Directive Beam-Steering Patch Antenna Using Adjustable Metamaterial Superstrate

Beam-steering antenna is the ideal solution for a variety of system applications, it is most commonly achieved through using phased array, where phase shifters are used to control the relative of the main-beam. However this technique cannot be used in the mobile terminals which use only single radiation element. In this work we present a high directivity and beam steering antenna using simple printed patch covered by adjustable left handed metamaterial superstrate. The design and simulations are carried out using HFSS software. The adjustable metamaterial is based on double omega shaped unit cell. The antenna used is a probe feed rectangular microstrip patch which operates at X band. An appropriate loading of the metamaterial unit cell, through the use of a varactor diodes, enables to vary the medium index of the superstrate within an interesting range, therefore 30 deflection of the antenna beam is obtained. Furthermore, using metamaterial superstrate, the antenna performance has been improved significantly, indicating that the directivity can achieve 11.31 dBi and the HPBW is about 23 for all beam-steering angles.