A Wideband Endfire Dual Circularly Polarized Antenna for 5G Millimeter-Wave Applications

In this letter, an all-metallized wideband dual circularly polarized antenna with endfire radiation is proposed for fifth-generation (5G) millimeter-wave applications. By introducing two rectangular notches on the side walls of open-ended waveguide, the vertical components are increased and close to the horizontal components in the broadband range so that the axial ratio (AR) bandwidth is enhanced. The simulated results show that the proposed antenna excited by wave port has 63.9% operation bandwidth (22.7-44.0 GHz), where reflection coefficients less than -10 dB, isolations greater than 20 dB, and AR less than 3 dB are achieved. To verify the design, the proposed antenna excited by coaxial connectors is fabricated and measured. Based on the measurement results, the reflection coefficients less than -10 dB, isolations greater than 20 dB, and AR less than 3 dB are achieved from 23.0-40.0 GHz, the endfire gain varies from 5.1 to 8.5 dBic at the frequencies mentioned above.