Experimental investigation of polarization diversity

Polarization diversity is an interesting alternative to space diversity, but the channel characteristics need to be investigated. To evaluate the dual polarized channels, a 2times2 multiple-input-multiple-output (MIMO) wireless testbed has been developed. In addition, a dual polarized microstrip patch antenna array has been designed to be used as the transmitter and receiver in this system. Performance evaluation has been based on symbol error rate (SER) and channel gain. Channel measurements were conducted in line-of-sight (LOS) and non-line-of-sight (NLOS) indoor office environments. The results indicate that the dual polarized patch antennas are either comparable or better than the spatially separated patch antennas in terms of SER. The channel gains are more beneficial for vertical polarization in LOS and horizontal polarization in NLOS, but in both environments the dual polarized combination performs in between the space diversity schemes. Thus, if the receiver location changes environments, polarization diversity will yield favorable results.