Compact Circularly Polarized Disc Patch Antenna Designed with Sector Mushroom Structures

A new compact circularly polarized (CP) disc patch antenna is designed with sector mushroom structures operating at 3.5GHz. The disc antenna is made from low permittivity dielectrics but featured with an electrically small patch with a diameter of 0.41λg, which is beyond the 0.58λg limitation for a conventional patch antenna. The relative -10dB impendence bandwidth for the new antenna is 6.5% while the 3dB axial ratio bandwidth is 1.5%. Moreover the metamaterial antenna has a peak CP gain of 5.9dBic. These performances can meet the demand of mobile communication application at 3.5GHz.