This paper describes a new antenna to realize the directional radiation of high-power microwave-helical array antenna fed from double-layer radial waveguide.The feed wire of each helix is connected with an H-coupled probe inserted into a radial waveguide

and excited by a TEM wave between the two parallel plates of the waveguide.Helices and probes are arranged on the upper plate to form a circular array.This antenna accepts directly an azimuthally symmetric output of a HPM source and radiates a high-gain pattern with a boresight peak.The use of H-coupled probes makes the array antenna compatible with the intense electric fields associated with high-power microwave sources.In addition

the array antenna has a simple structure and can project circular polarized electric field.In this paper

the fundamental theory of function is presented;an array antenna for a frequency band of 3.8GHz to 4.2GHz is designed and simulated.At 4.0GHz

the calculated aperture efficiency shows a high value of 72.3% and the axial ratio value at the normal direction is of 1.55.In the range of 3.8GHz to 4.2GHz

the aperture efficiency is over 69% and the axial ratio is below 1.7.