4세대 이동통신용 다중대역 MIMO 안테나

Abstract

In this dissertation, multi-band MIMO antennas for next generation wireless communication are proposed. The key performance parameters and the requirements for evaluating various multi-band MIMO antennas are classified. Then, multiband MIMO antenna structures and designs using various mutual coupling reduction techniques such as orthogonally polarized dipole elements, band stop matching circuit, decoupling network, and polarization diversity are implemented and analyzed on various parametric analyses. Even though, the MIMO antenna using orthogonally polarized dipole elements has the best overall performance, the ground size of the MIMO using orthogonally polarized dipole elements is 80 mm × 80 mm, which is larger and wider than that of other MIMO antennas (48 mm × 108 mm). A band stop matching circuit improves the isolation characteristic for a very narrow band, but the resonant frequency and isolation characteristic can be easily controlled by changing the value of an inductor. The third type multiple antenna systems utilizing a decoupling network has the advantage of improving the isolation characteristic between very closely located radiating elements. The decoupling network parameters can be extracted from the magnitude and phase of the measured or simulated S21 values. The performance of the MIMO antenna using polarization diversity is superior to that of other antennas, except for the MIMO antenna using orthogonally polarized dipole elements. In this approach, however, the effect of the hand and head on the antenna performance is critical because the ground plane is working as a part of an antenna. In conclusion, the proposed various multi-band MIMO antennas are suitable candidates for 4G mobile handset application.