Array-fed reflector antennas are being considered for various synthetic aperture radar (SAR) satellites. Mutual coupling between the array elements, as well as with the reflector, impact the antenna performance significantly. The impact of this coupling is assessed for an L-band antenna. Two different feedings and two different element spacings are considered. The impact of the mutual coupling versus frequency is assessed through extensive full-wave simulations in HFSS. Two methods to reduce the impact of mutual coupling are analyzed.