Design of a 65-69 GHz 1000:1 FMCW PLL in 65nm CMOS Technology

Frequency Modulated Continuous Wave (FMCW) radar systems have found extensive applications in the field of automotive radar and imaging. A fully integrated 65-69 GHz FMCW characteristic frequency synthesizer is presented in this work. The proposed phase locked-loop (PLL) features a 1000:1 frequency division ratio and a novel idea for a source follower buffer based LC voltage controlled oscillator. To achieve a highly linear transfer characteristic, an optimal frequency division topology is implemented. The overall system achieves a range resolution of 7.5 cm and exhibits a closed loop phase noise of -98.5 dBc/Hz at a 1MHz offset frequency. An initial locking period of 1.67 mu s is achieved by the system while exhibiting a linear VCO output characteristic over the desired frequency range.