Imaging algorithms can make the detection of buried objects easier. These algorithms use reflected power from different scatterers with different time delays. Reflected signals from almost perpendicular angles have a significant weight in the imaging algorithms. One additional main feature of these signals is that they have fewer time delays. In this paper, we investigate two parameters that can enhance the back projection (BP) imaging algorithm. The first parameter is the antenna pattern. It controls the ability of radar to sense different angles. The second one is the delays for a point of image based on different locations of radar. It is noticeable that nearfield imaging algorithms suffer from artifacts more than noise. The ground surface clutter can make artifacts more than other clutters. So, clutter cancellation is an important task. The time gating method accomplishes this task better in ultra-wideband (UWB) radars. An experimental setup is used to demonstrate the presented algorithm improvements.