A dual-band antenna for wireless USB dongle applications

In this paper, the design of a dual-band antenna for universal-serial-bus (USB) dongle applications in the 2.4-GHz wireless-local-area network (WLAN) and 3.5-GHz Worldwide Interoperability for Microwave Access (WiMAX) systems is presented. The antenna consists of two folded inverted-F radiating elements. One inverted- F element generates a 2.45-GHz band for the WLAN band (2.4-2.484 GHz), and both inverted-F elements together resonate at around 3.5 GHz to generate a wide frequency band for the WiMAX system (3.3-3.8 GHz). The antenna is designed on a 25×70 mm² printed-circuit board (PCB), same size of an USB dongle PCB. For verification of simulation results, a prototype is fabricated and measured. Measured results show that the antenna has two impedance bandwidths, 2.39-2.5 GHz and 3.24-3.8 GHz, for the WLAN and WiMAX applications, respectively. The simulated and measured radiation patterns, efficiencies and gains of the antenna are all presented.