Waveform design for FMCW MIMO radar based on frequency division

Classical radar systems can achieve the angular resolution based on linear phased array antenna technology. If a high angular resolution is required a large antenna aperture is needed. In case of a single transmitter (TX) the number N of receive antenna elements corresponds directly to the number of targets that may be separated and resolved by their different azimuth angle positions. The spacing between two adjacent receive antenna elements inside a uniform array determines the maximum unambiguous azimuth observation area. Therefore the antenna aperture is defined by the required angular resolution and the maximum unambiguous azimuth observation area. However, the angular resolution of a radar system can be increased dramatically by using multiple transmit antennas. Each transmitter generates an individual signal that can be clearly distinguished inside the different radar receivers (RX). This Multiple Input Multiple Output (MIMO) technology shifts some of the computation complexity from the receive antenna array into the transmitter side. For the special case of two transmit antennas and an arbitrary number of receive antenna elements a Frequency Modulated Continuous Wave (FMCW) signal is proposed in this paper. In this case the angular resolution of the radar system is improved by the factor of two compared to the same configuration with a single transmit antenna.