Dual-band Voltage-controlled Oscillator Research Articles

W-Band Switch-Less Reconfigurable-Push Dual-Band VCO Using Clover-Shaped Inductor and Robust Triple Cores for 6G Communications

This study proposes a switchless reconfigurable triple-push/push–push dual-band voltage-controlled oscillator (VCO) topology to design a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">W</i> -band metal–oxide–semiconductor (CMOS) for 6G communications. The proposed clover-shaped inductor consists of three branch inductors, where each node had a symmetrical layout, connecting to each another and to the output pad. This topology was demonstrated in a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">W</i> -band VCO using three cross-coupled cores with an ON/OFF-state control to achieve triple-push and push–push operations. An oscillating core based on a robust cross-coupled structure avoids the oscillation startup issue, while achieving a 120 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^\circ$</tex-math> </inline-formula> phase offset through a vector-sum-based method. The measured center frequencies of the bands were 91.04 and 102.33 GHz, with the tuning ranges of 10.4% and 14.1%, respectively. The proposed VCO with an independent core ON/OFF-state control enables a low parasitic switchless frequency band shift, resulting in a superior tuning range compared with those of conventional dual-/single-band VCOs. The effectiveness of this approach was demonstrated through fabrication in a 28-nm CMOS process, with a best FOM <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_T$</tex-math> </inline-formula> value of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula> 178.6 dBc/Hz for the full band.

A low phase noise dual‐band voltage‐controlled oscillator based on switchable tunable filter

AbstractIn this letter, a parallel‐feedback dual‐band voltage‐controlled oscillator (DVCO) with low phase noise and a wide tuning range is proposed. The DVCO is composed of two tunable filters associated with four switches and an active device. By controlling four switches, the oscillation frequency can be switched and oscillated in one of two bands. The employed tunable filter with maintained passband shape and wide frequency tuning range (FTR) is beneficial to designing wideband DVCO with low phase noise. Owing to the maintained frequency response, the sharp phase variation and high in‐band group delay can be maintained during the filter tuning process, which can enhance the phase noise improvement. Moreover, the sharp phase variation can realize the phase compensation in a wide FTR when tuning the DVCO. To develop a DVCO with a simple circuit scheme, the two‐pole tunable filters with two different FTRs are designed. For verification, the proposed DVCO is designed, manufactured, and measured. The measurement results show that each band of the DVCO has a tuning range of 1.97–2.58 GHz (27.8%) and 2.934–3.468 GHz (16.7%), respectively. For the lower band, the phase noise at 100 kHz and 1 MHz frequency offset is better than −99.2 and −126.4 dBc/Hz, respectively. While for the upper band, the phase noise at 100 kHz and 1 MHz frequency offset is better than −101.2 and −127.4 dBc/Hz, respectively.

Low Phase Noise Concurrent Dual-Band (5/7 GHz) CMOS VCO Using Gate Feedback on Nonuniformly Wound Transformer

A novel low phase noise concurrent dualband complementary metal-oxide-semiconductor (CMOS) voltage-controlled oscillator (VCO) employing a gate-feedback enabled, nonuniform multiwinding transformer is proposed. The transformer consists of the wide-width looped main inductors and surrounding narrow-width looped feedback inductors, featuring a high degree of design freedom, owing to its controllable width, gap, and coupling coefficients. This novel topology enables both simultaneous and independent oscillation in two frequency bands using the main inductors with oscillation cores. In addition, the resonant tank's noise contribution can be reduced by boosting the loaded quality factor using gate-driving feedback inductors. The proposed VCO was fabricated in a 0.28-μm silicon on insulator (SOI) CMOS process. The measured results show concurrent oscillation from 4.6 to 5.6 GHz and 6.1 to 7.4 GHz with phase noise of -119.3 and -120.1 dBc/Hz at 1 MHz offset, corresponding to a figure-of-merit (FOM) of -184.4 and -185.1, whereas the FOM for low-band and high-band single-tone oscillation is -182.7 and -184.8 dBc/Hz, respectively. Finally, the FOM of the proposed VCO is compared with that of similar size concurrent dual-band VCO devices previously presented in literature.

