Research On Ultra Wideband VCO

Oscillators usually play the role of ‘heart' in modern communication and radar system to provide the preference frequency.With the high requirement of modern communication and high resolution of radar system,it must have broadband high frequency stability and high resolution sourse,and now it usually be realized by suing phase lock loop technology.In phase lock loop,the most important component is VCO(Voltage Controlled Oscillator),in order to get broadband output frequency,a broadband VCO is required.In order to research how to realize broadband VCO,this thesis designs four kinds of VCOs with different frequence band.Two of them are series feedback oscillators and two of them are parallel oscillators.The first series feedback oscillator output frequence is from 1.221 GHz to1.516 GHz,output power is almost 10 dBm,turning band is 295 MHz,fractional turning band is 21.55%.The second series feedback oscillator output frequence is from 2.9625 GHz to 6.022 GHz,output power is almost 9 dBm,turning band is almost an octave wideband.The third one parallel feedback oscillator output frequence is from 2.058 GHz to 4.016 GHz,output power is almost 5 dBm,turning band is almost an octave wideband,covers all the S band.The last one parallel feedback oscillator output frequence is from 1.056 GHz to 1.910 GHz,output power is almost 5 dBm,turning band is almost an octave,cover all of the L band.All the oscillators have buffers,so they have good isolation and load pull character,all the oscillators can work in the load condition of full returning.Two of the oscillators have two couple output ports,so it is convenient to be used in phase lock loop.All the oscillators have voltage regulators so have a high DC power isolation.In order to achieve a wider output frequence,a VCO combination has been designed.By switch array,it realizes output frequency from 2 GHz to 6 GHz,what's more,this structure can realized arbitrary band in theory.Finally,this paper design a phase lock loop with broadband 2-6 GHz coupler and power divider,and use them to design a phase lock loop.The phase detection frequence of 2-6 GHz phase lock loop is 1 MHz,output frequence is 2-6 GHz,using two VCO switch array and Microprogrammed Controlled Unit named STM32.The phase noise is-86dBc/Hz@10KHz at 5.6 GHz.