Abstract:By exploiting the spatial and waveform diversity, multifunction radio frequency (MFRF) systems based on a multiple-input-multiple-output (MIMO) array can simultaneously support multiple functions, including radar detection, data communications, and electronic attack. Moreover, MIMO MFRF systems can achieve enhanced target detection performance, improved angle estimation accuracy, and lower probabilities of being intercepted and identified. Therefore, MIMO MFRF systems have shown great potentials in complex environments. In this paper, the detection performance of MIMO MFRF systems is investigated. The fundamental limits of the detection probability of a MIMO MFRF system are presented, and the factors influencing the detection performance are analyzed. Then, an angle estimation method based on a single pulse is proposed, and an algorithm for resolution enhancement via designing the waveforms is developed. Afterwards, by considering that the target angle estimation error is inevitable, a robust waveform design method for MIMO MFRF systems is proposed. Moreover, an algorithm for jointly designing the transmit waveforms and the receive filters is developed for MIMO MFRF systems operating in the clutter. The proposed joint design method not only supports multiple functions simultaneously, but also suppresses the clutter and enhances the target detection performance. Finally, several important research topics of MIMO MFRF systems, including the fundamental limits of target angle estimation accuracy, high-resolution parameter estimation, robust waveform design, fast implementation of waveform design algorithms, are discussed.