A wideband voltage-controlled oscillator with wideband harmonic tunability
By coordinating the design of LC resonant unit, negative resistance unit, head resonant unit and tuning transformer unit, and combining variable capacitor unit and capacitor array unit, the problems of narrow tuning range and phase noise degradation of LC oscillator in high frequency band are solved, and the performance improvement of wide bandwidth and low phase noise is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NORTHWESTERN POLYTECHNICAL UNIV
- Filing Date
- 2026-05-19
- Publication Date
- 2026-07-21
AI Technical Summary
Existing LC oscillators suffer from narrow tuning range and deteriorated phase noise at high frequencies due to the limited range of varactor tube capacitance and the influence of parasitic parameters, making it difficult to meet the performance requirements of wide bandwidth and low phase noise.
The design employs a collaborative approach of LC resonant unit, negative resistance unit, head resonant unit, and tuning transformer unit. The oscillation frequency is adjusted via magnetic tuning, and frequency adjustment is achieved by combining variable capacitor unit and capacitor array unit. This results in a wide-band adjustable range.
It widens the tuning range, reduces phase noise, and improves frequency tuning accuracy, making it suitable for high-frequency systems.
Smart Images
Figure CN122247351B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of radio frequency integrated circuit design technology, and more specifically, to a broadband harmonic-tunable voltage-controlled oscillator. Background Technology
[0002] With the rapid development of wireless communication technology, millimeter wave technology has been widely researched and applied due to its own advantages. In the process of high-speed wireless communication systems evolving to the millimeter wave band, the frequency source, as an important component of the millimeter wave system, determines the signal-to-noise ratio of the transmitted signal of the entire system. Among the frequency sources, the voltage-controlled oscillator is the most core module, which is widely used to provide a stable frequency and greatly affects the performance of the frequency source.
[0003] In systems such as phase-locked loops, frequency synthesizers, and wireless transceivers, the main performance requirements for voltage-controlled oscillators (VCOs) are wide operating range and low phase noise. Existing LC oscillator designs rely on varactor diodes to adjust the frequency. However, the capacitance of varactor diodes has a limited range of variation, and at high frequencies (such as millimeter-wave bands), the quality factor (i.e., Q value) drops sharply due to the influence of parasitic parameters in the circuit, resulting in a narrow tuning range and deteriorated phase noise. Summary of the Invention
[0004] The purpose of this invention is to provide a broadband harmonic-tunable voltage-controlled oscillator (VCO) to address the technical problems of existing LC oscillators that rely on varactor diodes to adjust the frequency. However, the varactor diodes have a limited capacitance range, and the quality factor drops sharply at high frequencies due to parasitic parameters in the circuit, resulting in a narrow tuning range and deteriorated phase noise. Therefore, this invention achieves this through the following solution.
[0005] This invention provides a broadband harmonic-tunable voltage-controlled oscillator, comprising: LC resonant unit, used to provide oscillation signal; The negative resistance unit is used to provide oscillation energy for the voltage-controlled oscillator. Its second terminal is connected to the power supply ground, and its first terminal is connected to the second terminal of the LC resonant unit. The head resonant unit is formed by a capacitor and an inductor. Its input terminal is connected to the power supply voltage, and its output terminal is connected to the first terminal of the LC resonant unit. A tuning transformer unit is formed by an inductor and a transistor. The inductance of the tuning transformer unit is coupled to the inductance of the LC resonant unit. The input terminal of the tuning transformer unit is connected to a first control voltage. The tuning transformer unit resonates at the first harmonic frequency of the voltage-controlled oscillator output frequency. The tuning transformer unit and the head resonant unit act simultaneously on the first and second harmonics. The oscillation frequency is adjusted by magnetic tuning controlled by the first control voltage to obtain a wide-band adjustable range.
