An analytical three dimensional correlation model for array with antennas having abitrarily oriented directions

Recent research shows that antenna correlation plays a crucial role in antenna diversity and capacity of MIMO system. In order to obtain lower correlation coefficient many methods have been developed, e. g.. using antennas of orthogonal polarization for transmitter or receiver. But few paper considers the arrays with arbitrarily oriented antennas. In this kind of antenna arrays, each antenna element has a different polarization and radiation pattern. In this paper, we express a closed form correlation function of two arbitrarily oriented antennas. This kind of antenna array will cause lower correlation coefficient then correlation coefficient of z-axis oriented antenna array. Our work gives a correlation formula that has the potential to be used in guiding the antenna array design for enhancing the diversity gain and capacity of MIMO system.