Small smart antenna composed of reconfigurable Inverted F-type Antenna

In this paper, a small size electronically steerable parasitic array radiator (ESPAR) antenna composed of six inverted F-type antennas (IFAs) that covers the frequency band from 2.4 to 2.5 GHz is proposed. Each of the IFAs can be reconfigured either as a driven element or a parasitic element equally. The radius of the proposed ESPAR antenna is 11.5 mm, which enables handheld wireless devices such as mobile phone and walkie talkie to employ a smart antenna. Despite its small size, the proposed ESPAR antenna achieves a gain of 3.5 dBi and a front-back ratio of 7 dB. The beam forming can be achieved by tuning the reactive load of varactors on each IFA radiator.