Design of Voltage Controlled Oscillators at mmWave Frequencies for FMCW Radars

Abstract

Recent advancements in the field of advanced driver assistance systems (ADAS) have led to increased demands for mmWave (millimeter-wave) radars operating within the 24 GHz and 77 GHz frequency bands. Among the various radar techniques, the Frequency Modulated Continuous Wave (FMCW) method has gained considerable popularity among mmWave radars. This approach relies on utilizing frequency synthesizers with low phase noise and high bandwidth to attain higher precision and accuracy in radar applications. Of particular interest in recent years is the growing demand for FMCW radars that operate within the 76-81 GHz frequency band due to their exceptional precision and accuracy, thanks to their wide bandwidth. These radars are well-suited for a range of applications, including autopilot systems and ADAS. The primary focus of this thesis is to present research efforts aimed at enhancing the performance of FMCW radars at the circuit level, with a strong emphasis on the design, optimization, and simulation of Voltage-Controlled Oscillators (VCOs). VCOs play a critical role in radar systems, and two crucial design considerations are minimizing phase noise and reducing power consumption. These parameters directly impact the sensitivity and energy efficiency of the radar system. Various VCO topologies are explored, primarily based on LC oscillators, and comprehensive optimization endeavors are done to simultaneously minimize phase noise and power consumption. The VCO designs are implemented using TSMC 65 nm CMOS technology, allowing us to investigate innovative techniques for mitigating phase noise in VCOs. In summary, this thesis encompasses recent developments in FMCW radar technology, specifically addressing improvements at the circuit level by focusing on the design and optimization of VCOs.