CPW-Fed Tri-Band Slot Antenna with Impedance Matching Stub

A capacitively CPW-fed multiband slot antenna is investigated in this paper. For 10-dB fractional bandwidth, the proposed antenna obtains 12.9%, 2.52%, and 5.33% at the center frequencies of 2.49 GHz, 3.57 GHz and 5.25 GHz, respectively. By using multiple protruded slots, one can achieve multiple operation bands with high design freedom. The three operation frequencies are for WLAN2400/5200 and WiMAX application. The antenna size is 70 mm (L) x 40 mm (W) x 0.8 mm (H). The proposed antenna achieves a near omnidirectional H-plane radiation patterns.