Dual-Band Circularly Polarized Antenna With Wide Axial Ratio Beamwidths for Upper Hemispherical Coverage

This paper presents a dual-band circularly polarized cross-dipole antenna with wide axial ratio beamwidths for full upper hemispherical coverage for GPS L1 and L2 bands. The antenna has curved radiating arms and a corrugated back cavity to enhance the beamwidth. A wideband hybrid coupler is used to feed the antenna at the two nearby frequency bands. Experimental results show that very wide 3-dB AR beamwidths of over 200° can be obtained, fully covering the upper hemisphere for the two GPS bands.