W-band low-phase-noise broadband voltage-controlled oscillator based on mode switching technology

Abstract

The invention relates to a W-band low-phase-noise broadband voltage-controlled oscillator based on a mode switching technology. The W-band low-phase-noise broadband voltage-controlled oscillator comprises a mode-switchable voltage-controlled oscillator and a signal processor, the mode-switchable voltage-controlled oscillator comprises four VCO cores and a mode switching switch array, wherein the four VCO cores have the same structure and work synchronously; the four VCO cores are connected in parallel through the series inductors to form an annular structure, and each VCO core is connected with the mode switching switch array; the mode change-over switch array is used for switching different resonance modes by switching on and off of an internal control switch, and outputting oscillation signals which are different in frequency mode and cover W wave bands; and the output end of one of the four VCO cores is coupled with the input end of the signal processor so as to perform signal processing on the oscillation signal output by the mode switchable voltage-controlled oscillator and output a final W-band signal. According to the device, the wide tuning range of the millimeter wave frequency band can be realized on the premise that the phase noise is not deteriorated.

Description

Technical Field

[0001] This invention belongs to the field of millimeter-wave integrated circuit technology, specifically relating to a W-band low phase noise broadband voltage-controlled oscillator based on mode switching technology. Background Technology

[0002] With the rapid development of advanced wireless systems such as fifth-generation (5G) and future sixth-generation (6G) mobile communications, millimeter-wave radar, high-speed satellite communications, and the Internet of Things, the performance requirements for the core frequency source—the voltage-controlled oscillator (VCO)—are becoming increasingly stringent. Modern systems not only require VCOs to have low phase noise to ensure signal purity, but also to achieve a wide frequency tuning range in millimeter-wave bands (such as the W-band) to cover increasingly fragmented spectrum resources and support multi-band, multi-standard operation.

[0003] Traditional single-mode VCOs face inherent technical bottlenecks in the millimeter-wave band: an irreconcilable trade-off exists between their tuning range and phase noise performance. Extending the tuning range typically comes at the cost of sacrificing phase noise, and vice versa. To cover a wide bandwidth, existing technologies often employ switched capacitor arrays or switched inductor arrays, achieving discrete frequency switching by switching the equivalent capacitance or inductance values ​​in the resonant network. However, in such solutions, the on-resistance of the integrated switches is directly introduced into the resonant cavity, leading to a significant decrease in the quality factor (Q value), which in turn deteriorates phase noise performance. Furthermore, to achieve multi-octave band coverage, multiple independent VCOs or multiple large-scale capacitor / inductor arrays are often required, which not only significantly increases chip area and manufacturing cost but also leads to increased system power consumption and reduced integration density.

[0004] Specifically, in millimeter-wave bands such as the W-band (75-110 GHz), the aforementioned contradictions are particularly prominent. The impact of parasitic effects is aggravated, further limiting the Q value of the resonant network, making it extremely challenging to achieve wideband tuning while maintaining low phase noise.

[0005] In short, existing voltage-controlled oscillators cannot solve the problem of achieving a wide tuning range in the millimeter-wave band without degrading phase noise. Summary of the Invention

[0006] To address the aforementioned problems in the prior art, this invention provides a W-band low-phase-noise broadband voltage-controlled oscillator based on mode switching technology. The technical problem to be solved by this invention is achieved through the following technical solution: This invention provides a W-band low-phase-noise broadband voltage-controlled oscillator based on mode-switching technology, comprising: a mode-switchable voltage-controlled oscillator and a signal processor; wherein, the mode-switchable voltage-controlled oscillator includes four identical and synchronously operating folded Colpitts VCO cores, and a mode-switching switch array; the four folded Colpitts VCO cores are connected in parallel in a ring structure via series inductors, and each folded Colpitts VCO core is connected to the mode-switching switch array through its two base nodes; the mode-switching switch array changes the equivalent inductance value of the series inductors by switching the on and off of internal control switches, thereby effectively changing the total inductance of the entire resonant system, switching different resonant modes, and outputting oscillation signals with multiple different frequency modes covering the W-band; and one of the four folded Colpitts VCO cores... The output of the VCO core is coupled to the input of the signal processor to perform power buffering, impedance transformation, and single-ended to differential processing on the oscillation signal output by the mode-switchable voltage-controlled oscillator, and output the final W-band signal.

[0007] Compared with the prior art, the beneficial effects of the present invention are as follows: To address the challenge of achieving a wide tuning range in the millimeter-wave band without degrading phase noise in existing voltage-controlled oscillators (VCOs), this invention provides a W-band low-phase-noise broadband VCO based on mode-switching technology. Through the synergistic innovation of a quad-core ring coupling structure and a multi-mode switching mechanism, it successfully overcomes the inherent contradiction between tuning range and phase noise in traditional VCOs. A mode-switching array is used to control the equivalent change in the total inductance of the entire resonant system, enabling continuous adjustment of the equivalent inductance and thus achieving broadband frequency coverage. A folded circuit structure and unique bias design optimize the oscillation waveform, and the multi-core power superposition effect significantly improves phase noise performance. The compact ring layout and integrated design effectively control chip area and power consumption while ensuring performance. Ultimately, this achieves a highly integrated frequency source solution in the millimeter-wave band, simultaneously possessing a wide tuning range, low phase noise, small chip area, and low power consumption. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the arrangement of a W-band low phase noise broadband voltage-controlled oscillator based on mode switching technology provided in an embodiment of the present invention; Figure 2 This is a circuit connection diagram of the mode switching switch array provided in an embodiment of the present invention; Figure 3 This is a circuit connection diagram of the four folded Colpitts VCO cores provided in an embodiment of the present invention; Figure 4This is a circuit connection diagram of the signal processor provided in an embodiment of the present invention.

