An eight-ring radial helical array antenna based on a novel slot-coupled structure is designed and simulated. The novel coupling structure has the advantages of high power-handling capacity and excellent coupling ability. The simulation results of the array antenna agree well with theoretical calculations, and the aperture efficiency is about 78.1% when the beam is in the normal direction. The power-handling capacity is about 100 MW on vacuum condition. The simulation results also show that the gain is 30.7 dB and the main lobe’s axial ratio is 0.25 dB. Furthermore, the structure of the antenna is compact, and it may be applied to larger circular helical arrays to realize higher gain and higher power-handling capacity.
