Ray tracing studies of multipath fading in the ionospheric HF channel

The total signal of an ionospheric multipath channel can be calculated by superimposing the amplitudes of the different paths with their proper polarisations and phases. The signal of each path suffers loss due to range of propagation, absorption, focusing due large scale inhomogeneities of the ionosphere and polarisation coupling with the receiving antenna. As each of these types of losses and also the phase path length can be calculated in the geometrical optics approximation, the total signal can be found. The present paper investigates the effect of interference due to multipath propagation through an ionospheric channel perturbed by a travelling ionospheric disturbance (TID). Both the multipath fading and the amplitude in the frequency domain of the channel are presented.