Novel aperiodic phased array with reduced number of active chains for space-borne SAR

A novel aperiodic phased array for space-borne synthetic aperture Radar (SAR) is presented which has fewer active chains than a corresponding periodic phased array while maintains comparable radiation performance. The design of proposed aperiodic phased array is based on equal amplitude sparse array. Compare to other aperiodic sparse phased array antennas for space-borne SAR which have been reported before, in the design of proposed sparse array a novel `active-passive array' technology is utilized to modify the equivalent aperture current distribution, therefore the radiation performance can be improved significantly in terms of gain and sidelobe level. Simulation results show that the proposed phased array possess similar radiation performance to a periodic array while reduces the active chains number to 75%. Simplified evaluation of SAR Ambiguity-to-Signal Ratio also show that the proposed array exhibits similar performance of traditional periodic array, which is obviously better than that of conventional aperiodic sparse array. The design principle of `active-passive array' as well as associated array synthesis method are also discussed.