Caltech Mixed-Signal, RF and Microwave Seminar
High-Resolution mm-Wave Pulsed Radar for Imaging and Gesture Detection
Wideband mm-wave beamforming arrays have applications in medical and structural imaging, gesture recognition, navigation, and high-speed communication. There has been a continued effort towards realizing low-cost, high-resolution, and large-scale arrays at microwave and mm-wave frequencies. This talk will highlight some of our recent work in designing scalable solutions for silicon-based sub-THz beamformers.
Key challenges with design of extremely wideband pulsed-based mm-wave arrays will be discussed. Several novel approaches for extreme wideband amplification plus narrow and accurately controllable mm-wave pulse generation, the major issues in attaining image quality, are addressed. In particular, a 94GHz single-chip pulsed-radar transceiver with over 30GHz of pulse bandwidth and 10GHz of center-frequency tuning range is presented. It incorporates true-time beamforming using a PLL/DLL hybrid topology and is capable of full-PRI time-shift, and as a result, large field-of-view 3D imaging. The silicon chip provides delay accuracy down to picosecond level translating to sub-mm RMS error in imaging voxels. Interferometric measurements, made possible by phase coherency of the pulsed-radar, enable sub-mm resolution in ranging. In the end, future directions and some of the applications of this technology will be discussed.