Research On MMIC Of Microwave Millimeter Wave 6 Bit Digital Phase Shifter

Since the 20th century,wireless communication has been booming,and new applications such as satellite communication,WiFi,Bluetooth,radar and so on have been developed rapidly,which has led to the continuous renovation of broadband phased array systems towards high-speed,low-cost,miniaturization.The continuous development and perfection of Microwave Monolithic Integrated Circuits has become the perfect choice for the design of the above-mentioned phased array system.However,phase shifter as the core module of phased array system,it is difficult to achieve ultra-broadband operation,and harder to realize chip miniaturization design in microwave low band.The purpose of this thesis is to design two compact,low-cost,high-performance ultra-broadband 6bit digital phase shifters based on MMIC.This thesis first introduces the CMOS phase shifter,analyzes the limitations of the current silicon-based process in designing high-performance phase shifter,and then introduces the III-V process as a comparison,which shows the advantages of GaAs process in the phase shifter design.The common types of phase shifters and switches are then introduced in detail and circuit analysis are carried out,and their performance characteristics and design points are summarized.Both chips are based on the 0.5?m GaAs pHEMT process,with similar design method and circuit structure.In our work,the equivalent model of pHEMT component in the on and off state of pHEMT elements is established,and the influence of gate width and isolation resistor on switch performance,how to select DC working points and extract the parasitic parameters of pHEMT components are analyzed.Based on the design index of the chip,the optimal topology selection method of the phase-shifting unit is studied,and finally the improved high-pass-low-pass network type topology is adopted by 45°,90°and 180°phase-shifting unit,and the embedded switching type topology is used at 22.5°,11.25°and 5.625°phase-shifting unit.In addition,the circuit also adopt the optimal cascading method,which reduces the interaction between the phase-shifting units.In order to realize compact chip design,the circuit structure and layout have been improved accordingly,and Monte Carlo analysis is also carried out in order to ensure the yield of the chip.The first chip in this paper works at 3-6GHz,the measured results show that the RMS phase error is less than 4°,the average insertion loss is 6dB,the relative bandwidth reaches 66.7%,and the final chip area is 1.8mm~2.The second chip works in the C-band,the simulation results show that in the frequency range of 2.5-4GHz,the RMS phase error is less than 2°,the average insertion loss is 5dB,the IP1dB is 30dBm,the relative bandwidth is 46%,the chip area is 2.684mm~2.The performance of the two chips fully verifies the validity of the design method of this paper,which is conducive to promoting the research of low-cost,miniaturized and ultra-broadband phase shifter in microwave low band.