A low-profile, wideband circularly polarized curl antenna backed by a polarization dependent reflector

The use of polarization dependent high impedance surface (PDHIS) as a reflector for a curl antenna, that can miniaturize the size and significantly enhance the axial ratio bandwidth of the curl antenna is presented. High impedance surfaces are able to exhibit interesting in-phase reflection and polarization-dependent (PD) characteristics. This paper describes a novel application of the PDHIS reflector built by microstrip technology as a ground plane for the curl antenna. As a consequence, for the curl antenna backed by a PD reflector, a 10% increases in 3-dB axial ratio bandwidth and about a quarter wavelength reduction in total size are achieved as compared to the curl antenna backed by a PEC reflector.