Optimized Design of Constant Beamwidth Beamformer Using Interpolated Nested Arrays

This paper proposes an optimized design procedure of wideband constant beam width beam former (WCBB) using interpolated nested arrays. With the incorporation of harmonic nesting and array interpolation, a nearly frequency invariant characteristic covering multiple octaves is achieved with compact array size, smaller number of elements and an improved array directivity, which is more favorable for the application of vessel radiated noise measurement. The WCBB is implemented in the frequency domain using the FFT and frequency dependent weighting. A representative design example is presented to demonstrate the improved beam forming performance in the far-field condition.