Spread Spectrum Digital Beamforming for Millimeter Wavelengths (MMW-SSDBF)

Key to phased arrays that can scale to high frequencies, bandwidth and large apertures is an architecture that enables full digital beamforming and large-array performance with minimum electronics per element. Out of the three proven beamforming methods for phased arrays: analog, conventional digital and spread spectrum digital beamforming (SSDBF), just the latter scales well to large arrays at high frequencies-and-bandwidth while being supportive of"one-shot"area search and simultaneous multiple-target tracking. SSBDF flexibility and scalability to MMW frequencies result from five complementary capabilities that will be included in the proposed MMW-SSDBF: (1) phase shifters used not for beamforming but for return signal multiplexing; (2) full-quality digital beamforming with one-bit phase shifters and single up/down converter and Nyquist rate DAC/ADC for the array; (3) orthogonal codes to detect cross-polarizations; (4) virtual array technologies supportive of high-resolution beamforming with spaced transmitters and receivers; (5) software-define radar implementation. Applied Radar proposes to develop the system architecture, design phase shifters and simulate the performance of a SSDBF system that will scale in frequency (e.g., up to 300 GHz) and to large virtual arrays in Phase I, and develop a prototype radar system and demonstrate its performance at 100 GHz in Phase II.