Comparison of 2-bitstream Polarization-MIMO Performance of 2 and 4-port Bowtie Antennas for LTE in Random-LOS
Paper in proceedings, 2015
We evaluate the performance of a dual-polarized wideband antenna in terms of polarization-MIMO in Random-LOS for two different modes of operation: 2 and 4-port excited mode. The 2-port mode was obtained by differential excitation of two opposite ports of the 4-port design by using two baluns. The Zero-Forcing receiver throughput is evaluated based on the Probability of Detection of two bitstreams when orthogonal polarizations provide the MIMO subchannels. Assuming a uniform distribution for the Angle of Arrivals and orthogonally polarized waves incident on the antennas, the overall PoD over coverage cones of 30 degrees, 60 degrees and 90 degrees are presented. The 2-bitstream multiplexing MIMO efficiency defined at the 95% Probability of Detection is evaluated for the two modes of operation at different frequencies and for different coverage cones. The 2-bitstream coverage pattern of the antenna for the two modes are plotted over the range of Angles-of-Arrival (AoA), by choosing fixed polarization (horizontal and vertical) for the incoming waves. The coverage pattern is significantly degraded for the 2-port mode, in particular in the middle of the band.
Digital threshold receiver
probabilty of detection