A Portable $K$ -Band 3-D MIMO Radar With Nonuniformly Spaced Array for Short-Range Localization

This paper presents a $K$ -band multiple-input-multiple-output (MIMO) radar for short-range localization. This radar features 3-D imaging capability, which can obtain the range, azimuth angle, and zenith angle of a target. The proposed radar system implements the concept of MIMO to synthesize a planar array that realizes 2-D digital beamforming with a small number of transmitter and receiver (T/R) channels. A nonuniformly spaced array configuration is also designed to further reduce the number of T/R channels without sacrificing the beamwidth and sidelobe level. The design principle is detailed in this paper. A prototype with eight transmitter channels and eight receiver channels has been built. A calibration procedure was developed to remove path delays of different MIMO channels. Experiments of the proposed ${K}$ -band MIMO radar prototype reveal its capability in the 3-D localization of multiple targets. This prototype features 7.2° 2-D angular resolution, 90° field of view, −10-dB sidelobe level, and wireless data transfer.