Continuous wave MIMO radar based on time division multiplexing

A radar system with multiple transmit and receive antennas (MIMO) is considered in this paper. A specific linear frequency modulated continuous wave (FMCW) signal is applied in this case, which allows a simultaneous and unambiguous measurement of target range and radial velocity even in multiple target situations. This frequency modulated signal is transmitted alternately by each transmit antenna. This means that each transmit antenna has exclusive access to the radio channel inside a very small time slot while all other transmit antennas are switched off. Each transmit antenna uses the same waveform however in an intertwined way. In this case all transmit signals are mutually orthogonal and no interferences will occur. The radar echo signal is processed in each receive antenna simultaneously. Due to the orthogonality of all transmit signals each receive antenna can separate perfectly all signals transmitted by different antennas. This transmit signal structure and the time division multiplexing (TDM) procedure is the basis for a MIMO radar system design described in this paper. The radar system will have a high azimuth angle resolution and a large artificial receive antenna aperture.