Miniaturized Four-Element Diversity PIFA

In this letter, two very compact designs of miniaturized four-element planar inverted-F antennas (PIFAs) are proposed for 2.45 GHz multiple-input-multiple-output (MIMO) applications. The first configuration exhibits pattern diversity, while the second exploits hybrid pattern and polarization diversity. Both the configurations are designed over a small ground plane measuring 105 × 55 mm ² in area, while each antenna element occupies a volume of only 0.455 cm³. Diversity performance criteria, namely envelope correlation coefficient (ECC) and mean effective gain (MEG), are studied. Effective diversity gain (EDG) using maximal ratio combining (MRC) and selection combining (SC) are then derived for a Rayleigh fading environment. The diversity gains are also measured in the reverberation chamber, which emulates Rayleigh fading, and show excellent agreement with the analytical results. In addition, MIMO channel capacities measured in the chamber depict how robust and efficient the two multiantenna configurations are in the rich scattering environment .