W Band Imaging System Using Linear Sparse Periodic Antenna Array and Compressive Sensing for Personnel Screening

Shaoqing Hu,Chao Shu,Yasir Alfadhl,Xiaodong Chen

doi:10.1109/access.2019.2956630

Abstract

This paper presents our study on a W band imaging system consisting of a linear sparse periodic antenna array (SPA) with only 10 transmitting (Tx) and 10 receiving (Rx) elements in simulation and experiment for the purpose of personnel screening. We have devised a simplified and low cost experimental set-up using only 1 Tx and 1 Rx channels located on two scanning tracks separated by a distance to verify the proposed multi-static array imaging scheme. The simulation has taken account of the effects of track separation and measured antenna patterns. The simulation and experiment correlate quite well, indicating a resolution of about 7 mm at 1.3 m distance. Furthermore, based on the experimental data, we have investigated the compressive sensing (CS) image reconstruction as an approach for further reducing the sampling points in such a multi-static array imaging system. It is shown that using a discrete SPA-CS imaging algorithm, the images can be successfully reconstructed with the data as few as 30% of that used in the traditional holographic/synthetic aperture radar (SAR) imaging algorithm. Therefore, the CS image reconstruction is proved to be feasible for building a low-cost and fast millimeter wave imaging system.

Highlights

There are demands for millimeter wave (MMW) personnel screening systems for detecting concealed threats like handguns, knives and explosive devices in public areas, such as airports and train stations
In contrast to a passive imaging system that relies on temperature and/or emissivity contrast to form images at a fast rate [1]–[5], an active imaging system transmits MMW signals and collects the reflected signals from the target to construct high quality images by using various advanced imaging algorithms [6]–[13]
The current active imaging products in the commercial market still mainly work at lower millimeter wave band because of availability of the matured and low-cost electronic components [6]

Summary

INTRODUCTION

There are demands for millimeter wave (MMW) personnel screening systems for detecting concealed threats like handguns, knives and explosive devices in public areas, such as airports and train stations. S. Hu et al.: W Band Imaging System Using Linear SPA and Compressive Sensing for Personnel Screening in the planar multi-static sparse array in which 736 Tx and 736 Rx have been used to achieve an array aperture of around 50 cm × 50 cm, the lateral resolution is about 2.0 mm because the operating frequency band is 72∼80 GHz and the target distance is 0.5 m [9]. Hu et al.: W Band Imaging System Using Linear SPA and Compressive Sensing for Personnel Screening in the planar multi-static sparse array in which 736 Tx and 736 Rx have been used to achieve an array aperture of around 50 cm × 50 cm, the lateral resolution is about 2.0 mm because the operating frequency band is 72∼80 GHz and the target distance is 0.5 m [9] Another sparse array named linear sparse periodic antenna array (SPA) have been proposed for the personnel screening systems [10]–[13].

CS IMAGING WITH THE LINEAR SPA

Findings

CONCLUSIONS