Efficacy of Transmission Poles Characteristics on K-Band VCOs Phase Noise Reduction

Abstract

In this paper, effectiveness of multi-resonance around the parallel resonance of an LC-tank circuit on the reduction of K-band Voltage-Controlled Oscillators (VCOs) phase noise is proposed. The skirt characteristics of the Scattering $(\vert \mathrm{S}\vert)$ parameters of the resonators is sharpened by introducing transmission poles beside the parallel resonance of the LC-tank circuit. In return, an enhanced the resonator loaded quality (Q) factor without compromising the unloaded Q-factor is obtained. Three designs are realized, verified and compared to the others in a differential VCO topology and the phase noise reduction in post-layout simulations is confirmed. Finally, two chips are fabricated in $0.18-\upmu \mathrm{m}$ CMOS technology and measured.