W-Band MIMO FMCW Radar System With Simultaneous Transmission of Orthogonal Waveforms for High-Resolution Imaging

This paper presents a multi-input multi-output (MIMO) radar with simultaneously transmitted orthogonal waveforms. The radar operates in W-band, 93.5-94.5 GHz, with frequency-modulated continuous wave (FMCW) signals. The radar is designed to be capable of simultaneous transmission rather than switching transmit channels. A suitable orthogonal waveform transmission method for the FMCW radar is selected and reflected in the transceiver design. The radar consists of a transceiver, antennas, and a signal processor. The design and specifications of each module are described in detail. The transceiver consists of two transmitting channels and two receiving channels. The transmitter is designed to have high transmit power aiming at the detection and imaging of objects with small radar cross section, up to 100-150-m range. A compact horn antenna and two-channel analog-to-digital converter with a high sampling rate are designed and fabricated. The performance of each module is measured and evaluated. The performance of the radar is tested through experiments. The MIMO capability of the radar was verified through the acquisition of the range profiles with respect to four distinct signal paths by distinguishing the simultaneously transmitted orthogonal signals. The experimental results verified that the specification of the radar system is feasible for high-resolution imaging applications.