Antennas multiple resonance modes are generated by incorporating slots in the patch in shapes such as L,U, E or cross as well as by employing edge perturbations asymmetric openings or parasitic elements. Circular polarization is achieved by exciting two orthogonal modes with equal amplitude and a 90-degree phase difference through a single feed point which is typically realized using techniques such as corner truncation of a square patch diagonal slots or asymmetric slits in the ground plane. Coaxial probe or microstrip line feeding methods are commonly used and the position of the feed plays a critical role in achieving impedance matching and maintaining polarization quality.

@Cem Güler, Thank you so much....