Reconfigurable long-term evolution/wireless wide area network antennas integrated with the metal frame of tablet computers

摘要

This study proposed a reconfigurable antenna design integrated with the metal frame of tablet computers that can switch between long-term evolution (LTE) and wireless wide area network (WWAN) frequencies. The antenna is installed in a 75x5mm clearance without the ground plane, and a 2mm opening is created on the metal frame on the top right side of the clearance, which create an open-slot structure. Moreover, this antenna structure contains a switch element; switching between on and off forms two antenna structures that generate two resonant modes of the antenna structure, as well as excites other resonant modes of the open-slot structure. Therefore, the proposed antenna design can cover both the low-frequency (i.e. LTE700/GSM850/900) and high-frequency (i.e. GSM1800/1900/UMTS/LTE2300/2500) bands of LTE/WWAN frequencies. Specifically, without using matching circuits, the proposed antenna can cover the eight frequency bands required for LTE/WWAN within a profile height of 5mm simply by incorporating a switch element in the structure; hence, the proposed design is highly suitable for application in tablet devices with a narrow border. In addition, this antenna can be closely integrated with its surrounding metal elements and the measured results revealed an antenna efficiency of50%, exceeding the requirement for actual application.