Simulation is well established as an essential part of the design of modern antennas and antenna systems including installed antennas on a platform and antenna arrays. With its “Complete Technology” and “System Assembly and Modelling” approaches, CST offers state-of-the-art technology to simulate not only the electromagnetic properties, but also the full circuit and system behavior with incomparable speed and flexibility. Evaluation is made easy by using the extensive built-in post-processing capabilities of the software.