A Sparse Multistatic Circular Array for Millimeter-wave Imaging System

In this paper, we address the problem of millimeter-wave imaging using a multistatic circular array. Circular array provides uniform omnidirectional beamforming, and simplified beam steering with the ability of full 360-degree coverage. It offers less grating lobes compared to planar arrays which improves signal quality. In this work, we focus on designing a sparse structure while maintaining the concept of the circular array with the objective of scanning the top view of the human body. The design is based on the compressed sensing model which allows us to design a very sparse structure. The proposed structure includes two sparse rings that use only 10 transmitters on one ring and 20 receivers on another ring. In total, 93.32% element reduction comparing a uniform double-ring array with a maximum SLL equal to $-7.71 \mathbf{d B}$ is achieved. The simulation results support our design and using the developed CS model, successful reconstruction has been obtained with a PSNR of more than 10 dB compared to the conventional recovery method.