Coherent Wide-Band Processing for Arbitrary Array Geometry

We present a new method for coherent wide-band direction finding of far-field sources impinging on a two-dimensional array with a known arbitrary geometry. This method, termed array manifold interpolation (AMI), is based on obtaining the array manifold at a desired frequency f₀ by linear interpolation of the array manifold at a given frequency f. We use a separable representation of the array manifold vector, which separates the array geometry and the frequency f from the direction 0, in order to derive the required array manifold interpolation matrix. The AMI method is practical, computationally efficient, and robust. For the special case of a uniform circular array, we present a fast implementation of the AMI method, which utilizes the FFT algorithm.