Derivation and Validation of Three-Dimensional Microwave Imaging Using a W-Band MIMO Radar

This study proposes a method for synthesizing 3-D microwave images using a multiple-input–multiple-output (MIMO) radar. Recent studies on MIMO radar technology have reported promising hardware that can be used in radar imaging. In particular, the increased amount of data acquired from MIMO radar is effective for 3-D radar imaging. Despite the demand for using 3-D radar imaging, the underlying technical challenges have not been addressed. Although the array synthetic aperture radar method is promising, realizing a multichannel radar with numerous channels requires significant effort in terms of hardware. Therefore, an MIMO radar can be used to effectively increase the number of channels with reduced hardware. Studies on beat frequency division (BFD) frequency-modulated continuous wave (FMCW) radars show that the simultaneously transmitted MIMO signal is suitable for radar imaging applications without hindering the along-track imaging performances. In this study, the signal of a BFD FMCW radar mounted on a movable platform is modeled according to the imaging geometry, and a fast Fourier transform-based imaging algorithm is derived to efficiently process the multichannel data. This algorithm is applied to the simulated radar data to verify the effectiveness of the proposed method. The method is further assessed by applying the imaging algorithm to the radar data acquired from a functional W-band BFD FMCW radar hardware. The radar transceiver was mounted on a movable table, and the data are measured at an outdoor experiment site. The results verify that the proposed method can be used for various 3-D radar imaging applications.