A ship-borne helical array antenna for maritime satellite communication

The characteristics of a helical array antenna which consists of four axial-mode helical antennas are analyzed and the effect of mutual coupling on the properties of this antenna is examined. It is determined that mutual coupling primarily causes the degradation of the axial ratio in the case of an array antenna composed of short helical antennas. In addition, a ship-borne helical array antenna, with performance characteristics corresponding to a standard-B ship station for the INMARSAT system, is analyzed, and it is found that the degradation of properties due to mutual coupling can be improved by small metallic cylinder rims. Finally, an effective technique is developed for the reduction of fading due to sea surface scattering.