Introduction

This chapter introduces the LO synthesis for FMCW radar applications. The fundamentals of FMCW radar system for target range and velocity detection is first presented. The LO performance metrics such as chirp nonlinearity and phase noise in the context of radar system performance is discussed. A closed loop radar LO implementation by using a PLL synthesizer is intensively researched for a number of years. Two PLL architecture are reviewed. The robust classical CP-PLL which is the industry workhorse is first introduced. This is followed by a SSPLL architecture definition, which tend to offer a low in-band phase noise LO synthesis. An overview of LMS-based calibration algorithms which are a mainstream solution for low jitter fractional synthesis are discussed.