RF Impact of Intercostal Structure on the Rear-Shell Performance of a DGR Antenna

A modeling and analysis approach is presented to accurately predict the RF impact of intercostal structure on the rear-shell performance of a dual gridded reflector (DGR) antenna. Hybrid physical optics method of moments (PO-MoM)-based electromagnetic analysis capability has been effectively utilized. The intercostal ribs have been identified as the main cause of copolar gain degradation and pattern distortion with smaller contribution from the intercostal ring.