A multi-layer planar microstrip array at X-band is presented for FMCW-Synthetic Aperture Radar application. A comparative study is provided for conventional corporate fed array and multilayered (proposed) array configurations. The proposed design exhibits an improvement in sidelobe level of the order of 6dB in both E-and H-planes with better cross-polarization level. The common ground plane separating the two stacked substrate layers, shields the antenna half-space from spurious radiation from the feed lines. The simulation results show that the radiation pattern in the operating frequency provides sidelobe level better than 23dB and 21dB with a 3dB beamwidths of 23° and 9° in E-plane and H-plane respectively. Array exhibits a gain of 21dBi at the centre frequency and cross-polarisation level of better than 30dB. © 2016 IEEE.