Design Of W-band Single-pole Double-throw Switch And Mixer Based On BiCMOS

With the rapid development of radio frequency integrated circuit and modern semiconductor technology,the application of millimeter-wave circuit such as wireless communication,electronic countermeasures,radar detection,imaging and other fields are becoming more and more integrated and miniaturized.The characteristic size of silicon-based process is decreasing,and the performance of silicon-based MMW and submmw chips is greatly improved.Based on the 130 nm SiGe BiCMOS process,a w-band single-pole double-throw switch(SPDT)and a w-band down-conversion mixer are analyzed and designed in this paper.First the advantages and main application fields of MMW frequency band are introduced,then it comes to the development of single-pole double-throw switch and mixer working in MMW frequency band.Secondly,the theory and main structures of the switch and mixer are introduced.The technical methods of the device performance optimization are analyzed.Then according to the design index,the appropriate topological structure is selected.The main research results are as follows:(1)Parallel MOSFET structure,inductance and capacitance matching network are used in the differential SPDT switch,the matching inductances occupying large area are optimized,two inductances that transmitting differential signal are stacked into screw coupling structure that can be equivalent to transformer model,half of the area can be reduced and common mode signal will be suppressed at the same time.The simulation results in 90~100 GHz show that good input and output matching is achieved in the W-band.Insertion losses of differential mode signals and common mode signals at 94 GHz are-4.1db and-7.4dB respectively,and the isolation is-22 dB.The common mode signal can be attenuated and suppressed under the condition of smaller area.The test results of single-ended switching chip show that the insertion loss is 4.6dB at 94 GHz and-5dB at 97 GHz.The isolation is below-24 dB within the band.The input return loss is between-10dB~-8dB,and the output return loss is between-12 dB ~-8dB.The SPDT used in the system is 570?m×140?m,and the size of the single chip is 1370?m×900?m.(2)The double-balanced gilbert structure is used in the down-conversion mixer,which can achieve high isolation and good conversion gain.Balun is used in the broadband input matching,and voltage bias can be input through the center tap of balun,improve the imbalance of balun.The tail current source is not used for avoiding circuit instability caused by negative resistance in higher frequency band.So the current mirror is used to provide current bias,RF signal is 90.5GHz-97.5GHz,and LO signal is 84 GHz.The simulation results show that the conversion gain is 7.5dB when the input LO power is 0dBm,the noise factor is 13.6dB when the IF output is 10 GHz,the power of the input 1dB compression point is-8.9dbm,and the isolation of each port is below-30 dB.The area of the chip is 430?m×320?m.In conclusion,this article is based on 130 nm SiGe BiCMOS process line,and the design method of W-band SPDT and mixer is researched,on the basis of the traditional structure circuit,in view of the device application and design target,optimizing the circuit to get better performance,the design goal is achieved and the chip area is reduced.The thesis has strong practical value.