A SIW Based Millimeter-Wave Slot Antenna with Circular Polarization

A circularly polarized antenna fed with substrate-integrated waveguide (SIW) based on semicircle slot elements for 67GHz is proposed in this paper. By employing aperture coupled method to couple the energy from the bottom layer to the top layer and the low-cost standard printed circuit board technology, the antenna can achieve low profile characteristic. To widen the axial ratio bandwidth and improve the radiation efficiency, two folded rotational symmetric semicircle slots are etched on the copper as the antenna elements. The impedance bandwidth of the proposed antenna is up to 17.5% and 12.8% 3-dB axial ratio bandwidth is achieved. The simulated maximal LHCP gain is 7.2dBi. With the advantages of low-cost, convenience of fabrication and desired performances, the proposed antenna is suitable for the millimeter-wave antenna applications.