[0006] Compared with the prior art, the broadband harmonic-tunable voltage-controlled oscillator of the present invention is provided with at least an LC resonant unit, a negative resistance unit, a head resonant unit, and a tuning transformer unit. The LC resonant unit is composed of an inductor (L) and a capacitor (C), and is used to provide the oscillation signal. The negative resistance unit is used to provide oscillation energy to the voltage-controlled oscillator, with its second terminal connected to the power supply ground and its first terminal connected to the second terminal of the LC resonant unit. The head resonant unit is formed by a capacitor and an inductor, with its input terminal connected to the power supply voltage and its output terminal connected to the first terminal of the LC resonant unit. The tuning transformer unit is formed by an inductor and a transistor, with the inductance of the tuning transformer unit corresponding to the inductance of the LC resonant unit and exhibiting transformer coupling. The input terminal of the tuning transformer unit is connected to a first control voltage. Based on the above structure, the tuning transformer unit resonates at the first harmonic frequency of the voltage-controlled oscillator output frequency. The tuning transformer unit and the head resonator unit act simultaneously on the first and second harmonics. The oscillation frequency is adjusted by magnetic tuning controlled by the first control voltage, thereby obtaining a wider adjustable range. Specifically, the above-mentioned wideband voltage-controlled oscillator adopts the synergistic effect of the head resonator unit and the tuning transformer unit. The head resonator unit resonates at the second harmonic, providing high impedance at the second harmonic frequency through the common-mode resonant frequency to reduce phase noise. The tuning transformer unit resonates at the fundamental frequency, adjusting the equivalent inductance value through the first control voltage to avoid the problem of varactor Q value degradation, and performing harmonic adjustment on the spectrum of the oscillation signal to enhance the harmonic amplitude and reduce phase noise. The head resonator unit and the tuning transformer unit synchronously control the frequency and impedance of the fundamental and second harmonics through magnetic coupling coefficients (K1 to K5) to obtain a new set of tuning bands, thereby achieving harmonic tuning over a wider range. Therefore, the above-mentioned technical solution of the present invention solves the technical problem that the design of existing LC oscillators relies on varactor tubes to adjust the frequency, but the range of the varactor tube's capacitance value is limited, and the quality factor drops sharply in the high-frequency range due to the influence of parasitic parameters in the circuit, resulting in a narrow tuning range and deterioration of phase noise.
[0007] Furthermore, the broadband harmonic-tunable wideband voltage-controlled oscillator of the present invention also includes a variable capacitor unit and a capacitor array unit; The variable capacitor unit is formed by a capacitor, a variable capacitor, and a resistor, and the capacitance value of the variable capacitor is changed by adjusting the second control voltage. The capacitor array unit includes 2 n A bit-swappable capacitor array, where n is an integer greater than or equal to zero; The second end of the LC resonant unit is connected to the variable capacitor unit, the variable capacitor unit is connected to the capacitor array unit, and the capacitor array unit is connected to the first end of the negative resistance unit.
[0008] Furthermore, in the broadband harmonic-tunable wideband voltage-controlled oscillator of the present invention, the LC resonant unit includes a first inductor, a second inductor, a third capacitor, and a fourth capacitor; The first end of the first inductor is connected to the first end of the second inductor, and the connection point is used as the first end of the LC resonant unit. The first terminal of the third capacitor is connected to the first terminal of the fourth capacitor; The second terminal of the first inductor is connected to the second terminal of the third capacitor; The second terminal of the second inductor is connected to the second terminal of the fourth capacitor; The connection point between the first inductor and the third capacitor, and the connection point between the second inductor and the fourth capacitor, are used as the second end of the LC resonant unit.
[0009] Furthermore, in the broadband harmonic-tunable wideband voltage-controlled oscillator of the present invention, the negative resistance unit includes a first NMOS transistor and a second NMOS transistor; The first NMOS transistor and the second NMOS transistor are cross-connected; The drain of the first NMOS transistor and the drain of the second NMOS transistor serve as the first terminal of the negative resistance unit; The source of the first NMOS transistor is connected to the source of the second NMOS transistor, and the connection point is used as the second end of the negative resistance unit.
