Research on Antenna Altitude Setting of Shore-base Microwave Over-The-Horizon Radar

Evaporation duct can increase radar detection range remarkably. Since this characteristic, the shore-based microwave over-the-horizon radar could be set on islands for sea area having no mountains and far away from main land, which can monitor distant targets on the sea continuously and efficiently. In order to find the best antenna altitude for shore-based microwave radar installed in tropic water island-reefs of Western Pacific, the statistic probability of evaporation duct heights were made and the average detect ranges were simulated for different radar frequency and antenna altitude with marine hydrometeorology data collected in recent 50 years, using the method of predicting radar detection range on the condition of evaporation duct. The Statistical results show that evaporation duct often occurs on the sea of Western Pacific, and the duct heights are always over 10 m. As a result, the average radar detection ranges are well above line-of-sight distance, which means it is very propitious to set shore-based microwave over-the-horizon radar. By comparison, OTH radar of C or X band is more suitable to be fixed on South China Sea than S or Ku band radar. When frequency is about 9 GHz and antenna altitude is at about 10m, the radar would get the furthest detection range.