A new design of a dual-band shared-aperture antenna based on frequency selective surface (FSS) for synthetic aperture radar (SAR) applications is presented. Bow-tie patches are used as the radiating elements both at L-band and C-band. The centre frequency of the L-band antenna is 1.3 GHz and the centre frequency of the C-band antenna is 5.2 GHz. The simulated impedance bandwidth (S11 ≤ −10dB) of the antenna reaches 16.2% for L- band and 26.8% for C-band. The simulated cross-polarization levels are all less than −48 dB for both L-band and C-band. The work confirms the practicability of the dual-band shared-aperture antenna based on frequency selective surface (FSS) design, and good bandwidth and cross-polarization performance of the antenna has been achieved.