[0010] Furthermore, in the broadband harmonic-tunable wideband voltage-controlled oscillator of the present invention, the head resonant unit includes a fifth inductor, a sixth inductor, and a fifth capacitor; The first end of the fifth inductor is connected to the first end of the fifth capacitor, and the connection point is used as the input end of the head resonant unit; The second terminal of the fifth capacitor is connected to the first terminal of the sixth inductor; The second end of the sixth inductor is connected to the second end of the fifth inductor, and the connection point is used as the output end of the head resonant unit; the fifth inductor and the sixth inductor are coupled by a transformer.
[0011] Furthermore, in the broadband harmonic-tunable wideband voltage-controlled oscillator of the present invention, the tuning transformer unit includes a third inductor, a fourth inductor, a seventh inductor, and a third NMOS transistor and a fourth NMOS transistor; The gate of the third NMOS transistor and the gate of the fourth NMOS transistor are connected to the first control voltage. The drain of the third NMOS transistor is connected to the first terminal of the third inductor; The source of the third NMOS transistor is connected to the first terminal of the fourth inductor; The drain of the fourth NMOS transistor is connected to the first terminal of the seventh inductor; The source of the fourth NMOS transistor is connected to the second terminal of the seventh inductor; The second terminal of the third inductor is connected to the second terminal of the fourth inductor; The third inductor is transformer-coupled with the first inductor, the fourth inductor is transformer-coupled with the second inductor, the seventh inductor is transformer-coupled with the sixth inductor, and the seventh inductor is transformer-coupled with the fifth inductor.
[0012] Furthermore, in the broadband harmonic-tunable wideband voltage-controlled oscillator of the present invention, the variable capacitor unit includes a first capacitor, a second capacitor, a first variable capacitor, a second variable capacitor, a first resistor, and a second resistor. The second end of the first resistor is connected to the second end of the second resistor, and a bias voltage is input at the connection point; the first end of the first resistor is connected to the second end of the first capacitor and the first end of the first variable capacitor; the first end of the second resistor is connected to the second end of the second capacitor and the first end of the second variable capacitor; the second end of the first variable capacitor is connected to the second end of the second variable capacitor, and a second control voltage is input at the connection point; the first end of the first capacitor and the first end of the second capacitor serve as the connection points of the variable capacitor unit.
[0013] Furthermore, in the broadband harmonic-tunable wideband voltage-controlled oscillator of the present invention, the capacitor array unit includes a 4-bit switched capacitor array, and each switched capacitor array includes an array NMOS transistor, a first array capacitor, and a second array capacitor. The gate connection bit control signal of the array NMOS transistor is connected to the drain of the first array capacitor and the source of the second array capacitor; the first terminals of the first array capacitor and the second array capacitor serve as the connection terminals of the capacitor array unit. Attached Figure Description
[0014] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1This is a schematic diagram of the broadband harmonic-tunable voltage-controlled oscillator of the present invention. Figure 2 This is a schematic diagram of the transient simulation results in Simulation 1 of this invention; Figure 3 This is a simulation diagram of the frequency tuning range in Simulation 2 of the present invention.
[0015] Figure label: exist Figure 1 In the diagram: L1, first inductor; L2, second inductor; L3, third inductor; L4, fourth inductor; L5, fifth inductor; L6, sixth inductor; L7, seventh inductor; C1, first capacitor; C2, second capacitor; C3, third capacitor; C4, fourth capacitor; C5, fifth capacitor; R1, first resistor; R2, second resistor; C V1 First variable capacitor; C V2 The second variable capacitor; C C1 First array capacitor; C C2 M1, M2, M3, M4, M5; M6, M7, M8; M9, M1, M1, M2, M3, M4, M5; M6, M7, M8, M9, M1, M1, M1, M2, M1, M1, M2, M1, M3, M1, M1, M2, M1 ... C Array NMOS transistors; VDD, power supply voltage; VCTRL1, first control voltage; VCTRL2, second control voltage; VBIAS, bias voltage; VBIT, bit control signal; K1, first coupling coefficient; K2, second coupling coefficient; K3, third coupling coefficient; K4, fourth coupling coefficient; K5, fifth coupling coefficient; GND, power ground; CAP_BANK<0:3> represents capacitor array unit. Detailed Implementation
[0016] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.
