Study On Design Of Multiple Antennas For MIMO Communication

With the enormous development of wireless communications, lots of dependent is coming up to make wireless devices with better performance, bringing in great challenge for quality and speed of wireless communications. As an important part of wireless communication systems, antenna of great performance could provide better quality and higher speed of wireless communications. The adoption of MIMO(multiple input multiple output) scheme can raise communication speed and add to signal capacity with the usage of same frequency sources. The combination of MIMO technology and antenna provides a qualitative leap for current wireless communication. Besides, with the feature of multi-mode of antennas in the present system, the mutual coupling between antennas will make the properties of the antenna system poorer. Thus, it is in great need to design multi-band antenna elements and arrays for MIMO systems. The main study content of the thesis is showing below:The thesis describes the background and the significance about our research, and this thesis expounds the necessity of improving isolation in MIMO communications. Moreover, it introduces the fundamental theory of MIMO system, and the decoupling methods widely used in MIMO technology are also given in detail in this thesis.In this thesis, the design of a dual-band MIMO antenna for mobile communication has been studied. Three MIMO antenna arrays with good performance are proposed, based on the research and analysis of MIMO fundamental mechanism of antenna and decoupling.1?A dual-band PIFA antenna MIMO array. It combines the structure of PIFA antenna and the slotting technology, designing two kinds of dual-band antenna, which could cover WLAN and Wi MAX band respectively. The MIMO array is composed of six PIFA elements, with the inverse p-stub and T-stub placing between antennas, achieving the isolation enhanced in the MIMO system.2?A dual-band magneto-electric dipole antenna MIMO array. It designs a dual-band magneto-electric dipole antenna, covering WLAN and Wi MAX band respectively, based on the structure and working principle of magneto-electric antenna. The MIMO array is composed of six dual-band magneto-electric dipole antennas with polarization diversity technology and placed perpendicular every adjacent two, which enhances the isolation between antennas in the MIMO system.3?A dual-band dipole antenna MIMO array with high gain. It consists of six dual-band dipole antennas, applying polarization diversity between every two adjacent elements, demonstrating good isolation performance. It also provides a dual-band artificial magnetic conductor(AMC), and the periodical AMC surfaces are introduced underneath the dipole elements to achieve a unidirectional radiation, high gain and low profile.