Analysis of electrical dipole linear array maximum directivity

In this paper, the maximum obtainable directivity of electrical dipole linear arrays has been theoretically investigated. Considering uniformly spaced three- and fourelement arrays, the maximum directivity has been calculated as a function of the inter-element distance. The amplitude and phase weights applied to each array element have been computed using an ad-hoc procedure based on spherical wave expansion (SWE). The obtained results, in accord with the Uzkov´s analysis, show that the directivity increases when the inter-element distance approaches to zero. A maximum simulated directivity of 10.4 and 12.7 dBi has been achieved in the case of the three- and fourelement array, respectively.