Miniaturized circularly polarized patch antenna by substrate integrated irregular ground

This paper presents a novel miniaturized circularly polarized (CP) patch antenna by introducing an irregular ground structure to provide capacitive and inductive loading to the patch. A pair of metallic walls is assigned at each corner individually. The metallic walls located underneath the patch, are constructed within the microwave substrate by connected vias. With the presence of these walls, the substrate integrated irregular ground structure is formed. To excite a CP operation, a square patch with unbalanced tails is proposed. The antenna works at 3.24GHz. It finds a significant size reduction by the capacitive and inductive loading effect. A total area reduction of 86% is achieved experimentally comparing with a traditional half-wavelength square patch antenna.