High capacity antennas for MIMO radio systems

The capacity of radio systems with multiple-transmit and multiple-receive antennas may be improved by antenna arrangements which reduce the effective Rician factor. Channel measurements indicate that the capacity in indoor environments may then be close to the independent Rayleigh fading channel even for large numbers of antennas. High capacities may be achieved with such antennas also in outdoor environments. Experiments in the same scenarios indicate significant improvements compared to patch arrays with an element spacing of λ/2.