An improved hat-shaped cavity-backed Archimedean spiral antenna

A novel Archimedean spiral antenna is designed and researched. The antenna is configured with a hat-shaped reflecting cavity and chip-resistor loads to improve the half power beam width and axial ratio. In the paper, the designing methodology and theoretical analysis are presented. The results show that the antenna has the broad beam width that more than 80° and low axial ratio that less than 4dB. They are better than those of traditional abnormal cavity-backed Archimedean spiral antennas. The designed antenna can be used in the ultra-wideband communication system on the mobile carrier.