A Novel Dual-Band Six-Phase Voltage-Control Oscillator.

The paper presents a novel dual-band six-phase voltage-control oscillator. The voltage-controlled oscillator (VCO) with a single-ended delay cell architecture has a lower power consumption, a smaller chip area, and a larger output swing than one with a differential delay cell architecture. However, the conventional even-phase outputs ring-type VCO cannot be implemented using single-ended delay cells. In other words, the VCO with single-ended delay cells meets most of the requirements of a sensor circuit system, except even-phase outputs function. This work presents a dual-band six-phase ring type VCO, which is implemented using the proposed single-ended delay cell. The proposed VCO both exhibits the advantages of single-ended delay cells and differential delay cells. The proposed delay cell has a band-switching function, which improves the jitter performance of a VCO in which it is used. The proposed VCO can be operated at 890–1080 MHz. The peak-to-peak jitter and the root mean square jitter are the 35.5 ps and 2.8 ps (at 1 GHz), respectively. The maximal power consumption is approximately 6.4 mW at a supply voltage of 1.8 V in a United Microelectronics Corporation 0.18 μm RF CMOS process. The area of the chip is 0.195 × 0.208 mm2.

Independent Control Function for Concurrent Dual-Band VCO

This letter presents a concurrent dual-band voltage-controlled oscillator (VCO) with independent control of the two oscillation frequencies based on a common dual-band bandpass filter (BPF). The odd- and even-mode resonant frequencies of the BPF can be independently tuned to realize the concurrent dual-band VCO. Based on the principle of the flexible tuning characteristics, analytical equations are obtained to introduce a method for circuit size reduction and tuning range extension. The measured results show that the two oscillation frequencies cover a tuning range of 1.59–1.802 and 3.314–3.42 GHz, respectively.

Independently Tunable Concurrent Dual-Band VCO Using Square Open-Loop Resonator

A concurrent dual-band voltage-controlled oscillator (VCO) with independently tunable dual oscillation frequencies is proposed. A shared square open-loop dual-mode resonator and two varactor diodes are the basic units offering flexible tuning for the dual-band operation. A back-to-back varactor diode between the split of the resonator controls the odd-mode resonant frequency, and a single varactor diode is placed at the center of the resonator to adjust the even-mode resonant frequency. By combining the other four resonators with the shared dual-mode resonator, two distinct three-pole tunable bandpass filters (BPF) are designed as two frequency selective elements. Based on the two elements, a parallel-feedback concurrent dual-band VCO is fabricated with independently-tuned dual oscillation frequencies. Moreover, the mathematical deductions are analyzed to optimize the tuning ranges of the dual-oscillation frequencies and the circuit sizes. The measured results show that the two oscillation frequencies cover a tuning range of 5.114–5.28 GHz and 7.61–7.97 GHz, respectively.

High-Performance Low-Cost Dual 15 GHz/30 GHz CMOS LC Voltage-Controlled Oscillator

A CMOS LC voltage-controlled oscillator (VCO) capable of covering both the Ku and Ka bands is presented. The Ku-band frequency source is generated from a low-noise cross-coupled LC VCO. A PMOS push-push frequency doubler, together with the inductor of the low-band LC VCO, is adopted to boost the low Ku-band toward high Ka-band. This proposed VCO is implemented in a standard 0.18 $\mu\text{m}$ CMOS with 1.35 V supply voltage. The dual-band VCO consumes a small active area of 0.49 mm $\times$ 0.2 mm and low DC power of 3 mW at both bands. At 1 MHz (10 MHz) offset, the measured output phase noises are −109.30 dBc/Hz (−130.54 dBc/Hz) at 15.126 GHz and −102.33 dBc/Hz (−124.10 dBc/Hz) at 30.251 GHz.

