Circularly Polarized One-Sided Directional Slot Antenna With Reflector Metal for 5.8-GHz DSRC Operations

This letter presents a new design for a circularly polarized one-sided directional slot antenna with reflector metal for 5.8-GHz dedicated short-range communications (DSRC) operations. Our proposed antenna was composed of a slot antenna, additional slots, a floating metal layer, and reflector metal. By optimizing the lengths and widths of the slots in the two orthogonal directions, circularly polarized radiation was generated. In order to improve the antenna gain, some slots were attached on the top metal layer, and a floating metal layer was attached to the bottom of the antenna. Moreover, an additional dielectric substrate and reflector metal layer were connected to the back of the antenna. The total antenna size including the reflector metal layer was 22.6 × 22.6 × 6.926 mm
³
. Our proposed antenna was fabricated on an FR4 substrate. The measured impedance bandwidth was 760 MHz from 5.82 to 6.58 GHz, and the measured circularly polarized gain was 4.59 dBic.