Mitigating High Cross-Polarized Radiation Issues Over the Diagonal Planes of Microstrip Patches

Complex nature and source of high cross-polarized (XP) radiations over the diagonal planes of microstrip patches have been addressed. A strategic solution using defected ground structure (DGS) has been conceived for the first time to mitigate this specific issue. A systematic design approach based on theoretical understanding has been successfully demonstrated for rectangular patch geometry. Thorough examination with C-band patches bearing varied length-to-width ratio promises an improvement of 5-8 dB across all skewed planes. They are experimentally verified using two sets of prototypes. The design provides co-to-cross polar isolation of about 25 dB across the diagonal planes and nearly 28 dB over H-plane. Improvement of XP isolation irrespective of the radiation plane by more than 8 dB compared with a conventional patch has been ensured without affecting the primary radiations. This design should initiate exploring newer and more efficient versions in the near future for useful applications especially in large microstrip arrays.