Design Of Millimeter Wave Up-conversion Mixer Based On CMOS Technology

With the advent of the 5G mobile era,the number and diversity of devices is rising exponentially.People have higher and higher requirements for mobile communication speed.At present,the low frequency spectrum resources below 6GHz tend to be exhausted,and the communication system is close to the limit Millimeter wave(MMW)communication technology leads a new round of research upsurge due to its absolute advantages of large bandwidth and high speed.At the same time,low-cost and highly integrated silicon-based integrated circuits are developing rapidly.The characteristic frequency and device speed of silicon based CMOS active devices increase gradually,which lays a technological foundation for the research of relevant circuits of silicon based millimeter-wave frequency communication system.Mixer is an important part of the transceiver,and its performance directly affects the transmission quality of the whole MMW communication system.It is of great significance to study the MMW up-conversion mixing of CMOS technology.It is of great significance to study the MMW up-conversion mixer in CMOS technology.In this thesis,two broadband mixer circuits are designed for 5G MMW communication based on 65nm CMOS process.Firstly,this thesis introduces the research background and significance.The current common up-conversion mixer circuit structure and its advantages and disadvantages are summarized by reviews the development of silicon based millimeter wave up-conversion mixers at home and abroad.Then it introduces the classification of mixer circuit and important performance index of mixer.Secondly,two millimetre wave up-conversion mixers based on the 65nm CMOS process have been designed.The first mixer was based on the Gilbert structure.A current multiplexing resistance negative feedback amplifier is used as a transconductance stage to improve the mixer conversion gain.Marchand balun is used in the circuit to achieve the broadband design.Impedance matching is performed by a parallel inductor with a center tap to reduce chip area while providing a bias circuit.The measured results show that the conversion gain of the mixer at 30-50GHZ is 2.36-4.81d B under the LO power of 0d Bm at a fixed IF frequency of 2GHz.The output 1d B compression point is-7.16d Bm.The total area of the designed chip is only 0.256mm~2.Due to the mirror interference problem in the practical application of mixer,it will affect the performance of the transceiver system.To solve this problem,a 35-45GHz quadrature up-conversion mixer was designed.The mixer core circuit achieves high conversion gain through independently biased current multiplexing transconductance stage and negative resistance technology.At the RF output end of mixer,a signal synthesis circuit with small area and simple structure is designed based on the transformer balun.A differential orthogonal coupler is used at the LO port to generate four orthogonal signals,which achieve a phase difference of less than 6.5°and an amplitude difference of less than 1.2d B within 32-38GHz.Simulation results show that the quadrature up-conversion mixer circuit achieves a maximum conversion gain of 4.53d B.The output third-order intermodulation point OIP3 of the mixer is 10.66d Bm,the output 1d B compression point is 3.25d Bm,and the mirror rejection is above 20d B.The port isolation of LO-RF is greater than 27d B.The miniaturization of the passive circuit makes the total area of the chip only 0.327mm~2.Two millimetre wave up-conversion mixers were designed using a 65nm CMOS process,and the problems encountered in the design and testing of the circuits are summarised.It is a good reference for subsequent researchers to study millimetre wave up-conversion mixers to provide some reference ideas.