Mimo Wireless Communication Terminal Multi-antenna Design

The recent and anticipated growth of wireless communication systems has fueled research efforts investigating methods to increase system capacity. Doubtlessly, the rapid advance in technology, on the one hand, and the exploding demand for efficient high-quality services of digital wireless communications, on the other hand, play a dramatic role in this trend. The demand for these services is growing at an extremely rapid pace and these trends are likely to continue for several years. As a promising approach, MIMO systems for wireless communications have demonstrated an ability to provide large capacity gains when used in multipath propagation channels and arouse interest in the communication society. MIMO system generally uses more than two antennas, so multi-antenna design, especially for the compact handheld terminals, become an important yet knotty issue. Because of the restricted space available for the antennas in handheld terminals, it should not only demand compact antenna structures, but also need skillful antenna arrangements to get low envelope correlation between the signals received by any two antennas for efficient MIMO communication. In this thesis, various diversity scheme are reviewed first, also the unify frame of diversity expression is derived, and the polarization diversity performance as well as the mean effective gain (MEG) between the orthogonal polarization antennas are investigated. In chapter 3, the analysis technics for microstrip antenna and various antenna miniaturization method are extensively reviewed. The electromagnetically coupled microstrip feed is simulated and show that it is suit for this multi-antenna designs. In chapter 4, and chapter 5 three type multi-antenna designs suited for handheld terminals and three type multi-antenna for notebook are proposed. The geometry as well as the test results and the diversity performance of proposed multiple-antenna are presented. In chapter 6, the experiment results included the correlation coefficients and SNR are presented when these proposed multi-antennas are used in the MIMO experiment system. The conclusions are drawn at last.