Capacity Stability Analysis for 4-Element Compact MIMO Systems

Abstract

In this paper, both 3-dimentional channel matrix eigenvalue probability distribution and a newly proposed generalized condition number (GCN) are used to analyze the capacity stability of 4-element compact MIMO systems when the mean angle of arrival (AoA) of the incident waves varies in the case that mutual coupling among array elements is considered. Theoretical analysis and numerical simulations show that comparing with the traditional 4-element linear array, 4-element square array with spatially symmetric structure is much less sensitive to the angle of incidence, indicating that the square array can maintain a more stable capacity.