A 195.6dBc/Hz peak FoM P-N class-B oscillator with transformer-based tail filtering

Abstract

A complementary p-n class-B oscillator with two magnetically coupled second harmonic tail resonators is presented. For the same oscillation amplitude (constrained by reliability considerations) and the same tank, the p-n oscillator achieves 3-4dB better Figure of Merit (FoM) than an n-only reference one. After frequency division by 2, the p-n oscillator has a measured phase noise that ranges from -150.8 to -151.5 dBc/Hz at 10MHz offset from the carrier when the frequency of oscillation is varied from 3.64 to 4.15GHz. With a power consumption of 6.3mW, a peak FoM of 195.6 dBc/Hz is achieved.

Design of low phase noise K‐band VCO using high quality factor resonator in 0.18 μm CMOS technology

“…Improving the phase noise is crucial in the oscillator's design and can be achieved using different ways, for example, using feedback capacitors to increase gm, using a tail bandpass filter at the second harmonic of the oscillation frequency, 1 improving the Q-factor of inductors using a patterned ground shield in the lower layers 2 or changing the inductor shape, 3 using a biasing technique such as class-C VCO 4,5 and so on. Particularly to mitigate the problem of low Q-factor and self-resonance of spiral inductors at the quasi-millimeter wave and above, we recently proposed a high Q-factor defected ground structure (DGS) resonator and demonstrated the effectiveness of a notch filter realized by the proposed DGS resonator to develop a low phase noise K-band VCO in 0.18 μm CMOS technology.…”