An electrically small circularly polarized antenna using a dipole-fed cross spiral antenna

Electrically small antennas that can radiate circularly polarized waves are presented in this paper. The authors have invented planar antennas that can radiate circularly polarized waves with only one port feeding. As the antennas can be used simultaneously for circularly and linearly polarized waves, they are especially attractive for mobile communication devices. Reducing the size of these antennas while maintaining their performance has been our highest aim in recent research. In this paper, adding spiral elements as one of the ways to miniaturize our antenna is suggested. This research focus successfully yielded an electrically small circularly polarized square antenna where the size of a side is 11% or less of its utilizing wavelength and its axial ratio is 3 dB or less at 920MHz.