Analysis and design of a four-element superdirective compact dipole antenna array

Abstract

This paper presents the design, optimization and experimental characterization of a four-element superdirective array based on a folded meandered dipole element. The proposed array is composed of an active and three parasitic elements. The optimal impedance loads associated to each parasitic elements have been extracted using an ad-hoc synthesis method based on spherical wave expansion. In order to optimize the realized gain, a printed balun has been integrated on the active element. A maximum directivity of 10.0 dBi and a realized gain equal to 0.82 dBi have been respectively demonstrated at 861 MHz when the element spacing is fixed to 0.15λο.