Range‐angle target indication using FDA‐MIMO with sinusoidal element spacing

By introducing a tiny frequency increment across the array elements, frequency diverse array (FDA) radar produces a range-angle-dependent beampattern. However, the range-angle coupling and time-variant problem block the application potential of the conventional FDA. Employing sinusoidal element spacing and symmetrical sinusoidal modulated frequency offsets, a novel scheme termed as Sin-FDA is proposed. To eliminate the time-varying effect, multiple-input multiple-output technique and multiple matched filters at receiver are adopted. The proposed scheme can generate a pencil-shaped beampattern with smaller spatial region of mainlobe in range-angle domains, which is helpful for improving the target indication performance. Furthermore, the beampattern produced by the proposed scheme has narrower mainlobe both in the range and angle dimensions as well as acceptable sidelobe level. The exploration of nonuniform element spacing can better direct the range-angle decoupled beampattern design for FDA radar. Simulation results validate the superiority of the proposed scheme over the existing decoupled FDA systems.