Efficient analysis of antennas on an electrically large platform

Antennas onboard a large platform are analyzed by a hybrid technique which combines the method of moments (MoM) and the physical optics (PO) method within a new framework. The problem region is divided into three regions. The first one is MoM region which consists of the antenna, antenna-platform junction and a small part of platform surrounding the junction, the second one is PO region which contains a large portion of platform at certain distance away from the junction, and the third one is PO-MoM region which includes the platform part between MoM and PO regions. The currents in MoM and PO regions are solved by the MoM and the PO method, respectively. As the interaction between the currents in PO-MoM region needs to be taken into account for accurate determination of the antenna current, the MoM is employed to solve the currents in this region. In conventional hybrid techniques, PO-MoM region is included into PO region, thus the interaction cannot be considered. The coupling between the currents in PO and PO-MoM regions is insignificant compared to that between the currents in PO and MoM regions, as such, it is not considered.