Harmonic self-aligned voltage-controlled resonator and frequency synthesizer

Abstract

This application provides a harmonic self-aligned voltage-controlled resonator and frequency synthesizer, belonging to the field of resonator technology. In this design, each port of a four-mode transformer is connected to a capacitor switch array to maintain capacitive symmetry between ports. A set of negative transconductance transistors is connected between the first and second ports of the four-mode transformer, and another set of negative transconductance transistors is connected between the third and fourth ports. The negative transconductance circuit provides negative resistance to compensate for the losses of the four-mode transformer. Each capacitor in the impedance balancing unit is connected to the two ends of the first and fourth ports to balance the impedance of each port of the four-mode transformer. A mode switching unit is connected between the second and third ports to control the switching of the local oscillator mode of the four-mode transformer. This application simplifies the phase-locked loop design of a quantum bit measurement and control system, improves phase noise performance in cryogenic environments, and provides a reliable local oscillator signal source.

Description

Technical Field

[0001] This application relates to the field of resonator technology, and more specifically, to a harmonic self-aligned voltage-controlled resonator and a frequency synthesizer. Background Technology

[0002] Solid-state quantum computing platforms, such as superconducting qubits and silicon spin qubits, rely on high-precision microwave signals for quantum state manipulation and readout. Their operating frequencies typically cover the C-band (4–8 GHz) to the Ku-band (12–18 GHz) or even higher. In quantum measurement and control systems, the frequency synthesizer, as the core module providing these frequency signals, usually employs an on-chip integrated voltage-controlled oscillator (VCO) to provide the local oscillator signal to the transceiver, thereby generating microwave pulses to drive the qubits. Since the qubit readout process requires a fidelity higher than 99.9%, the phase noise performance of the local oscillator signal becomes one of the key factors affecting the overall system performance. Traditional multi-harmonic voltage-controlled oscillators typically utilize second, third, or a combination of both harmonics to adjust the waveform of the oscillation signal, thereby reducing the effective impulse sensitivity function value and improving the phase noise of the local oscillator signal. However, the phase noise optimization of multi-harmonic voltage-controlled oscillators is highly dependent on the precise alignment of the higher-order resonant frequency with the resonant frequency, which is difficult to achieve when considering a large frequency tuning range and variations in process, voltage, and temperature.

[0003] In related technologies, harmonic alignment is typically achieved through adjustable capacitor arrays, combinations of multiple LC resonators, or transformer-based resonant structures, and relies on calibration circuits or feedback control for dynamic tuning.

[0004] However, harmonic alignment of voltage-controlled oscillators (VCOs) based on related technologies increases circuit complexity and power consumption. Furthermore, in cryogenic environments, maintaining optimal alignment becomes difficult due to changes in device characteristics, easily leading to phase noise degradation. Moreover, such tuning results often require complex mode switching and harmonic recalibration mechanisms during broadband tuning, significantly increasing the design and system integration complexity of the phase-locked loop (PLL). Summary of the Invention

[0005] The purpose of this application is to provide a harmonic self-aligned voltage-controlled resonator and frequency synthesizer, which can simplify the phase-locked loop design of the quantum bit measurement and control system, improve the phase noise performance in deep cryogenic scenarios, and provide a reliable local oscillator signal source.

[0006] The embodiments of this application are implemented as follows: A first aspect of this application provides a harmonic self-aligned voltage-controlled resonator, which includes: a four-mode transformer, a plurality of capacitor switch arrays, a negative transconductance circuit, an impedance balancing unit, and a mode switching unit. The negative transconductance circuit includes: two sets of cross-coupled negative transconductance transistors, and the impedance balancing unit includes: a plurality of capacitors. The four-mode transformer consists of two symmetrical and coupled distributed inductors and has four ports. Each port of the four-mode transformer is connected to a capacitor switch array to maintain the capacitance symmetry between the ports of the four-mode transformer. One set of negative transconductance transistors is connected between the first and second ports of the four-mode transformer, and another set of negative transconductance transistors is connected between the third and fourth ports of the four-mode transformer. The negative transconductance circuit is used to provide negative resistance to compensate for the losses of the four-mode transformer. Each capacitor in the impedance balancing unit is connected to the two ends of the first and fourth ports of the four-mode transformer, respectively, to balance the impedance of each port of the four-mode transformer. The mode switching unit is connected between the second and third ports of the four-mode transformer and is used to control the switching of the local oscillator mode of the four-mode transformer in order to switch the operating frequency band of the voltage-controlled resonator.

[0007] As one possible implementation, the aforementioned four-mode transformer includes: a first distributed inductor and a second distributed inductor. The first distributed inductor includes: a first inductor, a second inductor, a third inductor, and a fourth inductor. The second distributed inductor includes: a fifth inductor, a sixth inductor, a seventh inductor, and an eighth inductor. The multiple capacitor switch arrays include: a first capacitor switch array, a second capacitor switch array, a third capacitor switch array, and a fourth capacitor switch array. One end of the first inductor is connected to one end of the seventh inductor, the other end of the first inductor is connected to one end of the first capacitor switch array, one end of the second inductor is connected to the other end of the first capacitor switch array, the other end of the second inductor is connected to the other end of the eighth inductor, and the other end of the first inductor and one end of the second inductor are also connected to a capacitor in the impedance balancing unit. One end of the third inductor is connected to one end of the fifth inductor, the other end of the third inductor is connected to one end of the fourth capacitor switch array, one end of the fourth inductor is connected to the other end of the fourth capacitor switch array, the other end of the fourth inductor is connected to the other end of the sixth inductor, the other end of the first inductor, one end of the second inductor, the other end of the fifth inductor and one end of the sixth inductor are also connected to a set of negative transconductance transistors, and the other end of the third inductor and the other end of the fourth inductor are also connected to a capacitor in the impedance balancing unit; The other end of the fifth inductor is connected to one end of the second capacitor switch array, and one end of the sixth inductor is connected to the other end of the second capacitor switch array. The other end of the seventh inductor is connected to one end of the third capacitor switch array, and one end of the eighth inductor is connected to the other end of the third capacitor switch array. The other ends of the third inductor, the fourth inductor, the seventh inductor, and the eighth inductor are also connected to another set of negative transconductance transistors. The other ends of the fifth inductor, the sixth inductor, the seventh inductor, and the eighth inductor are also connected to the mode switching unit.

[0008] As one possible implementation, the aforementioned multiple capacitor switch arrays all include: a coarse-adjustment switched capacitor module and a fine-adjustment varactor diode module; One end of the coarse-adjustment switching capacitor module and one end of the fine-adjustment varactor diode module in each capacitor switch array are respectively connected to one end of the corresponding port in the four-mode transformer. The other end of the coarse-adjustment switching capacitor module and the other end of the fine-adjustment varactor diode module in each capacitor switch array are respectively connected to the other end of the corresponding port in the four-mode transformer.

[0009] As one possible implementation, the coarse-adjustment switching capacitor module includes: a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a ninth capacitor, a tenth capacitor, an eleventh capacitor, a twelfth capacitor, a thirteenth capacitor, a fourteenth capacitor, a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch, and a seventh switch; One end of the first capacitor, one end of the second capacitor, one end of the third capacitor, one end of the fourth capacitor, one end of the fifth capacitor, one end of the sixth capacitor, and one end of the seventh capacitor are all connected to one end of the corresponding port in the four-mode transformer. The other ends of the first capacitor, the second capacitor, the third capacitor, the fourth capacitor, the fifth capacitor, the sixth capacitor, and the seventh capacitor are respectively connected to the output terminals of the first switch, the second switch, the third switch, the fourth switch, the fifth switch, the sixth switch, and the seventh switch. The input terminals of the first, second, third, fourth, fifth, sixth, and seventh switches are respectively connected to one end of the eighth, ninth, tenth, eleventh, twelfth, thirteenth, and fourteenth capacitors. The other ends of the eighth, ninth, tenth, eleventh, eleventh, twelfth, thirteenth, and fourteenth capacitors are all connected to the other ends of the corresponding ports in the four-mode transformer. The control terminals of the first switch, the second switch, the third switch, the fourth switch, the fifth switch, the sixth switch, and the seventh switch are all connected to an external controller.

