Design of voltage controlled oscillators (VCOs) in D-band and their phase noise measurements using frequency down-conversion

In this paper, the design and characterization of fundamental voltage controlled oscillators (VCOs) operating in the range from 138 to 146 GHz (VCO-I) and 150.8 to 158.3 GHz (VCO-II) are presented. Both VCO-I and Π are based on Colpitts topology. Additionally, a frequency divider chain (with a divide ratio 8) is added in front of the VCO-I for the sake of precise frequency and phase noise measurements. The simulation results show that the dividers chain is working over a wide frequency range from 60 to 175 GHz. The measured phase noise for both VCOs is -85 dBc/Hz at an offset of 2 MHz. The DC power consumed by each of the VCO is 58 mW from -3 V supply. Both VCO-I and II can deliver maximum power of -3.5 dBm at 146 GHz and 158.3 GHz, respectively. The circuits are fabricated in IHP 0.13 μm SiGe BiCMOS technology with ft and fmax of 300 GHz and 500 GHz, respectively.