance multiplication unit. The transconductance multiplication unit has a first end and a second end; the input end of the negative transconductance unit is connected to the first end of the transconductance multiplication unit, and the energy storage unit is connected to the second end of the transconductance multiplication unit.

[0008] Further, in the SOI process-based anti-radiation low-phase-noise voltage-controlled oscillator, the transconductance multiplication unit comprises a first inductor and a second inductor. The first end of the first inductor and the first end of the second inductor are both connected to the negative transconductance unit. The second end of the first inductor and the second end of the second inductor are both connected to the energy storage unit.

[0009] Further, in the SOI process-based anti-radiation low-phase-noise voltage-controlled oscillator, the energy storage unit comprises a third inductor, a first variable capacitor and a second variable capacitor. The first end of the third inductor is connected to the second end of the first inductor, the second end of the third inductor is connected to the second end of the second inductor, and the third end of the third inductor is connected to a power supply. The first end of the first variable capacitor is connected to the second end of the first inductor, the second end of the first variable capacitor is connected to the first end of the second variable capacitor, and the connection is connected to a control voltage; the second end of the second variable capacitor is connected to the second end of the second inductor.

[0010] Further, in the SOI process-based anti-radiation low-phase-noise voltage-controlled oscillator, the first cross-coupled pair comprises a first NMOS transistor, a second NMOS transistor, a third NMOS transistor and a fourth NMOS transistor; the gate of the first NMOS transistor is connected to the drain of the second NMOS transistor, the drain of the first NMOS transistor is connected to the first end of the first inductor, and the source of the first NMOS transistor is connected to the drain of the third NMOS transistor; the gate of the second NMOS transistor is connected to the drain of the first NMOS transistor, the drain of the second NMOS transistor is connected to the first end of the second inductor, and the source of the second NMOS transistor is connected to the drain of the fourth NMOS transistor; the gate of the third NMOS transistor is connected to the drain of the second NMOS transistor; the gate of the fourth NMOS transistor is connected to the drain of the first NMOS transistor; the first cross-coupled pair is connected to the second cross-coupled pair through the source of the third NMOS transistor and the source of the fourth NMOS transistor.

[0011] Further, in the SOI process based anti-radiation low phase noise voltage controlled oscillator of the present application, the second cross-coupled pair comprises a fifth NMOS transistor, a sixth NMOS transistor, a seventh NMOS transistor and an eighth NMOS transistor; the gate of the fifth NMOS transistor is connected to the drain of the sixth NMOS transistor, the drain of the fifth NMOS transistor is connected to the source of the third NMOS transistor, and the source of the fifth NMOS transistor is connected to the drain of the seventh NMOS transistor; the gate of the sixth NMOS transistor is connected to the drain of the fifth NMOS transistor, the drain of the sixth NMOS transistor is connected to the source of the fourth NMOS transistor, and the source of the sixth NMOS transistor is connected to the drain of the eighth NMOS transistor; the gate of the seventh NMOS transistor is connected to the drain of the sixth NMOS transistor, and the source of the seventh NMOS transistor is grounded; and the gate of the eighth NMOS transistor is connected to the drain of the fifth NMOS transistor, and the source of the eighth NMOS transistor is grounded.

[0012] Further, in the SOI process based anti-radiation low phase noise voltage controlled oscillator of the present application, the body terminal of the first NMOS transistor is connected to the body terminals of the third NMOS transistor, the fifth NMOS transistor and the seventh NMOS transistor, and is commonly connected to the source of the fourth NMOS transistor and the drain of the sixth NMOS transistor.

[0013] Further, in the SOI process based anti-radiation low phase noise voltage controlled oscillator of the present application, the body terminal of the second NMOS transistor is connected to the body terminals of the fourth NMOS transistor, the sixth NMOS transistor and the eighth NMOS transistor, and is commonly connected to the source of the third NMOS transistor and the drain of the fifth NMOS transistor. BRIEF DESCRIPTION OF DRAWINGS

[0014] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings: Figure 1 Structure schematic diagram of the SOI process based anti-radiation low phase noise voltage controlled oscillator of the present application; Figure 2 Phase noise simulation schematic diagram of the SOI process based anti-radiation low phase noise voltage controlled oscillator of the present application.

