Dual Band, Dual Sense Circular Polarized Antenna for Sub-6G Band

A dual-band, dual-sense circularly polarized (CP) crossed dipole antenna is proposed. The proposed antenna consists of two dipole antennas, with 180-degree passive phase shifter and phase compensation line incorporated into it. Conventional dipole antenna radiates circular polarization when the amplitude of the orthogonal waves is equal with a quadrature phase difference. In this work, narrowband 180-degree phase shifters are introduced to offset phase difference and change polarization sense in specified operating band of the antenna. Measured axial ratio bandwidth are 7.1% over 3.09-3.32 GHz for left-handed CP and 10.1% over 4.94-5.47 GHz for right-handed CP. Measured gain above 2 dBic in both operating bands validates dual-band, dual sense characteristic of the proposed CP antenna.