Microstrip Patch With Nonproximal Symmetric Defected Ground Structure (DGS) for Improved Cross-Polarization Properties over Principal Radiation Planes

A symmetric as well as nonproximal defected ground structure has been conceived for a square microstrip patch to achieve high co- to cross-polarized (XP) isolation over the principal radiation planes. This design does not follow the thumb rule of earlier works where the defect was deployed either underneath or in close proximity to the patch boundary. The proposed configuration, therefore, appears to be ideal for some specific applications, such as dual-polarized or circularly polarized patches with improved polarization purity. A representative design in C-band has been discussed, leading to the proof of concept. Experimental verification confirms up to 8-10 dB improvement in XP level, particularly in the H-plane.