Multiple-input multiple-output wireless communication systems using antenna pattern diversity

Multiple-input multiple-output (MIMO) wireless communication systems employ multiple transmit and multiple receive antennas to obtain significant improvement in channel capacity. However, the capacity is limited by the correlation of subchannels in non-ideal scattering environments. In this paper, we investigate MIMO systems that use antennas with dissimilar radiation patterns to introduce decorrelation, hence increasing channel capacity. We develop a ray tracing model that takes into account both the propagation channel and the transmit and receive antenna patterns. Using a computational electromagnetic simulator, we show that: (1) MIMO systems that exploit antenna pattern diversity allow for improvement over dual-polarized antenna systems; and (2) the capacity increase of such MIMO systems depends on the characteristics of the scattering environment.