Digital phase tightening for improved spatial resolution in millimeter-wave imaging systems
Author(s)Lu, Ke, S.M. Massachusetts Institute of Technology
Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science.
Charles G. Sodini.
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Imaging systems using millimeter-wave frequencies allow for the possibilities of vehicular radar and concealed weapons detection. By using silicon technology, the integration of millimeter-wave circuits can reach new levels that were previously impossible. This thesis discusses the challenge and design of a mm-wave imaging system using a technique called digital phase tightening for improved spatial resolution. Digital phase tightening uses feedback and oversampling to accurately measure the amplitude and phase of an incoming signal. Furthermore, it can be implemented using only a delay-lock loop, an analog-to-digital converter, and a counter. A proof of concept system utilizing a 2.4GHz delay-lock loop with supporting circuitry is designed in 90nm CMOS. Test results demonstrate a proof of concept system with a measured DLL resolution of 41.7ps that consumes 36mW of power. The goal of the system is to reduce the jitter of phase measurements to the order of femto-seconds. In the proto system, the quantization error is larger than the Gaussian noise; therefore, significant improvements in the accuracy of the phase measurements were not observed.
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.Includes bibliographical references (leaves 68-69).
DepartmentMassachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science.
Massachusetts Institute of Technology
Electrical Engineering and Computer Science.