Design Of CMOS Millimeter-wave Voltage-controlled Oscillator

With the announcement of the latest fifth-generation?5G?products by telecom giants such as Huawei,Samsung and Qualcomm,it is found that the 5G era is coming soon.5G technology will bring at least three technological advancements:communications for large-scale electronic devices,ultra-reliable and low-latency communications,and enhanced mobile broadband.Automated driving is a typical application of 5G technology in transportation systems,and millimeter wave radar,one of the"eyes"of autonomous driving,is its most critical sensor.Millimeter wave radars mostly use the traditional?-?process,which is too expensive to be widely marketed due to the high cost of the process.Therefore,the research on millimeter wave radar based on CMOS process with lower price and higher hardware compatibility has received much attention from industry and academia.The Voltage-Controlled Oscillator is an indispensable key module in the millimeter-wave radar circuit.Its phase noise,tuning range and other parameters are critical to the radar's detection accuracy.This paper uses a 65-nm CMOS process to discuss the circuit design of the VCO in depth,which provides a reference for the design of the domestic 24 GHz millimeter wave radar.This paper first introduces the background and research significance of millimeter-wave voltage-controlled oscillators,and also compares the research status of related work at china and other countries,pointing out the shortcomings of relevant domestic design research.The basic knowledge of the voltage controlled oscillator is explained,so that the reader has a comprehensive understanding of the circuit design of the VCO.Finally,the key parameter of the VCO circuit,phase noise,is analyzed.The principle of phase noise is discussed in detail,and the optimization method is summarized.Based on the above understanding,this paper designed two different structure VCO chips using the standard 65 nm CMOS process.1.Based on the Class-B circuit structure,the 8 GHz VCO is multiplied by the tri-multiplier to 24 GHz.The measured frequency tuning range is 23²6.5 GHz,and the phase noise at 24 GHz is-104 dBc/Hz@1 MHz.2.Based on the Class-C circuit structure of the 24 GHz VCO,the circuit introduces two sets of switched capacitor arrays,which expands the frequency tuning range of the voltage controlled oscillator and also reduces theK_VCOof the VCO.The measured frequency tuning range is 21.95²4.25 GHz,and the phase noise at the frequency of 24.25 GHz is-100.79 dBc/Hz@1 MHz.The design of the two CMOS millimeter-wave VCO chips has deepened the author's understanding of the basic principles of VCO,and also provided some ideas for the research of domestic millimeter-wave VCO chips.