Design Of Silicon-based Millimeter-Wave Oscillator With High Output Power

With the rapid development of wireless communications and the Internet of Things,users increasingly request data transfer rates.According to Shannon's theorem,the increase of transmission rate needs higher bandwidth,and the congested spectrum in low frequency band limits the bandwidth.Therefore,millimeter wave circuit has become the main research direction of radio frequency circuit in recent years.The millimeter-wave has the advantages of wide frequency band and abundant spectrum resources.With the reduction of the size of the silicon-based process,the cut-off frequency f T and the maximum oscillation frequency fmax of the MOS device are increased,making the CMOS millimeter wave circuit possible.Voltagecontrolled oscillator(VCO)as the phase-locked loop(PLL)and RF transceiver module in the key part,is the research direction of this thesis.At the beginning of this thesis,the research significance of oscillators and the present situation of CMOS oscillators at home and abroad are mainly discussed.Then the principle of oscillator oscillation and several phase noise models are analyzed.Passive devices have a greater impact on the oscillator therefore also introduced accordingly.On this basis,this thesis designs a low-noise oscillator and a high-power oscillator,the main contents are as follows:1.The low phase noise voltage controlled oscillator is studied.By analyzing the constraints in the oscillator,the appropriate value of the inductor and capacitance are selected to optimize the phase noise.In addition,the noise induced by up-conversion of the tail current source is analyzed,so as to reduce the noise introduced by the tail current source by means of large-capacitance filtering,resonant network filtering and switched capacitor array.Through the above technique,an oscillator with oscillation frequency of 76 GHz and phase noise of-90.5d Bc/Hz@1MHz is designed and realized in 65 nm CMOS process with oscillation amplitude of 2.0V and tuning range of 75.11-77.63 GHz.2.The high-power oscillator is researched,the Mason invariant is introduced to analyze the active state of the MOS device to find out the best phase point and the best gain point,the multi-layer coplanar waveguide(MCPW)structure is used to optimize the passive device,then the quality factor of the oscillator is improved,and the fundamental frequency of the oscillator is close to the maximum oscillation frequency of the active device.Secondly,the triple-push structure is adopted to realize the third harmonic output,and the power synthesis technique is used to improve the harmonic output power.CMOS VCO in THz with high frequency and high power make the oscillation frequency break through the limit of cut-off frequency and maximum oscillation frequency.Based on the 65 nm CMOS process,the oscillation frequency is 291 GHz and the output power is-9.4dBm.