[0009] Figure 5 This is a simulation diagram of the phase noise of the three single-core VCO structures provided in the embodiments of the present invention at a 90GHz output frequency; Figure 6 This is the process of phase noise variation of the mode switching array at the 80GHz output frequency as a function of the mode switching bulk effect, provided in the embodiment of the present invention. Figure 7 This is a simulation diagram of the frequency variation of the W-band signal output by the W-band low phase noise broadband voltage-controlled oscillator provided in the embodiments of the present invention in three modes; Figure 8 This is a simulation diagram of the phase noise variation of the W-band low phase noise broadband voltage-controlled oscillator at a frequency offset of 1 MHz from the carrier throughout the entire tuning range, provided in an embodiment of the present invention. Detailed Implementation

[0010] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0011] In the description of this invention, 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.

[0012] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0013] The following is a detailed description of a W-band low phase noise broadband voltage-controlled oscillator based on mode switching technology proposed in this invention, with reference to the accompanying drawings.

[0014] Figure 1 This is a schematic diagram of the arrangement of a W-band low phase noise broadband voltage-controlled oscillator based on mode switching technology provided in an embodiment of the present invention. Figure 1As shown, it includes: a mode-switchable voltage-controlled oscillator and a signal processor; The mode-switching voltage-controlled oscillator includes four identical and synchronously operating folded Colpitts VCO cores and a mode-switching switch array. The four folded Colpitts VCO cores are connected in parallel in a ring structure via series inductors, and each folded Colpitts VCO core is connected to the mode-switching switch array through its two base nodes. The mode-switching switch array changes the equivalent inductance value of the four series inductors by switching the on and off of its internal control switches, thereby effectively changing the total inductance of the entire resonant system, switching different resonant modes, and outputting oscillation signals with multiple different frequency modes covering the W-band. Furthermore, the output of one of the four folded Colpitts VCO cores is coupled to the input of the signal processor to perform power buffering, impedance transformation, and single-ended to differential processing on the oscillation signal output by the mode-switchable voltage-controlled oscillator, and output the final W-band signal.

[0015] The specific structure and working principle of the mode-switchable voltage-controlled oscillator will now be described in detail.

[0016] Here, the mode switching array receives predefined digital voltage commands {V} from an external control circuit via eight control terminals. c1 V c2 V c3 V c4 Each pair of control terminals receives the same logic signal; and in response to the digital voltage command, each control terminal receives a logic signal and controls the on and off of the associated MOSFET switch group, thereby selectively short-circuiting the midpoint of the series inductor connected to the adjacent folded Colpitts VCO core to ground; wherein, the logic signal "1" in the digital voltage command is used to control the MOSFET switch group to close, and the logic signal "0" is used to control the MOSFET switch group to open. Among them, in the digital voltage command {V c1 =1, V c2 =0, V c3 =1, V c4 When =0}, the mode switching array switches to mode one (fully even mode), the midpoint of all series inductors remains floating, the resonant system presents the maximum equivalent inductance, and the first oscillation signal is output; In digital voltage command {V c1 =1, V c2 =0, V c3 =0, V c4When =1}, the mode switching array switches to mode two (alternating odd and even mode), the midpoint of part of the series inductor is short-circuited to ground by AC, the resonant system presents an intermediate equivalent inductor, and outputs the second oscillation signal; In digital voltage command {V c1 =0, V c2 =1, V c3 =0, V c4 When =1}, the mode switching array switches to mode three (all odd mode), the midpoint of all series inductors is short-circuited to ground by AC, the resonant system presents the minimum equivalent inductance, and the third oscillation signal is output.

[0017] It should be noted that the frequency range of the W-band signal corresponding to the first oscillation signal is 83.2 GHz to 89.7 GHz, the frequency range of the W-band signal corresponding to the second oscillation signal is 89.1 GHz to 96.2 GHz, and the frequency range of the W-band signal corresponding to the third oscillation signal is 95.6 GHz to 102.3 GHz. Here, the frequency overlap between any two adjacent resonant modes is greater than 0.5 GHz, ensuring that the entire system can continuously cover the W-band signal from 83.2 to 102.3 GHz.