[0017] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.
[0018] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. "Several" means one or more, unless otherwise explicitly specified.
[0019] In systems such as phase-locked loops, frequency synthesizers, and wireless transceivers, the main performance requirements for voltage-controlled oscillators (VCOs) are wide operating range and low phase noise. Existing LC oscillator designs rely on varactor diodes to adjust the frequency. However, the capacitance of varactor diodes has a limited range of variation, and at high frequencies (such as millimeter-wave bands), the quality factor (i.e., Q value) drops sharply due to the influence of parasitic parameters in the circuit, resulting in a narrow tuning range and deteriorated phase noise.
[0020] Please see Figure 1 To address the above technical problems, this invention provides a broadband harmonic-tunable voltage-controlled oscillator, comprising an LC resonant unit, a negative resistance unit, a head resonant unit, and a tuning transformer unit; wherein: The LC resonant unit provides the oscillation signal; the negative resistance unit provides oscillation energy to the voltage-controlled oscillator, with its second terminal connected to the power ground GND and its first terminal connected to the second terminal of the LC resonant unit; the head resonant unit is formed by a capacitor and an inductor, with its input terminal connected to the power supply voltage VDD and its output terminal connected to the first terminal of the LC resonant unit; the tuning transformer unit is formed by an inductor and a transistor, with the inductance of the tuning transformer unit corresponding to the inductance of the LC resonant unit, resulting in transformer coupling; the input terminal of the tuning transformer unit is connected to the first control voltage VCTRL1; the tuning transformer unit resonates at the first harmonic frequency of the voltage-controlled oscillator output frequency, and the tuning transformer unit and the head resonant unit simultaneously act on the first and second harmonics, adjusting the oscillation frequency through magnetic tuning controlled by the first control voltage VCTRL1 to obtain a wide-band adjustable range.
[0021] With the above technical solution, the broadband harmonic-tunable voltage-controlled oscillator of the present invention is provided with at least an LC resonant unit, a negative resistance unit, a head resonant unit, and a tuning transformer unit; wherein, the LC resonant unit is used to provide the oscillation signal, the negative resistance unit is used to provide oscillation energy for the voltage-controlled oscillator, its second terminal is connected to the power ground GND, its first terminal is connected to the second terminal of the LC resonant unit, the head resonant unit is formed by a capacitor and an inductor, its input terminal is connected to the power supply voltage VDD, its output terminal is connected to the first terminal of the LC resonant unit, the tuning transformer unit is formed by an inductor and a transistor, the inductance of the tuning transformer unit and the inductance of the LC resonant unit are correspondingly coupled by a transformer, and the input terminal of the tuning transformer unit is connected to the first control voltage VCTRL1. Based on the above structure, the tuning transformer unit resonates at the first harmonic frequency of the voltage-controlled oscillator output frequency. The tuning transformer unit and the head resonator unit act simultaneously on the first and second harmonics. The oscillation frequency is adjusted by magnetic tuning controlled by the first control voltage VCTRL1, thereby obtaining a wider adjustable range. Specifically, the above-mentioned wideband voltage-controlled oscillator adopts the synergistic effect of the head resonator unit and the tuning transformer unit. The head resonator unit resonates at the second harmonic, providing high impedance at the second harmonic frequency through the common-mode resonant frequency to reduce phase noise. The tuning transformer unit resonates at the fundamental frequency, adjusting the equivalent inductance value through the first control voltage VCTRL1 to avoid the problem of varactor Q value degradation, and performing harmonic modulation on the spectrum of the oscillation signal to enhance the harmonic amplitude and reduce phase noise. The head resonator unit and the tuning transformer unit synchronously control the frequency and impedance of the fundamental and second harmonics through magnetic coupling coefficients (K1 to K5) to obtain a new set of tuning bands, thereby achieving harmonic tuning over a wider range. To broaden the tuning range, some existing technologies employ switched capacitor arrays, but the parasitic effects introduced by capacitor switching reduce the Q value of the resonant circuit and increase phase noise. Other existing technologies use multiple resonant cavities for wideband coverage, but this undoubtedly increases area and power consumption. In contrast, the broadband harmonic-tunable voltage-controlled oscillator of this invention offers the advantages of a wide tuning range and high tuning accuracy, making it suitable for high-frequency systems. Through the above-mentioned technical solution of this invention, the technical problems of existing LC oscillators relying on varactor tubes to adjust the frequency are solved. However, the capacitance range of varactor tubes is limited, and the quality factor drops sharply at high frequencies due to the influence of parasitic parameters in the circuit, leading to a narrow tuning range and deteriorated phase noise.
