Wideband Substrate Integrated Waveguide Fed Circularly Polarized End-Fire Antenna with Tilted Beam

This paper presents a circularly polarized tilted beam end-fire antenna at the 60-GHz band. By exciting the antenna at different ports, the proposed pair of loop-based radiator creates tilted beam. In addition, with an E-plane 90° hybrid coupler in the middle of a two-layer substrate, it obtains wideband circularly polarization compared with radiator only. Numerically, this antenna achieves good performance that overlapping impedance and axial ratio (AR) bandwidth is about 21.3% from 52.5 to 65 GHz with an end-fire right-handed circular polarization (RHCP) gain varying from 2.43 to 4.03 dBic.