Beam Scanning Array Using Spatial Diversity

Abstract

In this work, an array antenna based on antenna spatial diversity is developed. The antenna system contains 16 elements arranged as a linear array. In operation, only four elements are activated via RF switches while others are disconnected. By changing the combination of activated elements, diverse radiation patterns are produced. Array factor patterns calculated from all possible combinations are searched to edit a switching sequence to maximize gains at desired directions. A scanning beam can be therefore synthesized. The beam scanning performance is verified via comparison of computed and measured radiation patterns. In order to minimize the gain differences during scanning, a linear array with non-uniform element spacing is proposed. Although the antenna array developed here is relatively large compared to conventional phased array, it is an attractive alternative because of features such as simple structure, low cost, and low insertion loss.