A 1.5-GHz 6.144T Correlations/s 64 $\times $ 64 Cross-Correlator With 128 Integrated ADCs for Real-Time Synthetic Aperture Imaging

A 65-nm CMOS, 18-mm
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, 1.5-GHz 64 × 64 crosscorrelator with 128 on-chip analog-to-digital converters (ADCs) enables real-time synthetic aperture radiometric imaging. This brief enables high-resolution synthetic aperture radiometry by greatly improving the integration and energy efficiency of the mixed-signal baseband cross-correlator. The design supports analog-in and digital correlation out, removing approximately 5 W of power that would otherwise be needed for I/O between the ADCs and the digital correlation core. The prototype 6.144T correlation/s 1.5 Gsamples/s 64 × 64 correlator is designed for satellite-based radiometric imaging of water in the atmosphere. Massive parallelism together with an optimized correlation scheme leads to a measured energy consumption of only 0.35 pJ/correlation/cycle. A correlation efficiency greater than 90% is achieved for input signal levels greater than -30 dBm.