A wideband slot antenna for moblie phone applications

A wideband impedance matching technique is presented on slot antenna for mobile handset applications at lower frequency band. The antenna is printed on a 60*115 mm² FR-4 substrate with 0.8 mm thickness. Two rectangular slots are etched on the ground with open ends at opposite edges. One of the two is called the main slot with size of 5 mm*50 mm, the other one is called the additional slot with size of 40 mm*1 mm. The main slot is fed by a 50 Ω microstrip connected with a folded strip surrounding around the boundary of the main slot inside the main slot region. The strip with folded shape can induce the current flowing around the main slot from the close end to the open end on the ground, which results in the increase of the current distribution path and the decrease of the frequency of the first resonant mode. The additional slot is etched on the top portion of the ground above the main slot to excite more current distributing around the main slot region. With the technique, two resonant modes are excited at the lower frequency band, and a wide frequency bandwidth of 0.82~1.18 GHz is obtained.