ELECTROMAGNETIC COUPLING ON AIRBORNE STRUCTURES AND SYSTEMS USING NEC

Abstract

Modern aircraft are increasingly packed with advanced and often sensitive electronic systems, making them very vulnerable to electromagnetic interference. Furthermore, the growing communication arena adds rapidly intot the environment high power transmitters that produce field strengths in excess of a 100 V/m in the vicinity of aircraft flight paths, rendering particularly the higher power HF a real hazard to the flying aircraft with dimension being within the resonant band of HF. This thesis presents a quantitative approach to analyze this coupling mechanism. The feasibility of using NEC wire-grid scheme for analyzing field penetration into enclosures and interior cablings has been established for the first time. A full NEC wire-grid model of a fighter aircraft is developed and used extensively for simulation in support of theoretical predictions. The variation of interference to cables, antenna-to-antenna coupling, as well as monopole antenna on finite ground are also investigated with implications to airborne environment. Practical results and numerical insights, which are useful for aircraft engineers, are obtained directly on penetrating fields and cable coupling with different plarizations and frequencies both near and off resonance.