Millimeter wave imaging: System modeling and phenomena discussion

This paper presents a simplified calculation method to model active millimeter wave imaging system based on Huygens´ principle. Though limited to its ability to do the calculation accurately, it still gives a good evaluation of the performance of practical 3D systems. Thus the simulator can act as an effectivel tool at the beginning of the system design. The inherent effects in coherent imaging such as ringing, speckle and glint will be shown. To deal with speckle, a Hadamard diffuser is suggested. Influence of the pattern and size of the Hadamard cell are discussed accompanied with the explanation from an array antenna point of view. Finally, mult-frequency and multi-angle illumination methods are shown with possible enhancement to the image.