A CMOS LC-tank VCO and phase-shifting network are described for a direct-conversion receiver of IEEE 802.11a. The direct-conversion receiver is configured to have sub-harmonic mixing structure which requires multi-phase local oscillator (LO) signals spaced by 45°. A poly-phase filter with 3and 4-stage RC networks generates multi-phase LO signals whose amplitude imbalance is removed by cascaded ...

This paper presents a complementary metal-oxidesemiconductor (CMOS) differential voltage-controlled oscillator (VCO) implemented with the push-push principle. The push-push VCO uses two frequency doublers stacked in series with an LC quadrature voltage-controlled oscillator (QVCO) to share the dc current with the QVCO for low power consumption. The proposed CMOS VCO has been implemented with th...

A wide-tuning monolithic LC-tuned VCO is presented. The proposed VCO accomplishes wide tuning by utilizing binary weighted switched varactor combinations operating at minimum or maximum value, in addition to a linearly varying interpolation varactor. Measurements show 74% of tuning at a range of 1.56–2.71 GHz, with the phase noise ranging from 136 dBc/Hz to 108 dBc/Hz at 1 MHz offset. The VCO i...

A new LC quadrature voltage-controlled oscillator (LCQVCO), made with direct coupling of two CMOS LC-VCOs, is presented. In the proposed circuit two identical cross-connected LC-VCOs are coupled together by directly connecting the bulk of the crossconnected transistors of one VCO to the bulk of the MOS varactors of the other VCO in such a way no extra devices are needed for coupling. Thus, no e...

A novel 12 GHz VCO designed and fabricated in a 0.18μm SiGe BiCMOS technology is presented. Strongly magnetic coupled dual LC tanks with fixed and tunable capacitive elements are introduced to extend tuning range and improve phase noise. By hybrid using of varactor tuning, loaded transformer tuning and switched capacitor tuning, the proposed VCO achieves a wide tuning range of 4.3GHz (36%) and ...

A new concept for quadrature coupling of LC oscillators is introduced and demonstrated on a 5GHz CMOS VCO. It uses injection-locking through commonmode inductive coupling to enforce quadrature. The technique provides quadrature over a wide tuning range without introducing any phase noiseor power consumption increase. The realized VCO is tunable between 4.6GHz and 5.2GHz and measures a phase noi...

A low-phase-noise voltage-controlled oscillator (VCO) has been demonstrated using a harmonically tuned LC resonance tank. In this circuit configuration, the voltage shape at the differential cell is almost rectangular; thus, the cell is switched effectively and the phase noise is reduced. More importantly, the proposed tank suppresses downconversion of the noise around 2f0 to the phase noise, d...

High costs, bulkiness, and larger power consumption makes transceiver integration and miniaturization a desired option to discretely implemented transceivers. Furthermore, a frequency synthesizer forms an important part of high-frequency transceivers. In this paper, the design of a fully-integrated dual loop frequency synthesizer is detailed. Previously, frequency synthesizers have already been...