The influence of antenna height on microwave propagation in evaporation duct

In this paper, the influence of antenna height on microwave propagation in evaporation duct is investigated, both from numerical simulation and experimental observation. Comparisons of microwave propagation with different antenna heights under different conditions, such as different evaporation duct heights (EDHs) and signal frequencies, are presented. At distinct conditions, the corresponding optimal antenna heights are not the same. When the EDH is low, microwaves cannot be trapped and propagate in the evaporation duct layer. The higher the antenna height, the smaller the path loss. For the case when the evaporation duct can trap microwaves well, a low antenna is more suitable for the propagation of microwaves in the evaporation duct layer. However, the optimal antenna height varies for different EDHs and frequencies. The influence of antenna height on microwave propagation was observed in the experiment held in the northern part of the South China Sea in December 2013. The experiment result shows that under good evaporation duct conditions, the path loss at antenna height 3 m are 10 dB lower in average than that at 6 m.