A 1.94 to 2.55 GHz, 3.6 to 4.77 GHz Tunable CMOS VCO Based on Double-Tuned, Double-Driven Coupled Resonators

A 54–69.3 GHz dual-band VCO with differential hybrid coupler for quadrature generation

“…This results in both high power consumption and more parasitic capacitance. In the dual-band resonator of Fig.2b the −G m cell is always enabled [6]. For low-band operation, G m2 is switched off.…”

“…The equivalent model for the high band is more complicated because of the feedback loop established by g m2 . Further quantitative analysis in [6] concludes that the quality factor improvement for one band will degrade the other one. For a dual-band VCO designed for wideband operation, such that the high band and the low band overlap, it is found that both bands need to be designed for similar quality factor.…”

High-performance cost-efficient dual-band CMOS LC VCO

“…Many high-performance signal processings call for the employment of LC voltagecontrolled oscillators (VCOs) [1,2,3,4,5,6,7,8,9]. Dual-band VCOs [1,3,6,7] find usages in many multi-standard multi-band wireless/wireline communication/ sensor systems.…”

“…Dual-band VCOs [1,3,6,7] find usages in many multi-standard multi-band wireless/wireline communication/ sensor systems. A theoretical study of the design constraints of fourth-order dualband LC VCOs is recently conducted [10].…”

Analysis of transformer-based resonator quality factor and bandwidth and the implications to VCOs

“…One such technique that has been of particular interest to researchers is that of using a transformer-based resonator [2]- [6]. Transformer-based (T-based) resonators have been demonstrated to improve the phase noise performance of VCOs [2], [3], and have also been used to realize high-order resonators in dual-band oscillators [4], [5]. It is often claimed that, all else being equal, a T-based resonator will improve the Q beyond that of a single inductorbased (L-based) resonator.…”