Effects of Unbalanced Currents on Mutual Coupling of Orthogonal Dipole Antennas

Abstract

In this paper, the effects of unbalanced currents on mutual coupling of two orthogonally and closely placed dipole antennas are investigated. Two orthogonal dipoles usually have low mutual coupling but the isolation between them deteriorates seriously when their relative position changes. The worst case has only an isolation of 8.2 dB but the underlined physics are not well disclosed. In this paper, it is revealed that mutual coupling of the orthogonally dipole antennas is mainly attributed to the appearance of unbalanced currents on the surface of antennas. The full-wave results verify the discovered phenomenon in this paper.