[0015] Reference signs: Figure 1L1, first inductor; L2, second inductor; L3, third inductor; C1, first variable capacitor; C2, second variable capacitor; M1, first NMOS transistor; M2, second NMOS transistor; M3, third NMOS transistor; M4, fourth NMOS transistor; M5, fifth NMOS transistor; M6, sixth NMOS transistor; M7, seventh NMOS transistor; M8, eighth NMOS transistor; VCtrl, control voltage. DETAILED DESCRIPTION

[0016] In order to make the technical problems to be solved by the present application, technical solutions and beneficial effects clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not intended to limit the present application.

[0017] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0018] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise explicitly and specifically limited. The meaning of "several" is one or more, unless otherwise explicitly and specifically limited.

[0019] Prior art voltage-controlled oscillators are usually standard bulk silicon CMOS (Complementary Metal Oxide Semiconductor) or bipolar process. However, the parasitic PN junction inherent in the bulk silicon process will produce significant leakage and charge accumulation under high dose radiation, resulting in frequency drift, tuning range compression, and even functional failure of the voltage-controlled oscillator. Although reinforcement measures such as deep well isolation can alleviate to some extent, these methods usually introduce additional parasitic capacitance, reduce the resonant cavity Q value, and instead degrade the phase noise. At the same time, the substrate coupling effect in the traditional process is serious and extremely sensitive to noise and radiation disturbance. The conventional circuit structure is still prone to significant deterioration in oscillation amplitude, frequency, and phase noise characteristics when facing the effects of threshold voltage drift and increased leakage current of MOS transistors caused by radiation. Therefore, the existing voltage-controlled oscillators based on SOI process often find it difficult to balance the pursuit of low phase noise and radiation resistance.

[0020] In order to solve the above technical problems, the application provides an anti-radiation low phase noise voltage controlled oscillator based on SOI process, which comprises an energy storage unit and a negative transconductance unit; wherein: The energy storage unit forms a resonant cavity through inductance and capacitance; the negative transconductance unit is connected with the energy storage unit; the negative transconductance unit is arranged to at least comprise a first cross-coupled pair and a second cross-coupled pair composed of multiple transistors; the first cross-coupled pair is used for generating negative resistance to compensate for the loss of the energy storage unit, and the second cross-coupled pair acts as a current switch network; the first cross-coupled pair and the second cross-coupled pair form a negative resistance characteristic, convert direct current energy into alternating current oscillation energy, compensate for the loss of the resonant cavity, and output the generated oscillation signal from an output node.

[0021] In the anti-radiation low phase noise voltage controlled oscillator based on SOI process, the energy storage unit forms a resonant cavity through inductance and capacitance, the varactor reverse bias technology can be used to eliminate the parasitic diode between the n-well and the substrate, the varactor n-well is grounded, the radiation hardening in the varactor is realized, and thus the anti-radiation capability of the voltage controlled oscillator is improved; the negative transconductance unit can use stacked tubes, when a radiation single particle enters one of the transistors, the other transistor is almost not affected, and thus only a small amount of single particle current pulse flows to the ground end or the power supply end, thereby effectively reducing the single particle effect of the circuit, further effectively improving the anti-radiation capability of the voltage controlled oscillator, and reducing the phase noise; further, in the above technical solution, the negative transconductance unit is arranged to at least comprise a first cross-coupled pair and a second cross-coupled pair composed of multiple transistors; the first cross-coupled pair is used for generating negative resistance to compensate for the loss of the energy storage unit, and the second cross-coupled pair acts as a current switch network; the first cross-coupled pair and the second cross-coupled pair form a negative resistance characteristic, convert direct current energy into alternating current oscillation energy, compensate for the loss of the resonant cavity, and output the generated oscillation signal from an output node; specifically, at the moment of initial power-on, the thermal noise of the transistor or the power supply disturbance generates a weak voltage difference at the output node, the inductance and the capacitance of the energy storage unit form a resonant cavity, oscillation is formed through alternating conversion of electromagnetic energy, the first cross-coupled pair and the second cross-coupled pair (cross-coupled transistors) form a negative resistance characteristic, continuously convert direct current energy into alternating current oscillation energy, and compensate for the loss of the resonant cavity; the generated oscillation signal is directly output as a sine wave from the output node of the voltage controlled oscillator; further, the anti-radiation low phase noise voltage controlled oscillator based on SOI process can use adaptive body bias technology, so that the threshold voltage is reduced, a larger negative transconductance is further generated, and the phase noise of the voltage controlled oscillator is improved. Through the above technical solution of the application, the technical problem that the existing voltage controlled oscillator based on SOI process cannot simultaneously realize low phase noise and high anti-radiation capability is solved.

