Study and Analysis of Distribution Pattern of Electromagnetic Field from HF-VHF Antennas Onboard Combat Vehicle Turret Surface

Abstract

Multi radio sets operating in different frequency ranges, different modulation modes, different transmitter power levels and with very high sensitivity receivers operating nearby in same vehicular platforms in particular, Combat tracked vehicles encounter serious electromagnetic interference [EMI] problems both from vehicle electronic packages [subsystems] and from radio set antennas as mutual interference coupling. In order to understand the type of EMI coupling, to resolve and implement appropriate EMI suppression measures, this study/survey was carried out .Radiated EM field emitted from HF and VHF Communication antennas distributed over the vehicle turret surface is studied in this paper. Computed values by simple approximation, using exact formula are presented along with 2D/3D simulation results by FEKO software solving the Maxwell`s equations to understand the probable radiated coupling between emitters and receptors situated [both outside and inside turret] , besides identifying the pattern of EM field distribution from the RF field mapping generated over the vehicle turret surface . This distribution study is very useful to locate antennas outside vehicle and also estimate immunity level to inside electronic equipments (to meet Mil-Std immunity levels) as the outer skin of vehicle le armour plate provides the EM shielding. Actually measured values of field strength assist the entire process.