SOME EXAMPLES OF THE PREDICTION AND VALIDATION OF NEAR-FIELD DEPENDENT AIRCRAFT HF ANTENNA PARAMETERS USING NEC

Abstract

Examples are presented of the application of a moment- method modelling procedure (using NEC) to calculate the near-field dependent parameters of aircraft HF antennas. The overall aim of the work from which the examples are drawn is to provide a 'recipe'; the application of which will generate predictions of parameters of interest which are both credible and sufficiently accurate for engineering purposes. A feature of the procedure is that no empirically derived information is incorporated. The examples encompass a range of generic aircraft and antenna types: both fixed and rotary wing airframes, and electric (wire) and magnetic (loop and notch) primary radiators. Particular emphasis is placed upon validation of the predictions. This is performed by direct measurement where possible, but where this is not practicable simple, but independent, calculations are performed based upon equivalent circuits. As for the moment-method procedure, these corroborative calculations do not depend upon empirical information. [Vol. 9, No. 1 (1994), pp 67-77]