Study of Folded Reflector Multibeam Antenna With Dielectric Rods as Primary Source

Based on a folded reflectarray antenna, a three-beam antenna is investigated using dielectric rods as primary feed placed in open-ended waveguides for obtaining an optimal illumination on the reflector. The performances for a dielectric rod and a combination of three rods are investigated using Ansoft HFSS software. In a first step, dielectric rods have been manufactured and measured at 77 GHz. In a second step, they are used as primary feed of the reflectarray. The corresponding shift of the phase center caused by the rods has been estimated in simulation and accounted for in the antenna arrangement. The radiation pattern measurements show a gain improvement of 2 dB.