Phase Shift Migration With SIMO Superposition for MIMO-Sidelooking Imaging at Terahertz Band

Guan Yang,Guangyou Fang,Chao Li,Hang Gao

doi:10.1109/access.2020.3017617

Abstract

In this paper, the enhanced phase shift migration (PSM) algorithm for multi-input-multi-output (MIMO) side-looking (SL) scheme was proposed for the 2-dimension (2D) fast image reconstruction in the terahertz (THz) band. By decomposing the MIMO imaging problem into a superposition of several single-input-multiple-output (SIMO) sub-arrays, the proposed algorithm can be applied to systems with randomly distributed transmitting array. By deriving and applying the modified phase shift factor and necessary phase compensation, zero-padding in the transmitting array and data reorganization in the spatial-frequency domain of the conventional wavenumber domain MIMO algorithm can be totally avoided, which will hopefully further reduce the amount of calculation. A comprehensive MIMO-SL-EPSM algorithm was established in the wavenumber domain. Proof-of-principle experiments in the 0.1-THz band were performed based on a MIMO-SL prototype system. The reconstructed images for different targets with high efficiency and quality demonstrate the theoretical results and the effectiveness of the proposed algorithm.

Highlights

THz waves are referred to the spectrum from 0.1 to 10 THz, which lie in the gap between the microwave and infrared
Terahertz antennas were difficult and expensive to manufacture, imaging systems were often developed based on a single transceiver combined with a mechanical scanning scheme, such as a quasi-optical element combined with a rotatable mirror for beam focusing and spatial scanning [12,13,14,15,16]
In this paper, the enhanced phase shift migration (PSM) algorithm for MIMO-SL imaging in THz band is studied

Summary

INTRODUCTION

THz waves are referred to the spectrum from 0.1 to 10 THz, which lie in the gap between the microwave and infrared. The range migration algorithm (RMA) applied for MIMO systems [29] based on the Fourier Transform (FT) fully utilizes the efficiency of the FFT algorithm and had been widely used. Considering the limitations of the RMA, in our previous work [3][30], the phase shift migration algorithm originated from reflection seismology was firstly extended for the MIMO imaging scheme. The beamwidth in the azimuth direction determines the range of the imaging scene along the x-axis

THEORY AND FORMULATION

EXPERIMENTAL RESULTS

CONCLUSION