An investigation of antenna element spacing on the quality of millimetre wave imaging

In this paper, a high gain horn which has a 10 degree beam width is used as the scanning antenna in a monostatic millimetre wave imaging radar system. The distances from the antenna to the object to be imaged are set in the near and far field range respectively. The backscattered electric field from the object is recorded from the measurement and an image is reconstructed by applying holographic processing algorithm. The investigation of the minimum required sampling density to form the target image is performed by varying the sampling density. Since the synthetic aperture is equivalent to the imaging array, the investigation provides vital information for millimetre wave imaging array design.