Small circularly polarized patch antenna

This paper presents a novel size reduced circularly polarized (CP) patch antenna by introducing a substrate integrated metallic wall structure to provide capacitive and inductive loading to the patch. Pairs of metallic walls are formed by conducting vias and assigned at four corners underneath the patch. To generate circular polarization, a square patch with unbalanced tails is applied. The antenna works at 3.24 GHz. With the presents of the proposed metallic wall structure, the antenna has a considerable size reduction by the capacitive and inductive loading effect. Comparing with a traditional half-wavelength square patch antenna, the proposed CP antenna has achieved 86% size reduction experimentally.