[0010] As one possible implementation, the above-mentioned adjustable varactor diode module includes: a first varactor diode, a second varactor diode, a third varactor diode, and a fourth varactor diode; The output terminal of the first varactor diode and the input terminal of the third varactor diode are both connected to one end of the corresponding port in the four-mode transformer. The input terminal of the first varactor diode is connected to the input terminal of the second varactor diode. The output terminal of the second varactor diode and the input terminal of the fourth varactor diode are both connected to the other end of the corresponding port in the four-mode transformer, and the output terminal of the third varactor diode is connected to the output terminal of the fourth varactor diode.

[0011] As one possible implementation, a set of negative transconductance transistors includes: a first P-type metal-oxide-semiconductor field-effect transistor and a first N-type metal-oxide-semiconductor field-effect transistor; The gate of the first P-type metal-oxide-semiconductor field-effect transistor is connected to the other end of the second port of the four-mode transformer, the drain of the first P-type metal-oxide-semiconductor field-effect transistor is connected to one end of the first port of the four-mode transformer, and the source of the first P-type metal-oxide-semiconductor field-effect transistor is grounded. The gate of the first N-type metal-oxide-semiconductor field-effect transistor is connected to one end of the second port of the four-mode transformer, the drain of the first N-type metal-oxide-semiconductor field-effect transistor is connected to the other end of the first port of the four-mode transformer, and the source of the first N-type metal-oxide-semiconductor field-effect transistor is connected to an external power supply.

[0012] As one possible implementation, another set of negative transconductance transistors includes: a second P-type metal-oxide-semiconductor field-effect transistor and a second N-type metal-oxide-semiconductor field-effect transistor; The gate of the second P-type metal-oxide-semiconductor field-effect transistor is connected to one end of the third port of the four-mode transformer, the drain of the second P-type metal-oxide-semiconductor field-effect transistor is connected to the other end of the fourth port of the four-mode transformer, and the source of the second P-type metal-oxide-semiconductor field-effect transistor is grounded. The gate of the second N-type metal-oxide-semiconductor field-effect transistor is connected to the other end of the third port of the four-mode transformer, the drain of the second N-type metal-oxide-semiconductor field-effect transistor is connected to one end of the fourth port of the four-mode transformer, and the source of the second N-type metal-oxide-semiconductor field-effect transistor is connected to an external power supply.

[0013] As one possible implementation, the impedance balancing unit mentioned above includes: a fifteenth capacitor and a sixteenth capacitor; One end of the fifteenth capacitor is connected to one end of the first port of the four-mode transformer, and the other end of the fifteenth capacitor is connected to the other end of the first port of the four-mode transformer. One end of the sixteenth capacitor is connected to one end of the fourth port of the four-mode transformer, and the other end of the sixteenth capacitor is connected to the other end of the fourth port of the four-mode transformer.

[0014] As one possible implementation, the above-mentioned mode switching unit includes: an eighth switch, a ninth switch, a tenth switch, and an eleventh switch; The input terminals of the eighth and tenth switches are both connected to one end of the second port of the four-mode transformer, and the output terminals of the eighth and eleventh switches are both connected to one end of the third port of the four-mode transformer. The input terminals of the ninth and eleventh switches are both connected to the other end of the second port of the four-mode transformer, and the output terminals of the ninth and tenth switches are both connected to the other end of the third port of the four-mode transformer. The control terminals of the eighth switch, the ninth switch, the tenth switch, and the eleventh switch are all connected to an external controller.

[0015] As one possible implementation, the voltage-controlled resonator described above also includes: a first main circuit inductor, a second main circuit inductor, a third main circuit inductor, and a fourth main circuit inductor; One end of the first main circuit inductor is connected to one end of the fifth inductor and one end of the third inductor, respectively. The other end of the first main circuit inductor is connected to one end of the second main circuit inductor, and the other end of the second main circuit inductor is connected to the other end of the sixth inductor and the other end of the fourth inductor, respectively. One end of the third main circuit inductor is connected to one end of the first inductor and one end of the seventh inductor, respectively. The other end of the third main circuit inductor is connected to one end of the fourth main circuit inductor, and the other end of the fourth main circuit inductor is connected to the other end of the second inductor and the other end of the eighth inductor, respectively.

[0016] A second aspect of this application provides a frequency synthesizer that integrates the voltage-controlled resonator described in the first aspect.

[0017] A third aspect of the embodiments of this application provides a quantum bit measurement and control system, which includes the frequency synthesizer described in the second aspect above, the frequency synthesizer being used to provide a local oscillator signal for the quantum bit.

[0018] The beneficial effects of the embodiments of this application include: This application provides a harmonic self-aligned voltage-controlled resonator, which uses two symmetrical and mutually coupled distributed inductors to form a four-port quad-mode transformer. A capacitor switch array is connected to each port of the quad-mode transformer to maintain capacitive symmetry between the ports. A set of independently cross-coupled negative transconductance transistors is connected between the first and second ports of the quad-mode transformer, and another set of independently cross-coupled negative transconductance transistors is connected between the third and fourth ports to provide negative resistance to compensate for the losses of the quad-mode transformer. An independent capacitor is connected to both ends of the first and fourth ports of the quad-mode transformer to form an impedance balancing unit, which balances the impedance of each port of the quad-mode transformer, ensuring consistent response at each port under multimode oscillation conditions. A mode switching unit is connected between the second and third ports of the quad-mode transformer. Under the action of an external controller, the mode switching unit controls the switching of the quad-mode transformer between different intrinsic modes, enabling the voltage-controlled resonator to switch between different operating frequency bands, thereby achieving broadband frequency coverage. The voltage-controlled resonator (VCR) utilizes the structural symmetry and symmetrical capacitance configuration of a four-mode transformer to achieve self-alignment between the fundamental frequency and higher harmonics, eliminating the need for external calibration or complex feedback circuits. Furthermore, based on a mode-switching unit, the VCR maintains excellent phase noise performance and frequency tuning capability across a wide frequency range, making it well-suited for cryogenic environments. This simplifies the phase-locked loop (PLL) design of quantum bit measurement and control systems, improves phase noise performance in cryogenic environments, and provides a reliable local oscillator signal source. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of a first type of voltage-controlled resonator provided in an embodiment of this application; Figure 2 This is a schematic diagram of the structure of the second type of voltage-controlled resonator provided in the embodiments of this application; Figure 3 This is a schematic diagram of the structure of a capacitor switch array provided in an embodiment of this application; Figure 4 A schematic diagram of a low-frequency equivalent impedance provided in an embodiment of this application; Figure 5 A waveform diagram corresponding to a low-frequency equivalent impedance is provided in an embodiment of this application; Figure 6 This is a schematic diagram of a high-frequency equivalent impedance provided in an embodiment of this application; Figure 7 A waveform diagram corresponding to a high-frequency equivalent impedance is provided in an embodiment of this application; Figure 8 This is a schematic diagram of the structure of a frequency synthesizer provided in an embodiment of this application; Figure 9 This is a schematic diagram of a quantum bit measurement and control system provided in an embodiment of this application.

