Circularly Polarized Microstrip Patch Antenna Using Artificial Magneto-Dielectric Substrate with Grid Structure

We propose a circularly polarized microstrip patch antenna using artificial magneto-dielectric (AMD) substrate. The proposed antenna has a square patch with dual feeding point using Wilkinson power divider in order to achieve circularly polarized radiation pattern. The AMD substrate is constructed by single sprit ring resonators, which are arrayed in both and directions. The designed antenna has the characteristics of the axial ratio less than 1.7 dB, the peak gain of 0.55 dBic, and the right handed circular polarized radiation pattern at Korea UHF RFID service band. The sizes of the antenna and radiating patch are 100 mm×100 mm×5.2 mm and 65 mm×65 mm (0.199λ×0.199 λ), respectively.