A Magnetically Tuned Quadrature Oscillator

A 200-GHz Inductively Tuned VCO With $-$7-dBm Output Power in 130-nm SiGe BiCMOS

“…Therefore, inductive tuning VCOs can be considered as viable candidates for wider tuning range and higher and relatively constant output power across the band at mm-wave and THz frequencies. Varactor-less voltage-controlled oscillators (VCOs) using transformer coupling feedback have already been proposed for a wide-tuning-range and high--factor LC tank [14]- [16]. The tuning range of this transformer-coupled inductance is determined by the mutual inductance and the primary and secondary windings' current ratio which degrades at high frequency.…”

Active Negative Inductor Based on Magnetic Flux

“…In contrast, the negative inductor that is presented here is based on modifying the magnetic flux linkage in a physical inductor, and is closer in principle to recently reported active magnetic metamaterials [8] or tunable inductors [9][10][11][12]. In the magnetic metamaterial [8], a current is induced in an input loop by an applied time-varying magnetic field, and this current is amplified, inverted, and applied to a parallel output loop a short distance away.…”

“…If the gain is sufficiently large, the driven response can overcome the natural response of the inductor, leading to negative inductance values. Pehlke et al [9] introduced a high-Q tunable inductor based on a similar principle, and tunable inductors using this idea have been discussed by a number of authors [9][10][11][12]. However, these authors do not discuss the possibility of achieving negative inductance values.…”

A self-correcting quadrature voltage controlled oscillator

“…Moreover, these standards require quadrature signal with low phase noise and accurate quadrature phase to cover higher and wider range of frequency for higher data rate wireless communication. The quadrature signal is generated in many ways, such as using frequency dividers [1,2], even stage ring oscillators [3,4], polyphase filters, injection locking [5] and quadrature voltage controlled oscillators (QVCOs) [6,7,8,9,10,11,12,13,14,15]. To generate local signals higher than 5 GHz for high data rate standards, polyphase filters are not suitable owing to the passive components variation in the fabrication process and the signal amplitude loss.…”

“…The quadrature phase accuracy is controlled by the coupling factor of the two VCOs and the coupling factor is controlled by the coupling current source. The higher coupling factor produces a precise quadrature phase, whereas it deteriorates the phase noise of the oscillation signal [8,9,10,11,12,14], because the extra noise source associated with the coupling current source is added to the oscillator. To overcome the tradeoff between phase noise and quadrature phase accuracy, a self-correcting QVCO is proposed.…”