Correlating numerical and scale modelled experimental radiation characteristics of a ship-mounted high frequency antenna

摘要

The radiation characteristics of high frequency (HF) wire antennas mounted on ships are affected by the irregularly shaped conducting ship structure. Computer codes based on the moment method (MM) and the geometrical theory of diffraction (GTD) can compute the radiation pattern of a wire antenna over a simplified model ship composed of a limited number of plates. Such computations do not consider high orders of multiple reflections and/or diffractions. A scale model ship could be built to resemble an actual ship and placed inside an anechoic chamber on a finite size ground plane. In this work, the radiation patterns of a vertical quarter-wave monopole mounted at different positions on top of a ship scale model were measured inside C-CORE's anechoic chamber and correlated with those patterns calculated for the simplified ship model using MM and GTD methods. A good agreement is observed between measured and calculated patterns. This work supports computer codes which are used to determine quantitatively the considerable impact of irregular ship structures on the radiation patterns of onboard antennas.