[0018] Figure 2 This is a circuit connection diagram of the mode switching switch array provided in an embodiment of the present invention. Figure 2As shown, the mode switching array includes: four identical mode control groups connected in parallel in a ring structure; each mode control group includes: four MOSFET switches, two bias resistors, and two DC blocking capacitors; wherein: the gates of the first and second MOSFET switches serve as the first control terminals of the mode control group; the gates of the third and fourth MOSFET switches serve as the second control terminals of the mode control group; each control terminal receives a logic signal; the sources of the first and third MOSFET switches are connected to one end of a bias resistor in an adjacent mode control group; the drains of the first and third MOSFET switches are connected to one end of a bias resistor in another adjacent mode control group; the sources of the second and fourth MOSFET switches are connected to one end of the first bias resistor, the other end of which is grounded; the drains of the second and fourth MOSFET switches are connected to one end of the second bias resistor, the other end of which is grounded; one end of the first bias resistor is also connected to one end of the first DC blocking capacitor, the other end of which is connected to a folded Colpitts. One input terminal of the VCO core is connected; one end of the second bias resistor is also connected to one end of the second DC blocking capacitor, and the other end of the second DC blocking capacitor is connected to one input terminal of another adjacent folded Colpitts VCO core.

[0019] It should be noted that the trace length from each MOSFET switch to the folded Colpitts VCO core should be strictly symmetrical to reduce phase shift caused by different trace lengths at high frequencies.

[0020] For example, the mode switching array includes transistors M1, M2, M3, M4, M5, M6, M7, M8, M9, and M1. 10 Transistor M 11 Transistor M 12 Transistor M 13 Transistor M 14 Transistor M 15 Transistor M 16 Capacitors C1, C2, C3, C4, C5, C6, C7, and C8; resistors R1, R2, R3, R4, R5, R6, R7, and R8; and the connection to the VCO input terminal V. s1 Input terminal V s2 Input terminal V s3 Input terminal V s4 Input terminal Vs5 Input terminal V s6 Input terminal V s7 Input terminal V s8 DC input terminal V c1 DC input terminal V c2 DC input terminal V c3 DC input terminal V c4 The drain of transistor M1 is connected to one end of capacitor C2, one end of resistor R2, the drain of transistor M4, the source of transistor M6, and the source of transistor M8. The other end of capacitor C2 is connected to the input terminal V. s2 The other end of resistor R2 is grounded. The drain of transistor M2 is connected to one end of capacitor C1, one end of resistor R1, the drain of transistor M3, the source of transistor M5, and the source of transistor M7. The other end of capacitor C1 is connected to the input terminal V. s1 The other end of resistor R1 is grounded. The drain of transistor M5 is connected to one end of capacitor C8, one end of resistor R8, the drain of transistor M8, and transistor M... 13 The source and transistor M 15 The source of the capacitor, the other end of which is connected to the input terminal V. s8 The other end of resistor R8 is grounded. The drain of transistor M6 is connected to one end of capacitor C7, one end of resistor R7, the drain of transistor M7, and transistor M... 14 The source and transistor M 16 The source of the capacitor is connected to the other end of the capacitor C7, which is connected to the input terminal V. s1 The other end of resistor R7 is grounded. Transistor M 16 The drain of the transistor is connected to one end of capacitor C6, one end of resistor R6, and transistor M. 13 The drain of transistor M9, the source of transistor M9, and transistor M 11 The source of the capacitor, the other end of which is connected to the input terminal V. s6 The other end of resistor R6 is grounded. Transistor M 15 The drain of the transistor is connected to one end of capacitor C5, one end of resistor R5, and transistor M. 14 The drain of the transistor M 10 The source and transistor M 12 The source of the capacitor, the other end of which is connected to the input terminal V. s5 The other end of resistor R5 is grounded. Transistor M 12 The drain of transistor M9 is connected to one end of capacitor C4, one end of resistor R4, the drain of transistor M9, the source of transistor M2, and the source of transistor M4. The other end of capacitor C4 is connected to the input terminal V. s4 The other end of resistor R4 is grounded. Transistor M 11 The drain of transistor M9 is connected to one end of capacitor C3, one end of resistor R3, the drain of transistor M9, the source of transistor M1, and the source of transistor M3. The other end of capacitor C3 is connected to the input terminal V.s3 The other end of resistor R3 is grounded.

[0021] Here, the VCO signal comes from V s The input ports are used to synchronize signals from different ports via control switches, enabling mode switching. Specifically, the first control terminals of both the first and third mode control groups are connected to the logic signal V. c1 The second control terminal is connected to the logic signal V. c2 The first control terminal of both the second and fourth mode control groups is connected to the logic signal V. c3 The second control terminal is connected to the logic signal V. c4 ;in: (1) In the digital voltage command {V c1 =1, V c2 =0, V c3 =1, V c4 When =0, In the first mode control group, the first MOSFET switch M1 and the second MOSFET switch M2 are turned on, and the third MOSFET switch M3 and the fourth MOSFET switch M4 are turned off. The first MOSFET switch M9 and the second MOSFET switch M in the second mode control group 10 Turn on, third MOSFET switch M 11 and the fourth MOSFET switch M 12 Turn off; The first MOSFET switch M in the third mode control group 13 Second MOSFET switch M 14 Turn on, third MOSFET switch M 15 and the fourth MOSFET switch M 16 Turn off; In the fourth mode control group, the first MOSFET switch M7 and the second MOSFET switch M8 are turned on, while the third MOSFET switch M5 and the fourth MOSFET switch M6 are turned off. (2) In the digital voltage command {V c1 =1, V c2 =0, V c3 =0, V c4 When =1}, In the first mode control group, the first MOSFET switch M1 and the second MOSFET switch M2 are turned on, and the third MOSFET switch M3 and the fourth MOSFET switch M4 are turned off. The first MOSFET switch M9 and the second M in the second mode control group 10 Turn on, third MOSFET switch M 11and the fourth MOSFET switch M 12 Turn off; The first MOSFET switch M in the third mode control group 13 Second MOSFET switch M 14 Turn off, third MOSFET switch M 15 and the fourth MOSFET switch M 16 Conduction; In the fourth mode control group, the first MOSFET switch M7 and the second MOSFET switch M8 are turned off, and the third MOSFET switch M5 and the fourth MOSFET switch M6 are turned on. (3) In the digital voltage command {V c1 =0, V c2 =1, V c3 =0, V c4 When =1}, In the first mode control group, the first MOSFET switch M1 and the second MOSFET switch M2 are turned off, and the third MOSFET switch M3 and the fourth MOSFET switch M4 are turned on. The first MOSFET switch M9 and the second MOSFET switch M in the second mode control group 10 Turn off, third MOSFET switch M 11 and the fourth MOSFET switch M 12 Conduction; The first MOSFET switch M in the third mode control group 13 Second MOSFET switch M 14 Turn off, third MOSFET switch M 15 and the fourth MOSFET switch M 16 Conduction; In the fourth mode control group, the first MOSFET switch M7 and the second MOSFET switch M8 are turned off, while the third MOSFET switch M5 and the fourth MOSFET switch M6 are turned on.

