A Size-Reduced, Circularly Polarized, Log-Periodic Dipole Array

A single-feed, circularly polarized, log-periodic dipole array (CPLPDA) with size-reduced cross-dipole elements is proposed. Size reduction in elements is achieved with curved, T-shaped top loading. Compared with the full-sized CPLPDA elements, the achieved element-length reduction is 50%. With six elements, the antenna shows a −10 dB impedance bandwidth (IBW) of 87.0% and a 3 dB axial ratio bandwidth (ARBW) of 50.0% in measurement. The common bandwidth (CBW) between the −10 dB IBW and 3 dB ARBW of the CPLPDA is 50.0%. The peak realized gain in the direction of the shortest element is 6.60 dBi over the CBW.