Near-Field MIMO-SAR Millimeter-Wave Imaging With Sparsely Sampled Aperture Data

Abstract

The primary challenge of a cost-effective and low-complexity near-field millimeter-wave (mmWave) imaging system is to achieve high resolution with a few antenna elements as possible. Multiple-input multiple-output (MIMO) radar using simultaneous operation of spatially diverse transmit and receive antennas is a good candidate to increase the number of available degrees of freedom. On the other hand, higher integration complexity of extremely dense transceiver electronics limits the use of MIMO only solutions within a relatively large imaging aperture. Hybrid concepts combining synthetic aperture radar (SAR) techniques and sparse MIMO arrays present a good compromise to achieve short data acquisition time and low complexity. However, compared with conventional monostatic sampling schemes, image reconstruction methods for MIMO-SAR are more complicated. In this paper, we propose a high-resolution mmWave imaging system combining 2-D MIMO arrays with SAR, along with a novel Fourier-based image reconstruction algorithm using sparsely sampled aperture data. The proposed algorithm is verified by both simulation and processing real data collected with our mmWave imager prototype utilizing commercially available 77-GHz MIMO radar sensors. The experimental results confirm that our complete solution presents a strong potential in high-resolution imaging with a significantly reduced number of antenna elements. INDEX TERMS Millimeter-wave radar (mmWave), near-field radar imaging, synthetic aperture radar (SAR), frequency-modulated continuous-wave (FMCW), multiple-input multiple-output (MIMO) radar, IWR1443 mmWave sensors.

Development and Demonstration of MIMO-SAR mmWave Imaging Testbeds

“…However, as summarized in Section II-C, most commercially available MIMO mmWave sensors typically have few transmit and receive antennas. Hence, the effective aperture sizes of both single-chip and four-chip cascaded sensors are not enough to achieve high cross-range resolution along the y−axis [44], [56]. In this paper, we propose to synthesize a 2-D aperture by mechanically moving the MIMO mmWave sensors continuously across the xy plane, along a parallel track pattern, as depicted in Fig.…”

“…In our previous studies, two different MIMO-SAR imaging testbeds are presented briefly using both single-chip [11], [56], [59] and multi-chip cascaded [60] mmWave sensors to validate the proposed image reconstruction algorithms and to investigate different performance metrics. In this paper, our goal is to focus on the system-level design perspective in more detail.…”

“…In this section, the first version of the MIMO-SAR mmWave imaging testbeds prototyped in [11], [56], [59] is summarized to provide a complete study and to demonstrate the improvements presented in this paper. The testbed shown in Fig.…”

Research on Rebound Jamming Against Multi-Input Multi-Output Synthetic Aperture Radar

“…MIMO-SAR system uses multiple antennas to radiate orthogonal signals to target region and multiple antennas to receive ground objects scattering echoes, which can obtain more ground information and form more equivalent phase centers than conventional Synthetic Aperture Radar (SAR), so that spatial sampling can replace time sampling and highresolution imaging can be achieved by combining sub-band synthesis technology [1]- [2]. MIMO-SAR emits orthogonal waveform, which reduces the probability of signal interception.…”

Sparsity-based three-dimensional image reconstruction for near-field MIMO radarimaging

“…However, recently there has been growing interest in using sparse multiple-input multiple-output (MIMO) arrays with spatially distributed transmit and receive antennas (i.e. multistatic array) because these can offer high resolution with reduced hardware complexity, cost, and acquisition time [10][11][12][13][14].…”