Naval structural antenna systems for broadband HF communications

This paper introduces the concept of multipurpose structural antenna system for shipborne installations. By combining properly shaped and loaded wire radiators together with an existing naval superstructure, such as the funnel or a big mast, it is possible to achieve a broadband high-frequency compact radiating system which permits handling both sea-wave and near vertical incidence sky-wave communications. When provided with a plurality of feeding points, the naval structural antenna may be used in multichannel mode, with a huge efficiency improvement over the conventional multichannel broadband systems requiring a combining network. Additionally it is shown that, when fed in monochannel mode, the structural antenna system exhibits focusing features with the possibility to achieve sectorial coverages. This paper demonstrates the advantage and limitation of this new system by carefully taking into account the interantenna coupling.