A high-power wide beamwidth circularly polarized antenna with lightning protection

A high-power wide beamwidth circularly polarized (CP) antenna with lightning protection is presented. The antenna is designed to operate at 1.41 GHz with a wide beamwidth for airport uses. It consists of four helix antenna elements forming a quadrifilar-helix antenna (QHA), a strip-line feeding network and a lightning rod for lightning protection. The QHA is fed using a high-power feeding network with sequential phase rotation of 90°. The lightning rod is installed at the center of the ground plane on the base of the antenna. Simulation is used to design and study the antenna which is also fabricated with housing for measurement. Simulation and measured results agree well. Results show that the QHA antenna has a hemispherical radiation pattern with a beamwidth of 100° and a CP beamwidth of 109° in elevation.