[0021] Figure reference numerals: 10: Voltage-controlled resonator; 101: Four-mode transformer; 1011: First distributed inductor; 111: First inductor; 112: Second inductor; 113: Third inductor; 114: Fourth inductor; 1012: Second distributed inductor; 121: Fifth inductor; 122: Sixth inductor; 123: Seventh inductor; 124: Eighth inductor; 102: Capacitor switch array; 1021: First capacitor switch array; 1022: Second capacitor switch array; 1023: Third capacitor switch array; 1024: Fourth capacitor switch array; 21: Coarse-adjustment switching capacitor module; 211: First capacitor; 212: Second capacitor; 213: Third capacitor; 214: Fourth capacitor; 215: Fifth capacitor; 216: Sixth capacitor; 217: Seventh capacitor; 218: Eighth capacitor; 219: Ninth capacitor; 2110: Tenth capacitor; 2111: Eleventh capacitor; 2112: Twelfth capacitor; 2113: Thirteenth capacitor; 2114: Fourteenth capacitor; 2115: First switch; 2116: Second switch; 2117: Third switch; 2118: Fourth switch; 2119: Fifth switch; 2120: Sixth switch; 2121: Seventh switch; 22: Fine-adjustment varactor diode module; 221: First varactor diode; 222: Second varactor diode; 223: Third varactor diode ; 224: Fourth varactor diode; 103: Negative transconductance transistor; 1031: First P-type metal-oxide-semiconductor field-effect transistor; 1032: First N-type metal-oxide-semiconductor field-effect transistor; 1033: Second P-type metal-oxide-semiconductor field-effect transistor; 1034: Second N-type metal-oxide-semiconductor field-effect transistor; 104: Impedance balancing unit; 1041: Fifteenth capacitor; 1042: Sixteenth capacitor; 105: Mode switching unit; 1051: Eighth switch; 1052: Ninth switch; 1053: Tenth switch; 1054: Eleventh switch; 106: First main circuit inductor; 107: Second main circuit inductor; 108: Third main circuit inductor; 109: Fourth main circuit inductor; 20: Frequency synthesizer; 30: Quantum bit measurement and control system. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0024] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0025] In the description of this application, it should be noted that the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0026] Traditional multi-harmonic voltage-controlled oscillators (MVOs) typically utilize second, third, or a combination of both harmonics to modulate the waveform of the oscillation signal, thereby reducing the effective impulse sensitivity function and improving the phase noise of the local oscillator signal. However, phase noise optimization in MVOs is highly dependent on the precise alignment of higher-order resonant frequencies with the resonant frequency, which is difficult to achieve when considering large frequency tuning ranges and variations in process technology, voltage, and temperature.

[0027] Currently, harmonic alignment is typically achieved through adjustable capacitor arrays, combinations of multiple LC resonators, or transformer-based resonant structures, relying on calibration circuits or feedback control for dynamic tuning. However, this approach increases circuit complexity and power consumption. Furthermore, in cryogenic environments, maintaining optimal alignment becomes difficult due to changes in device characteristics, easily leading to phase noise degradation. Moreover, broadband tuning often requires complex mode switching and harmonic recalibration mechanisms, significantly increasing the design and system integration complexity of the phase-locked loop.

[0028] To address this, this application provides a harmonic self-aligned voltage-controlled resonator (VCR). A four-port quad-mode transformer (TMR) is constructed using two symmetrical and mutually coupled distributed inductors. A capacitor switch array is connected to each of the four ports to maintain capacitive symmetry between the ports. A set of cross-coupled negative transconductance transistors (CVTs) is connected between the first and second ports of the TMR, and another set is connected between the third and fourth ports to compensate for circuit losses. A capacitor is placed at each of the first and fourth ports to balance the impedance of the TMR. A mode switching unit is connected between the second and fourth ports. Under external control, the mode switching unit controls the local oscillator mode switching of the TMR, thereby switching the operating frequency band of the VCR. This simplifies the phase-locked loop (PLL) design of the quantum bit measurement and control system, improves phase noise performance in cryogenic environments, and provides a reliable local oscillator signal source.

[0029] The following description, in conjunction with the accompanying drawings, provides a detailed explanation of the harmonic self-aligned voltage-controlled resonator, frequency synthesizer, and quantum bit measurement and control system provided in the embodiments of this application.

[0030] Figure 1 For a schematic diagram of a voltage-controlled resonator provided in this application, see [link to schematic diagram]. Figure 1 This application provides a harmonic self-aligned voltage-controlled resonator 10, which includes: a four-mode transformer 101, a plurality of capacitor switch arrays 102, a negative transconductance circuit, an impedance balancing unit 104, and a mode switching unit 105. The negative transconductance circuit includes: two sets of cross-coupled negative transconductance transistors 103, and the impedance balancing unit 104 includes: a plurality of capacitors.

[0031] The four-mode transformer 101 consists of two symmetrical and mutually coupled distributed inductors and has four ports. Each port of the four-mode transformer 101 is connected to a capacitor switch array 102 to maintain the capacitance symmetry between the ports of the four-mode transformer 101.

[0032] Optionally, the four-mode transformer 101 consists of two symmetrical and mutually coupled distributed inductors, forming a resonant structure with four ports. Each port of the four-mode transformer 101 is connected to a capacitor switch array 102 to ensure the capacitance symmetry between the ports of the four-mode transformer 101. Each capacitor switch array 102 includes a switched capacitor array for coarse frequency adjustment and a varactor diode for fine frequency adjustment, together achieving precise control of the resonant frequency.

[0033] A set of negative transconductance transistors 103 is connected between the first and second ports of the four-mode transformer 101, and another set of negative transconductance transistors 103 is connected between the third and fourth ports of the four-mode transformer 101. The negative transconductance circuit is used to provide negative resistance to compensate for the losses of the four-mode transformer 101.

[0034] Optionally, one set of negative transconductance transistors 103 is connected between the first and second ports of the four-mode transformer 101, and another set of negative transconductance transistors 103 is connected between the third and fourth ports of the four-mode transformer 101, forming two sets of independent cross-coupled negative resistance structures to provide negative resistance to compensate for the losses of the four-mode transformer 101 and maintain oscillation conditions.

[0035] Each capacitor in the impedance balancing unit 104 is connected to the two ends of the first and fourth ports of the four-mode transformer 101, respectively, to balance the impedance of each port of the four-mode transformer 101.

[0036] Optionally, each capacitor in the impedance balancing unit 104 is connected to both ends of the first port and the fourth port of the four-mode transformer 101, respectively, to balance the impedance of each port of the four-mode transformer 101, ensuring that the response of each port of the four-mode transformer 101 is consistent under multimode oscillation conditions, and further guaranteeing the harmonic self-alignment characteristics.

[0037] The mode switching unit 105 is connected between the second and third ports of the four-mode transformer 101 and is used to control the switching of the local oscillator mode of the four-mode transformer 101 to switch the operating frequency band of the voltage-controlled resonator 10.

[0038] Optionally, the mode switching unit 105 is connected between the second and third ports of the four-mode transformer 101 to control the switching of the four-mode transformer 101 between different intrinsic modes, thereby realizing the switching of the voltage-controlled resonator 10 between different operating frequency bands (such as low-frequency mode and high-frequency mode) and supporting broadband frequency coverage.

[0039] In this embodiment, a four-port quadrature transformer is constructed using two symmetrical and mutually coupled distributed inductors. A capacitor switch array is connected to each port of the quadrature transformer to maintain the capacitance symmetry between the ports. A set of independently cross-coupled negative transconductance transistors is connected between the first and second ports of the quadrature transformer, and another set of independently cross-coupled negative transconductance transistors is connected between the third and fourth ports to provide negative resistance to compensate for the losses of the quadrature transformer. An independent capacitor is connected to both ends of the first port and the fourth port of the quadrature transformer to form an impedance balancing unit, which is used to balance the impedance of each port of the quadrature transformer and ensure that the response of each port of the quadrature transformer is consistent under multimode oscillation conditions. A mode switching unit is connected between the second and third ports of the quadrature transformer. Under the action of an external controller, the mode switching unit controls the switching of the quadrature transformer between different intrinsic modes, so that the voltage-controlled resonator can switch between different operating frequency bands, thereby achieving broadband frequency coverage. The voltage-controlled resonator (VCR) utilizes the structural symmetry and symmetrical capacitance configuration of a four-mode transformer to achieve self-alignment between the fundamental frequency and higher harmonics, eliminating the need for external calibration or complex feedback circuits. Furthermore, based on a mode-switching unit, the VCR maintains excellent phase noise performance and frequency tuning capability across a wide frequency range, making it well-suited for cryogenic environments. This simplifies the phase-locked loop (PLL) design of quantum bit measurement and control systems, improves phase noise performance in cryogenic environments, and provides a reliable local oscillator signal source.

