Circularly polarized reconfigurable patch antenna using Y-branched feed circuit

This paper is devoted to a circularly polarized patch antenna with the Y-branch feeding structure for switching circular polarization (CP) between left-hand CP (LHCP) and right-hand CP (RHCP). In this structure, the feed circuit is installed behind the ground plane because the electromagnetic distribution on the feeding line has no effect on the radiation pattern. In addition, the slot coupled structure is adopted to avoid a complicated manufacturing process like via-hole structures resulting in ease of fabrication of multi-layered structure. This provides an interest for us in the effect of the slot structure on cross-polarization discrimination (XPD) because we need two adjacent slots in the present structure.