Characteristic Mode Cancellation for Radiation Pattern Decoupling of Asymmetric Dipole Antennas

1 × 2 asymmectric dipole antennas with radiation pattern decoupling (RPD) characteristic are presented in this paper. These two dipole antennas are connected by a cross shaped strip. Characteristic mode analysis (CMA) is used to analyze and design this kind of antenna. Observed with CMA, a pair of common and differential characteristic modes superposed together to obtain little current distribution under the coupled dipole antenna. Therefore, RPD characteristic can be realized with high isolation. To verify the concept, a prototype is designed, fabricated, and measured, with good agreement observed. A measured 22.5% 10-dB impedance bandwidth can be obtained, over which the measured isolation is higher than 23 dB. It should be mentioned that RPD effect can be found over entire impedance band, which is highly desired for practical applications.