This presentation describes how CST MICROWAVE STUDIO® (CST MWS) has been used in conjunction with POS 5 and GRASP 8 to design an X-Band circularly polarized Splashplate Antenna. The antenna essentially consists of a center fed reflector (17 wavelengths in diameter), the Splashplate feed (~2 wavelengths in diameter), and a septum polarizer to allow the Tx and Rx bands to operate in opposite polarizations. A significant factor in the design is that a short circuit had to be assumed at the other port of the septum polarizer meaning that the return loss of the Splashplate feed and the reflector were critical to the axial ratio performance. CST MWS enabled this aspect of the design to be modeled and analyzed using the T-solver. Comparison of the measured and predicted antenna performance has validated the design process. Although a compliant performance has been achieved, it is evident that some modeling improvements could be sought in order to get a better convergence between prediction and measurement.
Richard Roberts, Astrium Ltd