A 5.2/5.8 GHz Dual Band On-Off Keying Transmitter Design for Bio-Signal Transmission

AbstractAn architecture of 5.2/5.8-GHz dual-band on-off keying (DBOOK) modulated transmitter is designed in a 0.18-μm CMOS technology. The proposed DBOOK transmitter is used in the biosignal transmission system with high power efficiency and small area. To reduce power consumption and enhance output swing, two pairs of center-tapped transformers are used as both LC tank and source grounding choke for the designed voltage controlled oscillator (VCO). Switching capacitances are used to achieve dual band operations, and a complemented power combiner is used to merge the differential output power of VCO to a single-ended output. Besides, the linearizer circuits are used in the proposed power amplifier with wideband output matching to improve the linearity both at 5.2/5.8-GHz bands. The designed DBOOK transmitter is implemented by dividing it into two chips. One chip implements the dual-band switching VCO and power combiner, and the other chip implements a linear power amplifier including dual-band operation. The first chip drives an output power of 2.2mW with consuming power of 5.13 mW from 1.1 V supply voltage. With the chip size including pad of 0.61 × 0.91 m2, the measured data rate and transmission efficiency attained are 100 Mb/s and 51 pJ/bit, respectively. The second chip, for power enhanced mode, exhibits P1 dB of −9 dBm, IIP3 of 1 dBm, the output power 1 dB compression point of 12.42 dBm, OIP3 of about 21 dBm, maximum output power of 17.02/16.18 dBm, and power added efficiency of 17.13/16.95% for 5.2/ 5.8 GHz. The chip size including pads is 0:693 × 1:084mm2.

A 7/24-GHz CMOS VCO with High Band Ratio Using a Current-Source Switching Topology.

In this paper, a 7/24-GHz dual-band voltage-controlled oscillator (DVCO) using a current-source switching topology is designed, implemented, and verified in a 0.18-μm CMOS technology for C-band and K-band radar applications. The low- and high-frequency bands are obtained by the Colpitts mode oscillation and the cross-coupled pairs (CCP) mode oscillation, respectively. Unlike conventional dual-band VCOs realized by resonator-switching topologies, the proposed VCO is based on the composite Colpitts and CCP architecture to avoid additional losses in the resonator, or lower its power consumption. The fabricated VCO occupies a chip area of 0.95×0.71 mm2 including all testing pads. Measurements show that the VCO operating in the Colpitts mode provides a phase noise of -112.5 dBc/Hz at 1 MHz offset from the 7.4-GHz oscillation frequency under 7.5-mW power consumption. When the VCO operating in the CCP mode, it provides a phase noise of -99.9 dBc/Hz at 1 MHz offset from the 24-GHz oscillation frequency with 9.7-mW power dissipation. Moreover, the DVCO achieves a high band ratio (fH/fL=24/7) of 3.43. To the authors' best knowledge, the design features the highest band ratio, low power dissipation, and comparable electrical performances among previously reported DVCOs.

A New Low-Noise Dual-Band VCO for WLAN/WIMAX

In this paper, a new dual-band voltage-controlled oscillator (VCO) is proposed. The proposed VCO utilizes a fourth-order LC resonator that oscillates at two different frequencies. Moreover, its oscillation frequency can be chosen by switching the tail current between two different values. The switches are placed in a way that their resistances do not affect the quality factor of LC tanks, and phase noise does not increase. The proposed VCO is thoroughly analyzed by deriving a nonlinear model. The required conditions for oscillation and switching between two oscillation frequency bands are calculated approximately using averaging. Moreover, the VCO transient behavior in switching the oscillation frequency is investigated, and amplitudes of oscillation at two oscillation modes are calculated. The VCO is designed and simulated in $$0.18\,\upmu \hbox {m}$$0.18μm CMOS technology to verify the design and analytical equations and to evaluate the performance of the proposed VCO. In comparison with the literature, proposed simulations show acceptable phase noise and transient behavior. In addition, the accuracy of the analytical equations is also verified.

