Improved Cross-Polarized Radiation and Wide Impedance Bandwidth From Rectangular Microstrip Antenna With Dumbbell-Shaped Defected Patch Surface

Rectangular patch with dumbbell-shaped defected patch surface has been studied theoretically and experimentally to improve polarization purity over wide angular range and broad impedance bandwidth. More than 30 dB co- to cross-polarization (CP-XP) ratio over entire angular range around the broadside direction with wide impedance bandwidth is obtained. Moreover, the present structure is free from back radiation in terms of XP fields, and it can efficiently suppress the XP radiation in different diagonal planes. The present structure is very simple and easy to manufacture. The present investigation provides an insightful visualization-based understanding of concurrent improvement in impedance bandwidth and the XP radiation characteristics with the present structure.