Model and results for single mode PIFA antenna

The paper reviews the planar, inverted-F antenna which offers a low profile radiator capable of bandwidths covering typical cellular system bands. The PIFA is simply half of the usual square patch, where a short circuit is placed along the dividing edge. Although the corresponding square or circular patches are easier to manufacture because they do not require the short circuited edge, they use twice the cavity volume and so, in practice, have a higher Q for single feeds. A transmission model is derived from the cavity physics in the usual manner (Vaughan, R.G. and Andersen, J.B., "Channels, Propagation and Antennas for Mobile Communications", Peregrinus/IEEE, 2003). It has a principal transmission line for the end slot and also has parallel lines for the side slots. Including the side slots makes a significant difference to the impedance behaviour. Experimental results for the impedance confirm the model as suitable for narrowband design.