Design Of Millimeter-wave Broadband Mixer On CMOS Process

In the link of wireless communication receivers,the down-conversion mixer is the key part,which converts the RF signal to the baseband.In the field of IC technology,CMOS technology dominates.However,due to the performance limitations,it is hard to implement broadband mixer in the millimeter wave band based on this process.In order to alleviate the design pressure of the local oscillator(LO)of the millimeter-wave mixer,a scheme of doubler cascade mixer can be used.In addition,the research and design of broadband and low power devices are of great significance in order to meet the demand of multi-mode and multi-channel,highly integrated and low power consumption performance of millimeter-wave communication systems.Therefore,based on the CMOS process,this thesis designed a millimeter-wave broadband mixer with the scheme of obtaining the LO signal by doubling frequency.Firstly,this thesis introduces the commonly used passive devices in circuit design.Including the "zero" capacitor selection,the structure of the on-chip inductor.Then the structure and performance of three passive on-chip balun are compared and summarized.The usage advice of balun with compensation line in millimeter-wave integrated circuit is given.Aiming at the challenge of the millimeter wave broadband mixer,a brief analysis is made and a scheme of the millimeter wave broadband mixer using the doubler to obtain the LO signal is determined.For this scheme,two kinds of doublers are presented in 65 nm CMOS process.By using a single-balanced circuit topology whicn can strengthen the second harmonic frequency,while effectively suppressing the fundamental,a millimeter wave broadband doubler was designed.For the broadband matching effect,the broadband balun and the low Q transmission line with the grid structure is adopted.According to the measured and simulation results,the broadband doubler circuit covers the E-band and W-band(percentage bandwidth 66.7%),with-10~-7d B CG.Then,aiming at the problem of low efficiency matching effect and high conversion loss of the doubler,a low loss E-band frequency doubler was designed.A stacked transformer coupling structure is introduced at the input of the single-balanced geminate transistors to achieve low loss and high efficiency matching,which simplifies the input bias network and layout while maintaining excellent amplitude and phase balance.This doubler has a CG of-6~-3d B from 67 to 93 GHz.For the fundamental frequency mixer part,this circuit is based on the Gilbert structure.The matching structure of broadband Marchand balun series inductors is adopted,to obtain the broadband matching effect for radio frequency(RF)and LO port.Then the broadband fundamental frequency mixer with CG of 4~6.5d B in 31~120GHz(percentage bandwidth 117.9%)was realized.At the same time,the circuit retains low power consumption(2.9~3.6m W)by using the appropriate gate width and current injection technologyOn the basis of broadband doubler and broadband fundamental freuqency mixer,the design of a millimeter-wave broadband mixer was completed by cascading the two.According to the whole circuit's electromagnetic field simulation results,this mixer has a CG of 3~6d B in 69~122GHz(percentage bandwidth 55.5%),while alleviates the design pressure of the LO source and realizes the effect of broadband.Based on CMOS technology,this thesis designed a broadband doubler and a low loss doubler,an ultra-wideband fundamental frequency mixer and a broadband mixer respectively in the millimeter-wave band.It has promotion and reference significance to the design of mixer and douber modules in millimeter wave integrated circuits.