A rotary oscillator array (ROA) apparatus includes a plurality of rotary traveling wave oscillators (RTWOs) configured to generate a plurality of resonant clock signals. An RTWO of the plurality of RTWOs includes a plurality of inverter cells and a fractional divider. The inverter cells are coupled in parallel to each other between two metal interconnects. The fractional divider is coupled to the two metal interconnects. The fractional divider will output a resonant clock signal of the plurality of resonant clock signals based on a reset-out signal generated by a reset-out terminal of the RTWO.