[0022] As a possible implementation, the SOI process based anti-radiation low phase noise voltage controlled oscillator further comprises a transconductance multiplication unit; the transconductance multiplication unit has a first end and a second end; the input end of the negative transconductance unit is connected to the first end of the transconductance multiplication unit, and the energy storage unit is connected to the second end of the transconductance multiplication unit. In the case of adopting the technical scheme, the transconductance multiplication unit can be composed of multiple inductors, and by arranging the transconductance multiplication unit between the energy storage unit and the negative transconductance unit, the generated negative transconductance can be significantly enhanced, the power consumption is reduced, and the anti-radiation capability of the voltage controlled oscillator is further improved.

[0023] As a possible implementation, the SOI process based anti-radiation low phase noise voltage controlled oscillator further comprises a transconductance multiplication unit; the transconductance multiplication unit has a first end and a second end; the input end of the negative transconductance unit is connected to the first end of the transconductance multiplication unit, and the energy storage unit is connected to the second end of the transconductance multiplication unit. In the case of adopting the technical scheme, the transconductance multiplication unit can be composed of multiple inductors, and by arranging the transconductance multiplication unit between the energy storage unit and the negative transconductance unit, the generated negative transconductance can be significantly enhanced, the power consumption is reduced, and the anti-radiation capability of the voltage controlled oscillator is further improved.

[0024] As a possible implementation, the SOI process based anti-radiation low phase noise voltage controlled oscillator further comprises a transconductance multiplication unit; the transconductance multiplication unit has a first end and a second end; the input end of the negative transconductance unit is connected to the first end of the transconductance multiplication unit, and the energy storage unit is connected to the second end of the transconductance multiplication unit. In the case of adopting the technical scheme, the transconductance multiplication unit can be composed of multiple inductors, and by arranging the transconductance multiplication unit between the energy storage unit and the negative transconductance unit, the generated negative transconductance can be significantly enhanced, the power consumption is reduced, and the anti-radiation capability of the voltage controlled oscillator is further improved.

[0025] As a possible implementation, in the SOI process based anti-radiation low phase noise voltage controlled oscillator of the present application, the first cross-coupled pair comprises a first NMOS transistor M1, a second NMOS transistor M2, a third NMOS transistor M3 and a fourth NMOS transistor M4; the gate of the first NMOS transistor M1 is connected to the drain of the second NMOS transistor M2, the drain of the first NMOS transistor M1 is connected to the first end of a first inductor L1, and the source of the first NMOS transistor M1 is connected to the drain of the third NMOS transistor M3; the gate of the second NMOS transistor M2 is connected to the drain of the first NMOS transistor M1, the drain of the second NMOS transistor M2 is connected to the first end of a second inductor L2, and the source of the second NMOS transistor M2 is connected to the drain of the fourth NMOS transistor M4; the gate of the third NMOS transistor M3 is connected to the drain of the second NMOS transistor M2; the gate of the fourth NMOS transistor M4 is connected to the drain of the first NMOS transistor M1; the first cross-coupled pair is connected to the second cross-coupled pair through the source of the third NMOS transistor M3 and the source of the fourth NMOS transistor M4. In the case of using this technical solution, the first cross-coupled pair compensates for the loss of the tank circuit by generating negative resistance.

