A Wideband High-frequency Circularly Polarized Cross-Dipole Antenna

A novel wideband circularly polarized (CP) dipole antenna operated at high-frequency band is proposed in this paper. In contrast to the traditional cross-dipole antennas which are operated at low frequency with coaxial feed and reflective cavity, the proposed cross dipole is designed on a double layered dielectric substrate and fed by the centered via on the substrate. This design contributes to the improvement of radiation performance of the dipole at high-frequency. For a more effective excitation of CP radiation pattern, a curved-delay line is attached at the corners of the sequentially rotated elements to provide an orthogonal phase difference. Through proper selection of the radius of curved-delay line and optimization of the structural parameters, impedance matching over wide-band range can be realized. The simulation results prove that the proposed antenna shows a good CP characteristics and wide bandwidth. The impedance bandwidth and the 3dB AR bandwidth are 31.58% (16∼22 GHz) and 7.14% (18.9∼20.3 GHz), respectively.