Efficiency Improvement of Handset Antennas by Suppressing Higher-Order Modes

In this work, a method is proposed to improve the radiation efficiency of practical mobile handset antennas by suppressing the higher-order modes within the operating band. The method is based on N-port characteristic mode theory and genetic algorithm. With the optimization, the modal coefficients of the higher-order modes within the operating band are minimized or moved out of the band to mitigate their impact. With the proposed method, antenna efficiency has been improved by 1.27 dB, without changing its main resonances.