[0040] In one alternative implementation, see [link to implementation details]. Figure 2 The four-mode transformer 101 in the harmonic self-aligned voltage-controlled resonator 10 provided in this application embodiment includes: a first distributed inductor 1011 and a second distributed inductor 1012. The first distributed inductor 1011 includes: a first inductor 111, a second inductor 112, a third inductor 113 and a fourth inductor 114. The second distributed inductor 1012 includes: a fifth inductor 121, a sixth inductor 122, a seventh inductor 123 and an eighth inductor 124. The plurality of capacitor switch arrays 102 include: a first capacitor switch array 1021, a second capacitor switch array 1022, a third capacitor switch array 1023 and a fourth capacitor switch array 1024.

[0041] It should be noted that in the diagram, P1 and P2 are used to represent the two ends of the first port of the four-mode transformer 101, P3 and P4 are used to represent the two ends of the second port of the four-mode transformer 101, P5 and P6 are used to represent the two ends of the third port of the four-mode transformer 101, and P7 and P8 are used to represent the two ends of the fourth port of the four-mode transformer 101.

[0042] It should also be noted that all L11 in the figure are used to characterize the first distributed inductor 1011, all L12 in the figure are used to characterize the second distributed inductor 1012, and k1, k2, k3, and k4 in the figure are used to characterize the mutual inductance coefficient and self-inductance coefficient between the inductors in the voltage-controlled resonator 10. This application does not make specific limitations on these.

[0043] One end of the first inductor 111 is connected to one end of the seventh inductor 123, and the other end of the first inductor 111 is connected to one end of the first capacitor switch array 1021. One end of the second inductor 112 is connected to the other end of the first capacitor switch array 1021, and the other end of the second inductor 112 is connected to the other end of the eighth inductor 124. The other end of the first inductor 111 and one end of the second inductor 112 are also connected to a capacitor in the impedance balancing unit 104. One end of the third inductor 113 is connected to one end of the fifth inductor 121, and the other end of the third inductor 113 is connected to one end of the fourth capacitor switch array 1024. One end of the fourth inductor 114 is connected to the other end of the fourth capacitor switch array 1024, and the other end of the fourth inductor 114 is connected to the other end of the sixth inductor 122. The other ends of the first inductor 111, one end of the second inductor 112, one end of the fifth inductor 121, and one end of the sixth inductor 122 are also connected to a set of negative transconductance transistors 103. The other ends of the third inductor 113 and the fourth inductor 114 are also connected to a capacitor in the impedance balancing unit 104. The other end of the fifth inductor 121 is connected to one end of the second capacitor switch array 1022, and one end of the sixth inductor 122 is connected to the other end of the second capacitor switch array 1022. The other end of the seventh inductor 123 is connected to one end of the third capacitor switch array 1023, and one end of the eighth inductor 124 is connected to the other end of the third capacitor switch array 1023. The other ends of the third inductor 113, the fourth inductor 114, the seventh inductor 123, and the eighth inductor 124 are also connected to another set of negative transconductance transistors 103. The other ends of the fifth inductor 121, the sixth inductor 122, the seventh inductor 123, and the eighth inductor 124 are also connected to the mode switching unit 105.

[0044] Wherein, the other end of the first inductor 111 serves as one end of the first port of the four-mode transformer 101, and one end of the second inductor 112 serves as the other end of the first port of the four-mode transformer 101; the other end of the fifth inductor 121 serves as one end of the second port of the four-mode transformer 101, and one end of the sixth inductor 122 serves as the other end of the second port of the four-mode transformer 101; the other end of the seventh inductor 123 serves as one end of the third port of the four-mode transformer 101, and one end of the eighth inductor 124 serves as the other end of the third port of the four-mode transformer 101; the other end of the third inductor 113 serves as one end of the fourth port of the four-mode transformer 101, and one end of the fourth inductor 114 serves as the other end of the fourth port of the four-mode transformer 101.

[0045] Optionally, the connection structure between each inductor and capacitor switch array 102, negative transconductance transistor 103, mode switching unit 105 and impedance balancing unit 104 in the four-mode transformer 101 ensures that the four-mode transformer 101 has electrical symmetry. Each port of the four-mode transformer 101 achieves capacitance balance through the matched capacitor switch array 102, supports multimode resonance and harmonic self-alignment functions, and the mode switching unit 105 can realize flexible selection of operating frequency band.

[0046] In one alternative implementation, see [link to implementation details]. Figure 3 The multiple capacitor switch arrays 102 in the harmonic self-aligned voltage-controlled resonator 10 provided in this application embodiment all include: a coarse-adjustment switched capacitor module 21 and a fine-adjustment varactor diode module 22.

[0047] One end of the coarse adjustment switching capacitor module 21 and one end of the fine adjustment varactor diode module 22 in each capacitor switch array 102 are respectively connected to one end of the corresponding port in the four-mode transformer 101, and the other end of the coarse adjustment switching capacitor module 21 and the other end of the fine adjustment varactor diode module 22 in each capacitor switch array 102 are respectively connected to the other end of the corresponding port in the four-mode transformer 101.

[0048] Optionally, in each capacitor switch array 102, one end of the coarse adjustment switch capacitor module 21 is connected to one end of the fine adjustment varactor diode module 22, and together they are connected to one end of the corresponding port in the four-mode transformer 101; correspondingly, the other end of the coarse adjustment switch capacitor module 21 is connected to the other end of the fine adjustment varactor diode module 22, and together they are connected to the other end of the corresponding port in the four-mode transformer 101.

[0049] Thus, each capacitor switch array 102, through the parallel coarse-tuning switch capacitor module 21 and fine-tuning varactor diode module 22, provides the corresponding port in the four-mode transformer 101 with a capacitor tuning capability that combines wide range and high precision, together forming a composite tuning network for the resonant frequency.

[0050] Optionally, the structural design of the capacitor switch array 102 can ensure that the capacitors loaded at each port of the four-mode transformer 101 maintain electrical symmetry during the tuning process, which is the benchmark for the four-mode transformer 101 to achieve multi-resonant mode self-alignment and broadband frequency coverage.

[0051] Among them, the coarse-adjustment switching capacitor module 21 is used to realize a wide range of step selection of the operating frequency band of the voltage-controlled resonator 10, and the fine-adjustment varactor diode module 22 is used to perform continuous and fine frequency calibration within the currently selected operating frequency band of the voltage-controlled resonator 10. The two work together to support the stable oscillation and harmonic self-alignment characteristics of the voltage-controlled resonator 10 in a wide frequency range.

[0052] In one alternative implementation, see [link to implementation details]. Figure 3 The coarse-tuning switching capacitor module 21 in each capacitor switch array 102 of the harmonic self-aligned voltage-controlled resonator 10 provided in this application embodiment includes: a first capacitor 211, a second capacitor 212, a third capacitor 213, a fourth capacitor 214, a fifth capacitor 215, a sixth capacitor 216, a seventh capacitor 217, an eighth capacitor 218, a ninth capacitor 219, a tenth capacitor 2110, an eleventh capacitor 2111, a twelfth capacitor 2112, a thirteenth capacitor 2113, a fourteenth capacitor 2114, a first switch 2115, a second switch 2116, a third switch 2117, a fourth switch 2118, a fifth switch 2119, a sixth switch 2120, and a seventh switch 2121.

