A NOVEL WIDE BAND AND BROAD BEAMWIDTH CIRCULARLY POLARIZED ANTENNA

Abstract

A novel printed crossed dipole with broad axial ratio (AR) bandwidth and enhanced beamwidth is proposed. the proposed antenna consists of two dipoles crossed through a 90° phase delay line, which produces one minimum AR point due to the sequentially rotated configuration and 4 parasitic ring loops, which generate one additional minimum AR point. By combining these two minimum AR points, the proposed dipole achieves a broadband circularly polarized (CP) performance. under the dipoles are 8 erect parasitical monopoles and a reflector, which are placed to broaden the beamwidth. the proposed antenna has not only a broad 3 db AR bandwidth of 9.84% (155 MHz, 1.495–1.650 GHz) with respect to the CP center frequency 1.575 GHz, but also a broad 3 db beamwidth of about 180. this paper deals with the designs and experimental results of the proposed crossed dipole with parasitic ring loops and erect monopoles.