A fundamental 229–240 GHz VCO with integrated dynamic frequency divider chain

A fundamental 229–240 GHz voltage-controlled oscillator (VCO) driving directly a divide-by-8 dynamic frequency divider chain is presented. To our best knowledge, this is the highest reported fundamental VCO integrated with a frequency divider in silicon. Furthermore, the high-frequency divider operational range up to 240 GHz is a record value for dynamic dividers in silicon. The down-converted signal (<30 GHz) at the output of the divider chain has a measured constant single-ended power of ∼-11.5 dBm within the VCO operation range. The presented circuit makes possible the addition of further low-frequency dividers and a phase-locked loop (PLL) needed for the stabilization of a VCO. The circuit is fabricated in a 130 nm SiGe BiCMOS technology with f
T
/fmax = 250/370 GHz.