Multi-Radiating-Element Printed Inverted-F Antenna With Independent Resonant Frequencies for Bandwidth Enhancement

This letter demonstrates a simple yet very effective method of bandwidth enhancement for popular printed inverted-F antennas (PIFAs). An additional radiating element is printed on the other side of the substrate, on the same side as the partially modified ground plane. Together with the primary radiating element, these provide different three electrical paths. The bandwidth of the antenna can be enhanced substantially by optimally locating the corresponding resonant frequencies. Most of all, each of the three radiators has negligible effect on the performance of the other two radiators, implying that they can be designed independently. While maintaining the far-field radiation patterns, as much as 12.6% increase in the relative bandwidth over the 7.0% bandwidth of a conventional PIFA is demonstrated.