[0022] For example, the negative resistance unit includes a first NMOS transistor M1 and a second NMOS transistor M2; the first NMOS transistor M1 and the second NMOS transistor M2 are cross-connected; the drain of the first NMOS transistor M1 and the drain of the second NMOS transistor M2 serve as the first end of the negative resistance unit; the source of the first NMOS transistor M1 and the source of the second NMOS transistor M2 are connected, and the connection point serves as the second end of the negative resistance unit.
[0023] As one possible implementation, the broadband harmonic-tunable wideband voltage-controlled oscillator of the present invention further includes a variable capacitor unit and a capacitor array unit; the variable capacitor unit is formed by a capacitor, a variable capacitor, and a resistor, and the capacitance value of the variable capacitor is changed by adjusting the second control voltage VCTRL2; the capacitor array unit includes 2 n A 1-position switched capacitor array, where n is an integer greater than or equal to zero; the second terminal of the LC resonant unit is connected to a variable capacitor unit, which is connected to the capacitor array unit, and the capacitor array unit is connected to the first terminal of the negative resistance unit. For example, the variable capacitor unit includes a first capacitor C1, a second capacitor C2, and a first variable capacitor C... V1 The second variable capacitor C V2 And a first resistor R1 and a second resistor R2; the second end of the first resistor R1 is connected to the second end of the second resistor R2, and a bias voltage VBIAS is input at the connection point; the first end of the first resistor R1 is connected to the second end of the first capacitor C1 and the first variable capacitor C V1 The first terminal of the second resistor R2 is connected to the second terminal of the second capacitor C2 and the second variable capacitor C. V2 The first terminal; the first variable capacitor C V1 The second terminal is connected to the second variable capacitor C V2 The second terminal is connected, and a second control voltage VCTRL2 is input at the connection point; the first terminal of the first capacitor C1 and the first terminal of the second capacitor C2 serve as the connection terminals of the variable capacitor unit. For example, the capacitor array unit includes a 4-bit switched capacitor array, and each bit of the switched capacitor array includes an array NMOS transistor M. C First array capacitor C C1 Second array capacitor C C2 ; Array NMOS transistor M C The gate is connected to the bit control signal VBIT, and the drain is connected to the first array capacitor C. C1 The second terminal, with its source connected to the second array capacitor C C2 The second terminal; the first array capacitor C C1 Second array capacitor C C2The first end serves as the connection end of the capacitor array unit; CAP_BANK<0:3> represents the capacitor array unit, where <0:3> specifies the bit width index, from bit 0 to bit 3, a total of 4 bits, each bit corresponding to a switched capacitor sub-unit.
