應用於79-GHz FMCW短距離車用雷達系統之注入鎖定除頻器與電壓控制振盪器設計

Abstract

With the continuous development of CMOS process, the researches for millimeter-wave circuits and systems have become more and more attractive recently. The W-band lies in the frequency bands from 75 to 110 GHz, and applications within W-band include the automotive radar systems, point-to-point communication systems, passive image sensor and so on. At present day, the frequency band from 77 to 81 GHz is assigned to automotive short-range-radar system application. However, because of severe specifications and requirements, so far this radar system is mainly implemented by GaAs process; therefore, how to realize a high performance automotive radar system in low-cost CMOS process is a very difficult challenge. This thesis will present various circuit techniques to alleviate the difficulties from CMOS process, and meanwhile, the functionality will be justified by practical chip measurement results. Chapter 2 discusses the theory and derivation of this automotive short-range-radar system realizing in the FMCW radar system; furthermore, the specifications and requirements of the frequency synthesizer are derived. Then the Matlab simulation is used to justify the functionality of this frequency synthesizer. Chapter 3 proposes a divide-by-two injection-locked frequency divider with wide locking range and low power operation. This circuit is fabricated in 90 nm CMOS process and uses the current-reuse pre-amplifier technique to extend the locking range without any extra power consumption. The circuit has a measured 12.6 GHz locking range and only consumes 2.33 mW. Chapter 4 proposes a push-push VCO with wide tuning range and low power operation. This chip is fabricated in 90 nm CMOS process and uses the full-wave rectification and distributed-LC-tank techniques to enhance the 2nd harmonic swing and increase the frequency tuning range. This circuit has a measured 2.77 GHz tuning range, and measured phase noise is -104.2 dBc/Hz @ 10 MHz while power consumption is only 2.66 mW. Chapter 5 proposes a fundamental VCO with negative-gm-boosted technique. This circuit is fabricated in 90 nm CMOS process and uses the negative-gm-boosted technique to lower the power dissipation and enhance the frequency tuning range. This circuit has measured only 1.14 GHz tuning range and power consumption is 4.6 mW, and measured phase noise is -88.2 dBc/Hz @10 MHz. The inconsistency between simulation and measurement will be analyzed and discussed in detail, and finally the modified simulation is provided to justify the inconsistency.