A 24 GHz FMCW/Doppler Dual-Mode Frequency Synthesizer With 68.8 kHz RMS FM Error and 1.25 GHz Chirp Bandwidth

A high-linear PLL-based FMCW frequency synthesizer with 42-kHz rms FM error and 1.2-GHz chirp bandwidth

“…Although digital PLLs [14][15][16][17][18][19][20][21][22] promise greater flexibility and area efficiency, performance limitations due to the TDC and DCO requires complicated back-end calibration, resulting in significant power and area penalty. Analog fractional-N PLLs [23][24][25][26][27][28] provide better phase noise and chirp linearity. Techniques including phase compensation [29], nested-PLL-based FMCW modulator [30] and cascade PLLs [31] have been developed to improve the chirp linearity.…”