In order to consider all potential designs and quickly produce antennas that fit their specifications, engineers choose to use antenna synthesis. In addition to synthesis tools, full-wave 3D simulation can complement synthesis tools and allow designs to be checked and fine-tuned for effects that cannot be accounted for analytically. This article explains how the Antenna Magus, an antenna synthesis tool, and CST MICROWAVE STUDIO®, a full-wave 3D electromagnetic simulation program, are used to design a planar phased array.