In recently, mobile communication technology is developing toward the 4th generation communication technology. The LTE (Long Term Evolution) is the leading candidate technology in the 4th generation mobile communication. The LTE technology is combined with the MIMO (Multiple Input Multiple Output) technology and this coupled technology has a high-quality data transfer rate and an expended channel capacity [1]. The MIMO antenna technology is applied by a mobile handy terminal for 4th generation. The 4G mobile handy terminal antenna is composed a main antenna and a sub antenna. Main antenna has to satisfy not only conventional operating frequency service such as CDMA (824∼849 MHz), GSM900 (880∼960 MHz), DCS (1,710∼1,880 MHz), USPCS (1,850∼1,990 MHz), WCDMA (1,920∼2,170 MHz), and WiFi (2,400∼2,499 MHz) but also LTE (698∼798 MHz) frequency band. In order to realize the maximum channel capacity, the 4G handy terminal antenna must employ the sub antenna operated LTE frequency band. LTE frequency band by reference [2] has from 1 to 43 channels with respect from 699 to 3,800 MHz. Authors consider only for the LTE class 13 and 14 band in this paper, because many mobile companies use these channels for 4 G mobile service. However, because the LTE class 13 and 14 band have a relatively low operating frequency band (746∼798 MHz) for the current mobile handy terminal applications, it may still be difficult to obtain a wide bandwidth and high isolation because of two closely located antennas within the limited space [3]. In order to solve the above problems, authors have been simulated for structure of main and sub antenna, and for feeding position of two antennas, iteratively. As a result, high isolation between main and sub antenna, and bandwidth satisfying for the LTE class 13 and 14 have been realized experimentally.
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