Aperture synthesis for imaging systems using rectangular boundary arrays

Abstract

A planar antenna array, the elements of which are deployed on the boundary of some finite region in the aperture plane, is known as a boundary array. Such a deployment of array elements can produce a point spread function with a narrow mainlobe, but this type of deployment also results in high sidelobes. Because of the potential for high resolution from a small number of array elements inherent in these arays, it is of interest to investigate their use, both in the context of passive (receive-only) imaging of incoherent source distributions and in the context of active (transmit/receive) imaging of coherent source distributions. In recent years, a technique has been proposed for creating the effect of imaging with a filled circular or elliptical aperture using an aperture consisting only of the boundary of the same circular or elliptical region. This technique consists of the addition of multiple images that are formed with different point spread functions to synthesize an image with the desired point spread function, and it is applicable to both active and passive imaging. In this paper, a technique is presented for creating the effect of imaging with a rectangular aperture using only the boundary of that aperture. This technique is also applicable both for active and passive imaging. Also, simulated images are given of small numbers of point targets from the imaging systems discussed. These are used to motivate a discussion of some of the interesting features of the aperture synthesis scheme.