Low phase noise 130nm CMOS ring VCO

This paper reports on a voltage controlled ring oscillator fabricated in a 130nm CMOS technology. The oscillator was obtained cascading three delay cells. The schematic of the single delay cell was kept as simple as possible by avoiding the use of cross-coupled pairs. The achieved low phase noise makes the presented ring VCO useful for the design of a correlation radar to be used in medicine for short distance vital signal detection.