Performance analysis of orbital angular momentum(OAM) transmission using dual polarization antenna based uniform circular array architecture

Communication exploiting orbital angular momentum(OAM) was proposed recently to improve transmission performance while the method utilizing spin angular momentum(SAM) was researched actively already. A dual polarization antenna is a typical example using SAM. Taking advantage of OAM transmission, multiplexing gain can be achieved by transmitting multi-modes of OAM in line of sight(LOS) environment. To exploit OAM in radio frequency domain, uniform circular array(UCA) architecture assigning signals with different phase to each antenna was proposed to generate OAM carrying beam. However, only single polarization antenna was considered in existing research, so there is a limitation to increase channel capacity. Also, conventional research only considered ideal antennas that radiate isotropically, which are not much practical. In this paper, we propose a new system utilizing both OAM and SAM by using practical dual polarization antenna based UCA architecture to increase the channel capacity. Then, a receive array is located at off-axis to apply practical environment. The channel capacity according to the distance between transmit and receive array called T-R distance is investigated to analyze the performance of proposed system for three antenna configurations that are vertical polarization, horizontal polarization and dual polarization antenna configuration. Furthermore, bit error rate(BER) performances are observed for each antenna configuration.