Research And Design Of Millimeter-Wave Class-F Voltage Controlled Oscillator

Millimeter-wave(MMW)transceiver usually has high communication rate and high precision requirement of local vibration in MMW application,so high performance MMW phase-locked loop(PLL)has important research value.At the same time,E-band(71-76 GHz,81-86 GHz)is widely used in automobile radar,wireless return and other scenarios.In order to solve the problems caused by the traditional generation of E-band frequency source,the method of extracting the third harmonic of Class-F Voltage Controlled Oscillator(VCO)has been proposed and become a research hotspot.Therefore,the main work of this dissertation is to design the Class-F VCO and the third-harmonic extraction buffer in E-band PLL using 40 nm CMOS technology.The proposed MMW Class-F VCO works at the fundamental frequency of 25 GHz,and an equivalent model of the fourth-order resonant tank based on the transformer is established.According to the model analysis and optimization iteration of simulation,the appropriate parameters of each element are obtained,in order to achieve a large third-harmonic component.On the one hand,the output signal can form pseudo-square wave to obtain lower phase noise;On the other hand,the enhanced third-harmonic component can directly achieve triple frequency by harmonic-extraction buffer with lower power consumption.And then,a buffer which can suppress fundamental and extract third harmonic is designed,and cascode structure is used to provide good reverse isolation.the buffer uses source gain degradation to achieve fundamental suppression,and its suppression gain is less than-35 d B.A transformer with low coupling coefficient k_m is used as the cascode load to achieve 20 GHz third-harmonic bandwidth.Besides,the baron circuit is used as the output stage to drive the 50Ωload,which is convenient for testing and amplify the third harmonic again,so that the third harmonic gain of the buffer can reach more than 5 d B to ensure the accuracy of signal frequency.Finally,the post simulation results of the cascade of the overall circuit show that the frequency tuning range is 69.0～91.6 GHz,with 28.1%relative bandwidth.And the phase noise is about-91～-94 d Bc/Hz@1MHz.When the supply voltage is 0.9 V,the DC power consumption of the designed Class-F VCO core is 18.6 m W,the Buffer is 20.7 m W,and the overall circuit is about39.3 m W.Therefore,compared with the traditional MMW oscillator,this design can realize higher and wider E-band frequency source with lower power consumption.