Low Sidelobe Level CSRR Loaded Weighted Array Antenna

Abstract

A novel complementary split-ring resonator (CSRR) loaded amplitude tapering technique is proposed to create a low sidelobe level array antenna. Low sidelobe levels are realized by loading single, double, and hybrid CSRRs couplets, in the ground plane of a uniformly excited array antenna. Design curves are created for various amplitude taper values to achieve low sidelobe levels. Amplitude tapering is accomplished by varying CSRRs parameters in the ground plane of the array. The method is demonstrated on a $6 \times 2$ rectangular microstrip patch array antenna configuration operating at a center frequency of 10.9 GHz. Three array configurations incorporating single CSRRs couplets, double CSRRs couplets, and hybrid (combination of single and double CSRR couplets) CSRRs couplets are analyzed to create low sidelobe level array. Single CSRR couplet loaded configuration exhibits a measured first sidelobe level of 24 dB and second sidelobe level of 19.5 dB. Hybrid CSRR couplet loaded array antenna provides the first sidelobe level of 23 dB and the second sidelobe level of 25 dB. Measured gain of the proposed antenna at 10.9 GHz is 16.1 dB. The proposed method exhibits an improvement of nearly 10 and 4 dB of first and second sidelobe suppressions, respectively.