Research And Design On Ku-band MMIC Digital Phase Shifter And Digital Attenuator

With the development of microwave communication technology,microwave monolithic integrated circuits(MMIC)are widely applied in military electronic countermeasures and civil communication systems due to their advantages of small size,compactness,good stability,strong anti-interference ability,low mass production cost and good consistency.The Ku-band MMIC digital phase shifter and digital attenuator designed in this paper are an important part of T/R modules in the active phased array radar,their performance directly determines the overall radar.Firstly,the paper summarizes the research status of Ku-band digital phase shifter and digital attenuator at home and aboard,and analyzes the theoretical knowledge of MMIC,including MMIC device process,active and passive device model,pHEMT switch principle and model.Then the basic theoretical knowledge of digital phase shifter and digital attenuator is introduced in detail,including technical index analysis,basic circuit topology,working principle analysis and so on.Then according to the specific design indicators,six bits of phase shift and attenuation topologies are selected appropriately,and the microwave simulation software ADS is used to simulate the schematic and layout.Then the overall circuit is determined by cascading the six bits of phase shift and attenuation,and used the electromagnetic simulation to ensure the overall performance which meets the design indicators requirement.Finally,based the test system of probe test platform,vector network analyzer and switch matrix,the digital phase shifter and digital attenuator chips are tested.The main work and result of this paper are as follows:(1)Aiming at the application requirements of Ku-band phased array system,the design and tapeout of a Ku-band six bits digital phase shifter is completed on the 0.25?m GaAs pHEMT process.The mearsured results that less-than-2.4deg of the 64-state root-mean-square(RMS)phase error,less-than-9.4dB of insertion loss,less-than-0.3dB of RMS parasitic attenuation error,and less-than-1.5 of the input/output voltage standing wave ratio(VSWR)in frequence range of 14~18GHz are shown.The size of chip is 3mm×1.25 mm.The comprehensive performance index is at the leading level among similar products at home and abroad.And it lays a solid foundation for the development of Ku-band phased array antenna T/R chipset.(2)Aiming at the application requirements of Ku-band phased array system,the design and tapeout of a Ku-band six bits digital attenuator is completed on the 0.25?m GaAs pHEMT process.The mearsured results that less-than-0.25 dB of the 64-state RMS attenuation error,less-than-4.9dB of insertion loss,-0.5deg~9.5deg of parasitic phase error,and less-than-1.5 of the input/output voltage standing wave ratio(VSWR)in frequence range of 12~18GHz are shown.The size of chip is 3mm×0.75 mm.The comprehensive performance index is at the leading level among similar products at home and abroad.And it lays a solid foundation for the development of Ku-band phased array antenna T/R chipset.