If, Microwave Digital Phase Shifter

Phase shifter is a key component of phased-array radar. It's performance has direct effects to phased-array radar system. In this thesis, research on the IF broad-band five-bit digital phase shifter and Ku-band six-bit digital phase shifter is presented.In order to meet the requirement of phase-error and physical dimension, high-pass/low-pass filter phase shifter and solid-structure are applied in the design of IF broad-band five-bit digital phase shifter. Analysis of the design theory and theoretic phase-error are carried out in this paper. Based on the design results, the circuit design, assembling and testing are given as well, and samples pass the verification of fifth graduate school.For the 32 phase states, within the frequency band of 60MHz±10MHz, the insertion loss of the phase shifter is lower than 2.3dB, The imbalance of scope is lower than±0.3dB, The phase error is better than±3.3 degree, The input/output VSWR is lower than 1.7. Physical dimension is 40mmX30mmX20mm. All of performances are better than design requirements, and its volume reduce 30% more compared with like products.The loaded-line-type, switched-line-type and reflection-type phase shifters are studied in this thesis. Considering the defect of loaded-line phase shifter, a new type of switched-line with loaded-line phase shifter is proposed in this thesis. This design not only make advantageous debugging of circuit, but also minimize phase-error in a given frequency band. Five cell circuits are designed, fabricated and tested, including 5.625 degree and 45 degree using loaded-line phase shifter, 90 degree using 3dB branch-line coupler phase shifter, 90 degree and 180 degree using switched-line with loaded-line phase shifter. According to the testing result of cell circuits, and requirement of Ku-band six-bit digital phase shifter, the scheme for Ku-band six-bit digital phase shifter is chosen. Finally, the phase shifter is fabricated and tested.The measured results show that: Within the frequency band of 15GHz±100MHz, for the 64 phase states, the insertion loss of the phase shifter is lower than 6dB, The imbalance of scope is lower than±0.9dB, The input/output VSWR is lower than 1.92. Moreover, at the mid-frequency of 15GHz, the maximum of the phase error is lower than±3.4 degree. All of performances are better than design requirements.