Four-arm spiral antenna

The invention provides a four-arm spiral antenna. Four radiating lines arranged in a left spiral manner are used as an antenna main body, a gap balun and a phase shift network are adopted to from a feed network, four equivalent-amplitude feed signals with phase difference sequentially being 90 degrees are generated by the phase shift network and are transferred to the four radiating lines by the gap balun, and finally, the four radiating lines emit right-handed circular polarization electromagnetic waves. In the four-arm spiral antenna provided by the invention, the four radiating lines adopt left spiral direction designs, so that the four-arm spiral antenna has favorable wide beam and circular polarization characteristic; and moreover, by the gap balun, the input impedance of the four-arm spiral antenna can be adjusted, and thus, the four-arm spiral antenna has favorable impedance bandwidth. 本发明提供的四臂螺旋天线，采用左螺旋设置的四条辐射线作为天线主体，并采用缝隙巴伦和相移网络构成馈电网络。通过相移网络产生四个相位依次相差90°的等幅馈电信号，并通过缝隙巴伦传递给四条辐射线，最终使四条辐射线发射右旋圆极化电磁波。本发明提