Performance comparison of sparse array millimeter wave imager configurations.

Millimeter wave imaging systems are a promising candidate for several applications such as indoor security, industrial non-destructive evaluation, and automotive radar systems. In this paper, we compare the performance of various array configurations that can be enabled by recent automotive radar chips, for imaging applications. High resolution real-time imaging requires an extensive number of measurements which demands a large number of emitters and receivers. Hence, cost and size become major considerations in the design process. In an attempt to reduce the number of emitter and receiver elements, we compare various antenna array architectures to optimize the hardware implementation for high resolution imaging. We consider mono-static single-input-single-output (SISO), multi-static multiple-input-multiple-output (Full-MIMO), and hybrid localized MIMO-SISO (Local-MIMO) architectures. The computationally reconstructed image quality and point spread function from each architecture are compared and traded for the system engineering complexity and cost. We present measurement results from a Synthetic Aperture Radar (SAR) system based on an automotive radar sensor to ensure it is representative of the system's physics. The comparative results of the SISO, Full-MIMO and Local-MIMO simulations provide for affordable alternatives to the high cost SISO approach.