[0022] Figure 3 This is a circuit connection diagram of the four folded Colpitts VCO cores provided in an embodiment of the present invention. Figure 3 As shown, an inductor is connected in series between adjacent folded Colpitts VCO cores; the first folded Colpitts VCO core includes: transistor Q1, transistor Q2, and capacitor C. F1 Capacitor C F2 Inductor L1, Inductor L2, Inductor L3, Inductor L4, Varactor diode C V1 varactor diode C V2 and resistance R T1The drains of both transistors Q1 and Q2 are connected to a DC power supply V. CC1 The source of transistor Q1 is connected to capacitor C. F1 One end, varactor diode C V1 One end of transistor Q1 is connected to the inductor L1; the source of transistor Q2 is connected to capacitor C. F2 One end, varactor diode C V2 One end of transistor Q1 is connected to the inductor L4, and the other end of inductor L4 is connected to the capacitor C. F1 The other end, one end of inductor L2, and inductor L connecting the first folded Colpitts VCO core and the fourth folded Colpitts VCO core. S4 One end of the transistor is connected to the first input terminal of the first folded Colpitts VCO core; the gate of transistor Q2 is connected to capacitor C. F2 The other end, one end of inductor L3, and inductor L connecting the first folded Colpitts VCO core and the second folded Colpitts VCO core. S1 One end is connected together, serving as the second input terminal of the first folded Colpitts VCO core; varactor diode C V1 The other end is connected to the varactor diode C V2 The other end is connected, and a tap is provided between the two to provide a DC input terminal for connecting the tuning voltage V. cont ; Tuning voltage V cont Used for continuously adjusting the oscillation frequency of each resonant mode; the other end of inductor L2 is connected to the other end of inductor L3, and a bias voltage V is applied. B The other end of inductor L1 is connected to the other end of inductor L4, and both are connected to resistor R. T1 One end is connected to resistor R T1 The other end is grounded; inductors L1 and L2, and inductors L3 and L4 are coupled to form a base-emitter magnetic feedback structure.

[0023] Here, adjustments can be made. L 1, L 2 and C F1 The ratio is used to improve the phase noise of the folded Colpitts VCO. Emitter inductor L 1 and base L 2 is the center-tapped inductor with a coupling coefficient of 0.3. Tail resistor. R T1 and bias voltage V BTogether, they are used to set the current of the folded Colpitts VCO core, while at high frequencies, replacing the transistor in the traditional tail current source with a tail resistor can significantly reduce noise.

[0024] It should be noted that the transistors in each folded Colpitts VCO core are heterojunction bipolar transistors (HBTs). The circuit arrangement of a single folded Colpitts VCO core ensures that the fundamental frequency is AC-coupled at the HBT collector, and the second harmonic is AC-coupled at the tail resistor, ultimately resulting in good single-core noise performance. Simultaneously, high-Q inductors are connected in series between adjacent resonant cavity inductors. L S Used for mode switching to avoid direct loss of the resonant cavity Q value in different modes.

