Planar Inverted-F Antennas for Mobile Devices: An Empirical Study of the Resonant Frequency

The paper presents empirical formulas for predicting the resonant frequency of planar inverted-F antenna (PIFA). The physical parameters of PIFA including the dimensions and positions of (top) planar element, shorting plate, feed plate, and ground plane, are studied. The influence of various parameters on antenna characteristics (resonant frequency) has been investigated comprehensively using simulation software HFSS. Comparison with existing empirical expressions are provided. We believe these results are useful in the design of PIFA.