A Low-Profile Circularly Polarized Cross-Dipole Antenna With AMC Reflector

A low-profile circularly polarized (CP) cross-dipole antenna utilizing an artificial magnetic conductor (AMC) is presented. The antenna contains a pair of elliptical crossed dipoles, four parasitic patches, an AMC reflector, and metallic posts. A pair of vacant-quarter rings is used to connect the orthogonally placed elliptical dipole arms, producing a 90° phase difference to meet the conditions for achieving CP radiation. The AMC reflector consists of periodic patterns printed on a substrate, a metal ground, and the air layer between them. The metallic posts are used to stabilize the radiation patterns. The antenna has an impedance bandwidth (IBW) of 55.1% (1.63-2.87 GHz), an axial ratio bandwidth (ARBW) of 39.0% (1.88-2.79 GHz) and a profile of $0.12 \lambda_{0}$. The peak gain is 8.44 dBic.