In developing a synthetic aperture radar onboard a satellite, one component of concern is the antenna. In designing such an antenna, the selection of material types should be considered in order for the effects of expansion and shrinkage due to drastic temperature variations not to result in significant performance changes. In this study, the effect of adoption of various material types to the antenna performance was evaluated when applied to the antenna design by incorporating the changing of dimensions caused by temperature changes through the simulation. The first step involves the making of antenna design using Solidworks, where the design for the reflector is made for various types and material designs. Then a simulated temperature change is performed to find out the change in antenna design dimension to temperature changes that approximate real operating conditions onboard satellite. After that, electromagnetic field for the antenna design before and after heat-induced expansion is simulated to learn antenna performance. Comparison of performances is done to get the best type and material design. From among several designs and types of materials selected, the simulation results show that molybdenum with gold coated design produces the best performance.