[0025] Please see Figures 1 to 3 Each mode control group controls the connection state between the base node of two adjacent folded Colpitts VCO cores and ground; among them, The other end of the first DC blocking capacitor in the first mode control group is connected to the second input terminal V of the first folded Colpitts VCO core. s2 The connection is made so that the other end of the second DC blocking capacitor in the first mode control group is connected to the first input terminal V of the second folded Colpitts VCO core. s3 connect; The other end of the first DC blocking capacitor in the second mode control group is connected to the second input terminal V of the second folded Colpitts VCO core. s4 The other end of the second DC blocking capacitor in the second mode control group is connected to the first input terminal V of the third folded Colpitts VCO core. s5 connect; The other end of the first DC blocking capacitor in the third mode control group is connected to the second input terminal V of the third folded Colpitts VCO core. s6 The connection is made between the other end of the second DC blocking capacitor of the third mode control group and the first input terminal V of the fourth folded Colpitts VCO core. s7 connect; The other end of the first DC blocking capacitor in the fourth mode control group is connected to the second input terminal V of the fourth folded Colpitts VCO core. s8 The other end of the second DC blocking capacitor in the fourth mode control group is connected to the first input terminal V of the first folded Colpitts VCO core. s1 connect; In the first mode, the first input terminals of all four folded Colpitts VCO cores are left floating, while the second input terminals are grounded, thus all series inductors L...S1 To L S4 The midpoints of all remain suspended in the air; In the second mode, the two input terminals of the first folded Colpitts VCO core and the two input terminals of the third folded Colpitts VCO core are grounded, while the remaining input terminals remain floating. Therefore, the inductor L... S1 and inductor L S3 Short-circuited to ground by AC, inductor L S2 and inductor L S4 The midpoint remains suspended in the air; In the third mode, the first input terminals of all four folded Colpitts VCO cores remain grounded, while the second input terminals are left floating; consequently, all series inductors L S1 To L S4 The midpoints of all were short-circuited to ground by AC.

[0026] Figure 4 This is a circuit connection diagram of the signal processor provided in an embodiment of the present invention. Figure 4 As shown, the signal processor includes: a buffer matching network and an on-chip balun; The buffer matching network includes: inductor L 17 -L 22 Capacitor C9-C 12 Transistor Q9, Transistor Q 10 Resistor R9 and resistor R 10 Inductance L 17 and inductor L 18 In series, to form a resonant cavity with inductors L2 and L3 of the first folded Colpitts VCO core; inductor L 17 Also with inductor L 19 Connect one end of capacitor C9, and inductor L 19 The other end of capacitor C9 is grounded, and is connected to one end of resistor R9 and the gate of transistor Q9 respectively; the other end of resistor R9 is connected to a bias voltage V. B The source of transistor Q9 is grounded, and its drain is connected to inductor L. 21 One end is connected to the inductor L 21 The other end is connected to capacitor C. 11 One end of the capacitor is connected to the first input terminal of the on-chip balun; capacitor C 11 The other end is grounded; inductor L 18 Also with inductor L 20 and capacitor C 10 One end is connected to the inductor L 20 Grounding, capacitor C 10 The other end is connected to resistor R respectively 10 One end, transistor Q 10Gate connection; resistor R 10 The other end is connected to a bias voltage V B Transistor Q 10 The source is grounded, and the drain is connected to the inductor L. 22 One end is connected to the inductor L 22 The other end is connected to capacitor C. 12 One end of the capacitor is connected to the second input terminal of the on-chip balun; capacitor C 12 The other end is grounded; The barron's chip includes: inductor L 23 -L 26 Inductance L 23 and inductor L 24 Connect them together, and tap the DC power supply V between them. CC2 Inductance L 23 One end serves as the first input terminal of the on-chip balun, inductor L 24 One end serves as the second input terminal of the on-chip balun; Inductor L 25 and inductor L 26 Commonly connected, and with inductor L 23 and inductor L 24 Coupling, Inductance L 26 One end is grounded, inductor L 25 One end is used to output the final W-band signal.

[0027] It should be noted that this invention is manufactured using SiGe BiCMOS technology, where the active device of the VCO core is a heterojunction bipolar transistor (HBT), and the mode switching switch is a field-effect transistor (MOSFET), fully combining the performance advantages of both devices. All inductors adopt a top-thick metal design provided by the process, and the capacitors adopt a MIM capacitor structure.

[0028] It should be noted that the inductance L 25 and inductor L 26 Employing a tapped symmetrical structure, inductor L 23 -L 26 All are designed with a thick metal top layer.

[0029] The above describes the circuit structure and working principle of the W-band low phase noise broadband voltage-controlled oscillator based on mode switching technology provided in this embodiment of the invention. Its performance is now verified using simulation software. The HBT directly calls the model from the process library. For the passive connections on the transistors, the Momentum electromagnetic simulation tool in ADS is used to perform electromagnetic simulation. The HBT from the process library and the passive connections on the transistors are encapsulated into a Symbol for easy access. The remaining passive parts are subjected to full-board electromagnetic simulation using the Momentum electromagnetic simulation tool in ADS. The results obtained through this co-simulation method are closer to the actual results during chip testing.

[0030] Figure 5 This is a simulation diagram of the phase noise of the three single-core VCO structures provided in the embodiments of the present invention at a 90GHz output frequency. Figure 5 As shown, the phase noise of the structure using both tail resistor and folded inductor is improved by 1.3 dBc / Hz compared to the traditional structure, demonstrating that the folded design has a significant effect on improving phase noise.

[0031] Figure 6 This describes the change in phase noise of the mode switching array at the 80GHz output frequency as a function of the mode switching bulk effect. For example... Figure 6 As shown, the body effect voltage is reduced by adding a DC blocking capacitor and a bias resistor to ground. V BS This achieves phase noise reduction from 95.7dBc / Hz to The 100.3dBc / Hz improvement demonstrates that suppressing the bulk effect of the switching transistor significantly improves the final output phase noise.

