Frequency reconfigurable planar inverted-F antennas for portable wireless devices

In this paper, two approaches for frequency reconfigurable planar inverted F-antennas (PIFAs) are proposed and experimentally studied. In the first PIFA, an electrically-controlled frequency shift is achieved with a tuning circuit designed for the grounded PCB beside the antenna, while in the second PIFA the tuning circuit is integrated directly into the antenna with no separate DC wiring. The measured return losses, radiation patterns and total efficiencies of the antennas are presented and briefly discussed.