[0024] With the above technical solution, the variable capacitor unit, based on its structure, changes the capacitance value of the variable capacitor by adjusting the second control voltage VCTRL2, and obtains a frequency band with the center frequency as the reference frequency, thereby achieving fine-tuning of the output oscillation signal frequency; the capacitor array unit, based on its structure, changes the capacitance value of the connected circuit by adjusting the bit control signal VBIT, and obtains frequency bands with different center frequencies, thereby achieving coarse-tuning of the output oscillation signal frequency; the variable capacitor unit and the capacitor array unit work together to adjust the frequency of the output oscillation signal, which has the advantages of wide tuning range and high tuning accuracy. In other words, the broadband harmonic adjustable wideband voltage-controlled oscillator of the present invention uses a variable capacitor unit (fine tuning) and a capacitor array unit (coarse tuning) to tune the output frequency of the voltage-controlled oscillator in stages, thereby achieving a wide tuning range and high tuning accuracy.
[0025] In one possible implementation, the broadband harmonic-tunable voltage-controlled oscillator of the present invention includes an LC resonant unit comprising a first inductor L1, a second inductor L2, a third capacitor C3, and a fourth capacitor C4. The first end of the first inductor L1 is connected to the first end of the second inductor L2, and this connection serves as the first end of the LC resonant unit. The first end of the third capacitor C3 is connected to the first end of the fourth capacitor C4. The second end of the first inductor L1 is connected to the second end of the third capacitor C3. The second end of the second inductor L2 is connected to the second end of the fourth capacitor C4. The connection points of the first inductor L1 and the third capacitor C3, and the second inductor L2 and the fourth capacitor C4, serve as the second ends of the LC resonant unit. Using this technical solution, the LC resonant unit can convert a DC signal into an AC signal, generating a periodic resonance at a fixed frequency.
[0026] In one possible implementation, the broadband harmonic-tunable voltage-controlled oscillator of the present invention includes a head resonant unit comprising a fifth inductor L5, a sixth inductor L6, and a fifth capacitor C5. The first terminal of the fifth inductor L5 is connected to the first terminal of the fifth capacitor C5, and this connection serves as the input terminal of the head resonant unit. The second terminal of the fifth capacitor C5 is connected to the first terminal of the sixth inductor L6. The second terminal of the sixth inductor L6 is connected to the second terminal of the fifth inductor L5, and this connection serves as the output terminal of the head resonant unit. The fifth inductor L5 and the sixth inductor L6 are transformer-coupled, with a coupling coefficient of the third coupling coefficient K3. Using this technical solution, the head resonant unit generates an oscillation signal with a fixed resonant frequency, which couples with the second harmonic of the original oscillator.
[0027] In one possible implementation, the broadband harmonic-tunable voltage-controlled oscillator of the present invention includes a tuning transformer unit comprising a third inductor L3, a fourth inductor L4, a seventh inductor L7, a third NMOS transistor M3, and a fourth NMOS transistor M4; the gate of the third NMOS transistor M3 and the gate of the fourth NMOS transistor M4 are connected to a first control voltage VCTRL1; the drain of the third NMOS transistor M3 is connected to the first terminal of the third inductor L3; the source of the third NMOS transistor M3 is connected to the first terminal of the fourth inductor L4; and the drain of the fourth NMOS transistor M4 is connected to... The first terminal of the seventh inductor L7 is connected; the source of the fourth NMOS transistor M4 is connected to the second terminal of the seventh inductor L7; the second terminal of the third inductor L3 is connected to the second terminal of the fourth inductor L4; the third inductor L3 is transformer-coupled with the first inductor L1, with a coupling coefficient of the first coupling coefficient K1; the fourth inductor L4 is transformer-coupled with the second inductor L2, with a coupling coefficient of the second coupling coefficient K2; the seventh inductor L7 is transformer-coupled with the sixth inductor L6, with a coupling coefficient of the fourth coupling coefficient K4; and the seventh inductor L7 is transformer-coupled with the fifth inductor L5, with a coupling coefficient of the fifth coupling coefficient K5. With this technical solution, the tuning transformer unit can control the switching on and off of the third NMOS transistor M3 and the fourth NMOS transistor M4 by adjusting the first control voltage VCTRL1, thereby controlling the inductor coupling of the third inductor L3, the fourth inductor L4, and the seventh inductor L7 with the LC resonant unit and the head resonant unit, and simultaneously acting on the first and second harmonics to achieve wide tuning.
