Narrowband and Wideband Directional Beamformer with Reduced Side Lobe Level

Abstract

In this paper, the synthesis of narrow and wideband beamformers with reduced side lobe level and wide beam steering capability is presented. A closed form expression with slope equalization technique is derived for array factor of the beamformer to meet the desired beam-pattern specifications of Half Power Beam-Width (HPBW)and Side Lobe Level (SLL). The proposed beamformer design is adaptable to any bandwidth and null placement in the desired direction. The slope equalization method improves the SLL of the beamformer. Compared to Kaiser, Chebyshev, DPSS and Taylor beamformers, the proposed narrowband and wideband beamformers exhibit lower and tapered side lobes, hence improved First Null to Last Null (FNLN)ratio. The proposed wideband beamformer exhibits superior performance in the wideband frequency range of 1-3GHz.