Wideband Circularly Polarized Wide-Beamwidth Antenna Using S-Shaped Dipole

This paper presents a novel circularly polarized (CP) printed antenna with wide bandwidth and wide axial ratio (AR) beamwidth. The presented antenna is realized by bending a linearly polarized dipole into "S" shape with variable line width, which achieves circularly polarized radiation. Key parameters in designing such an "S" antenna are discussed and studied. It is found that this "S" antenna has some similar features to the linear polarized dipole, such as the feeding method, the radiation pattern in some main planes and nearly omnidirectional radiation in one main plane. To verify its performance, a ground plane backed inverted-S antenna is fabricated and characterized. Measured results confirm that the proposed antenna has good CP radiation, wide CP beamwidth from 4 to 6 GHz. The antenna is promising for applications in Global Navigation Satellite Systems (GNSS), and wideband wide-angle-scanning CP phased arrays.