CSRR Loaded Microstrip Array Antenna With Low Sidelobe Level

A novel technique for obtaining low sidelobes pattern in a planar microstrip array antenna is proposed. This technique involves the addition of two external complementary split ring resonators (CSRRs) at both the ends of each row of the antenna in the ground plane. These two CSRRs together produce an interferometer pattern for the reduction of sidelobes. An 8×4 planar array at 9.9 GHz is designed and fabricated to demonstrate the concept and a sidelobe reduction of 4.3 dB achieved.