[0032] Figure 7 This is a simulation diagram of the frequency variation of the W-band signal output by the W-band low phase noise broadband voltage-controlled oscillator provided in this embodiment of the invention in three modes. Figure 7 As shown in the simulation results, the oscillator can achieve continuous frequency coverage from 83.2 to 102.3 GHz, with a relative bandwidth of 20.5%. The frequency ranges of the four modes are 83.2–89.7 GHz, 89.1–96.2 GHz, and 95.6–102.3 GHz, respectively. It is evident that the frequency overlap between any two adjacent modes is greater than 0.5 GHz.

[0033] Figure 8 This is a simulation diagram showing the variation of phase noise across the entire tuning range of a W-band low phase noise broadband voltage-controlled oscillator with a frequency offset of 1 MHz from the carrier wave, provided in an embodiment of the present invention. Figure 8 As shown, the phase noise at a frequency offset of 1MHz is respectively 100.4~ 95.2dBc / Hz.

[0034] comprehensive Figure 5-8 It can be seen that the mode-switching VCO proposed in this invention, by combining mode-switching technology and multi-core resonant technology, achieves a tuning range of 83.2~102.3GHz, and the phase noise at a frequency offset of 1MHz is as follows: 100.4~ The final circuit achieves 95.2 dBc / Hz power consumption at a 1.5V supply voltage of 70mW. The mode-switching VCO operates within most of the W-band and exhibits good phase noise performance.

[0035] To address the challenge of achieving a wide tuning range in the millimeter-wave band without degrading phase noise in existing voltage-controlled oscillators (VCOs), this invention provides a W-band low-phase-noise broadband VCO based on mode-switching technology. Through the synergistic innovation of a quad-core ring-coupled structure and a multi-mode switching mechanism, it successfully overcomes the inherent contradiction between tuning range and phase noise in traditional VCOs. A mode-switching switch array controls the coupling phase between the oscillating cores, enabling continuous adjustment of the equivalent inductance of the resonant system, thereby achieving broadband frequency coverage. A folded circuit structure and unique bias design optimize the oscillation waveform, and the multi-core power superposition effect significantly improves phase noise performance. The compact ring layout and integrated design effectively control chip area and power consumption while ensuring performance. Ultimately, this achieves a highly integrated frequency source solution in the millimeter-wave band, simultaneously possessing a wide tuning range, low phase noise, small chip area, and low power consumption.

[0036] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A W-band low phase noise broadband voltage-controlled oscillator based on mode switching technology, characterized in that, include: The mode can switch between voltage-controlled oscillator and signal processor; The mode-switching voltage-controlled oscillator includes four identical and synchronously operating folded Colpitts VCO cores and a mode-switching switch array. The four folded Colpitts VCO cores are connected in parallel in a ring structure via series inductors, and each folded Colpitts VCO core is connected to the mode-switching switch array through its two base nodes. The mode-switching switch array changes the equivalent inductance value of the series inductors by switching the on and off of its internal control switches, thereby effectively changing the total inductance of the entire resonant system, switching different resonant modes, and outputting oscillation signals with multiple different frequency modes covering the W-band. Furthermore, the output of one of the four folded Colpitts VCO cores is coupled to the input of the signal processor to perform power buffering, impedance transformation, and single-ended to differential processing on the oscillation signal output by the mode-switchable voltage-controlled oscillator, and output the final W-band signal.

2. The W-band low phase noise broadband voltage-controlled oscillator based on mode switching technology according to claim 1, characterized in that, The mode switching array receives predefined digital voltage commands {V} from an external control circuit via eight control terminals. c1 V c2 V c3 V c4 Each pair of control terminals receives the same logic signal; and in response to the digital voltage command, each control terminal receives a logic signal and controls the on and off of the associated MOSFET switch group, thereby selectively short-circuiting the midpoint of the series inductor connected to the adjacent folded Colpitts VCO core to ground; wherein, the logic signal "1" in the digital voltage command is used to control the MOSFET switch group to close, and the logic signal "0" is used to control the MOSFET switch group to open; Among them, in the digital voltage command {V c1 =1, V c2 =0, V c3 =1, V c4 When =0}, the mode switching switch array switches to mode one, the midpoint of all series inductors remains floating, the resonant system presents the maximum equivalent inductance, and outputs the first oscillation signal; In the digital voltage command {V c1 =1, V c2 =0, V c3 =0, V c4 When =1}, the mode switching switch array switches to mode two, the midpoint of part of the series inductor is short-circuited to ground by AC, the resonant system presents an equipotential inductor, and outputs a second oscillation signal; In the digital voltage command {V c1 =0, V c2 =1, V c3 =0, V c4 When =1}, the mode switching array switches to mode three, the midpoint of all series inductors is short-circuited to ground by AC, the resonant system presents minimum equivalent inductance, and outputs the third oscillation signal.