[0028] Furthermore, a simulation experiment was conducted on the broadband harmonic-tunable voltage-controlled oscillator of the present invention. Specifically, the components used in the simulation experiment were manufactured using SMIC55LLRF technology. A complete broadband harmonic-tunable voltage-controlled oscillator circuit was built on the Cadence IC617 simulation platform under a Linux system environment. The Spectre RF simulation tool was used during the simulation, with the power supply voltage VDD set to 1.2V, the operating temperature set to 25℃, the first control voltage VCTRL1 set to 1.0V, and the second control voltage VCTRL2 set to 1.0V.
[0029] Simulation 1: Under the above operating conditions, transient simulation was performed using the Spectre RF simulation tool, with the output port set at the differential output terminal of the broadband harmonic-tunable voltage-controlled oscillator of this invention. The transient simulation results are as follows: Figure 2 As shown, the horizontal axis represents time (in nanoseconds, ns), and the vertical axis represents voltage (in volts, V). Figure 2 It reflects the swing amplitude and oscillation pattern of the output waveform.
[0030] Simulation 2: Under the same operating conditions, using the Spectre RF simulation tool, the waveform output diagram was set in the simulation interface of the broadband harmonic-tunable wideband voltage-controlled oscillator of this invention, and a frequency range sweep simulation was performed. The frequency range sweep simulation results are as follows: Figure 3 As shown, in Figure 3 In the diagram, the horizontal axis represents the second control voltage VCTRL2, in V, and the vertical axis represents the output frequency, both in GHz, with an output frequency range of 6.0~13.5GHz. Figure 3 Simulation results show that, due to the use of the head resonant unit and the tuning transformer unit, a new set of selectable tuning frequency bands can be obtained in synergy. At the same time, the variable capacitor unit and the capacitor array unit work together to adjust the frequency of the output oscillation signal by the second control voltage VCTRL2. The simulation results demonstrate the wide tuning range and high tuning accuracy of the broadband harmonic adjustable voltage-controlled oscillator of the present invention.
[0031] The simulation results above demonstrate that the broadband harmonic-tunable voltage-controlled oscillator of the present invention, while ensuring low power consumption and low phase noise, possesses a wide frequency tuning range and high tuning accuracy. These performance indicators fully verify the technical advantages of the broadband harmonic-tunable voltage-controlled oscillator of the present invention, providing a high-performance preferred solution for wireless communication systems or their applications.
[0032] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.
[0033] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.
Claims
1. A broadband harmonic-tunable voltage-controlled oscillator, characterized in that, include: LC resonant unit, used to provide oscillation signal; The negative resistance unit is used to provide oscillation energy for the voltage-controlled oscillator. Its second terminal is connected to the power supply ground, and its first terminal is connected to the second terminal of the LC resonant unit. The head resonant unit is formed by a capacitor and an inductor. Its input terminal is connected to the power supply voltage, and its output terminal is connected to the first terminal of the LC resonant unit. A tuning transformer unit is formed by an inductor and a transistor. The inductance of the tuning transformer unit is coupled to the inductance of the LC resonant unit. The input terminal of the tuning transformer unit is connected to a first control voltage. The tuning transformer unit resonates at the first harmonic frequency of the voltage-controlled oscillator output frequency. The tuning transformer unit and the head resonant unit act simultaneously on the first and second harmonics. The oscillation frequency is adjusted by magnetic tuning controlled by the first control voltage to obtain a wide-band adjustable range. The LC resonant unit includes a first inductor, a second inductor, a third capacitor, and a fourth capacitor; the first end of the first inductor is connected to the first end of the second inductor, and the connection point is used as the first end of the LC resonant unit. The first terminal of the third capacitor is connected to the first terminal of the fourth capacitor; The second terminal of the first inductor is connected to the second terminal of the third capacitor; The second terminal of the second inductor is connected to the second terminal of the fourth capacitor; The