24 GHz CMOS voltage controlled oscillator based on the open loop multiple split ring resonator

In this paper, CMOS voltage controlled oscillator (VCO) using the square open loop multiple split ring resonator (OLMSRR) structure is presented for the reduction of the phase noise. Compared with the conventional CMOS LC based resonator, the proposed CMOS resonator using the OLMSRR structure has the larger coupling coefficient value, which makes a higher Q-factor, and has improved the phase noise of the CMOS VCO. The output power and phase noise of the proposed CMOS VCO is -1.67 dBm and -99.67 dBc/Hz at 1 MHz offset in the oscillation frequency, respectively.. The power consumption of the proposed CMOS VCO is 3.2 mW at 1.2-V VDD and the figure-of-merit (FOM) is -182.5 dBc/Hz. The prototype of the proposed CMOS VCO is implemented in 130nm CMOS technology and occupies a compact die area of 0.42 mm².