3. The W-band low phase noise broadband voltage-controlled oscillator based on mode switching technology according to claim 2, characterized in that, The mode switching array includes: four identical mode control groups connected in parallel in a ring structure; Each mode control group includes: four MOSFET switches, two bias resistors, and two DC blocking capacitors; wherein: The gates of the first and second MOSFET switches serve as the first control terminals of this mode control group; the gates of the third and fourth MOSFET switches serve as the second control terminals of this mode control group; each control terminal receives a logic signal. The sources of the first MOSFET switch and the third MOSFET switch are both connected to one end of a bias resistor in an adjacent mode control group; the drains of the first MOSFET switch and the third MOSFET switch are both connected to one end of a bias resistor in another adjacent mode control group. The sources of the second MOSFET switch and the fourth MOSFET switch are both connected to one end of the first bias resistor, and the other end of the first bias resistor is grounded; the drains of the second MOSFET switch and the fourth MOSFET switch are both connected to one end of the second bias resistor, and the other end of the second bias resistor is grounded. One end of the first bias resistor is also connected to one end of the first DC blocking capacitor, and the other end of the first DC blocking capacitor is connected to one input of a folded Colpitts VCO core. One end of the second bias resistor is also connected to one end of the second DC blocking capacitor, and the other end of the second DC blocking capacitor is connected to one input terminal of another adjacent folded Colpitts VCO core.

4. The W-band low phase noise broadband voltage-controlled oscillator based on mode switching technology according to claim 3, characterized in that, The first control terminal of both the first mode control group and the third mode control group is connected to the logic signal V. c1 The second control terminal is connected to the logic signal V. c2 The first control terminal of both the second and fourth mode control groups is connected to the logic signal V. c3 The second control terminal is connected to the logic signal V. c4 ;in: (1) In the digital voltage command {V c1 =1, V c2 =0, V c3 =1, V c4 When =0, In the first mode control group, the first MOSFET switch M1 and the second MOSFET switch M2 are turned on, and the third MOSFET switch M3 and the fourth MOSFET switch M4 are turned off. The first MOSFET switch M9 and the second MOSFET switch M in the second mode control group 10 Turn on, third MOSFET switch M 11 and the fourth MOSFET switch M 12 Turn off; The first MOSFET switch M in the third mode control group 13 Second MOSFET switch M 14 Turn on, third MOSFET switch M 15 and the fourth MOSFET switch M 16 Turn off; In the fourth mode control group, the first MOSFET switch M7 and the second MOSFET switch M8 are turned on, while the third MOSFET switch M5 and the fourth MOSFET switch M6 are turned off. (2) In the digital voltage command {V c1 =1, V c2 =0, V c3 =0, V c4 When =1}, In the first mode control group, the first MOSFET switch M1 and the second MOSFET switch M2 are turned on, and the third MOSFET switch M3 and the fourth MOSFET switch M4 are turned off. The first MOSFET switch M9 and the second M in the second mode control group 10 Turn on, third MOSFET switch M 11 and the fourth MOSFET switch M 12 Turn off; The first MOSFET switch M in the third mode control group 13 Second MOSFET switch M 14 Turn off, third MOSFET switch M 15 and the fourth MOSFET switch M 16 Conduction; In the fourth mode control group, the first MOSFET switch M7 and the second MOSFET switch M8 are turned off, and the third MOSFET switch M5 and the fourth MOSFET switch M6 are turned on. (3) In the digital voltage command {V c1 =0, V c2 =1, V c3 =0, V c4 When =1}, In the first mode control group, the first MOSFET switch M1 and the second MOSFET switch M2 are turned off, and the third MOSFET switch M3 and the fourth MOSFET switch M4 are turned on. The first MOSFET switch M9 and the second MOSFET switch M in the second mode control group 10 Turn off, third MOSFET switch M 11 and the fourth MOSFET switch M 12 Conduction; The first MOSFET switch M in the third mode control group 13 Second MOSFET switch M 14 Turn off, third MOSFET switch M 15 and the fourth MOSFET switch M 16 Conduction; In the fourth mode control group, the first MOSFET switch M7 and the second MOSFET switch M8 are turned off, while the third MOSFET switch M5 and the fourth MOSFET switch M6 are turned on.

5. The W-band low phase noise broadband voltage-controlled oscillator based on mode switching technology according to claim 4, characterized in that, An inductor is connected in series between adjacent folded Colpitts VCO cores; The first folded Colpitts VCO core includes: transistor Q1, transistor Q2, and capacitor C. F1 Capacitor C F2 Inductor L1, Inductor L2, Inductor L3, Inductor L4, Varactor diode C V1 varactor diode C V2 and resistance R T1 ; The drains of both transistors Q1 and Q2 are connected to a DC power supply V. CC1 ; The source of transistor Q1 is connected to capacitor C. F1 One end of the varactor diode C V1 One end of the transistor Q2 is connected to one end of the inductor L1; the source of the transistor Q2 is connected to the capacitor C. F2 One end of the varactor diode C V2 One end of the inductor L4 is connected to the other end of the inductor L4. The gate of transistor Q1 is connected to the capacitor C. F1 The other end, one end of the inductor L2, and the inductor L connecting the first folded Colpitts VCO core and the fourth folded Colpitts VCO core. S4 One end is connected together, serving as the first input terminal of the first folded Colpitts VCO core; The gate of transistor Q2 is connected to the capacitor C. F2 The other end, one end of the inductor L3, and the inductor L connecting the first folded Colpitts VCO core and the second folded Colpitts VCO core S1 One end is connected to the same terminal, serving as the second input terminal of the first folded Colpitts VCO core; The varactor diode C V1 The other end is connected to the varactor diode C V2 The other end is connected, and a tap is provided between the two to provide a DC input terminal for connecting the tuning voltage V. cont The tuning voltage V cont Used to continuously adjust the oscillation frequency of each resonant mode; The other end of inductor L2 is connected to the other end of inductor L3, and a bias voltage V is applied. B ; The other end of inductor L1 is connected to the other end of inductor L4, and both are connected to resistor R. T1 One end is connected, the resistor R T1 The other end is grounded; The inductors L1 and L2, and L3 and L4 are coupled to form a base-emitter magnetic feedback structure.