[0053] One end of the first capacitor 211, one end of the second capacitor 212, one end of the third capacitor 213, one end of the fourth capacitor 214, one end of the fifth capacitor 215, one end of the sixth capacitor 216, and one end of the seventh capacitor 217 are all connected to one end of the corresponding port in the four-mode transformer 101. The other ends of the first capacitor 211, the second capacitor 212, the third capacitor 213, the fourth capacitor 214, the fifth capacitor 215, the sixth capacitor 216, and the seventh capacitor 217 are respectively connected to the output terminals of the first switch 2115, the second switch 2116, the third switch 2117, the fourth switch 2118, the fifth switch 2119, the sixth switch 2120, and the seventh switch 2121. The input terminals of the first switch 2115, the second switch 2116, the third switch 2117, the fourth switch 2118, the fifth switch 2119, the sixth switch 2120, and the seventh switch 2121 are respectively connected to one end of the eighth capacitor 218, one end of the ninth capacitor 219, one end of the tenth capacitor 2110, one end of the eleventh capacitor 2111, one end of the twelfth capacitor 2112, one end of the thirteenth capacitor 2113, and one end of the fourteenth capacitor 2114. The other ends of the eighth capacitor 218, the ninth capacitor 219, the tenth capacitor 2110, the eleventh capacitor 2111, the twelfth capacitor 2112, the thirteenth capacitor 2113, and the fourteenth capacitor 2114 are all connected to the other ends of the corresponding ports in the four-mode transformer 101. The control terminals of the first switch 2115, the second switch 2116, the third switch 2117, the fourth switch 2118, the fifth switch 2119, the sixth switch 2120, and the seventh switch 2121 are all connected to an external controller.

[0054] Optionally, the coarse adjustment switching capacitor module 21 in each capacitor switch array 102 can be a one-bit digitally controlled programmable capacitor array. The coarse adjustment switching capacitor module 21 includes: a first capacitor 211, a second capacitor 212, a third capacitor 213, a fourth capacitor 214, a fifth capacitor 215, a sixth capacitor 216, a seventh capacitor 217, an eighth capacitor 218, a ninth capacitor 219, a tenth capacitor 2110, an eleventh capacitor 2111, a twelfth capacitor 2112, a thirteenth capacitor 2113, a fourteenth capacitor 2114, a first switch 2115, a second switch 2116, a third switch 2117, a fourth switch 2118, a fifth switch 2119, a sixth switch 2120, and a seventh switch 2121. These capacitors and switches together form a 7-bit binary weighted switched capacitor network, which is used to realize digital step-by-step coarse adjustment of the resonant frequency.

[0055] Specifically, one end of the first capacitor 211, the second capacitor 212, the third capacitor 213, the fourth capacitor 214, the fifth capacitor 215, the sixth capacitor 216, and the seventh capacitor 217 are interconnected and connected to one end of the corresponding port in the four-mode transformer 101. The other ends of the first capacitor 211, the second capacitor 212, the third capacitor 213, the fourth capacitor 214, the fifth capacitor 215, the sixth capacitor 216, and the seventh capacitor 217 are respectively connected to the output terminals of the first switch 2115, the second switch 2116, the third switch 2117, the fourth switch 2118, the fifth switch 2119, the sixth switch 2120, and the seventh switch 2121; the first switch 211... 5. The input terminals of the second switch 2116, the third switch 2117, the fourth switch 2118, the fifth switch 2119, the sixth switch 2120, and the seventh switch 2121 are respectively connected to one end of the eighth capacitor 218, the ninth capacitor 219, the tenth capacitor 2110, the eleventh capacitor 2111, the twelfth capacitor 2112, the thirteenth capacitor 2113, and the fourteenth capacitor 2114. The other ends of the eighth capacitor 218, the ninth capacitor 219, the tenth capacitor 2110, the eleventh capacitor 2111, the twelfth capacitor 2112, the thirteenth capacitor 2113, and the fourteenth capacitor 2114 are interconnected and connected together to the other end of the corresponding port in the four-mode transformer 101.

[0056] Optionally, the control terminals of the first switch 2115, the second switch 2116, the third switch 2117, the fourth switch 2118, the fifth switch 2119, the sixth switch 2120, and the seventh switch 2121 are all connected to an external controller. The external controller sends digital control signals to the control terminals of each switch to independently control the closed or open state of each switch.

[0057] Specifically, when a switch in the capacitor switch array 102 is closed, a first group of capacitors (first capacitor 211, second capacitor 212, third capacitor 213, fourth capacitor 214, fifth capacitor 215, sixth capacitor 216 and seventh capacitor 217) and a second group of capacitors (eighth capacitor 218, ninth capacitor 219, tenth capacitor 2110, eleventh capacitor 2111, twelfth capacitor 2112, thirteenth capacitor 2113 and fourteenth capacitor 2114) are connected in series through the switch and then connected in parallel to the resonant port of the four-mode transformer 101, thereby contributing a specific capacitance value.

[0058] It is worth noting that by controlling the state combinations of the first switch 2115, the second switch 2116, the third switch 2117, the fourth switch 2118, the fifth switch 2119, the sixth switch 2120, and the seventh switch 2121 through an external controller, the total equivalent capacitance of the parallel connection port can be changed, thereby realizing the switching of the resonant frequency between multiple discrete frequency points and completing the coarse adjustment of the frequency coverage range.

[0059] In one alternative implementation, see [link to implementation details]. Figure 3 The fine-tuning varactor diode module 22 in each capacitor switch array 102 of the harmonic self-aligned voltage-controlled resonator 10 provided in this application embodiment includes: a first varactor diode 221, a second varactor diode 222, a third varactor diode 223 and a fourth varactor diode 224.

[0060] The output terminal of the first varactor diode 221 and the input terminal of the third varactor diode 223 are both connected to one end of the corresponding port in the four-mode transformer 101. The input terminal of the first varactor diode 221 is connected to the input terminal of the second varactor diode 222. The output terminal of the second varactor diode 222 and the input terminal of the fourth varactor diode 224 are both connected to the other end of the corresponding port in the four-mode transformer 101, and the output terminal of the third varactor diode 223 is connected to the output terminal of the fourth varactor diode 224.

[0061] Optionally, the fine-tuning varactor diode module 22 in each capacitor switch array 102 is used to continuously and precisely fine-tune the resonant frequency near the coarse-tuned operating frequency band. The fine-tuning varactor diode module 22 includes a first varactor diode 221, a second varactor diode 222, a third varactor diode 223, and a fourth varactor diode 224, which are connected symmetrically back-to-back to form a high-performance differential tuning unit.

[0062] Optionally, the first varactor diode 221 and the second varactor diode 222 are connected in series back-to-back, and the third varactor diode 223 and the fourth varactor diode 224 are also connected in series back-to-back. These two series branches are then connected in parallel with opposite polarities between the resonant ports of the four-mode transformer. This not only effectively suppresses common-mode interference introduced by varactor diode junction voltage fluctuations or power supply noise, improving the linearity and stability of frequency tuning, but also reduces the impact of harmonic distortion caused by the varactor diode's own nonlinearity on the purity of the resonant waveform. Furthermore, this design structure helps maintain the consistency of device parameters in cryogenic environments, ensuring reliable tuning characteristics.

[0063] Optionally, by applying a variable control voltage to each varactor diode, the effective capacitance value of the four varactor diodes can be changed synchronously, thereby achieving continuous and precise adjustment of the resonant frequency.

[0064] In one alternative implementation, see [link to implementation details]. Figure 2 The set of negative transconductance transistors 103 in the harmonic self-aligned voltage-controlled resonator 10 provided in this application embodiment includes: a first P-type metal-oxide-semiconductor field-effect transistor 1031 and a first N-type metal-oxide-semiconductor field-effect transistor 1032.

