Small Internal 2.4-GHz/UWB Antenna for Wireless Dongle Applications

A small 2.4-GHz/ultrawideband (UWB) antenna suitable for integration with the printed circuit board (PCB) of a wireless universal serial bus (WUSB) dongle is presented. The antenna mainly comprises a folded radiator with bended stubs mounted on the top of a small metal box that plays the role of a ground plane. Inside the metal box, the PCB is integrated, and the potential interactive interference between the PCB and the antenna itself can be prevented. Details of this antenna are described. The overall size of this design is 7 x 13 x 42.6 mm(3), approximately equal to that of a normal USB flash disk. Experimental results of the constructed prototype show that the impedance bandwidth of the proposed antenna is about 8.76 GHz, from 2.24 to more than 11 GHz, covering the whole operating band of WLAN and UWB with good radiation characteristics. Moreover, the influence of the laptop as well as the wood or metal desk on the performance of the antenna is also studied.