Wide-Beam Circularly Polarized Crossed Scythe-Shaped Dipoles for Global Navigation Satellite Systems

Ta, Son Xuat; Han, Jea Jin; Park, Ikmo; Ziolkowski, Richard W.

doi:2013.13.4.224

J. Electromagn. Eng. Sci > Volume 13(4); 2013 > Article

Journal of Electromagnetic Engineering and Science 2013;13(4):224-232.
DOI: https://doi.org/10.5515/JKIEES.2013.13.4.224

Wide-Beam Circularly Polarized Crossed Scythe-Shaped Dipoles for Global Navigation Satellite Systems

Son Xuat Ta¹, Jea Jin Han¹, Ikmo Park¹, Richard W. Ziolkowski²

¹Department of Electrical and Computer Engineering, Ajou University
²Department of Electrical and Computer Engineering, University of Arizona

Abstract

This paper describes composite cavity-backed crossed scythe-shaped dipoles with wide-beam circularly polarized (CP) radiation for use in Global Navigation Satellite Systems. Each branch of the dipole arm contains a meander line, with the end shaped like a scythe to achieve a significant reduction in the size of the radiator. For dual-band operation, each dipole arm is divided into two branches of different lengths. The dipoles are crossed through a $90^{circ}$ phase delay line of a vacant-quarter printed ring to achieve CP radiation. The crossed dipoles are incorporated with a cavity-backed reflector to make the CP radiation unidirectional and to improve the CP radiation beamwidth. The proposed antennas have broad impedance matching and 3-dB axial ratio bandwidths, as well as right-hand CP radiation with a wide-beamwidth and high front-to-back ratio.

Key words: Cavity-Backed Reflector, Circular Polarization, Meander Line, Phase Delay Line, Scythe Shape