[0065] The gate of the first P-type metal-oxide-semiconductor field-effect transistor 1031 is connected to the other end of the second port of the quad-mode transformer 101, the drain of the first P-type metal-oxide-semiconductor field-effect transistor 1031 is connected to one end of the first port of the quad-mode transformer 101, and the source of the first P-type metal-oxide-semiconductor field-effect transistor 1031 is grounded. The gate of the first N-type metal-oxide-semiconductor field-effect transistor 1032 is connected to one end of the second port of the four-mode transformer 101, the drain of the first N-type metal-oxide-semiconductor field-effect transistor 1032 is connected to the other end of the first port of the four-mode transformer 101, and the source of the first N-type metal-oxide-semiconductor field-effect transistor 1032 is connected to an external power supply.

[0066] Optionally, a set of negative transconductance transistors 103 is specifically implemented as a complementary cross-coupled pair structure to generate and provide stable negative resistance in the resonant cavity of the quad mode transformer 101 to compensate for the inherent energy loss of the quad mode transformer 101, thereby exciting and maintaining stable radio frequency oscillations.

[0067] Optionally, the gate of the first P-type metal-oxide-semiconductor field-effect transistor 1031 and the gate of the first N-type metal-oxide-semiconductor field-effect transistor 1032 are respectively cross-connected to the opposite end port to form a positive feedback loop.

[0068] Specifically, when the resonant cavity of the four-mode transformer 101 generates a differential voltage disturbance at the target frequency, the cross-coupling structure, through the amplification and inversion effects of the first P-type metal-oxide-semiconductor field-effect transistor 1031 and the first N-type metal-oxide-semiconductor field-effect transistor 1032, presents an equivalent negative resistance characteristic between the differential ports of the resonant cavity of the four-mode transformer 101, which can accurately offset the equivalent positive resistance loss of the resonant cavity and its load.

[0069] It is worth noting that, compared with the negative transconductance pair of a single type of transistor, the complementary structure can provide a more symmetrical and stable negative resistance value over a wider voltage swing range, which helps to improve the symmetry of the oscillation waveform and reduce the impact of flicker noise upconversion on near-carrier phase noise.

[0070] In one alternative implementation, see [link to implementation details]. Figure 2The other set of negative transconductance transistors 103 in the harmonic self-aligned voltage-controlled resonator 10 provided in this application embodiment includes: a second P-type metal-oxide-semiconductor field-effect transistor 1033 and a second N-type metal-oxide-semiconductor field-effect transistor 1034.

[0071] The gate of the second P-type metal-oxide-semiconductor field-effect transistor 1033 is connected to one end of the third port of the four-mode transformer 101, the drain of the second P-type metal-oxide-semiconductor field-effect transistor 1033 is connected to the other end of the fourth port of the four-mode transformer 101, and the source of the second P-type metal-oxide-semiconductor field-effect transistor 1033 is grounded. The gate of the second N-type metal-oxide-semiconductor field-effect transistor 1034 is connected to the other end of the third port of the quad-mode transformer 101, the drain of the second N-type metal-oxide-semiconductor field-effect transistor 1034 is connected to one end of the fourth port of the quad-mode transformer 101, and the source of the second N-type metal-oxide-semiconductor field-effect transistor 1034 is connected to an external power supply.

[0072] Optionally, another set of negative transconductance transistors 103 and the aforementioned set of negative transconductance transistors 103 are complementary cross-coupled structures, with a completely symmetrical circuit topology. The second P-type metal-oxide-semiconductor field-effect transistor 1033 and the second N-type metal-oxide-semiconductor field-effect transistor 1034 provide negative resistance between the differential port pair formed by the third and fourth ports of the four-mode transformer 101, thereby collaboratively compensating for the overall loss of the resonant cavity in the four-mode transformer 101 and ensuring the stability of multimode oscillation.

[0073] Optionally, by cross-connecting the gate of the second P-type metal-oxide-semiconductor field-effect transistor 1033 and the gate of the second N-type metal-oxide-semiconductor field-effect transistor 1034 to the corresponding ports to form a positive feedback path, the second P-type metal-oxide-semiconductor field-effect transistor 1033 and the second N-type metal-oxide-semiconductor field-effect transistor 1034 present an equivalent negative resistance between the third and fourth ports of the four-mode transformer, thereby accurately offsetting the resonant loss of this branch.

[0074] It is worth noting that the two sets of mirror-symmetrical negative transconductance transistors are respectively connected to the two pairs of symmetrical resonant ports of the four-mode transformer 101, which can ensure that the four-mode transformer 101 oscillates in a balanced manner under multi-mode operation. In this way, energy can be uniformly injected into the symmetrical modes of the four-mode transformer 101, supporting the effective excitation and maintenance of the fundamental frequency and higher harmonic modes.

[0075] In one alternative implementation, see [link to implementation details]. Figure 2 The impedance balancing unit 104 in the harmonic self-aligned voltage-controlled resonator 10 provided in this application embodiment includes: a fifteenth capacitor 1041 and a sixteenth capacitor 1042.

[0076] One end of the fifteenth capacitor 1041 is connected to one end of the first port of the four-mode transformer 101, and the other end of the fifteenth capacitor 1041 is connected to the other end of the first port of the four-mode transformer 101. One end of the sixteenth capacitor 1042 is connected to one end of the fourth port of the four-mode transformer 101, and the other end of the sixteenth capacitor 1042 is connected to the other end of the fourth port of the four-mode transformer 101.

[0077] Optionally, the impedance balancing unit 104 is used to finely adjust and ensure the symmetry of the ground or differential impedance of the resonant port of the four-mode transformer 101. It is an important passive network for maintaining multimode resonance conditions and harmonic self-alignment characteristics.

[0078] Optionally, the fifteenth capacitor 1041 is used to provide an additional, precisely settable parallel capacitor for the first port of the quad mode transformer 101, and the sixteenth capacitor 1042 is used to provide an additional, precisely settable parallel capacitor for the second port of the quad mode transformer 101, to compensate for the minor asymmetry between the resonant ports caused by layout parasitic parameters, transistor input capacitance, and interconnect differences, to ensure that the equivalent load capacitance of the four resonant ports of the quad mode transformer 101 is electrically highly consistent, so that the resonant frequencies of the intrinsic modes of the quad mode transformer 101 can maintain a fixed proportional relationship.

[0079] In addition, the fifteenth capacitor 1041, the sixteenth capacitor 1042, and the adjustable capacitor switch array 102 together constitute the load capacitor of the resonant port of the four-mode transformer 101, which helps to stabilize the baseline value of the resonant frequency and reduce frequency disturbances caused by active device parameter drift or switching state changes.

[0080] In one alternative implementation, see [link to implementation details]. Figure 2 The mode switching unit 105 in the harmonic self-aligned voltage-controlled resonator 10 provided in this application embodiment includes: an eighth switch 1051, a ninth switch 1052, a tenth switch 1053, and an eleventh switch 1054.

[0081] The input terminals of the eighth switch 1051 and the tenth switch 1053 are both connected to one end of the second port of the four-mode transformer 101, and the output terminals of the eighth switch 1051 and the eleventh switch 1054 are both connected to one end of the third port of the four-mode transformer 101. The input terminals of the ninth switch 1052 and the eleventh switch 1054 are both connected to the other end of the second port of the four-mode transformer 101, and the output terminals of the ninth switch 1052 and the tenth switch 1053 are both connected to the other end of the third port of the four-mode transformer 101. The control terminals of the eighth switch 1051, the ninth switch 1052, the tenth switch 1053, and the eleventh switch 1054 are all connected to an external controller.

[0082] Optionally, the mode switching unit 105 is used to purposefully select and switch the operating mode (such as low-frequency mode and high-frequency mode) of the voltage-controlled resonator 10 by changing the electrical connection between the key resonant ports inside the four-mode transformer 101.

[0083] Optionally, when an external controller issues a control command to switch the operating mode, the eighth switch 1051, the ninth switch 1052, the tenth switch 1053, and the eleventh switch 1054 are turned on or off under the action of the control command.

