Modeling and Calculation of Coupling Between Antenna on Aircraft by Calculation of Geodesic

Antennas that are installed on the aircraft, must have minimum mutual coupling so that the function of the transmitter and receiver will not be interfered. For coupling calculation, we must obtain wave pass from transmitter antenna to receiver antenna. In case that antennas are LOS, this pass is a direct pass. But in case that antennas are NLOS, a kind of surface wave causes mutual coupling. The best way for calculation of coupling is through obtaining geodesics. Then by calculation of surface loss, we can get the amount of coupling. if the aircraft is modeled with a cylinder, calculation of geodesics is easy and practical. the advantage of this approximation is that we can extend it for any aircrafts with cylindrical fuselages. in this approximation, the effect of obstacles and diffraction in edges is not considered. in this paper, results of mutual coupling calculation, results of simulation as well as the measured data is compared in approximated model of the aircraft. It will finally be shown that in the worst case, calculation results are not greater than 15db.