Synthetic Aperture Radars (SAR) have demonstrated to be great instruments for space-based Earth observation in the microwave frequency. Metasurface antennas, on the other side, are a new type of planar antennas with a great potential for space applications, as they are compact and easy to produce. Several methods have been developed in the past years addressing one or many parts of the design and applications of these antennas, which rely in more or less measure in locally developed tools. However, some parts of these methods can take a great amount of time to implement, making this process more difficult than it should especially if the user has commercial electromagnetic simulation tools available that could accelerate this process. In this work, different procedures have been adapted to the design of a high-gain SAR anisotropic metasurface antenna for a multi-static Earth observation mission, showing that the proposed methodology produces accurate results.