Forward-nulling passive millimeter wave imaging using cooling dielectric tube

In order to improve the quality of object recognition characteristics in passive millimeter-wave (PMMW) imaging, a new method to form a null in the direction of human body and objects is proposed. The forward-nulling passive millimeter-wave imaging using a dielectric tube occupied by cooling water placed on focus line of a parabolic cylinder are performed. It is shown experimentally that the contrast between human body and conducting scatterers such as a conducting plate and a conducting sphere in the PMMW images is improved by the presence of cooling dielectric tube with parabolic cylinder.