[0026] As a possible implementation, in the SOI process based anti-radiation low phase noise voltage controlled oscillator of the present application, the second cross-coupled pair comprises a fifth NMOS transistor M5, a sixth NMOS transistor M6, a seventh NMOS transistor M7 and an eighth NMOS transistor M8; the gate of the fifth NMOS transistor M5 is connected to the drain of the sixth NMOS transistor M6, the drain of the fifth NMOS transistor M5 is connected to the source of the third NMOS transistor M3, and the source of the fifth NMOS transistor M5 is connected to the drain of the seventh NMOS transistor M7; the gate of the sixth NMOS transistor M6 is connected to the drain of the fifth NMOS transistor M5, the drain of the sixth NMOS transistor M6 is connected to the source of the fourth NMOS transistor M4, and the source of the sixth NMOS transistor M6 is connected to the drain of the eighth NMOS transistor M8; the gate of the seventh NMOS transistor M7 is connected to the drain of the sixth NMOS transistor M6, and the source of the seventh NMOS transistor M7 is grounded; the gate of the eighth NMOS transistor M8 is connected to the drain of the fifth NMOS transistor M5, and the source of the eighth NMOS transistor M8 is grounded. In the case of using this technical solution, the second cross-coupled pair acts as a current switching network, and improves the generated negative transconductance by providing greater loop gain.

[0027] As a possible implementation, in the SOI process based anti-radiation low phase noise voltage controlled oscillator of the present application, the body terminal of the first NMOS transistor M1 is connected to the body terminals of the third NMOS transistor M3, the fifth NMOS transistor M5 and the seventh NMOS transistor M7, and is connected to the source of the fourth NMOS transistor M4 and the drain of the sixth NMOS transistor M6. In the case of using this technical solution, the threshold voltage of the transistor can be reduced by forward body bias, thereby generating greater negative transconductance, and the phase noise of the voltage controlled oscillator can be effectively improved.

[0028] As a possible implementation, in the SOI process based anti-radiation low phase noise voltage controlled oscillator of the present application, the body terminal of the second NMOS transistor M2 is connected to the body terminals of the fourth NMOS transistor M4, the sixth NMOS transistor M6 and the eighth NMOS transistor M8, and is connected to the source of the third NMOS transistor M3 and the drain of the fifth NMOS transistor M5. In the case of using this technical solution, the threshold voltage of the transistor can be reduced by forward body bias, thereby generating greater negative transconductance, and the phase noise of the voltage controlled oscillator can be effectively improved.

[0029] Further, the SOI process based anti-radiation low phase noise voltage controlled oscillator of the present application is simulated. Specifically, the simulation experiment element of the present application adopts XMC 55nm RFSOI CMOS process, and the simulation circuit of the present application is built based on the Cadence IC617 simulation experiment platform under the Linux system. The simulation experiment of the present application uses the Specture RF simulation tool to simulate the circuit of the present application, and the given power supply voltage VDD is 0.8V and the working temperature is 27℃.

[0030] The simulation process is as follows: under the above working conditions, the Specture RF simulation tool is used, the corresponding output ports are added to the positive output end OUTP and the negative output end OUTN respectively, and the SOI process based anti-radiation low phase noise voltage controlled oscillator of the present application is simulated by PSS+PNOISE; the specific simulation results are shown in Figure 2 Figure 2 The phase noise simulation results are shown in Figure 2 , in which the abscissa represents the offset frequency (HZ), and the ordinate represents the output signal phase noise (dBc / Hz). From Figure 2 ​The phase noise simulation result shows that the phase noise of the voltage-controlled oscillator without using the bulk bias technology is-119.7dBc / Hz at 10MHz frequency offset under the working frequency of 25GHz, the phase noise is improved to-122.4dBc / Hz by using the bulk bias technology, and the power consumption is only 2.85mW. The simulation result shows that the SOI process based anti-radiation low phase noise voltage-controlled oscillator has the characteristics of high frequency, low phase noise and excellent anti-radiation performance.

[0031] In the description of the above-described embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0032] The above description is merely specific implementation of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A radiation-resistant low phase noise voltage-controlled oscillator based on SOI technology, characterized in that: include: Energy storage unit, which forms a resonant cavity through inductance and capacitance; a negative transconductance unit connected to the energy storage unit; The negative transconductance unit is configured to include at least a first cross-coupling pair and a second cross-coupling pair consisting of a plurality of transistors; the first cross-coupling pair is used to generate a negative resistance to compensate for the loss of the energy storage unit, and the second cross-coupling pair acts as a current switching network; The first cross-coupling pair and the second cross-coupling pair form a negative resistance characteristic, converting DC energy into AC oscillation energy to compensate for the loss of the resonant cavity, and the generated oscillation signal is output from the output node.

