An Empirical Equation for Predicting the Resonant Frequency of Planar Inverted-F Antennas

The planar inverted-F antenna (PIFA) is widely used in mobile systems due to its excellent performance. This letter introduces a new empirical equation for predicting the resonant frequency of PIFA, taking into account all the important parameters that significantly affect the resonant frequency. The comparisons between the new and the previously used empirical equations are provided to show the comparative accuracy of the new equation. The average % error found between the predicted and the actual operational frequencies is less than 3%. This proposed equation should be very useful to aid the PIFA design.