Design of low profile MIMO antennas for mobile handset using characteristic mode theory

Designing highly integrated and efficient MIMO antennas for mobile handset is challenging, especially for low frequency bands below 1 GHz. In this work, by analyzing and manipulating the characteristic modes of a mobile handset, we propose a low profile dual-band MIMO antenna with high integration ability. Both antennas cover a bandwidth of 100 MHz at the center frequency of 0.9 GHz. The isolation between the antennas is over 10 dB, and the envelope correlation is below 0.1, which ensures high efficiency of the antenna system and good MIMO performance.