[0084] When the eighth switch 1051, the ninth switch 1052, the tenth switch 1053, and the eleventh switch 1054 are all turned off under the control of the external controller, the second and third ports of the four-mode transformer 101 exchange energy through the inherent mutual inductance characteristics of the four-mode transformer 101. The equivalent inductance of the four-mode transformer 101 is relatively large, and the voltage-controlled resonator 10 operates in a lower frequency band. When the eighth switch 1051, the ninth switch 1052, the tenth switch 1053, and the eleventh switch 1054 are all turned on under the control of the external controller, the second and third ports of the four-mode transformer 101 establish a direct, low-impedance electrical connection through the turned-on switches. This forces the two distributed inductors of the four-mode transformer 101 to be associated or short-circuited and reconstructed, significantly changing the equivalent inductance and coupling coefficient of the resonant circuit, so that the voltage-controlled resonator 10 operates in a higher frequency band.

[0085] Additionally, see Figure 4 When the eighth switch 1051 and the ninth switch 1052 are turned on under the control of the external controller, and the tenth switch 1053 and the eleventh switch 1054 are turned off under the control of the external controller, a direct electrical connection is established between the second and third ports of the four-mode transformer 101 through the eighth switch 1051 and the ninth switch 1052. (See [link to relevant documentation]). Figure 5 Under this operating condition, the equivalent inductance of the four-mode transformer 101 is relatively large, and the voltage-controlled resonator 10 operates in the low-frequency band.

[0086] Further, see Figure 6 When the eighth switch 1051 and the ninth switch 1052 are turned off under the control of the external controller, and the tenth switch 1053 and the eleventh switch 1054 are turned on under the control of the external controller, a direct electrical connection is established between the second and third ports of the four-mode transformer 101 through the tenth switch 1053 and the eleventh switch 1054. (See [link to relevant documentation]). Figure 7Under this operating condition, the equivalent inductance of the four-mode transformer 101 is relatively small, and the voltage-controlled resonator 10 operates in the high-frequency band.

[0087] Optionally, the mode switching unit 105 adopts four switches, namely the eighth switch 1051, the ninth switch 1052, the tenth switch 1053, and the eleventh switch 1054, to form a differential symmetrical structure. This ensures that the influence of the voltage-controlled resonator 10 on the differential signal path of the resonant cavity of the four-mode transformer 101 is balanced during the mode switching process, avoiding the introduction of additional common-mode disturbances or asymmetries, thereby maintaining the phase noise performance of the oscillation.

[0088] In one alternative implementation, see [link to implementation details]. Figure 2 The harmonic self-aligned voltage-controlled resonator 10 provided in this application embodiment further includes: a first main circuit inductor 106, a second main circuit inductor 107, a third main circuit inductor 108, and a fourth main circuit inductor 109.

[0089] One end of the first main circuit inductor 106 is connected to one end of the fifth inductor 121 and one end of the third inductor 113 respectively. The other end of the first main circuit inductor 106 is connected to one end of the second main circuit inductor 107. The other end of the second main circuit inductor 107 is connected to the other end of the sixth inductor 122 and the other end of the fourth inductor 114 respectively. One end of the third main circuit inductor 108 is connected to one end of the first inductor 111 and one end of the seventh inductor 123, respectively. The other end of the third main circuit inductor 108 is connected to one end of the fourth main circuit inductor 109, and the other end of the fourth main circuit inductor 109 is connected to the other end of the second inductor 112 and the other end of the eighth inductor 124, respectively.

[0090] Optionally, the first main circuit inductor 106, the second main circuit inductor 107, the third main circuit inductor 108, and the fourth main circuit inductor 109 provide DC and low-frequency paths for the voltage-controlled resonator 10, enhance the structural symmetry of the voltage-controlled resonator 10, and participate in the formation of the resonant mode.

[0091] Among them, multiple main circuit inductors not only provide a low-impedance path for the DC operating point of the active devices in the main circuit of the voltage-controlled resonator 10, but also act as RF chokes to effectively suppress the leakage of RF signals to the power supply and ground, thereby improving the quality factor of the resonant cavity of the four-mode transformer 101.

[0092] Furthermore, the voltage-controlled resonator 10 further enhances the electrical symmetry and coupling strength between the first distributed inductor 1011 and the second distributed inductor 1012 through the symmetrical connection of multiple low-inductance main circuit inductors, which helps to stabilize the fixed proportional relationship between multimode resonant frequencies and consolidate the physical basis of harmonic self-alignment.

[0093] Furthermore, under specific high-frequency operating modes, the small inductance of the main circuit inductor, together with the distributed parameters of the four-mode transformer 101, can produce a beneficial fine-tuning effect on the precise frequency and impedance characteristics of the high-frequency resonant mode.

[0094] Figure 8 For a schematic diagram of a frequency synthesizer provided in this application, see [link to schematic diagram]. Figure 8 The frequency synthesizer 20 provided in this application embodiment integrates the voltage-controlled resonator 10 described in the above embodiment. The harmonic self-alignment of the frequency synthesizer 20 is achieved by the internally integrated voltage-controlled resonator 10. Its working principle and implementation process are the same as those described above, and will not be repeated here.

[0095] Figure 9 For a quantum bit measurement and control system provided in this application, see [link to relevant documentation]. Figure 9 This application provides a quantum bit measurement and control system 30, including... Figure 8 The frequency synthesizer 20 shown is used to provide a local oscillator signal for the process of generating qubits in the quantum bit measurement and control system 30. The process of generating the local oscillator signal is consistent with the working principle of the voltage-controlled resonator 10 described above, and will not be described in detail here.

[0096] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0097] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A harmonic self-aligned voltage-controlled resonator, characterized in that, The voltage-controlled resonator includes: a four-mode transformer, multiple capacitor switch arrays, a negative transconductance circuit, an impedance balancing unit, and a mode switching unit. The negative transconductance circuit includes: two sets of cross-coupled negative transconductance transistors. The impedance balancing unit includes: multiple capacitors. The four-mode transformer consists of two symmetrical and mutually coupled distributed inductors and has four ports. Each port of the four-mode transformer is connected to a capacitor switch array to maintain the capacitance symmetry between the ports of the four-mode transformer. A set of negative transconductance transistors is connected between the first and second ports of the four-mode transformer, and another set of negative transconductance transistors is connected between the third and fourth ports of the four-mode transformer. The negative transconductance circuit is used to provide negative resistance to compensate for the losses of the four-mode transformer. Each capacitor in the impedance balancing unit is connected to the two ends of the first and fourth ports of the four-mode transformer, respectively, to balance the impedance of each port of the four-mode transformer. The mode switching unit is connected between the second and third ports of the four-mode transformer and is used to control the switching of the local oscillator mode of the four-mode transformer to switch the operating frequency band of the voltage-controlled resonator.

2. The harmonic self-aligned voltage-controlled resonator according to claim 1, characterized in that, The four-mode transformer includes: a first distributed inductor and a second distributed inductor. The first distributed inductor includes: a first inductor, a second inductor, a third inductor, and a fourth inductor. The second distributed inductor includes: a fifth inductor, a sixth inductor, a seventh inductor, and an eighth inductor. The plurality of capacitor switch arrays include: a first capacitor switch array, a second capacitor switch array, a third capacitor switch array, and a fourth capacitor switch array. One end of the first inductor is connected to one end of the seventh inductor, the other end of the first inductor is connected to one end of the first capacitor switch array, one end of the second inductor is connected to the other end of the first capacitor switch array, the other end of the second inductor is connected to the other end of the eighth inductor, and the other end of the first inductor and one end of the second inductor are also connected to a capacitor in the impedance balancing unit. One end of the third inductor is connected to one end of the fifth inductor, and the other end of the third inductor is connected to one end of the fourth capacitor switch array. One end of the fourth inductor is connected to the other end of the fourth capacitor switch array, and the other end of the fourth inductor is connected to the other end of the sixth inductor. The other ends of the first inductor, the second inductor, the fifth inductor, and the sixth inductor are also connected to a set of negative transconductance transistors. The other ends of the third inductor and the fourth inductor are also connected to a capacitor in the impedance balancing unit. The other end of the fifth inductor is connected to one end of the second capacitor switch array, and one end of the sixth inductor is connected to the other end of the second capacitor switch array; The other end of the seventh inductor is connected to one end of the third capacitor switch array, and one end of the eighth inductor is connected to the other end of the third capacitor switch array. The other ends of the third inductor, the fourth inductor, the seventh inductor, and the eighth inductor are also connected to another set of negative transconductance transistors. The other ends of the fifth inductor, the sixth inductor, the seventh inductor, and the eighth inductor are also connected to the mode switching unit.

