Suppression of Cross Polarized Radiation for Circular Patch Antenna Using Different Substrates and Defected Ground Structure

The cross-polarization (XP) radiation of probe fed circular patches is investigated. Two different designing examples are presented to analyze the cross-polarization radiation of the probe fed circular patches having conventional ground planes and different dielectric substrates. The proposed antenna experimentally demonstrates how the XP radiation of the patch with conventional ground plane increases with the dielectric constant of the substrate. It is observed that the XP radiation is minimum for optimum feed location. To improve the XP performances, the ground plane of the circular patch is defected with single and dual arc shaped defects beneath the circular patch. The defects on the ground plane are so placed that the XP field reduces without altering the resonant frequency. The impedance bandwidth and gain of the proposed structures for different dielectric constants are studied. Application of the DGS structure offers maximum suppression of the XP radiation of 14.54 dB for FR4 epoxy substrate with the highest impedance bandwidth of 0.43 GHz and maximum gain of 7.56 dB is obtained using Rogers RT/duroid 5870 with optimized DGS structure.