This book chapter introduces the application of a millimeter-wave Frequency-Modulated Continuous Wave (FMCW) radar system as an imaging modality. We commence by providing a concise overview of signal modeling for FMCW radar systems, offering expressions for estimating range, velocity, and angle of arrival. A short discussion covering key metrics such as range, velocity, and angular resolution, as well as maximum unambiguous range and velocity is also provided. Furthermore, we present a short introduction to Multiple-Input-Multiple-Output (MIMO) radar and detail the development of a fully integrated FMCW radar transceiver operating in the D-band, briefly explaining the MMIC architecture, design, and on-chip measurements. Two of these MMICs are used to develop a 2-transmitter (2-TX), 4-receiver (4-RX) MIMO radar system, which is complemented by a custom-built pyramidal horn antenna assembly. We showcase the construction of range-Doppler maps for various target scenarios, illustrating the radar system’s capabilities. Finally, we demonstrate the practical application of a 120-GHz MIMO radar system in simultaneous localization and mapping, focusing on scenes with static targets through the utilization of synthetic aperture processing.