In recent years, researchers have been focusing on the capabilities of radar-based microwave imaging in detection of concealed objects in sealed packages, through-the-wall imaging approach which faces challenge in suppress unwanted return signals. This disclosure relates a method to detect objects in sealed packages. One or more parameters associated with a conveyor are received to obtain a scan time of a radar. A sequence of scanning is determined between one or more antenna pairs based on corresponding position. A sealed package is scanned in the predetermined sequence to obtain range-time datasets with identifiers. The range-time datasets are processed by virtual antenna-pattern-weighted delay-multiply-and-sum technique based on one or more positions of each virtual antenna to determine one or more object signature images. A trained classification model based on extracted features associated with one or more object signature images.