3. The harmonic self-aligned voltage-controlled resonator according to claim 1, characterized in that, The plurality of capacitor switch arrays each include: a coarse-adjustment switched capacitor module and a fine-adjustment varactor diode module; One end of the coarse-adjustment switching capacitor module and one end of the fine-adjustment varactor diode module in each capacitor switch array are respectively connected to one end of the corresponding port in the four-mode transformer. The other end of the coarse-adjustment switching capacitor module and the other end of the fine-adjustment varactor diode module in each capacitor switch array are respectively connected to the other end of the corresponding port in the four-mode transformer.

4. The harmonic self-aligned voltage-controlled resonator according to claim 3, characterized in that, The coarse adjustment switching capacitor module includes: a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a ninth capacitor, a tenth capacitor, an eleventh capacitor, a twelfth capacitor, a thirteenth capacitor, a fourteenth capacitor, a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch, and a seventh switch; One end of the first capacitor, one end of the second capacitor, one end of the third capacitor, one end of the fourth capacitor, one end of the fifth capacitor, one end of the sixth capacitor, and one end of the seventh capacitor are all connected to one end of the corresponding port in the four-mode transformer. The other ends of the first capacitor, the second capacitor, the third capacitor, the fourth capacitor, the fifth capacitor, the sixth capacitor, and the seventh capacitor are respectively connected to the output terminals of the first switch, the second switch, the third switch, the fourth switch, the fifth switch, the sixth switch, and the seventh switch. The input terminals of the first switch, the second switch, the third switch, the fourth switch, the fifth switch, the sixth switch, and the seventh switch are respectively connected to one end of the eighth capacitor, one end of the ninth capacitor, one end of the tenth capacitor, one end of the eleventh capacitor, one end of the twelfth capacitor, one end of the thirteenth capacitor, and one end of the fourteenth capacitor. The other ends of the eighth capacitor, the ninth capacitor, the tenth capacitor, the eleventh capacitor, the twelfth capacitor, the thirteenth capacitor, and the fourteenth capacitor are all connected to the other end of the corresponding port in the four-mode transformer. The control terminals of the first switch, the second switch, the third switch, the fourth switch, the fifth switch, the sixth switch, and the seventh switch are all connected to an external controller.

5. The harmonic self-aligned voltage-controlled resonator according to claim 3, characterized in that, The fine-tuning varactor diode module includes: a first varactor diode, a second varactor diode, a third varactor diode, and a fourth varactor diode; The output terminal of the first varactor diode and the input terminal of the third varactor diode are both connected to one end of the corresponding port in the four-mode transformer, and the input terminal of the first varactor diode is connected to the input terminal of the second varactor diode. The output terminal of the second varactor diode and the input terminal of the fourth varactor diode are both connected to the other end of the corresponding port in the four-mode transformer, and the output terminal of the third varactor diode is connected to the output terminal of the fourth varactor diode.

6. The harmonic self-aligned voltage-controlled resonator according to claim 1, characterized in that, A set of negative transconductance transistors includes: a first P-type metal-oxide-semiconductor field-effect transistor and a first N-type metal-oxide-semiconductor field-effect transistor; The gate of the first P-type metal-oxide-semiconductor field-effect transistor is connected to the other end of the second port of the four-mode transformer, the drain of the first P-type metal-oxide-semiconductor field-effect transistor is connected to one end of the first port of the four-mode transformer, and the source of the first P-type metal-oxide-semiconductor field-effect transistor is grounded. The gate of the first N-type metal-oxide-semiconductor field-effect transistor is connected to one end of the second port of the four-mode transformer, the drain of the first N-type metal-oxide-semiconductor field-effect transistor is connected to the other end of the first port of the four-mode transformer, and the source of the first N-type metal-oxide-semiconductor field-effect transistor is connected to an external power supply.

7. The harmonic self-aligned voltage-controlled resonator according to claim 1, characterized in that, Another set of negative transconductance transistors includes: a second P-type metal-oxide-semiconductor field-effect transistor and a second N-type metal-oxide-semiconductor field-effect transistor; The gate of the second P-type metal-oxide-semiconductor field-effect transistor is connected to one end of the third port of the four-mode transformer, the drain of the second P-type metal-oxide-semiconductor field-effect transistor is connected to the other end of the fourth port of the four-mode transformer, and the source of the second P-type metal-oxide-semiconductor field-effect transistor is grounded. The gate of the second N-type metal-oxide-semiconductor field-effect transistor is connected to the other end of the third port of the four-mode transformer, the drain of the second N-type metal-oxide-semiconductor field-effect transistor is connected to one end of the fourth port of the four-mode transformer, and the source of the second N-type metal-oxide-semiconductor field-effect transistor is connected to an external power supply.

8. The harmonic self-aligned voltage-controlled resonator according to claim 1, characterized in that, The impedance balancing unit includes: a fifteenth capacitor and a sixteenth capacitor; One end of the fifteenth capacitor is connected to one end of the first port of the four-mode transformer, and the other end of the fifteenth capacitor is connected to the other end of the first port of the four-mode transformer. One end of the sixteenth capacitor is connected to one end of the fourth port of the four-mode transformer, and the other end of the sixteenth capacitor is connected to the other end of the fourth port of the four-mode transformer.

9. The harmonic self-aligned voltage-controlled resonator according to claim 1, characterized in that, The mode switching unit includes: an eighth switch, a ninth switch, a tenth switch, and an eleventh switch; The input terminals of the eighth switch and the tenth switch are both connected to one end of the second port of the four-mode transformer, and the output terminals of the eighth switch and the eleventh switch are both connected to one end of the third port of the four-mode transformer. The input terminals of the ninth switch and the eleventh switch are both connected to the other end of the second port of the four-mode transformer, and the output terminals of the ninth switch and the tenth switch are both connected to the other end of the third port of the four-mode transformer. The control terminals of the eighth switch, the ninth switch, the tenth switch, and the eleventh switch are all connected to an external controller.

10. The harmonic self-aligned voltage-controlled resonator according to claim 2, characterized in that, The voltage-controlled resonator further includes: a first main circuit inductor, a second main circuit inductor, a third main circuit inductor, and a fourth main circuit inductor; One end of the first main circuit inductor is connected to one end of the fifth inductor and one end of the third inductor, respectively; the other end of the first main circuit inductor is connected to one end of the second main circuit inductor, and the other end of the second main circuit inductor is connected to the other end of the sixth inductor and the other end of the fourth inductor, respectively. One end of the third main circuit inductor is connected to one end of the first inductor and one end of the seventh inductor, respectively. The other end of the third main circuit inductor is connected to one end of the fourth main circuit inductor, and the other end of the fourth main circuit inductor is connected to the other end of the second inductor and the other end of the eighth inductor, respectively.

11. A frequency synthesizer, characterized in that, The frequency synthesizer integrates a voltage-controlled resonator as described in any one of claims 1 to 10.

12. A quantum bit measurement and control system, characterized in that, The quantum bit measurement and control system includes the frequency synthesizer as described in claim 11, which is used to provide a local oscillator signal for the quantum bit.

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