By making the random mutation operator in the classical genetic algorithm(GA) play an additional role,the beam pattern produced by thinned planar or linear arrays with arbitrary thinned factor is optimized.

To achieve this goal, one way is to increase the element number of the array, but it will bring higher cost and more complexity with respect to the system; another way is to use sparse antenna array, whose element spacing is relatively larger thanλ/ 2, it has larger aperture without increasing the number of element, the sparse array can meet the design goal o.

A modified genetic algorithm is presented to optimize the element spacing of the nonuniform sparse array in this paper.

A synthesis technique for linear sparse arrays with optimization constraint of minimum element spacing;

The trends of the key technology by the follow ways,increasing bandwidth,the improvement of the power added efficiency of transmit/receive modules,the technology of phase shifter,digital circuit and the sparse arrays are discussed.

Compared with the synthesis method of thinned arrays,this new approach can exploit more degree of freedom of elements to control the characters of the sparse arrays.

Sparse-array Synthetic Impulse and A perture Radar (SIAR) can isotropicly radiate by etnploying multiple frequencies (synthetic pulse) and multiple antennas(synthetic antenna) without beam spanning.

Generally,side lobe level of a sparse-array at arbitrary position is high.