6. The W-band low phase noise broadband voltage-controlled oscillator based on mode switching technology according to claim 5, characterized in that, Each mode control group controls the connection state between the base node of two adjacent folded Colpitts VCO cores and ground; wherein... The other end of the first DC blocking capacitor of the first mode control group is connected to the second input terminal V of the first folded Colpitts VCO core. s2 The other end of the second DC blocking capacitor of the first mode control group is connected to the first input terminal V of the second folded Colpitts VCO core. s3 connect; The other end of the first DC blocking capacitor of the second mode control group is connected to the second input terminal V of the second folded Colpitts VCO core. s4 The connection is made so that the other end of the second DC blocking capacitor of the second mode control group is connected to the first input terminal V of the third folded Colpitts VCO core. s5 connect; The other end of the first DC blocking capacitor of the third mode control group is connected to the second input terminal V of the third folded Colpitts VCO core. s6 The connection is made so that the other end of the second DC blocking capacitor of the third mode control group is connected to the first input terminal V of the fourth folded Colpitts VCO core. s7 connect; The other end of the first DC blocking capacitor of the fourth mode control group is connected to the second input terminal V of the fourth folded Colpitts VCO core. s8 The other end of the second DC blocking capacitor of the fourth mode control group is connected to the first input terminal V of the first folded Colpitts VCO core. s1 connect; In the first mode, the first input terminals of the four folded Colpitts VCO cores are all left floating, and the second input terminals are all grounded, thus all series inductors L S1 To L S4 The midpoints of all remain suspended in the air; In the second mode, the two input terminals of the first folded Colpitts VCO core and the two input terminals of the third folded Colpitts VCO core are grounded, while the remaining input terminals remain floating. Therefore, the inductor L... S1 and inductor L S3 Short-circuited to ground by AC, inductor L S2 and the inductor L S4 The midpoint remains suspended in the air; In the third mode, the first input terminals of the four folded Colpitts VCO cores are all grounded, and the second input terminals are all left floating; consequently, all series inductors L S1 To L S4 The midpoints of all were short-circuited to ground by AC.

7. The W-band low phase noise broadband voltage-controlled oscillator based on mode switching technology according to claim 2, characterized in that, The frequency range of the W-band signal corresponding to the first oscillation signal is 83.2 GHz to 89.7 GHz, the frequency range of the W-band signal corresponding to the second oscillation signal is 89.1 GHz to 96.2 GHz, and the frequency range of the W-band signal corresponding to the third oscillation signal is 95.6 GHz to 102.3 GHz.

8. The W-band low phase noise broadband voltage-controlled oscillator based on mode switching technology according to claim 5, characterized in that, The signal processor includes: a buffer matching network and an on-chip balun; wherein... The buffer matching network includes: inductor L 17 -L 22 Capacitor C9-C 12 Transistor Q9, Transistor Q 10 Resistor R9 and resistor R 10 ; The inductor L 17 and inductor L 18 They are connected in series to form a resonant cavity with the inductors L2 and L3 of the first folded Colpitts VCO core; the inductor L... 17 Also with inductor L 19 The inductor L is connected to one end of the capacitor C9. 19 Grounded, the other end of capacitor C9 is connected to one end of resistor R9 and the gate of transistor Q9; the other end of resistor R9 is connected to the bias voltage V. B ; The source of transistor Q9 is grounded, and its drain is connected to inductor L. 21 One end is connected, the inductor L 21 The other end is connected to capacitor C. 11 One end of the capacitor is connected to the first input terminal of the on-chip balun; the capacitor C 11 The other end is grounded; The inductor L 18 Also with inductor L 20 and the capacitor C 10 One end is connected, the inductor L 20 Grounded, the capacitor C 10 The other end is connected to the resistor R respectively 10 One end of the transistor Q 10 The gate connection; the resistor R 10 The other end is connected to the bias voltage V B ; The transistor Q 10 The source is grounded, and the drain is connected to the inductor L. 22 One end is connected, the inductor L 22 The other end is connected to capacitor C. 12 One end of the capacitor is connected to the second input terminal of the on-chip balun; the capacitor C 12 The other end is grounded; The on-chip balun includes: an inductor L 23 -L 26 The inductor L 23 and inductor L 24 Connect them together, and tap the DC power supply V between them. CC2 The inductor L 23 One end serves as the first input terminal of the on-chip balun, and the inductor L 24 One end serves as the second input terminal of the on-chip balun; Inductor L 25 and inductor L 26 Commonly connected, and with the inductor L 23 and the inductor L 24 Coupling, the inductor L 26 One end of the inductor L is grounded. 25 One end is used to output the final W-band signal.

9. The W-band low phase noise broadband voltage-controlled oscillator based on mode switching technology according to claim 5, characterized in that, The transistors in each of the folded Colpitts VCO cores are heterojunction bipolar transistors.

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