Sparse multiple-input multiple-output arrays for high-resolution near-field ultra-wideband imaging

This study investigates the utilisation of a multiple-input multiple-output (MIMO) array technique for high-resolution near-field ultra-wideband (UWB) imaging. Using this technique, a classical array can be replaced with an MIMO array with a similar resolution and beam pattern but using a smaller number of elements. A deterministic approach to factorise a desired effective array topology into topologies of transmit and receive sub-arrays is suggested. Based on it, an MIMO array design procedure is proposed. A few examples of linear array topologies are suggested and their performances in the near-field are compared for different values of the operational bandwidth. The experimental results verify the correctness and effectiveness of the proposed design procedure for UWB near-field imaging.