Correlation Effects on the MIMO Capacity for Conformal Antennas on a Paraboloid

The use of conformal antennas in a MIMO link scenario is investigated. Conformal slotantennas are considered both in the transmitter and the receiver. First, a new modified correlationcoefficient is derived that goes beyond the Clarke coefficient and takes into account the elementradiation pattern. Secondly, a hybrid formulation that accounts for the impact of the mutual couplingand the pattern dependent correlation on the capacity is presented. The mutual coupling for slotsplaced circumferentially on a paraboloid substrate is derived using a rigorous approach based onUniform Theory of Diffraction (UTD). The capacity is evaluated for the case of Rayleigh fadingchannel considering the new pattern dependent correlation coefficient and the conformal antenna mutualcoupling. The planar case is included as a limiting case. It is shown that for conformal antennas on aparaboloid the capacity degradation compared to the planar case is up to 0.5 bps/Hz due to couplingand correlation.