Dual C- and S-Band CMOS VCO Using the Shunt Varactor Switch

This paper proposes a high-performance CMOS voltage-controlled oscillator (VCO) with two subfrequency bands. The VCO consists of two cross-coupled VCOs coupled by a pair of mode-switched inductors. Two pairs of shunt varactors are used to switch high- and low-frequency bands. With the varactors as the mode switches, the odd mode VCO operates at the high frequency (C-band) and the even mode VCO operates at the low frequency (S-band). The proposed VCO has been implemented with the TSMC 0.18- $\mu $ m 1P6M CMOS technology and it can generate differential signals in the frequency range of 5.21–6.66 GHz (IEEE 802.11a) and 3.26–3.84 GHz (IEEE 802.16a) and it also has high output voltage swings at both low- and high-frequency bands. The die area of the dual-band VCO is 0.976 mm $\times 1.092$ mm. At the supply voltage of 0.75 V, the high(low)-band figure of merit is −190.5(−190.4) dBc/Hz.

A dual-band quadrature VCO with gain proportional to oscillation frequency

This paper presents a novel dual-band quadrature voltage controlled oscillator (VCO) with the gain proportional to the oscillation frequency. Frequency synthesizers with this VCO can reduce the bandwidth fluctuation over all the frequency ranges without compensation or calibration. Besides the original switched capacitor array, an extra switched varactor array is adopted for the implementation of the proposed VCO. The tuning technique of changing the values of the capacitor and varactor at the same ratio is also derived. For verification purposes, a 2.5 G/3.5 G dual-band quadrature VCO is fabricated in a 0.13 μm CMOS process for WiMAX applications. Measurement results show that the VCO gain is closely proportional to the oscillation frequency with ±16% variation over the entire frequency range. The phase noise is −138.15 dBc/Hz at 10 MHz from the 2.5 GHz carrier and −137.44 dBc/Hz at 10 MHz from the 3.5 GHz carrier.

Poststress RF-drifts of dual-band LC VCO in 0.18-μm CMOS technology

This article studies the RF-property of a dual-band voltage-controlled oscillator (VCO). The designed circuit consists of a dual-resonance LC resonator and a Colpitts negative resistance cell. The dual-resonance LC resonator comprises a series-tuned LC resonator and a parallel resonant resonator. The proposed VCO has been implemented with the TSMC 0.18 μm 1P6M CMOS technology. The VCO can generate differential signals in the frequency range of 3.0–3.37 GHz and 6.95–7.40 GHz with core power consumption of 10.08 and 10.24 mW at the dc drain-source bias VDD of 1.4 V, respectively. The die area of the dual-band VCO is 0.485 × 0.800 mm2. The circuit was operated at VDD = 3 V for 8 h and significant drift in RF parameters was found. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:243–248, 2014.

A low phase noise differential dual-resonance complementary colpitts VCO

A dual-resonance complementary Colpitts voltage-controlled oscillator (VCO) is proposed to serve as a dual-band oscillator operated at 4.3 and 11.7 GHz.The VCO consists of two single-ended dual-resonance LC-tank complementary Colpitts oscillators sharing a common varactor-switching LC resonator. The proposed VCO has been implemented with the TSMC 0.18 μm 1P6M CMOS technology and the core power consumption is 3.60/3.96 mW at the supply voltage of 1.2 V. The VCO has figure of merit −192.7/−189.4 dBc/Hz at high/low band, respectively. The die area of the dual-band VCO is 0.822 × 0.628 mm2. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1494–1497, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27626

Dual-band VCO with composite right-/left-handed resonator

This article proposes a high-performance CMOS voltage-controlled oscillator (VCO) implemented with composite right-/left-handed nonmobius-connected LC-rings to provide dual-band differential outputs.The VCO consists of two cross-coupled sub-VCOs sharing series-LC resonators. nMOSFET switches are used to control high- and low-band outputs. The proposed VCO has been implemented with the TSMC 0.18 μm SiGe BiCMOS technology. The die area of the VCO is 1.16 × 1.12 mm2. With the switch on, the odd-mode VCO operates at the high-frequency 6 GHz band, and when the switch is off, the even-mode VCO operates at the low-frequency 4 GHz band. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:468–471, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27375

Switched inductor dual-band CMOS cross-coupled VCO

This letter proposes a high-performance CMOS dual-band voltage-controlled oscillator (VCO). The VCO consists of two cross-coupled VCOs coupled by a pair of switched inductors or LC resonators to va...

