Split Sleeve-Based Cross-Band Decoupling Between Adjacent Dipoles

Balun is usually applied for dipole antennas to obtain balanced currents on arms. However, more serious coupling may be caused by balun for two dipoles operating at adjacent frequency bands. The coupling mechanism between two dipoles with adjacent frequency bands is analyzed in this paper. Finally, a sleeve-based cross-band decoupling method is proposed to increase cross-band isolation. The enhanced total efficiency of the high-band dipole can also be observed.