Research On Voltage Controlled Oscillator And High-speed Prescaler Applied In Millimeter Wave Frequency Synthesizer

5G communication millimeter-wave(MMW)band is included in Ka band,which is a key research field of current radio technology.And the development of silicon-based semiconductor technology has made MMW integrated circuits based on CMOS technology a research focus.This article mainly studies and designs the Voltage Controlled Oscillator(VCO)and Injection Locked Frequency Divider(ILFD)circuit,which are applied to the CMOS MMW broadband Charge-Pump Phase Locked Loop(PLL)system.The PLL is used to generate local oscillator signals for 5G communication systems.This article analyzed the mechanism and circuit design of the VCO and the ILFD in detail.Further,the layouts of VCO and ILFD are given,and the back-end simulation results are given.VCO generates an output signal for the PLL,which directly effects the frequency range and phase noise of the PLL.This article firstly analyzed the classification,mechanism and performance indicators of oscillators,and then designed a Ka-band broadband VCO based on 40 nm CMOS process,controlled by 3-bit capacitor-switchs.The circuit design firstly introduced the inductor,capacitor-switchs,varactor design,and then introduced the phase noise optimization.The backend simulation shows that under the 0.9V power supply voltage,the tuning range of the VCO is26.8GHz to 34.4GHz,and the relative bandwidth is about 25%.At 1MHz relative frequency,the phase noise at the lowest frequency point is-101.3d Bc/Hz.ILFD is another circuit that operates at the highest frequency in PLL.This structure has the characteristics of high frequency and narrow band,so improving the bandwidth is the main design difficulty.This article established an equivalent model of ILFD,and analyzes the mechanism of ILFD based on this model,and then analyzes the technology to increase the working bandwidth.Further,an equivalent model of the fourth-order resonant cavity ILFD based on the transformer is established,and the input impedance of the fourth-order resonant cavity is analyzed.In order to analyze the effects of the ILFD on the loop phase noise,this article analyzed the phase noise model.This article designed a transformer-based broadband ILFD based on 40 nm CMOS process.The simulation shows the operating frequency range is 20 GHz to 48 GHz under 0 d Bm input power.According to the simulation results,both the VCO and the ILFD of this design meet the design index requirements.