P. Das, Deepak A, Nithin V, S. Kundu
• A dual band circularly polarized antipodal Vivaldi antenna loaded with a non-uniform array of circular polarizer-based unit cells is proposed for exhibiting planar chirality. • Better signal reception and less susceptibility to antenna direction are the main benefits of circularly polarized (CP) Ground Penetrating Radar (GPR) antennas over linearly polarized (LP) ones. • The proposed antenna does not operate as a classical end-fire Vivaldi. Broadside radiation is caused due to metasurface loading due to presence of circulating surface currents induced by the proximity of the metasurfaces. • Two different types of transmissive type circular polarizers have been loaded on the top and bottom layer of the antenna for transforming the incident LP waves into CP waves in two frequency bands 5-7 GHz and 13.8-15 GHz. • Circular polarizer I is designed to transform LP to CP waves in the frequency range 6.4-7.6 GHz. Circular polarizer II is designed to transform LP to CP waves in the frequency range 15.2-16.2 GHz. • The proposed antipodal Vivaldi antenna exhibits a wide impedance bandwidth ranging from 1.7-40 GHz. • The proposed CP antenna can be used for subsurface scanning for detection of buried objects. This work reports the formation of a dual band circularly polarized antipodal Vivaldi antenna by loading it with a non-uniform array of circular polarizer-based unit cells which exhibit planar chirality. Better signal reception and less susceptibility to antenna direction are the main benefits of circularly polarized (CP) Ground Penetrating Radar (GPR) antennas over linearly polarized (LP) ones. The proposed antenna does not operate as a classical end-fire Vivaldi. Broadside radiation is caused due to metasurface loading due to presence of circulating surface currents induced by the proximity of the metasurfaces. Two different types of transmissive type circular polarizers have been loaded on the top and bottom layer of the antenna for transforming the incident LP waves into CP waves in two frequency bands 5-7 GHz and 13.8-15 GHz. Circular polarizer I is designed to transform LP to CP waves in the frequency range 6.4-7.6 GHz. Circular polarizer II is designed to transform LP to CP waves in the frequency range 15.2-16.2 GHz. The proposed antipodal Vivaldi antenna exhibits a wide impedance bandwidth ranging from 1.7-40 GHz. The proposed CP antenna is used for subsurface scanning for detection of buried objects. Measured results match closely with simulated results.