Near Field Pattern Computations for Airborne Antennas.

This report presents the results of a newly formulated analysis for computing patterns of aperture or monopole antennas mounted on the fuselage of aircraft. Approximate models of the aircraft structure are employed in conjunction with the Geometrical Theory of Diffraction to obtain the computed fields. A major feature of the analysis is that it can accommodate receiver range specifications varying from as close as a wavelength to the aircraft surface to the true far field. This feature is especially useful in that computed on-aircraft pattern performance can be compared with measurements taken at any convenient range, including the near field. Further, after such crucial checks between computations and measurements have been made, the numerical solution can be employed to accurately predict the far field performance of the on-aircraft antenna system. A general computer code, based on the new analysis has been written. The accuracy of the numerical solutions obtainable with the analysis is demonstrated by comparison with numerous model measurements. Author