Inverted-F antenna-based on-frame GPS/WLAN antenna for the metal-casing tablet computer

An on-frame antenna for the 1.575/2.4/5.2/5.8-GHz multiband GPS/WLAN operation in the metal-casing tablet computer is presented. The antenna is based on a T-shape inverted-F antenna (IFA) structure and comprises an on-frame metal plate and a feed circuit board. The metal plate is disposed at about the center of the top-edge metal frame of the metal casing and has a simple rectangular shape of small size 25.5 × 7 mm2. The IFA's feeding and shorting strips with matching circuits are disposed on the feed circuit board. In this case, no metal clearance on the metal back cover of the casing and no planar board space on the main circuit board in the tablet computer are required by the antenna. With the T-shape IFA structure, dual-band operation to cover either the 1.575/5.2/5.8-GHz bands or the 2.4/5.2/5.8-GHz bands can be obtained for the antenna. By applying a novel band-pass shorting strip to the T-shape IFA, a multiband operation to cover the 1.575/2.4/5.2/5.8-GHz GPS/WLAN operation is obtained. The bandpass shorting strip is designed to have a band-pass characteristic at about 2.4 GHz, and its effect on the multiband operation of the antenna is discussed. Details of the proposed antenna and experimental results are presented.