connection point between the first inductor and the third capacitor, and the connection point between the second inductor and the fourth capacitor, are used as the second end of the LC resonant unit; The head resonant unit includes a fifth inductor, a sixth inductor, and a fifth capacitor; The first end of the fifth inductor is connected to the first end of the fifth capacitor, and the connection point is used as the input end of the head resonant unit; The second terminal of the fifth capacitor is connected to the first terminal of the sixth inductor; The second end of the sixth inductor is connected to the second end of the fifth inductor, and the connection point is used as the output terminal of the head resonant unit; the fifth inductor and the sixth inductor are coupled by a transformer; The tuned transformer unit includes a third inductor, a fourth inductor, a seventh inductor, a third NMOS transistor, and a fourth NMOS transistor; The gate of the third NMOS transistor and the gate of the fourth NMOS transistor are connected to the first control voltage. The drain of the third NMOS transistor is connected to the first terminal of the third inductor; The source of the third NMOS transistor is connected to the first terminal of the fourth inductor; The drain of the fourth NMOS transistor is connected to the first terminal of the seventh inductor; The source of the fourth NMOS transistor is connected to the second terminal of the seventh inductor; The second terminal of the third inductor is connected to the second terminal of the fourth inductor; The third inductor is transformer-coupled with the first inductor, the fourth inductor is transformer-coupled with the second inductor, the seventh inductor is transformer-coupled with the sixth inductor, and the seventh inductor is transformer-coupled with the fifth inductor.
2. The broadband harmonic-tunable voltage-controlled oscillator according to claim 1, characterized in that, It also includes variable capacitor units and capacitor array units; The variable capacitor unit is formed by a capacitor, a variable capacitor, and a resistor, and the capacitance value of the variable capacitor is changed by adjusting the second control voltage. The capacitor array unit includes 2 n A bit-swappable capacitor array, where n is an integer greater than or equal to zero; The second end of the LC resonant unit is connected to the variable capacitor unit, the variable capacitor unit is connected to the capacitor array unit, and the capacitor array unit is connected to the first end of the negative resistance unit.
3. The broadband harmonic-tunable voltage-controlled oscillator according to claim 2, characterized in that, The negative resistance unit includes a first NMOS transistor and a second NMOS transistor; The first NMOS transistor and the second NMOS transistor are cross-connected; The drain of the first NMOS transistor and the drain of the second NMOS transistor serve as the first terminal of the negative resistance unit; The source of the first NMOS transistor is connected to the source of the second NMOS transistor, and the connection point is used as the second end of the negative resistance unit.
4. The broadband harmonic-tunable voltage-controlled oscillator according to claim 3, characterized in that, The variable capacitor unit includes a first capacitor, a second capacitor, a first variable capacitor, a second variable capacitor, a first resistor, and a second resistor; The second end of the first resistor is connected to the second end of the second resistor, and a bias voltage is input at the connection point; the first end of the first resistor is connected to the second end of the first capacitor and the first end of the first variable capacitor; the first end of the second resistor is connected to the second end of the second capacitor and the first end of the second variable capacitor; the second end of the first variable capacitor is connected to the second end of the second variable capacitor, and a second control voltage is input at the connection point; the first end of the first capacitor and the first end of the second capacitor serve as the connection points of the variable capacitor unit.
5. The broadband harmonic-tunable voltage-controlled oscillator according to claim 4, characterized in that, The capacitor array unit includes a 4-bit switched capacitor array, and each switched capacitor array includes an array of NMOS transistors, a first array capacitor and a second array capacitor. The gate connection bit control signal of the array NMOS transistor is connected to the drain of the first array capacitor and the source of the second array capacitor; the first terminals of the first array capacitor and the second array capacitor serve as the connection terminals of the capacitor array unit.