Research And Design Of A CMOS Rotary Travelling Wave Oscillator

Recently,in most applications,the requirement for high-speed computing increases the demand for high-performance,high-speed processors.However,it is very challenging to distribute a high-speed clock over a limited area of the chip due to the parasitic capacitance of the circuit device.On the other hand,high-speed clocks require clock generators with low offset and low jitter to avoid timing failures,which is difficult to achieve at microwave radio frequencies.An effective way to overcome this challenge is to use rotating travelling wave technology.As the core circuit of rotating travelling wave technology,rotary travelling wave oscillator is able to generate and distribute high-frequency clock signals,which attracts researchers' interests.In this work,firstly,two voltage controlled oscillators were designed using the same process.The two voltage controlled oscillators have the same component size,bias current,power supply voltage,and layout,except the inductance in the resonator tank.The inductors in the two resonators have the same shape,width and spacing,but different length.By comparing the simulation and measurement of the oscillation frequency of the two voltage controlled oscillators circuits,the deviation between the measured value and the simulated value of the fully customized inductor can be obtained,which can provide guidance for designing the rotary travelling wave oscillator circuit.Secondly,the basic circuit of the rotary travelling wave oscillator is designed,and the oscillation frequency,power consumption and phase noise are derived.The basic circuit structure of the rotary travelling wave oscillator is divided into oscillation circuit,energy compensation circuit and output buffer circuit.The oscillating circuit is based on the transmission line effect,the energy compensation circuit uses a complementary cross-coupled CMOS inverter pair without tail current source,the output buffer circuit is composed of buffer amplifier and AC coupling capacitor.In addition,in order to extend the frequency tuning range of the rotating travelling wave oscillator,the adjustable capacitor provided by the foundry is used to achieve;and the phase noise is reduced through the series DC blocking capacitor.Finally,layout design,chip implementation and measurement are introduced.The designed layout is highly symmetrical,with an area of only 425.99?m×425.99?m.In the simulation and measurement environment,the control voltage range is 0-1.2V,and the step size is 0.05 V.The simulation results show that the oscillation frequency range is9.653-12.499 GHz,and the phase noise at 1MHz offset ranges from-115.940 to-121.564 d Bc/Hz.The measurement results show that the oscillation frequency range is9.542-12.134 GHz,and the phase noise at 1MHz offset ranges from-105.33 to-114.27 d Bc/Hz.