Edinburgh Napier University

  An extension of the planar inverted F-antenna (PIFA) concept is proposed, combining two such antennas (one of them fed parasitically) to extend the usable bandwidth to cover the WiFi wireless local area network, worldwide interoperability for microwave access and lower-band ultra wideband spectra. The broad impedance bandwidth is achieved by combining a driven slotted PIFA, having bandwidth-enhanced rectangular strip feed, with a parasitic inverted F-shaped element, hence describable as a dual PIFA. The geometry parameters of these two radiators are selected to enhance the impedance bandwidth and hence to encompass the entire required set of operating frequency bands. The overall optimised dimensions of the antenna are 30 mm × 15 mm × 8 mm, thus making it compatible with installation on portable wireless electronic devices. The results show that the proposed antenna can achieve a gain between 2.0 and 4.0 dBi across the entire impedance bandwidth 2.4-6.2 GHz (i.e. 88.4% relative bandwidth) for a reflection coefficient of |S 11 | , 210 dB. The radiation patterns of the antenna show low-gain broad-beam coverage, as is essential for a wireless electronic device. Computed and experimental results are compared and are shown to be in satisfactory agreement.