A novel filter design for spatially interpolated beamformer

This paper proposes a novel design approach for a linear phase lowpass FIR filter for digital beamformer applications. The simple filter design has good stopband attenuation with the use of trigonometric functions and less filter complexity. Novel slope equalization technique of the filter design reduces ripple at the transition edges of the filter hence further improves its stop band attenuation. Proposed filter replaces Dolph-Chebyshev window in the design of a uniform linear array spatially interpolated beamformer. The resulting beamformer yields narrow main beamwidth and low sidelobe level with reduced complexity. The beamformer provides for precise and independent control of main beamwidth, null to null main beamwidth and sidelobe level.