A Compact Circularly Polarized Planar Antenna for Endfire Radiation

A compact endfire planar antenna with circular polarization is proposed. Different from the conventional planar complementary antenna, an integrated design is adopted to realize miniaturization for the proposed antenna. First, vertical polarization is provided by a magnetic dipole based on a substrate integrated waveguide cavity with half mode. Then, another orthogonal polarization is produced by four embedded tapered slots structure. The 90° phase difference is obtained through adjusting the length and position of four tapered slots. Finally, the endfire circularly polarized waves can be radiated. Because of the exquisite arrangement of the embedded tapered slots, a compact size is reached of the proposed antenna. For verifying the idea, the counterpart antenna is designed at 2.4 GHz. The simulated results proved that the proposed antenna can be a suitable compact candidate for various WLAN systems.