Mutual coupling between two identical planar inverted-F antennas

The planar inverted-F antenna (PIFA) is widely used for cellular telephones due to its compactness and size. The objective of this paper is to present the results of numerical investigations of the coupling between two equal PIFA antennas. To analyse the antenna, the method of moment computer program, IE3D, was used to predict the performance of the antennas in terms of the scattering parameters. The simulated results for the PIFA located above a finite ground plane are compared to the corresponding experimental results to show the validity of this approach. Symmetrical as well as unsymmetrical coupling scenarios using two identical PIFA located close to each other are investigated in order to determine the mutual coupling versus distance for fixed orientations, and mutual coupling versus rotation of the antennas for fixed distance. The results illustrate that the orientation and the location could be optimised to obtain minimum coupling.