Design and prototyping of a real-time millimeter wave imaging system

The goal of this work is to design, prototype and test an innovative millimeter wave imaging system that operates in the frequency range of 33-35 GHz and is capable of producing rapid images of various diverse scenes. In particular, the imaging system includes two main sections, one is related to the hardware design of the system, and the other focuses on the development of a novel comprehensive image reconstruction algorithm. The hardware design includes custom transmitter and receiver sub-systems, and a sparse switched array which was optimized for 320 mm x 220 mm aperture plane, and also included an improved antipodal Vivaldi antenna featuring a substantial reduction in unwanted radiation as the array element. All aspects of the hardware system were simulated, prototyped and tested in this work prior to final system integration. As it relates to the reconstruction algorithm, traditionally bistatic imaging systems utilized an equivalent monostatic imaging algorithm. However, this leads to degradation in image quality. The level of this degradation was analyzed using image error metrics and conditions for minimum image error were obtained. Additionally, a robust amplitude compensated range migration algorithm (AC-RMA) was developed that is applicable for both bistatic and monosatic configurations. The AC-RMA is capable of successfully reconstructing target images independent of the dielectric contrast between the target and background, additive noise power, and bandwidth of the imaging system. In addition, while the formulation of the AC-RMA is more complicated than the traditional (phase compensation only) RMA, the processing time necessary for images created with the AC-RMA is just 1.2 times greater than that of the traditional RMA processing time --Abstract, page iv