Design of a Simple Circularly Polarized Antenna for Millimeter-Wave Applications

A low-profile right-handed circularly polarized antenna for millimeter-wave applications has been proposed. The planar antenna consists of two substrates with a short-ended substrate integrated waveguide (SIW) obtained in the lower substrate. The electromagnetic wave is excited by SIW and coupled by a rectangular slot etched in the top ground. Furthermore, the circularly polarized wave is generated by printing two mirrored L-shaped dipoles which are connected to the ground plane. Compared with other circularly polarized antennas, the proposed antenna design has the merits of low-profile, broad bandwidth, good circularly polarized performance and easy fabrication. The obtained results can confirm that the proposed antenna has achieved an impedance bandwidth (|S11| ≤ - 10 dB) of 23.6-26.2GHz, the 3-dB axial ratio bandwidth of 24-25.2GHz and a stable realized gain from 3.5-3.9dBi.