Interpolation beamforming with a bent array

An interpolation beamformer (IBF) may be defined as a line-array beamformer where the output for a given beam is formed from the weighted sum of relatively few Fourier coefficients taken from the (spatial) Fast-Fourier transform of the narrowband data measured across the array. Such an implementation may be computationally efficient. It is the intent of this paper to discuss the application of the method to a bent line array where the weights are chosen to offer both array shading and bend compensation. It will be demonstrated that for reasonable amounts of array curvature the IBF has a beampattern close to the benchmark delay-and-sum beamformer and a rule-of-thumb is given for the number of weights necessary for Kaiser-Bessel shading of a uniform line-array bent into a circular arc of known radius