A Research Of Frequency Source Based On Graphene

Graphene is a new popular semiconductor material following wide bandgap semiconductor materials such as GaN and SiC.It has an ideal planar two-dimensional structure and is one of the emerging research materials for great potential.Graphene has a wide range of applications,including storage,display fields,sensors,semiconductor materials,biomedical fields,microwave fields.Graphene is in constant exploration and application because of the great research value.This paper briefly introduced the characteristics of graphene materials,the development status of preparation techniques,and expounds the development and application fields of graphene electronic devices and circuits.The nonlinear characteristics of the odd-order harmonic generation of graphene are analyzed.The development of the graphene electronic devices and circuits is summarized.This paper introduced the working principle of phase-locked frequency synthesis technology.The operating principle of the voltage controlled oscillator,phase detector,and the design criteria of the loop filter are introduced.The phase detector,loop filter,and the entire loop are analyzed from the transfer function.Based on this,the factors that affect the phase-locked time,phase noise,and spurious are analyzed.A K-band phase locked frequency multipliers source based on graphene is studied.A graphene multiplier,which can recycle high order harmonics is designed and made.The frequency multiplier set the graphene in the microstrip gap,and produced the odd harmonic performance.A harmonic reflection network is designed before and after the graphene,which achieves frequency multiplication and reduces conversion loss.After testing,it reduces the conversion loss of 1.12 dB compared to similar foreign designs when the input frequency is 6GHz and the input power is 14 dBm.In order to improve the linearity and output power of the single frequency multiplier,a combiner is used to increase the output power.The frequency conversion loss is 27 dB when the input frequency is 7GHz,It means that the graphene multiplier meets the system requirements.In order to provide a pure,well-performing signal source for the graphene frequency multiplier,a C-band phase-locked frequency source is designed,fabricated and tested in this paper.The phase-locked loop is composed of TCD4112 crystal oscillator,HMC704 phase-detection and HMC507 voltage controlled oscillator,and the three order passive loop filter.In order to provide enough power for the graphene frequency multiplier,a power amplifier circuit board was designed,manufactured and debugged using the HMC1122 power amplifier chip.After testing,the amplifier can output enough power to achieve the design in advance.PLL can provide good phase noise,low spurious pure signal.The frequency source has a frequency range of 6.65 GHz to 7.65 GHz,a frequency step of 20 MHz,a spur of better than-70 dBc,and a phase noise of better than-90 dBC/Hz at 10 KHz.In this paper,studies on the harmonic recovery and power enhancement of grapheme frequency multiplier have important significance and prospects for the application of grapheme in the microwave field.