Millimeter-Wave Imaging and Perception

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We focus on the design of next-generation radar systems for applications such as gesture recognition (e.g., implemented on handhelds, laptops or televisions) and vehicular situational awareness. The goal is to co-design imaging/recognition algorithms and hardware (through collaborations with theory/system researchers), using innovations in system-level modeling and algorithms to define and simplify the hardware requirements while approaching fundamental estimation-theoretic performance limits.

We have used a customized compact mm-wave stepped-frequency continuous wave (SFCW) radar testbed to demonstrate several reconstruction and synthetic focusing techniques for gesture detection or other imaging-radar scenarios [1, 2]. Using new primitives – for example, the patch-based reconstruction algorithm – we have demonstrated performance superior to conventional synthetic aperture radar (SAR) processing, both in theory and in measurements.

To achieve real-time operation, mechanical raster scanning methods to collect data must be replaced with state-of the-art systems made of an actual array of antennas. To reduce associated complexity, weight, and cost, the number of antennas should be minimized by moving toward a sparse array – but this introduces grating lobes and results in loss of information. We have focused on grating lobe suppression by modifying the point scatterer model and matched-filtering SAR technique in order to work with new basis functions, and have verified the theoretical results with experimental data collected by a compact radar setup at 60 GHz [3].

Measurement setup: radar with horn antennas operating at 60 GHz to scan the sample.

Produced image using conventional SAR algorithm with sparsely collected data (sampling on 2*lambda x 2*lambda grid points).

[1] B. Mamandipoor, G. Malysa, A. Arbabian, U. Madhow, and K. Noujeim, "60 GHz Synthetic Aperture Radar for Short-Range Imaging: Theory and Experiments," Proc. 48th Asilomar Conf. Sig. Syst. Comp., Pacific Grove, CA, 2014, pp. 553-558.

[2] K. Noujeim, G. Malysa, A. Babveyh, and A. Arbabian, "A Compact Nonlinear-Transmission-Line-Based mm-Wave SFCW Imaging Radar," Proc. 44th Euro. Microw. Conf., Rome, 2014, pp. 1766-1769.

[3] B. Mamandipoor, M. Fallahpour, G. Malysa, K. Noujeim, U. Madhow, and A. Arbabian, "Spatial-Domain Technique to Overcome Grating Lobes in Sparse Monostatic mm-Wave Imaging Systems," Proc. IEEE Int. Microw. Symp., San Francisco, CA, 2016.