Research On Phase Shifter In Silicon Technology For RF Phase-Shifting Phased-Array Systems

As phased-array antennas technique has the merit to improve the signal-to-noise ratio(SNR)and the functions of beamforming and beam-steering,it attracts more and more research interests.Phased-array systems have three architectures-RF Phase-shifting,LO Phase-shifting and Digital Arrays according to the place where phase-shifters are incorporated in the transmitter/receiver chain to achieve phased-array functionality.Compared to the other two architectures,RF Phase-shifting architecture has the advantages of small volume and low power consumption.Therefore,the RF Phase-shifting architecture would be the best choice for commercial electronic devices because they have very strict requirements for the cost,volume and power consumption.In the manufacturing aspect,silicon technologies bring the opportunity to replace the III-V process with low-cost,low-volume and low-power consumption phased-array systems.As the most crucial component in the phased-array systems,phase shifters are used to control the phase of EM wave.Their performances have great effect on the phase-array systems.It is meaningful to do the research on the phase shifters in silicon technologies.In this dissertation,the research focuses on the design and analysis of on-chip phase shifter in silicon technologies.The main contributions are summarized as follows:The effects of phase shifter' performance on the beam-steering resolution,beam-pointing error,sidelobe rejection ratio(SLRR)of phased-array systems are analyzed and it finds out that the resolution bits,RMS phase error and gain error are three most key performances of the phase shifter,which are given most consideration in the design.The phase shifter structures and latest research are investigated and the quadrature error of the quadrature signal generator on the RMS phase error and gain error of active phase shifter is analyzed,which gives a solid theoretical guidance for the design and optimization of the active phase shifter.Three key blocks of the active phase shifter are analyzed,which are input balun,quadrature signal generator and the current generator.For the input balun,a two-staged 2-22GHz broadband active balun is proposed using the JAZZ 0.18?m SiGe process with the imbalance of the differential output less than 0.26 dB in amplitude and less than 0.80° in phase.For the quadrature signal generator,a method for the n-stage PPF analysis is proposed using the matrix,which can be used to design and optimize the high accurate quadrature signal generator.For the current generator,a method to synthesize the current generator is proposed and a current generator for 6-bit active phase shifter is proposed based on the method.Three active phase shifters are designed which operate under the millimeter wave frequency.Two of them are 5-bit active phase shifters at 5-20GHz and the left one is an X-band 6-bit active phase shifter.For the two 5-bit active phase shifters,the differential adders of the two 5-bit active phase shifters are implemented with CMOS transistors and with bipolar transistors in RF-path respectively.An analysis of the sensitivity of the relative phase shifts of the two active phase shifters to the current generator is made and the analysis is verified by the layout simulation.The result shows the active phase shifter which uses bipolar transistors in RF path is more sensitive.For the X-band active phase shifter,the detailed design and optimization are given.Furthermore,a noise-cancelling amplifier is designed before the input active balun to reduce the NF and the work is verified by the layout simulation.For the millimeter wave phase shifter,a 52-57 GHz 6-bit hybrid phase shifter that combines both passive and active structures is proposed.The small phase steps are realized by the passive structure and the big phase steps are realized by the active structure.In this method,it simultaneously takes the advantage of the ability of passive phase shifters to realize small phase steps and the advantage of small area of active phase shifters.The proposed 6-bit phase shifter is implemented with TSMC 40nm CMOS 7X1Z1U technology with the help of electromagnetic simulation.A detailed discuss about the on-wafer test and results are given.The RMS phase error is less than 3.76° at 52-57 GHz(<2.8° at 52-55 GHz)and the RMS gain error is<2.23 dB at 52-57 GHz.The proposed phase shifter achieves a low RMS phase error and meanwhile has a compact size,which has a good innovation and guidance.In this dissertation,an elaborate discuss about the design and optimization of the phase shifter in silicon technologies is described,and circuit is described both theoretically and practically.Three active phase shifters operate under millimeter wave frequency and a hybrid phase shifter operate at millimeter wave frequency.In a conclusion,this dissertation provides a theoretical guidance and design method for the phase shifter design in silicon technology.