Spatial Correlation Functions in Three-Dimensional APS With $\cos^n\theta$

This letter describes a generalized formula for spatial correlation of three-dimensional incoming waves with an angular power spectrum of cos
ⁿ
θ. Based on the proposed formula, spatial correlation performances at antennas or an antenna array can be approximated by simple computation with closed-form solutions in Cartesian coordinates. The validity of the proposed method is verified numerically.