A 11-15 GHz CMOS ÷2 frequency divider for broad-band I/Q generation

This paper presents a 0.13 μm CMOS frequency divider for I/Q generation. To achieve a wide locking range, a novel topology based on two stages injection-locking ring oscillator is adopted. This architecture can reach a larger input frequency range and better phase accuracy with respect to injection-locking LC oscillators, because of the smoother slope of its phase-frequency plot. Post layout simulations show that the circuit is able to divide an input signal spanning from 6 to 24 GHz, although the available tuning range of the signal source (integrated VCO) limited the experimental verification to the interval 11-15 GHz, with a consequent measured 31% locking range. A single divider dissipates 3 mA from 1.2 V power supply.