Research On Compact MIMO Antenna For Mobile Terminal Application

With the rapid development of wireless communication services, the conflictbetween the finite frequency spectrum and communication capacity has been becomingmore and more serious. MIMO (Multiple Input Multiple Output) technology breaksthrough the Shannon capacity limit and can elevate the channel capacity manifoldlywithout additional bandwidth and transmitting power consumptions in a fading channel.Thus MIMO technology has been considered as the revolutionary technology for thenext generation wideband wireless communications.Currently, antenna design is still one of the important factors that make MIMOtechnology difficult to apply in wireless communication systems. To take the advantageof MIMO technology, there must be multielement antenna in the system, which brings achallenge to the design of the antenna element and array. At the same time, the problemof mutual coupling between antenna elements is becoming more and more serious as thedevices of wireless communication is more and more compact. Thus the design of theMIMO antenna is becoming more difficult.With the development of MIMO technology, it is urgent and important to study theMIMO antenna. Considering the fact of wireless communication, the author investigatesthe antenna issues of MIMO system, and the schemes are listed in this dissertation.The author’s main work can be divided into two parts:1. Theory research. The author studies theories and investigates methods in thearea of MIMO technology. The basic theory of the antenna is introduced. The mutualcoupling between antenna elements is emphatically discussed and the methods ofimproving the isolation between antennas are summarized. Finally, the demand andmethods of MIMO antenna design are given.2. MIMO antenna design. On the basis of research in the theory, the author designsseveral MIMO antennas pertaining to mobile terminals. The design process is given aswell as the impact of the relative parameters on the performance of the antenna. Thesimulated and measured results verified the correction of the design process.