Design Of 36~40GHz VCO Applied To Ultra Wide Band Millimeter Wave Signal Source

With the development of smart terminal,communication speed is expected to become higher and higher.Nowadays the electromagnetic spectrum for wireless communication is in shortage which severely limits the development of high speed wireless communication.Besides there are abundant spectrum resources in Millimeter wave frequency range,Millimeter wave has strong ability to anti-interference and has become the hot point of high speed communication research.And with the continuous improvement of Si-based technologies,high speed transistors and high quality passive devices are realized with much cheaper price and more integration.Voltage controlled oscillator is the key component of phase locked loop system and has important influence on the whole system performance.Therefore voltage controlled oscillator with wide frequency range and low phase noise that woks in the millimeter wave frequency using Si-based technology is of great research value and commercial value.A 0.13?m SiGe BiCMOS technology is chosen to design a voltage controlled oscillator with a frequency range of 36~40GHz in this thesis.Phase noise is of great difficulty in this design,differential Colpitts oscillator is selected for its superior phase noise performance and its fitness for high frequency oscillation.Moreover cascode buffer is added to achieve more output power and more isolation between the tank and the load.In the millimeter wave frequency,layout has important influence on the performance of oscillator.Thus transmission line inductor is selected as the resonant tank inductor and EM simulation is used to optimize the layout.An inductor bias scheme is utilized to bias pn junction varactor with the aim to avoid extra noise degrading phase noise performance.Considering that temperature has huge influence on the resonant frequency,the voltage controlled oscillator is designed to have some frequency margin to ensure work properly.EM simulation has shown that under room temperature the voltage controlled oscillator has an output frequency range of 37.0~41.5GHz and the corresponding phase noise is-80.98 ~-75.73 dBc/Hz@100kHz and-101.6 ~-95.9 dBc/Hz@1MHz.The peak value of the differential output amplitude is about 1.1V,and the working current is about 20 mA.Above all,the voltage controlled oscillator designed in this thesis satisfies the requirement and can be used in the design of ultra wide band millimeter wave signal source.