57–64 GHz Imaging/Detection Sensor—Part II: Experiments on Concealed Weapons and Threatening Materials Detection

In this paper, experimental evaluations over the frequency range of a 57-64 GHz for an improved millimeter wave (MMW) imaging/detection system have been conducted. The main objective behind this work is to examine the performance of a high gain and low profile multi sine corrugated AFTSA antenna sensor in the detection of metallic, non-metallic weapons and suspected liquids hidden by clothing, plywood, and plastics. A microwave holography technique based on time domain reflectometry (TDR), which utilizes amplitude information recorded over a 2D aperture, reconstructs a focused image of the target. 60 GHz ISM band imaging detection experiments elaborate the ability for the detection of concealed weapons or other threatening items placed on a body phantom, easily penetrating clothing material of different thicknesses, as well as able to detect through plywood and plastics. The MMW image is detected using a 2D linear scanning platform which generates XY movement, with a 30 × 30 cm
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mechanical range for the object field of view and oriented perpendicular with respect to a lens focal plane. This work is performed with a cross range resolution of δx = δy = 3 mm achieving a 100 × 100 pixels MMW image. The mechanical setup scanning method is similar to synthetic aperture array with a single AFTSA antenna element measurement, ideal for investigating the probe for 60 GHz band imaging and in detecting concealed threatening items at security surveillance checkpoints.