Broadband Dual Circularly Polarized Antenna for Millimeter-Wave Communications

This paper presents a broadband dual circularly polarized (CP) antenna for millimeter-Wave (mm-Wave) communications. The fundamental structure consists of a patch antenna loaded with a parasitic patch. Initially, the driven and parasitic patches are truncated, in order to achieve CP radiation. Then, each performance, especially gain flatness, is improved by introducing a “+”-shaped slot in the parasitic patch. Furthermore, to broaden the 3 dB axial ratio (AR) bandwidth, all four parasitic patches, segmented by the “ + “-shaped slot, are also truncated. Finally, the proposed antenna achieves an impedance bandwidth of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$33.2 \%(22.9-32 \text{GHz})$</tex> and a 3 dB AR bandwidth of 30.3 % (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$22.1-30 \text{GHz}$</tex>), with a stable gain response throughout the operating frequency range. This antenna offers advantages such as wide bandwidth, low cost, and ease of integration, making it highly suitable for the requirements of dual-CP antennas in mm-Wave communication systems.