2. The radiation-resistant low phase noise voltage-controlled oscillator based on SOI process according to claim 1, characterized in that: Also included is a transconductance multiplication unit; The transconductance multiplying unit has a first end and a second end; the input end of the negative transconductance unit is connected to the first end of the transconductance multiplying unit, and the energy storage unit is connected to the second end of the transconductance multiplying unit.

3. The radiation-resistant low phase noise voltage-controlled oscillator based on SOI process according to claim 2, characterized in that: The transconductance multiplication unit includes a first inductor and a second inductor; The first end of the first inductor and the first end of the second inductor are both connected to the negative transconductance unit; The second end of the first inductor and the second end of the second inductor are both connected to the energy storage unit.

4. The radiation-resistant low phase noise voltage-controlled oscillator based on SOI process according to claim 3, characterized in that: The energy storage unit includes a third inductor, a first variable capacitor and a second variable capacitor; A first end of the third inductor is connected to the second end of the first inductor, a second end of the third inductor is connected to the second end of the second inductor, and a third end of the third inductor is connected to a power supply; The first end of the first variable capacitor is connected to the second end of the first inductor, the second end of the first variable capacitor is connected to the first end of the second variable capacitor, and the connection point is commonly connected to the control voltage; the second end of the second variable capacitor is connected to the second end of the second inductor.

5. The radiation-resistant low phase noise voltage-controlled oscillator based on SOI process according to claim 4, characterized in that: The first cross-coupled pair includes a first NMOS transistor, a second NMOS transistor, a third NMOS transistor, and a fourth NMOS transistor; The gate of the first NMOS transistor is connected to the drain of the second NMOS transistor, the drain of the first NMOS transistor is connected to the first end of the first inductor, and the source of the first NMOS transistor is connected to the drain of the third NMOS transistor; the gate of the second NMOS transistor is connected to the drain of the first NMOS transistor, the drain of the second NMOS transistor is connected to the first end of the second inductor, and the source of the second NMOS transistor is connected to the drain of the fourth NMOS transistor; the gate of the third NMOS transistor is connected to the drain of the second NMOS transistor; the gate of the fourth NMOS transistor is connected to the drain of the first NMOS transistor; and the first cross-coupled pair is connected to the second cross-coupled pair via the source of the third NMOS transistor and the source of the fourth NMOS transistor.

6. The radiation-resistant low phase noise voltage-controlled oscillator based on SOI process according to claim 5, characterized in that: the second cross-coupled pair comprising a fifth NMOS transistor, a sixth NMOS transistor, a seventh NMOS transistor, and an eighth NMOS transistor; The gate of the fifth NMOS transistor is connected to the drain of the sixth NMOS transistor, the drain of the fifth NMOS transistor is connected to the source of the third NMOS transistor, and the source of the fifth NMOS transistor is connected to the drain of the seventh NMOS transistor; the gate of the sixth NMOS transistor is connected to the drain of the fifth NMOS transistor, the drain of the sixth NMOS transistor is connected to the source of the fourth NMOS transistor, and the source of the sixth NMOS transistor is connected to the drain of the eighth NMOS transistor; the gate of the seventh NMOS transistor is connected to the drain of the sixth NMOS transistor, and the source of the seventh NMOS transistor is grounded; the gate of the eighth NMOS transistor is connected to the drain of the fifth NMOS transistor, and the source of the eighth NMOS transistor is grounded.

7. The radiation-resistant low phase noise voltage-controlled oscillator based on SOI process according to claim 6, characterized in that: The body terminal of the first NMOS transistor is connected to the body terminals of the third NMOS transistor, the fifth NMOS transistor, and the seventh NMOS transistor, and is commonly connected to the source of the fourth NMOS transistor and the drain of the sixth NMOS transistor.

8. The radiation-resistant low phase noise voltage-controlled oscillator based on SOI process according to claim 7, characterized in that: The body terminal of the second NMOS transistor is connected to the body terminals of the fourth NMOS transistor, the sixth NMOS transistor, and the eighth NMOS transistor, and is commonly connected to the source of the third NMOS transistor and the drain of the fifth NMOS transistor.

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