A 18.2-29.3 GHz Colpitts VCOs bank with -119.5 dBc/Hz Phase Noise at 1 MHz Offset for 5G Communications

Abstract

This paper describes a bank of four SiGe BiCMOS oscillators tailored to cover the 18.2-29.3 GHz frequency range, needed to tackle the needs of 5G communications. The Colpitts oscillator topology is leveraged to achieve a lower absolute phase noise compared to Class-C oscillators, at the expense of deteriorated figure of merit. Benefiting from the proper technology choice, a careful tank design was carried out to maximize Q, minimize KVCO and phase noise variations. The four oscillators feature state-of-the-art phase noise, ranging from -119.5 dBc/Hz to -116.5 dBc/Hz at 1MHz offset for 18.2 GHz and 29.3 GHz carrier frequency, respectively. For each oscillator the phase noise variation is only <2 dB over -20°C to 85°C temperature range and <6 dB over the whole 47% tuning range.