A balanced dual-resonance colpitts VCO in 0.18 μm CMOS

A dual-resonance balanced voltage-controlled oscillator (VCO) is proposed to serves as a dual-band oscillator operated at 3.5 and 8.5 GHz. The VCO consists of two single-ended dual-resonance LC-tank complementary Colpitts oscillators configured in a balanced topology. The proposed VCO has been implemented with the TSMC 0.18 μm 1P6M CMOS technology and the core power consumption is 4.21 mW at the supply voltage of 1.2 V. The figure of merit is −190.22/−190.3 dBc/Hz at high/low band. The die area of the dual-band VCO is 0.995 × 0.55 mm2. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:194–197, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27234

A 28/56 GHz dual-band CMOS VCO using reversely tunable LC source degeneration and the push-push technique

A 28/56 GHz dual-band voltage-controlled oscillator (VCO) using reversely tunable LC source-degeneration and the push–push technique is demonstrated in a standard 0.13 μm CMOS process. The reversely tunable LC source degeneration is made by adding two reversely tunable LC tanks, which use varactors as the needed capacitors, to the source terminals of the cross-coupled transistor pair of the VCO. Compared with the traditional cross-coupled transistor pair, the proposed one significantly decreases the equivalent parallel capacitance (CEQ). This in turn results in the increase of both the operation frequency and the tuning range of the VCO. The VCO core draws 10.48 mA current from a 0.9 V power supply, that is, it only consumes 9.43 mW. The VCO achieves a tuning range of 27.7–28.7 GHz at the fundamental port and a tuning range of 55.176–58.124 GHz at the push–push port. In addition, at the fundamental port, the VCO achieves a low phase noise of −120.46 dBc/Hz at 1-MHz offset from 28.19 GHz. The corresponding figure-of-merit is −199.7 dBc/Hz, one of the best results ever reported for a K-band or Ka-band CMOS VCO. The circuit occupies a chip area of 0.724 × 0.681 mm2, that is, 0.493 mm2, including the test pads. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2272–2278, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27046

Dual-band CMOS voltage-controlled oscillator with comparable outpower at both bands

A low phase noise dual-band voltage-controlled oscillator (VCO) is proposed to achieve large voltage swings at both high-frequency and low-frequency bands. The VCO consists of a dual-resonance LC resonator and a cross-coupled switching transistor pair. The dual-resonance LC resonator comprises a parallel-tuned LC resonator and a series-resonant resonator. The proposed VCO has been implemented with the TSMC 0.18-μm 1P6M CMOS technology and the core power consumption is 1.99 mW at the DC drain-source bias of 0.51 V. The VCO can generate differential signals in the frequency range of 8.19–8.77 GHz and 3.38–3.84 and it also has comparable high output voltage swings at both low- and high-frequency bands. The die area of the dual-band VCO is 0.47 × 0.748 mm2. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2349–2352, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27097

A Dual-Resonant Mode 10/22-GHz VCO With a Novel Inductive Switching Approach

This paper presents a novel dual-band voltage-controlled oscillator (VCO) in a standard 0.18-μm CMOS technology. With special design in the LC tank, the circuit exhibits two oscillation modes in different frequency bands. The frequency band selection is achieved by a switched coupled inductor with the tunable inductance and quality factor. This VCO can operate in a 10-GHz band with 7.6% tuning range and a 22-GHz band with 8% tuning range, while the core circuit draws a dc current of 8.44 mA from a 1.8-V supply voltage. The figures-of-merit at 10- and 22-GHz bands are - 184.63 and - 181.81 dBc/Hz, respectively. These performances are comparable with state-of-the-art dual-band LC-VCOs.