Compact Circularly Polarized SIW Cavity-Backed Antenna Based on Slot SRR

A circularly polarized (CP) substrate integrated waveguide (SIW) cavity-backed antenna based on slot split ring resonator is proposed. The circularly polarized wave is generated by a split ring-slot etched in the upper metal layer of SIW cavity resonator. A simple coaxial probe is employed to excite this slot split ring resonator and radiate left-handed circularly polarized (LHCP) wave. The proposed antenna retains the advantages of both conventional planar antennas and metallic cavity backed antennas, including compact sizes of 14x14 mm(2), light weight, easy low cost fabrication and high gain, low cross polarized level. It is experimentally proved that an impedance bandwidth of 10.5% for the reflection coefficient less than 10 dB, the axial ratio (AR) bandwidth of 2.06% for AR less than 3 dB, and the LHCP gain 5.2 dBi has been obtained..