Mimo System, The Mobile Terminal Unit Antenna Design

With the development of the mobile communication, the demands of users for the capacity of the communication system becomes higher and higher. But the frequency useable is limited, so how to utilize the limited frequency and enhance the efficiency of the frequency become the hot topic of the mobile communication. A creative technology has provided a novel solution to deal with this problem, which names Multiple-Input and Multiple-Output(MIMO).wireless systems, characterized by multiple antenna elements at the transmitter and receiver, can increased capacity and reliability in rich multipath environments. Such systems operate by exploiting the spatial properties of the multipath channel, thereby offering a new dimension which can be used to enable enhanced communication performance. While coding and signal processing are key elements to successful implementation of a MIMO system, the propagation channel and antenna design represent major parameters that ultimately impact system performance. So design high efficiency antenna and low relation antenna array is important for MIMO system.firstly, a introduction of the diversity is made, then a explain about the antenna diversity and the demand for the antenna design are all provided in this paper.Secondly, the various theoretical methods for the analysis of the microstrip antenna are briefly described. and the cavity model of the rectangular microstrip antenna is reviewed detaily. Then the techniques for broadbanding and compacting of microsrtip antennas are also discussed. At last a compact and broadband microstrip antenna and a high isolation array are devised.Lastly, to make the best use of the low profile attribute of the designed microstrip anenna a printed invert F antenna is design, operating frequency is 2.4～2.5GHz and 5.2～5.4GHz. and a 2D array with high isolation, constituted by two PIFA and a microstrip antenna, is contrived.