HF broadband antenna design considerations on warships

Abstract

In view of the expected EM interaction of the metallic super structure of the ship with that of the physical elements which form the HF antenna, design analysis carried out in isolation with just the equipment and antenna cannot be implemented onboard. However basic limitations imposed on the performance of MF/HF antennae by the ship's structures can be overcome by coordinating the design of the antennae with the ship's super structure by way of carrying out scale model measurement in the preliminary and detailed design stages of the ship building activity. The number of communication circuits required to satisfy the operational commitments of shipboard HF communication system have increased to such a degree that it is not possible to install tuned HF monopole antennas for each circuit as in the case of tuned 35 feet whips presently being deployed onboard warships. It is therefore relevant that in order to overcome the problem of lack of real estate and the avoidable mutual coupling, the necessary design, analysis and measurements be incorporated in the ship design and building process to provide broadband antennae. The authors focus attention on the practical design considerations that go into the design of a lower band HF frequency broadband wire antenna onboard a typical warship. They also touch upon scale model measurements and the design and evaluation of the requisite antenna matching network.