Sparse virtual array synthesis for MIMO radar imaging systems

Multiple‐input‐multiple‐output (MIMO) radar imaging systems require a high angular resolution to realize a high detectability level of the target directly related to the aperture size of the virtual array. Since in MIMO radars, the virtual array topology depends on the transmit and receive array topologies, two methods are proposed for the synthesis of sparse virtual arrays by designing the sparse transmit and receive arrays using a two‐step synthesis procedure (TSP) for antenna array sparsity via convex optimization. Both methods are formulated in detail, and it is shown that adjustments in formulations with respect to physical constraints in design specifications are feasible. In the first method, both the sparse transmit and the sparse receive array are synthesized using the TSP independently of each other. In the second method, the sparse receive array is synthesized based on the transmit array topology or vice versa using the method of least squares. With the help of numerical examples, it is shown that a sparse virtual array has better performance in terms of beamwidth and side lobe level compared with the traditional dense virtual array with the same number of transmit and receive array elements. It is also shown that the proposed design methods lead to broadband performance.