The CubeSat nanosatellite standard puts strict limitations on the antenna volume, resulting in a low impedance and axial-ratio (AR) bandwidths of patch antennas. The AR of a circularly polarized patch antenna can be improved with the introduction of a dedicated feeding network. However, the antenna gain cannot be influenced, and it will be comparable to a conventional single-feed CP patch. This is demonstrated on three different feeding networks for dual-feed stacked-patch antennas in L and S bands, based on T-junction dividers, Wilkinson dividers, and branchline couplers. Based on their performance and size, the model based on Wilkinson dividers has the optimal performance for CubeSat applications in L and S bands.