Compact base station antennas using meta-materials

Abstract

The paper deals with the modelling, practical implementa- tion and characterization of a directional antenna controllable through 360° in the [2-2.5 GHz] frequency band. The antenna is composed of a central omnidirectional broadband monopole feed surrounded by a metamaterial made of one or two controllable layers of metallic strips printed on a dielectric substrate, which can be electrically continuous or discontinuous. Following the electrical state of these strips, the metamaterial can be reflective or transparent. Then by controlling the distribution of reflective and transparent regions of the latter metama- terial around the central feed, a directional emission having an angular beamwidth lower or equal to 60° and controllable through 360° is pro- duced in the UMTS and WIFI frequency bands, demonstrating the wideband operation of this antenna.