Aperture Sampling Limitations of Linear and Circular Arrays for Direction Finding and Nulling

摘要

Is there an upper limit to the number of elements or, equivalently, samples, that can be usefully employed for direction finding or nulling a set of incoming wavefronts within a fixed size aperture. Mathematical theory states that this number is unlimited, but this result requires a perfect knowledge of the wavefront correlation matrix (i.e., a noise- and error-free environment) and infinite precision. To answer the question realistically, one must consider the element-to-element correlation matrix resulting from a set of incoming wavefronts impinging on an array of antenna elements. This matrix becomes ill- conditioned as the number of elements within the aperture increases.