A wideband planar pattern reconfigurable antenna for IEEE 802.11ac WLAN applications

Abstract

A novel planar pattern reconfigurable antenna is presented. The proposed antenna consists of four identical antenna elements distributed at different positions on a F4B255 substrate forming a cross shape. Each antenna element is composed of a direct fed magnetic dipole with bow tie shape and four coupling fed magnetic dipoles with rectangular shape which achieves wide bandwidth and titled radiation pattern. The ground plane under each antenna element is etched with taper shape to reduce the coupling among antenna elements. The four antenna elements are linked to and fed by one port via a step shaped metal strip on the ground plane and radiation layer, respectively. A PIN diode is mounted in each strip to switch the connection/disconnection of each antenna element with the feeding port. Pattern reconfiguration is obtained by electrically choosing the excitation of each antenna element. The proposed antenna operates in four states with four steerable beam directions of θ = ±45° in both xoz and yoz planes. The measured common bandwidth for the four states is 5.15–5.93 GHz and the measured gain ranges from 6.14 to 8.45 dBi for four states within the bandwidth. The proposed antenna has a low profile and wide bandwidth which makes it a good candidate of micro base station for IEEE 802.11ac Wireless Local Area Network (WLAN) (5.15–5.85 GHz) applications.