Array rotation aperture synthesis for short-range imaging at millimeter wavelengths



[1] Millimeter-wave interferometric synthetic aperture imagers are currently being developed for short-range applications such as concealed weapons detection. In contrast to the traditional snapshot imaging approach, we investigate the potential of mechanical scanning between the scene and the array in order to reduce the number of antennas and correlators. We assess the trade-off between this hardware reduction, the radiometric sensitivity and the imaging frame rate of the system. We show that rotational scanning achieves a more uniform coverage of the (u, v) plane than the more conventional linear scanning. We use a genetic algorithm to optimize two-dimensional arrays for maximum uniform (u, v) coverage after a rotational mechanical scan and demonstrates improvements in the array point spread function. Imaging performance is assessed with simulated millimeter-wave scenes. Results show an increased image quality is achieved with the optimized array compared with a conventional power law Y-shaped array. Finally we discuss the increased demands on system stability and calibration that the increased acquisition time of the proposed technique places.