Design of array with multiple interleaved subarrays based on subarray excitation energy-matching

The shared aperture array antennas with multiple interleaved subarrays is an effective solution of the design of multi-functional array antennas. A new method for interleaving multiple subarrays based on excitation energy-matching is proposed in this paper. In light of the Fourier transform mapping between the element excitations and array factor of uniform linear array, the spectrum of the array factor is first obtained by fast Fourier transform (FFT) and its excitation energy distributions are analyzed thoroughly. The element positions are then selected carefully in a staggered way which ensures that the uniform distribution of the excitation energy of the array antenna elements and the similar patterns can be obtained. Then the peak sidelobe levels (PSL) of the subarrays are reduced with the iterative FFT algorithm. Futhermore, the design of shared aperture antenna array with low sidelobe levels and same performance is achieved. Some numerical simulations and experiments demonstrate that the interleaved subarrays generated from the proposed method possess many favorable characteristics, such as, reduced computational burden, high aperture efficiency, lower PSL than the random thinned array, and perfect matched patterns. By controlling the mainbeam direction, the multi-functional array antenna can be easily designed with multiple beam lobes.