WiMAX/MIMO Antenna using L-shaped Folded Monopole Antennas

In recent days, the Worldwide Interoperability for Microwave Access (WiMAX) technology has widely used for wireless mobile devices such as handsets, notebook PCs and so on. In addition, Multi-antenna systems for handsets such as diversity and Multiple-input Multiple-out (MIMO) applications has developed, which are seen as the potential technologies for enhancing the performance and capacity with high-speed transmission rate in the wireless communications [1]-[3]. WiMAX implementations that use MIMO technology have become important. The use of MIMO technology improves the reception and allows for a better reach and rate of transmission. The implementation of MIMO also gives WiMAX a significant increase in spectral efficiency. If we attempt to install adaptive array antennas in the limited space like handsets, accordingly, it is desired that the antenna has a more compact size, but its performances such as bandwidth and gain should be maintained. Furthermore, it is known that when the distance of antenna elements is close, the effect of mutual coupling become stronger and it influences antenna performances [4]. In our previous study, the Built in Folded Dipole Antenna (BFDA), which has a small size and low-profile, has been proposed and its characteristics have been analyzed. In order to make a more compact antenna, the L-shaped Folded Monopole Antenna (LFMA), which has a folded monopole element bent into L-shape, has been studied. This antenna configuration is a half size of BFDA and has low mutual coupling [5]. From these view points, LFMA can be considered as one of the effective multi-antenna systems for WiMAX. In this paper, WiMAX/MIMO antenna using LFMA is investigated.