Research And Design Of High Linear Frequency Conversion Circuit Based On CMOS Technology

With the rapid development of wireless communication technology,technological iterations are changing with each passing day.Sub-6GHz communication and life science and technology are deeply bound,and the interconnection of all things is an important development trend in the future.At the same time,with the gradual release of highfrequency frequency bands,the millimeter-wave frequency band has advantages such as large bandwidth and high data rate.5G mobile communication,satellite communication,etc.have made great progress.Many millimeter-wave communication products in the industry have entered the market,and millimeter-wave communication technology has gradually matured.The mixer is an indispensable module for the transceiver system to realize the frequency conv-ersion function,and has research value.Compared with other processes,the CMOS process has the advantages of low cost and easy integration.Based on the CMOS process,this thesis studies and analyzes the linearity of key technical indicators of the frequency conversion circuit,and designs mixers suitable for three different scenarios.Firstly,the technical development of mixer circuits in recent years is reviewed,and the commonly used radio frequency components in circuit design are introduced.At the same time,the key indicators such as gain,linearity,isolation,noise,and bandwidth are also quantitatively analyzed.It provides theoretical guidance for circuit design in different application scenarios.Secondly,the design of a high linearity single sideband mixer with high sideband suppression for 5G radar system is introduced.Based on the standard 180 nm CMOS process,in order to meet the requirements of sideband and spurious suppression,the Fourier characteristics of the square wave are used,and the sequential circuit is used to generate four channels of 1/3 duty cycle differential quadrature local oscillator signals,which are combined with the differential quadrature IF The signal is mixed to improve the suppression of harmonics such as the even-order sideband and the third-order sideband of the output signal,and achieve high sideband suppression and high linearity.The 5.88 GHz mixer achieves a sideband suppression greater than 45.26 dBc,harmonic suppression greater than 16.08 dBc,and an input 1dB compression point of 16.68 dBm when the local oscillator power is 3dBm.For millimeter-wave communication,a high-gain high-linear up-mixer for V-band communication chip is designed.Based on the standard 65 nm CMOS process,in order to meet the requirements of linearity and gain,connecting a common source stage buffer at the RF output end of the mixer is equivalent to a post-transconductance,improving the linearity and gain of the mixer;at the same time,at the input end of the local oscillator Connect a LO buffer to improve the isolation between the mixer gain and the input source.In the case of the local oscillator 66 GHz signal-3dBm,the gain S21 of the mixer is ?-2.7dB,the 3dB bandwidth is 2.85GHz?15.2GHz,and the input 1dB compression point is 3.51 dBm.Finally,the phased array application for high-speed wireless communication system brings the requirement of phase shifting,and a dual local oscillator mixer with high spurious suppression for K-band communication system chip is designed.Based on the standard 65 nm CMOS process and using the high linearity of the passive structure of the traditional architecture,the stray suppression enhancement technology of the dual local oscillator mixer is further explored,and the parasitic capacitance elimination technology of the FET is proposed by using the transconductance-like superposition technology.When the two-way local oscillator power is 0dBm,the spurious suppression in the RF24.5?28GHz operating bandwidth is greater than 42.7dBc,the input 1dB compression point is-5dBm,the intermediate frequency bandwidth is 3.5?10GHz,and the local oscillator bandwidth is 16?26GHz.