Hybrid modelling of installed antennas

The performance of an installed antenna can be markedly different from its performance in free space owing to its interaction with the structure and interference with other antennas installed on the vehicle. Although full wave solvers have proved to be successful in modelling free space antennas, current computer technology cannot provide solutions to Maxwell´s equations at microwave frequencies for antennas installed on electrically large structures such as aircraft. For this reason BAE Systems Antenna Modelling Facility at Warton have invested in the development of the INSTANT software. INSTANT analyses antenna performance using the asymptotic ray-tracing approximations of the uniform theory of diffraction (UTD). However, ray-tracing methods by themselves can only model the interactions of electrically small, simple antennas such as wire dipoles. The hybrid method described offers a way of calculating ray launch coefficients for realistic installed antennas, thereby enabling INSTANT to calculate accurate and reliable predictions of installed antenna performance at microwave frequencies.