Analysis of the Finite Array on the Scanning Performance of Phased Array Antennas

Abstract

Modern high performance phased array antennas require large apertures to achieve both high gain and narrow beamwidth. It is not practical to manufacture such large apertures, so the full array is composed of smaller sub-arrays known as line-replaceable units (LRU) which will then be assembled to create the final array. When the radiation patterns of an individual LRU are measured, the array will be in a finite environment. This means that the array will be impacted by edge effects, amongst other factors, which will limit the measured array scanning performance. This project focuses on the use of finite array embedded elements patterns to predict scanning performance in the full array.

First, the fundamentals of scanning array antennas are reviewed. Then, the main impacts of finite size on phased array scanning performance are discussed. In particular, theoretical phased arrays with and without both mutual coupling and diffraction fields will be used to determine the impact these factors have on antenna scanning patterns in the finite environment. The average element pattern is then introduced as a way to accurately predict scanned radiation patterns of a full array using a single element pattern. Individual antenna elements within a finite LRU are then used to reproduce theoretical scanned array patterns along the principle planes. Finally, future work is proposed to further validate the results.