Wideband circularly polarized cross‐dipole antenna with folded ground plane

Abstract

A wideband circularly polarized (CP) cross-dipole antenna with folded ground plane is presented. The antenna consists of an L-shaped stepped patch as driven elements and four rotated L-shaped metallic ground strips as parasitic elements. A sequential phase feeding structure is used to provide 90° phase difference, which is composed of a pair of vacant-quarter printed rings. It is noticed that the four rotated parasitic L-shaped metallic ground strips and ground plane are directly connected to form a folded ground plane instead of the traditional disconnection between parasitic elements and ground plane. By using these elements, multiple CP resonances can be excited to meet the requirement for the wideband CP radiation. The presented antenna shows outstanding CP feature with a broad axial-ratio bandwidth (ARBW) of 85.7% (1.3–3.25 GHz) and a wide impedance bandwidth (IBW) of 100% (0.95–2.85 GHz).