Abstract: In this paper,an aperture designing technique of multi—stepamplitude quantization for two—dimensional solid—state active phasedarrays to transmit low sidelobe is described.It is shown that this methodis effective to reduce the Peak sidelobe level of solid-state active Phasedarrays and can be applied to the arbitrary complex aperture antennas.In addition,gain loss and sidelobe degradation due to random amplitudeand phase errors and element(or T/R module)failure are investigated.