60-GHz Circularly Polarized Annular Patch Antenna Fed by Substrate Integrated Waveguide

Abstract

A low-profile circularly polarized (CP) slot-coupled microstrip annular patch antenna (MPA) excited by substrate integrated waveguide (SIW) is suggested as a building block for large-scale phased arrays used in various millimeter wave wireless technologies. L-shaped slot is used to excite two orthogonal modes of the patch with equal amplitude and 90 degree phase difference. The antenna structure is simulated by the Full-wave EM solver from ANSYS. The antenna exhibits wide impedance bandwidth (reflection coefficient less than -10 dB) of 57-65 GHz and axial ratio (AR) of less than 3dB in the range of 56-61.7 GHz.